CREATE IF NOT EXISTS INDEX

diff --git a/doc/src/sgml/ref/create_index.sgml b/doc/src/sgml/ref/create_index.sgml
index e469b17..7886729 100644
--- a/doc/src/sgml/ref/create_index.sgml
+++ b/doc/src/sgml/ref/create_index.sgml
@@ -21,7 +21,7 @@ PostgreSQL documentation
 
  <refsynopsisdiv>
 <synopsis>
-CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] [ <replaceable class="parameter">name</replaceable> ] ON <replaceable class="parameter">table_name</replaceable> [ USING <replaceable class="parameter">method</replaceable> ]
+CREATE [ IF NOT EXISTS ] [ UNIQUE ] INDEX [ CONCURRENTLY ] [ <replaceable class="parameter">name</replaceable> ] ON <replaceable class="parameter">table_name</replaceable> [ USING <replaceable class="parameter">method</replaceable> ]
     ( { <replaceable class="parameter">column_name</replaceable> | ( <replaceable class="parameter">expression</replaceable> ) } [ COLLATE <replaceable class="parameter">collation</replaceable> ] [ <replaceable class="parameter">opclass</replaceable> ] [ ASC | DESC ] [ NULLS { FIRST | LAST } ] [, ...] )
     [ WITH ( <replaceable class="PARAMETER">storage_parameter</replaceable> = <replaceable class="PARAMETER">value</replaceable> [, ... ] ) ]
     [ TABLESPACE <replaceable class="parameter">tablespace_name</replaceable> ]
@@ -99,6 +99,16 @@ CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] [ <replaceable class="parameter">name</
 
     <variablelist>
      <varlistentry>
+      <term><literal>IF NOT EXISTS</literal></term>
+      <listitem>
+       <para>
+        Do nothing (except issuing a notice) if a index with the same name
+        already exists.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry>
       <term><literal>UNIQUE</literal></term>
       <listitem>
        <para>
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index ee10594..8905e30 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -697,7 +697,8 @@ index_create(Relation heapRelation,
 			 bool allow_system_table_mods,
 			 bool skip_build,
 			 bool concurrent,
-			 bool is_internal)
+			 bool is_internal,
+			 bool if_not_exists)
 {
 	Oid			heapRelationId = RelationGetRelid(heapRelation);
 	Relation	pg_class;
@@ -773,10 +774,22 @@ index_create(Relation heapRelation,
 		elog(ERROR, "shared relations must be placed in pg_global tablespace");
 
 	if (get_relname_relid(indexRelationName, namespaceId))
+	{
+		if (if_not_exists)
+		{
+			ereport(NOTICE,
+					(errcode(ERRCODE_DUPLICATE_TABLE),
+					 errmsg("relation \"%s\" already exists, skipping",
+							indexRelationName)));
+			heap_close(pg_class, RowExclusiveLock);
+			return InvalidOid;
+		}
+
 		ereport(ERROR,
 				(errcode(ERRCODE_DUPLICATE_TABLE),
 				 errmsg("relation \"%s\" already exists",
 						indexRelationName)));
+	}
 
 	/*
 	 * construct tuple descriptor for index tuples
diff --git a/src/backend/catalog/toasting.c b/src/backend/catalog/toasting.c
index 160f006..5ef6dcc 100644
--- a/src/backend/catalog/toasting.c
+++ b/src/backend/catalog/toasting.c
@@ -342,7 +342,7 @@ create_toast_table(Relation rel, Oid toastOid, Oid toastIndexOid,
 				 rel->rd_rel->reltablespace,
 				 collationObjectId, classObjectId, coloptions, (Datum) 0,
 				 true, false, false, false,
-				 true, false, false, true);
+				 true, false, false, true, false);
 
 	heap_close(toast_rel, NoLock);
 
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 8a1cb4b..a03773b 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -610,7 +610,14 @@ DefineIndex(Oid relationId,
 					 stmt->isconstraint, stmt->deferrable, stmt->initdeferred,
 					 allowSystemTableMods,
 					 skip_build || stmt->concurrent,
-					 stmt->concurrent, !check_rights);
+					 stmt->concurrent, !check_rights,
+					 stmt->if_not_exists);
+
+	if (!OidIsValid(indexRelationId))
+	{
+		heap_close(rel, NoLock);
+		return indexRelationId;
+	}
 
 	/* Add any requested comment */
 	if (stmt->idxcomment != NULL)
diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index 225756c..39b55db 100644
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -2907,6 +2907,7 @@ _copyIndexStmt(const IndexStmt *from)
 	COPY_SCALAR_FIELD(deferrable);
 	COPY_SCALAR_FIELD(initdeferred);
 	COPY_SCALAR_FIELD(concurrent);
+	COPY_SCALAR_FIELD(if_not_exists);
 
 	return newnode;
 }
diff --git a/src/backend/nodes/equalfuncs.c b/src/backend/nodes/equalfuncs.c
index 905468e..4cf91e0 100644
--- a/src/backend/nodes/equalfuncs.c
+++ b/src/backend/nodes/equalfuncs.c
@@ -1210,6 +1210,7 @@ _equalIndexStmt(const IndexStmt *a, const IndexStmt *b)
 	COMPARE_SCALAR_FIELD(deferrable);
 	COMPARE_SCALAR_FIELD(initdeferred);
 	COMPARE_SCALAR_FIELD(concurrent);
+	COMPARE_SCALAR_FIELD(if_not_exists);
 
 	return true;
 }
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 77d2f29..ff738c3 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -6427,20 +6427,21 @@ defacl_privilege_target:
  * willing to make TABLESPACE a fully reserved word.
  *****************************************************************************/
 
-IndexStmt:	CREATE opt_unique INDEX opt_concurrently opt_index_name
+IndexStmt:	CREATE opt_if_not_exists opt_unique INDEX opt_concurrently opt_index_name
 			ON qualified_name access_method_clause '(' index_params ')'
 			opt_reloptions OptTableSpace where_clause
 				{
 					IndexStmt *n = makeNode(IndexStmt);
-					n->unique = $2;
-					n->concurrent = $4;
-					n->idxname = $5;
-					n->relation = $7;
-					n->accessMethod = $8;
-					n->indexParams = $10;
-					n->options = $12;
-					n->tableSpace = $13;
-					n->whereClause = $14;
+					n->if_not_exists = $2;
+					n->unique = $3;
+					n->concurrent = $5;
+					n->idxname = $6;
+					n->relation = $8;
+					n->accessMethod = $9;
+					n->indexParams = $11;
+					n->options = $13;
+					n->tableSpace = $14;
+					n->whereClause = $15;
 					n->excludeOpNames = NIL;
 					n->idxcomment = NULL;
 					n->indexOid = InvalidOid;
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 12811a8..ab169c9 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -2803,8 +2803,8 @@ getRowSecurity(Archive *fout, TableInfo tblinfo[], int numTables)
 			continue;
 
 		if (g_verbose)
-			write_msg(NULL, "reading row-security enabled for table \"%s\"",
-					  tbinfo->dobj.name);
+			write_msg(NULL, "reading row-security enabled for table \"%s\".\"%s\"\n",
+					  tbinfo->dobj.namespace->dobj.name, tbinfo->dobj.name);
 
 		/*
 		 * Get row-security enabled information for the table.
@@ -2833,8 +2833,8 @@ getRowSecurity(Archive *fout, TableInfo tblinfo[], int numTables)
 		}
 
 		if (g_verbose)
-			write_msg(NULL, "reading row-security policies for table \"%s\"\n",
-					  tbinfo->dobj.name);
+			write_msg(NULL, "reading row-security policies for table \"%s\".\"%s\"\n",
+					  tbinfo->dobj.namespace->dobj.name, tbinfo->dobj.name);
 
 		/*
 		 * select table schema to ensure regproc name is qualified if needed
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index 006b180..098ac7d 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -60,7 +60,8 @@ extern Oid index_create(Relation heapRelation,
 			 bool allow_system_table_mods,
 			 bool skip_build,
 			 bool concurrent,
-			 bool is_internal);
+			 bool is_internal,
+			 bool if_not_exists);
 
 extern void index_constraint_create(Relation heapRelation,
 						Oid indexRelationId,
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index f3aa69e..a326dc4 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -2255,6 +2255,7 @@ typedef struct IndexStmt
 	bool		deferrable;		/* is the constraint DEFERRABLE? */
 	bool		initdeferred;	/* is the constraint INITIALLY DEFERRED? */
 	bool		concurrent;		/* should this be a concurrent index build? */
+	bool		if_not_exists;	/* just do nothing if index already exists */
 } IndexStmt;
 
 /* ----------------------
diff --git a/src/test/regress/expected/create_index.out b/src/test/regress/expected/create_index.out
index a2bef7a..5bd1392 100644
--- a/src/test/regress/expected/create_index.out
+++ b/src/test/regress/expected/create_index.out
@@ -6,6 +6,8 @@
 -- BTREE
 --
 CREATE INDEX onek_unique1 ON onek USING btree(unique1 int4_ops);
+CREATE IF NOT EXISTS INDEX onek_unique1 ON onek USING btree(unique1 int4_ops);
+NOTICE:  relation "onek_unique1" already exists, skipping
 CREATE INDEX onek_unique2 ON onek USING btree(unique2 int4_ops);
 CREATE INDEX onek_hundred ON onek USING btree(hundred int4_ops);
 CREATE INDEX onek_stringu1 ON onek USING btree(stringu1 name_ops);
@@ -2290,10 +2292,14 @@ create unique index hash_f8_index_3 on hash_f8_heap(random) where seqno > 1000;
 CREATE TABLE concur_heap (f1 text, f2 text);
 -- empty table
 CREATE INDEX CONCURRENTLY concur_index1 ON concur_heap(f2,f1);
+CREATE IF NOT EXISTS INDEX CONCURRENTLY concur_index1 ON concur_heap(f2,f1);
+NOTICE:  relation "concur_index1" already exists, skipping
 INSERT INTO concur_heap VALUES  ('a','b');
 INSERT INTO concur_heap VALUES  ('b','b');
 -- unique index
 CREATE UNIQUE INDEX CONCURRENTLY concur_index2 ON concur_heap(f1);
+CREATE IF NOT EXISTS UNIQUE INDEX CONCURRENTLY concur_index2 ON concur_heap(f1);
+NOTICE:  relation "concur_index2" already exists, skipping
 -- check if constraint is set up properly to be enforced
 INSERT INTO concur_heap VALUES ('b','x');
 ERROR:  duplicate key value violates unique constraint "concur_index2"
diff --git a/src/test/regress/sql/create_index.sql b/src/test/regress/sql/create_index.sql
index d4d24ef..2c80605 100644
--- a/src/test/regress/sql/create_index.sql
+++ b/src/test/regress/sql/create_index.sql
@@ -8,6 +8,8 @@
 --
 CREATE INDEX onek_unique1 ON onek USING btree(unique1 int4_ops);
 
+CREATE IF NOT EXISTS INDEX onek_unique1 ON onek USING btree(unique1 int4_ops);
+
 CREATE INDEX onek_unique2 ON onek USING btree(unique2 int4_ops);
 
 CREATE INDEX onek_hundred ON onek USING btree(hundred int4_ops);
@@ -711,10 +713,12 @@ create unique index hash_f8_index_3 on hash_f8_heap(random) where seqno > 1000;
 CREATE TABLE concur_heap (f1 text, f2 text);
 -- empty table
 CREATE INDEX CONCURRENTLY concur_index1 ON concur_heap(f2,f1);
+CREATE IF NOT EXISTS INDEX CONCURRENTLY concur_index1 ON concur_heap(f2,f1);
 INSERT INTO concur_heap VALUES  ('a','b');
 INSERT INTO concur_heap VALUES  ('b','b');
 -- unique index
 CREATE UNIQUE INDEX CONCURRENTLY concur_index2 ON concur_heap(f1);
+CREATE IF NOT EXISTS UNIQUE INDEX CONCURRENTLY concur_index2 ON concur_heap(f1);
 -- check if constraint is set up properly to be enforced
 INSERT INTO concur_heap VALUES ('b','x');
 -- check if constraint is enforced properly at build time

diff --git a/doc/src/sgml/ref/create_index.sgml b/doc/src/sgml/ref/create_index.sgml
index e469b17..7886729 100644
--- a/doc/src/sgml/ref/create_index.sgml
+++ b/doc/src/sgml/ref/create_index.sgml
@@ -21,7 +21,7 @@ PostgreSQL documentation
 
  <refsynopsisdiv>
 <synopsis>
-CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] [ <replaceable class="parameter">name</replaceable> ] ON <replaceable class="parameter">table_name</replaceable> [ USING <replaceable class="parameter">method</replaceable> ]
+CREATE [ IF NOT EXISTS ] [ UNIQUE ] INDEX [ CONCURRENTLY ] [ <replaceable class="parameter">name</replaceable> ] ON <replaceable class="parameter">table_name</replaceable> [ USING <replaceable class="parameter">method</replaceable> ]
     ( { <replaceable class="parameter">column_name</replaceable> | ( <replaceable class="parameter">expression</replaceable> ) } [ COLLATE <replaceable class="parameter">collation</replaceable> ] [ <replaceable class="parameter">opclass</replaceable> ] [ ASC | DESC ] [ NULLS { FIRST | LAST } ] [, ...] )
     [ WITH ( <replaceable class="PARAMETER">storage_parameter</replaceable> = <replaceable class="PARAMETER">value</replaceable> [, ... ] ) ]
     [ TABLESPACE <replaceable class="parameter">tablespace_name</replaceable> ]
@@ -99,6 +99,16 @@ CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] [ <replaceable class="parameter">name</
 
     <variablelist>
      <varlistentry>
+      <term><literal>IF NOT EXISTS</literal></term>
+      <listitem>
+       <para>
+        Do nothing (except issuing a notice) if a index with the same name
+        already exists.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry>
       <term><literal>UNIQUE</literal></term>
       <listitem>
        <para>
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index ee10594..8905e30 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -697,7 +697,8 @@ index_create(Relation heapRelation,
 			 bool allow_system_table_mods,
 			 bool skip_build,
 			 bool concurrent,
-			 bool is_internal)
+			 bool is_internal,
+			 bool if_not_exists)
 {
 	Oid			heapRelationId = RelationGetRelid(heapRelation);
 	Relation	pg_class;
@@ -773,10 +774,22 @@ index_create(Relation heapRelation,
 		elog(ERROR, "shared relations must be placed in pg_global tablespace");
 
 	if (get_relname_relid(indexRelationName, namespaceId))
+	{
+		if (if_not_exists)
+		{
+			ereport(NOTICE,
+					(errcode(ERRCODE_DUPLICATE_TABLE),
+					 errmsg("relation \"%s\" already exists, skipping",
+							indexRelationName)));
+			heap_close(pg_class, RowExclusiveLock);
+			return InvalidOid;
+		}
+
 		ereport(ERROR,
 				(errcode(ERRCODE_DUPLICATE_TABLE),
 				 errmsg("relation \"%s\" already exists",
 						indexRelationName)));
+	}
 
 	/*
 	 * construct tuple descriptor for index tuples
diff --git a/src/backend/catalog/toasting.c b/src/backend/catalog/toasting.c
index 160f006..5ef6dcc 100644
--- a/src/backend/catalog/toasting.c
+++ b/src/backend/catalog/toasting.c
@@ -342,7 +342,7 @@ create_toast_table(Relation rel, Oid toastOid, Oid toastIndexOid,
 				 rel->rd_rel->reltablespace,
 				 collationObjectId, classObjectId, coloptions, (Datum) 0,
 				 true, false, false, false,
-				 true, false, false, true);
+				 true, false, false, true, false);
 
 	heap_close(toast_rel, NoLock);
 
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 8a1cb4b..a03773b 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -610,7 +610,14 @@ DefineIndex(Oid relationId,
 					 stmt->isconstraint, stmt->deferrable, stmt->initdeferred,
 					 allowSystemTableMods,
 					 skip_build || stmt->concurrent,
-					 stmt->concurrent, !check_rights);
+					 stmt->concurrent, !check_rights,
+					 stmt->if_not_exists);
+
+	if (!OidIsValid(indexRelationId))
+	{
+		heap_close(rel, NoLock);
+		return indexRelationId;
+	}
 
 	/* Add any requested comment */
 	if (stmt->idxcomment != NULL)
diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index 225756c..39b55db 100644
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -2907,6 +2907,7 @@ _copyIndexStmt(const IndexStmt *from)
 	COPY_SCALAR_FIELD(deferrable);
 	COPY_SCALAR_FIELD(initdeferred);
 	COPY_SCALAR_FIELD(concurrent);
+	COPY_SCALAR_FIELD(if_not_exists);
 
 	return newnode;
 }
diff --git a/src/backend/nodes/equalfuncs.c b/src/backend/nodes/equalfuncs.c
index 905468e..4cf91e0 100644
--- a/src/backend/nodes/equalfuncs.c
+++ b/src/backend/nodes/equalfuncs.c
@@ -1210,6 +1210,7 @@ _equalIndexStmt(const IndexStmt *a, const IndexStmt *b)
 	COMPARE_SCALAR_FIELD(deferrable);
 	COMPARE_SCALAR_FIELD(initdeferred);
 	COMPARE_SCALAR_FIELD(concurrent);
+	COMPARE_SCALAR_FIELD(if_not_exists);
 
 	return true;
 }
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 77d2f29..03a04af 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -6427,20 +6427,32 @@ defacl_privilege_target:
  * willing to make TABLESPACE a fully reserved word.
  *****************************************************************************/
 
-IndexStmt:	CREATE opt_unique INDEX opt_concurrently opt_index_name
+IndexStmt:	CREATE opt_if_not_exists opt_unique INDEX opt_concurrently opt_index_name
 			ON qualified_name access_method_clause '(' index_params ')'
 			opt_reloptions OptTableSpace where_clause
 				{
 					IndexStmt *n = makeNode(IndexStmt);
-					n->unique = $2;
-					n->concurrent = $4;
-					n->idxname = $5;
-					n->relation = $7;
-					n->accessMethod = $8;
-					n->indexParams = $10;
-					n->options = $12;
-					n->tableSpace = $13;
-					n->whereClause = $14;
+					n->if_not_exists = $2;
+					n->unique = $3;
+					n->concurrent = $5;
+					n->idxname = $6;
+
+					/*
+					 * Throw an exception when IF NOT EXISTS is used without a named
+					 * index
+					 */
+					if (n->if_not_exists && n->idxname == NULL)
+						ereport(ERROR,
+								(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+								 errmsg("IF NOT EXISTS requires that you name the index."),
+								 parser_errposition(@2)));
+
+					n->relation = $8;
+					n->accessMethod = $9;
+					n->indexParams = $11;
+					n->options = $13;
+					n->tableSpace = $14;
+					n->whereClause = $15;
 					n->excludeOpNames = NIL;
 					n->idxcomment = NULL;
 					n->indexOid = InvalidOid;
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 12811a8..ab169c9 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -2803,8 +2803,8 @@ getRowSecurity(Archive *fout, TableInfo tblinfo[], int numTables)
 			continue;
 
 		if (g_verbose)
-			write_msg(NULL, "reading row-security enabled for table \"%s\"",
-					  tbinfo->dobj.name);
+			write_msg(NULL, "reading row-security enabled for table \"%s\".\"%s\"\n",
+					  tbinfo->dobj.namespace->dobj.name, tbinfo->dobj.name);
 
 		/*
 		 * Get row-security enabled information for the table.
@@ -2833,8 +2833,8 @@ getRowSecurity(Archive *fout, TableInfo tblinfo[], int numTables)
 		}
 
 		if (g_verbose)
-			write_msg(NULL, "reading row-security policies for table \"%s\"\n",
-					  tbinfo->dobj.name);
+			write_msg(NULL, "reading row-security policies for table \"%s\".\"%s\"\n",
+					  tbinfo->dobj.namespace->dobj.name, tbinfo->dobj.name);
 
 		/*
 		 * select table schema to ensure regproc name is qualified if needed
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index 006b180..098ac7d 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -60,7 +60,8 @@ extern Oid index_create(Relation heapRelation,
 			 bool allow_system_table_mods,
 			 bool skip_build,
 			 bool concurrent,
-			 bool is_internal);
+			 bool is_internal,
+			 bool if_not_exists);
 
 extern void index_constraint_create(Relation heapRelation,
 						Oid indexRelationId,
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index f3aa69e..a326dc4 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -2255,6 +2255,7 @@ typedef struct IndexStmt
 	bool		deferrable;		/* is the constraint DEFERRABLE? */
 	bool		initdeferred;	/* is the constraint INITIALLY DEFERRED? */
 	bool		concurrent;		/* should this be a concurrent index build? */
+	bool		if_not_exists;	/* just do nothing if index already exists */
 } IndexStmt;
 
 /* ----------------------
diff --git a/src/test/regress/expected/create_index.out b/src/test/regress/expected/create_index.out
index a2bef7a..0c48d58 100644
--- a/src/test/regress/expected/create_index.out
+++ b/src/test/regress/expected/create_index.out
@@ -6,6 +6,12 @@
 -- BTREE
 --
 CREATE INDEX onek_unique1 ON onek USING btree(unique1 int4_ops);
+CREATE IF NOT EXISTS INDEX onek_unique1 ON onek USING btree(unique1 int4_ops);
+NOTICE:  relation "onek_unique1" already exists, skipping
+CREATE IF NOT EXISTS INDEX ON onek USING btree(unique1 int4_ops);
+ERROR:  IF NOT EXISTS requires that you name the index.
+LINE 1: CREATE IF NOT EXISTS INDEX ON onek USING btree(unique1 int4_...
+               ^
 CREATE INDEX onek_unique2 ON onek USING btree(unique2 int4_ops);
 CREATE INDEX onek_hundred ON onek USING btree(hundred int4_ops);
 CREATE INDEX onek_stringu1 ON onek USING btree(stringu1 name_ops);
@@ -2290,10 +2296,14 @@ create unique index hash_f8_index_3 on hash_f8_heap(random) where seqno > 1000;
 CREATE TABLE concur_heap (f1 text, f2 text);
 -- empty table
 CREATE INDEX CONCURRENTLY concur_index1 ON concur_heap(f2,f1);
+CREATE IF NOT EXISTS INDEX CONCURRENTLY concur_index1 ON concur_heap(f2,f1);
+NOTICE:  relation "concur_index1" already exists, skipping
 INSERT INTO concur_heap VALUES  ('a','b');
 INSERT INTO concur_heap VALUES  ('b','b');
 -- unique index
 CREATE UNIQUE INDEX CONCURRENTLY concur_index2 ON concur_heap(f1);
+CREATE IF NOT EXISTS UNIQUE INDEX CONCURRENTLY concur_index2 ON concur_heap(f1);
+NOTICE:  relation "concur_index2" already exists, skipping
 -- check if constraint is set up properly to be enforced
 INSERT INTO concur_heap VALUES ('b','x');
 ERROR:  duplicate key value violates unique constraint "concur_index2"
diff --git a/src/test/regress/sql/create_index.sql b/src/test/regress/sql/create_index.sql
index d4d24ef..973a709 100644
--- a/src/test/regress/sql/create_index.sql
+++ b/src/test/regress/sql/create_index.sql
@@ -8,6 +8,10 @@
 --
 CREATE INDEX onek_unique1 ON onek USING btree(unique1 int4_ops);
 
+CREATE IF NOT EXISTS INDEX onek_unique1 ON onek USING btree(unique1 int4_ops);
+
+CREATE IF NOT EXISTS INDEX ON onek USING btree(unique1 int4_ops);
+
 CREATE INDEX onek_unique2 ON onek USING btree(unique2 int4_ops);
 
 CREATE INDEX onek_hundred ON onek USING btree(hundred int4_ops);
@@ -711,10 +715,12 @@ create unique index hash_f8_index_3 on hash_f8_heap(random) where seqno > 1000;
 CREATE TABLE concur_heap (f1 text, f2 text);
 -- empty table
 CREATE INDEX CONCURRENTLY concur_index1 ON concur_heap(f2,f1);
+CREATE IF NOT EXISTS INDEX CONCURRENTLY concur_index1 ON concur_heap(f2,f1);
 INSERT INTO concur_heap VALUES  ('a','b');
 INSERT INTO concur_heap VALUES  ('b','b');
 -- unique index
 CREATE UNIQUE INDEX CONCURRENTLY concur_index2 ON concur_heap(f1);
+CREATE IF NOT EXISTS UNIQUE INDEX CONCURRENTLY concur_index2 ON concur_heap(f1);
 -- check if constraint is set up properly to be enforced
 INSERT INTO concur_heap VALUES ('b','x');
 -- check if constraint is enforced properly at build time

diff --git a/doc/src/sgml/ref/create_index.sgml b/doc/src/sgml/ref/create_index.sgml
index e469b17..7886729 100644
--- a/doc/src/sgml/ref/create_index.sgml
+++ b/doc/src/sgml/ref/create_index.sgml
@@ -21,7 +21,7 @@ PostgreSQL documentation
 
  <refsynopsisdiv>
 <synopsis>
-CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] [ <replaceable class="parameter">name</replaceable> ] ON <replaceable class="parameter">table_name</replaceable> [ USING <replaceable class="parameter">method</replaceable> ]
+CREATE [ IF NOT EXISTS ] [ UNIQUE ] INDEX [ CONCURRENTLY ] [ <replaceable class="parameter">name</replaceable> ] ON <replaceable class="parameter">table_name</replaceable> [ USING <replaceable class="parameter">method</replaceable> ]
     ( { <replaceable class="parameter">column_name</replaceable> | ( <replaceable class="parameter">expression</replaceable> ) } [ COLLATE <replaceable class="parameter">collation</replaceable> ] [ <replaceable class="parameter">opclass</replaceable> ] [ ASC | DESC ] [ NULLS { FIRST | LAST } ] [, ...] )
     [ WITH ( <replaceable class="PARAMETER">storage_parameter</replaceable> = <replaceable class="PARAMETER">value</replaceable> [, ... ] ) ]
     [ TABLESPACE <replaceable class="parameter">tablespace_name</replaceable> ]
@@ -99,6 +99,16 @@ CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] [ <replaceable class="parameter">name</
 
     <variablelist>
      <varlistentry>
+      <term><literal>IF NOT EXISTS</literal></term>
+      <listitem>
+       <para>
+        Do nothing (except issuing a notice) if a index with the same name
+        already exists.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry>
       <term><literal>UNIQUE</literal></term>
       <listitem>
        <para>
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index ee10594..8905e30 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -697,7 +697,8 @@ index_create(Relation heapRelation,
 			 bool allow_system_table_mods,
 			 bool skip_build,
 			 bool concurrent,
-			 bool is_internal)
+			 bool is_internal,
+			 bool if_not_exists)
 {
 	Oid			heapRelationId = RelationGetRelid(heapRelation);
 	Relation	pg_class;
@@ -773,10 +774,22 @@ index_create(Relation heapRelation,
 		elog(ERROR, "shared relations must be placed in pg_global tablespace");
 
 	if (get_relname_relid(indexRelationName, namespaceId))
+	{
+		if (if_not_exists)
+		{
+			ereport(NOTICE,
+					(errcode(ERRCODE_DUPLICATE_TABLE),
+					 errmsg("relation \"%s\" already exists, skipping",
+							indexRelationName)));
+			heap_close(pg_class, RowExclusiveLock);
+			return InvalidOid;
+		}
+
 		ereport(ERROR,
 				(errcode(ERRCODE_DUPLICATE_TABLE),
 				 errmsg("relation \"%s\" already exists",
 						indexRelationName)));
+	}
 
 	/*
 	 * construct tuple descriptor for index tuples
diff --git a/src/backend/catalog/toasting.c b/src/backend/catalog/toasting.c
index 160f006..5ef6dcc 100644
--- a/src/backend/catalog/toasting.c
+++ b/src/backend/catalog/toasting.c
@@ -342,7 +342,7 @@ create_toast_table(Relation rel, Oid toastOid, Oid toastIndexOid,
 				 rel->rd_rel->reltablespace,
 				 collationObjectId, classObjectId, coloptions, (Datum) 0,
 				 true, false, false, false,
-				 true, false, false, true);
+				 true, false, false, true, false);
 
 	heap_close(toast_rel, NoLock);
 
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 8a1cb4b..a03773b 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -610,7 +610,14 @@ DefineIndex(Oid relationId,
 					 stmt->isconstraint, stmt->deferrable, stmt->initdeferred,
 					 allowSystemTableMods,
 					 skip_build || stmt->concurrent,
-					 stmt->concurrent, !check_rights);
+					 stmt->concurrent, !check_rights,
+					 stmt->if_not_exists);
+
+	if (!OidIsValid(indexRelationId))
+	{
+		heap_close(rel, NoLock);
+		return indexRelationId;
+	}
 
 	/* Add any requested comment */
 	if (stmt->idxcomment != NULL)
diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index 225756c..39b55db 100644
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -2907,6 +2907,7 @@ _copyIndexStmt(const IndexStmt *from)
 	COPY_SCALAR_FIELD(deferrable);
 	COPY_SCALAR_FIELD(initdeferred);
 	COPY_SCALAR_FIELD(concurrent);
+	COPY_SCALAR_FIELD(if_not_exists);
 
 	return newnode;
 }
diff --git a/src/backend/nodes/equalfuncs.c b/src/backend/nodes/equalfuncs.c
index 905468e..4cf91e0 100644
--- a/src/backend/nodes/equalfuncs.c
+++ b/src/backend/nodes/equalfuncs.c
@@ -1210,6 +1210,7 @@ _equalIndexStmt(const IndexStmt *a, const IndexStmt *b)
 	COMPARE_SCALAR_FIELD(deferrable);
 	COMPARE_SCALAR_FIELD(initdeferred);
 	COMPARE_SCALAR_FIELD(concurrent);
+	COMPARE_SCALAR_FIELD(if_not_exists);
 
 	return true;
 }
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 77d2f29..03a04af 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -6427,20 +6427,32 @@ defacl_privilege_target:
  * willing to make TABLESPACE a fully reserved word.
  *****************************************************************************/
 
-IndexStmt:	CREATE opt_unique INDEX opt_concurrently opt_index_name
+IndexStmt:	CREATE opt_if_not_exists opt_unique INDEX opt_concurrently opt_index_name
 			ON qualified_name access_method_clause '(' index_params ')'
 			opt_reloptions OptTableSpace where_clause
 				{
 					IndexStmt *n = makeNode(IndexStmt);
-					n->unique = $2;
-					n->concurrent = $4;
-					n->idxname = $5;
-					n->relation = $7;
-					n->accessMethod = $8;
-					n->indexParams = $10;
-					n->options = $12;
-					n->tableSpace = $13;
-					n->whereClause = $14;
+					n->if_not_exists = $2;
+					n->unique = $3;
+					n->concurrent = $5;
+					n->idxname = $6;
+
+					/*
+					 * Throw an exception when IF NOT EXISTS is used without a named
+					 * index
+					 */
+					if (n->if_not_exists && n->idxname == NULL)
+						ereport(ERROR,
+								(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+								 errmsg("IF NOT EXISTS requires that you name the index."),
+								 parser_errposition(@2)));
+
+					n->relation = $8;
+					n->accessMethod = $9;
+					n->indexParams = $11;
+					n->options = $13;
+					n->tableSpace = $14;
+					n->whereClause = $15;
 					n->excludeOpNames = NIL;
 					n->idxcomment = NULL;
 					n->indexOid = InvalidOid;
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 12811a8..076ff8d 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -2803,7 +2803,7 @@ getRowSecurity(Archive *fout, TableInfo tblinfo[], int numTables)
 			continue;
 
 		if (g_verbose)
-			write_msg(NULL, "reading row-security enabled for table \"%s\"",
+			write_msg(NULL, "reading row-security enabled for table \"%s\"\n",
 					  tbinfo->dobj.name);
 
 		/*
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index 006b180..098ac7d 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -60,7 +60,8 @@ extern Oid index_create(Relation heapRelation,
 			 bool allow_system_table_mods,
 			 bool skip_build,
 			 bool concurrent,
-			 bool is_internal);
+			 bool is_internal,
+			 bool if_not_exists);
 
 extern void index_constraint_create(Relation heapRelation,
 						Oid indexRelationId,
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index f3aa69e..a326dc4 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -2255,6 +2255,7 @@ typedef struct IndexStmt
 	bool		deferrable;		/* is the constraint DEFERRABLE? */
 	bool		initdeferred;	/* is the constraint INITIALLY DEFERRED? */
 	bool		concurrent;		/* should this be a concurrent index build? */
+	bool		if_not_exists;	/* just do nothing if index already exists */
 } IndexStmt;
 
 /* ----------------------
diff --git a/src/test/regress/expected/create_index.out b/src/test/regress/expected/create_index.out
index a2bef7a..0c48d58 100644
--- a/src/test/regress/expected/create_index.out
+++ b/src/test/regress/expected/create_index.out
@@ -6,6 +6,12 @@
 -- BTREE
 --
 CREATE INDEX onek_unique1 ON onek USING btree(unique1 int4_ops);
+CREATE IF NOT EXISTS INDEX onek_unique1 ON onek USING btree(unique1 int4_ops);
+NOTICE:  relation "onek_unique1" already exists, skipping
+CREATE IF NOT EXISTS INDEX ON onek USING btree(unique1 int4_ops);
+ERROR:  IF NOT EXISTS requires that you name the index.
+LINE 1: CREATE IF NOT EXISTS INDEX ON onek USING btree(unique1 int4_...
+               ^
 CREATE INDEX onek_unique2 ON onek USING btree(unique2 int4_ops);
 CREATE INDEX onek_hundred ON onek USING btree(hundred int4_ops);
 CREATE INDEX onek_stringu1 ON onek USING btree(stringu1 name_ops);
@@ -2290,10 +2296,14 @@ create unique index hash_f8_index_3 on hash_f8_heap(random) where seqno > 1000;
 CREATE TABLE concur_heap (f1 text, f2 text);
 -- empty table
 CREATE INDEX CONCURRENTLY concur_index1 ON concur_heap(f2,f1);
+CREATE IF NOT EXISTS INDEX CONCURRENTLY concur_index1 ON concur_heap(f2,f1);
+NOTICE:  relation "concur_index1" already exists, skipping
 INSERT INTO concur_heap VALUES  ('a','b');
 INSERT INTO concur_heap VALUES  ('b','b');
 -- unique index
 CREATE UNIQUE INDEX CONCURRENTLY concur_index2 ON concur_heap(f1);
+CREATE IF NOT EXISTS UNIQUE INDEX CONCURRENTLY concur_index2 ON concur_heap(f1);
+NOTICE:  relation "concur_index2" already exists, skipping
 -- check if constraint is set up properly to be enforced
 INSERT INTO concur_heap VALUES ('b','x');
 ERROR:  duplicate key value violates unique constraint "concur_index2"
diff --git a/src/test/regress/sql/create_index.sql b/src/test/regress/sql/create_index.sql
index d4d24ef..973a709 100644
--- a/src/test/regress/sql/create_index.sql
+++ b/src/test/regress/sql/create_index.sql
@@ -8,6 +8,10 @@
 --
 CREATE INDEX onek_unique1 ON onek USING btree(unique1 int4_ops);
 
+CREATE IF NOT EXISTS INDEX onek_unique1 ON onek USING btree(unique1 int4_ops);
+
+CREATE IF NOT EXISTS INDEX ON onek USING btree(unique1 int4_ops);
+
 CREATE INDEX onek_unique2 ON onek USING btree(unique2 int4_ops);
 
 CREATE INDEX onek_hundred ON onek USING btree(hundred int4_ops);
@@ -711,10 +715,12 @@ create unique index hash_f8_index_3 on hash_f8_heap(random) where seqno > 1000;
 CREATE TABLE concur_heap (f1 text, f2 text);
 -- empty table
 CREATE INDEX CONCURRENTLY concur_index1 ON concur_heap(f2,f1);
+CREATE IF NOT EXISTS INDEX CONCURRENTLY concur_index1 ON concur_heap(f2,f1);
 INSERT INTO concur_heap VALUES  ('a','b');
 INSERT INTO concur_heap VALUES  ('b','b');
 -- unique index
 CREATE UNIQUE INDEX CONCURRENTLY concur_index2 ON concur_heap(f1);
+CREATE IF NOT EXISTS UNIQUE INDEX CONCURRENTLY concur_index2 ON concur_heap(f1);
 -- check if constraint is set up properly to be enforced
 INSERT INTO concur_heap VALUES ('b','x');
 -- check if constraint is enforced properly at build time

diff --git a/doc/src/sgml/ref/create_index.sgml b/doc/src/sgml/ref/create_index.sgml
index e469b17..06c2567 100644
--- a/doc/src/sgml/ref/create_index.sgml
+++ b/doc/src/sgml/ref/create_index.sgml
@@ -21,7 +21,7 @@ PostgreSQL documentation
 
  <refsynopsisdiv>
 <synopsis>
-CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] [ <replaceable class="parameter">name</replaceable> ] ON <replaceable class="parameter">table_name</replaceable> [ USING <replaceable class="parameter">method</replaceable> ]
+CREATE [ IF NOT EXISTS ] [ UNIQUE ] INDEX [ CONCURRENTLY ] [ <replaceable class="parameter">name</replaceable> ] ON <replaceable class="parameter">table_name</replaceable> [ USING <replaceable class="parameter">method</replaceable> ]
     ( { <replaceable class="parameter">column_name</replaceable> | ( <replaceable class="parameter">expression</replaceable> ) } [ COLLATE <replaceable class="parameter">collation</replaceable> ] [ <replaceable class="parameter">opclass</replaceable> ] [ ASC | DESC ] [ NULLS { FIRST | LAST } ] [, ...] )
     [ WITH ( <replaceable class="PARAMETER">storage_parameter</replaceable> = <replaceable class="PARAMETER">value</replaceable> [, ... ] ) ]
     [ TABLESPACE <replaceable class="parameter">tablespace_name</replaceable> ]
@@ -99,6 +99,16 @@ CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] [ <replaceable class="parameter">name</
 
     <variablelist>
      <varlistentry>
+      <term><literal>IF NOT EXISTS</literal></term>
+      <listitem>
+       <para>
+        Do not throw an error if the index already exists. A notice is issued
+        in this case.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry>
       <term><literal>UNIQUE</literal></term>
       <listitem>
        <para>
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index ee10594..8905e30 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -697,7 +697,8 @@ index_create(Relation heapRelation,
 			 bool allow_system_table_mods,
 			 bool skip_build,
 			 bool concurrent,
-			 bool is_internal)
+			 bool is_internal,
+			 bool if_not_exists)
 {
 	Oid			heapRelationId = RelationGetRelid(heapRelation);
 	Relation	pg_class;
@@ -773,10 +774,22 @@ index_create(Relation heapRelation,
 		elog(ERROR, "shared relations must be placed in pg_global tablespace");
 
 	if (get_relname_relid(indexRelationName, namespaceId))
+	{
+		if (if_not_exists)
+		{
+			ereport(NOTICE,
+					(errcode(ERRCODE_DUPLICATE_TABLE),
+					 errmsg("relation \"%s\" already exists, skipping",
+							indexRelationName)));
+			heap_close(pg_class, RowExclusiveLock);
+			return InvalidOid;
+		}
+
 		ereport(ERROR,
 				(errcode(ERRCODE_DUPLICATE_TABLE),
 				 errmsg("relation \"%s\" already exists",
 						indexRelationName)));
+	}
 
 	/*
 	 * construct tuple descriptor for index tuples
diff --git a/src/backend/catalog/toasting.c b/src/backend/catalog/toasting.c
index 160f006..5ef6dcc 100644
--- a/src/backend/catalog/toasting.c
+++ b/src/backend/catalog/toasting.c
@@ -342,7 +342,7 @@ create_toast_table(Relation rel, Oid toastOid, Oid toastIndexOid,
 				 rel->rd_rel->reltablespace,
 				 collationObjectId, classObjectId, coloptions, (Datum) 0,
 				 true, false, false, false,
-				 true, false, false, true);
+				 true, false, false, true, false);
 
 	heap_close(toast_rel, NoLock);
 
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 8a1cb4b..a03773b 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -610,7 +610,14 @@ DefineIndex(Oid relationId,
 					 stmt->isconstraint, stmt->deferrable, stmt->initdeferred,
 					 allowSystemTableMods,
 					 skip_build || stmt->concurrent,
-					 stmt->concurrent, !check_rights);
+					 stmt->concurrent, !check_rights,
+					 stmt->if_not_exists);
+
+	if (!OidIsValid(indexRelationId))
+	{
+		heap_close(rel, NoLock);
+		return indexRelationId;
+	}
 
 	/* Add any requested comment */
 	if (stmt->idxcomment != NULL)
diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index 225756c..39b55db 100644
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -2907,6 +2907,7 @@ _copyIndexStmt(const IndexStmt *from)
 	COPY_SCALAR_FIELD(deferrable);
 	COPY_SCALAR_FIELD(initdeferred);
 	COPY_SCALAR_FIELD(concurrent);
+	COPY_SCALAR_FIELD(if_not_exists);
 
 	return newnode;
 }
diff --git a/src/backend/nodes/equalfuncs.c b/src/backend/nodes/equalfuncs.c
index 905468e..4cf91e0 100644
--- a/src/backend/nodes/equalfuncs.c
+++ b/src/backend/nodes/equalfuncs.c
@@ -1210,6 +1210,7 @@ _equalIndexStmt(const IndexStmt *a, const IndexStmt *b)
 	COMPARE_SCALAR_FIELD(deferrable);
 	COMPARE_SCALAR_FIELD(initdeferred);
 	COMPARE_SCALAR_FIELD(concurrent);
+	COMPARE_SCALAR_FIELD(if_not_exists);
 
 	return true;
 }
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 77d2f29..47b0a14 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -6434,6 +6434,7 @@ IndexStmt:	CREATE opt_unique INDEX opt_concurrently opt_index_name
 					IndexStmt *n = makeNode(IndexStmt);
 					n->unique = $2;
 					n->concurrent = $4;
+					n->if_not_exists = false;
 					n->idxname = $5;
 					n->relation = $7;
 					n->accessMethod = $8;
@@ -6451,6 +6452,41 @@ IndexStmt:	CREATE opt_unique INDEX opt_concurrently opt_index_name
 					n->initdeferred = false;
 					$$ = (Node *)n;
 				}
+			| CREATE opt_unique INDEX opt_concurrently IF_P NOT EXISTS opt_index_name
+			ON qualified_name access_method_clause '(' index_params ')'
+			opt_reloptions OptTableSpace where_clause
+				{
+					IndexStmt *n = makeNode(IndexStmt);
+					n->unique = $2;
+					n->concurrent = $4;
+					n->if_not_exists = true;
+					n->idxname = $8;
+
+					/*
+					 * Throw an exception when IF NOT EXISTS is used without an index name
+					 */
+					if (n->idxname == NULL)
+						ereport(ERROR,
+								(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
+								 errmsg("IF NOT EXISTS requires that you name the index."),
+								 parser_errposition(@5)));
+
+					n->relation = $10;
+					n->accessMethod = $11;
+					n->indexParams = $13;
+					n->options = $15;
+					n->tableSpace = $16;
+					n->whereClause = $17;
+					n->excludeOpNames = NIL;
+					n->idxcomment = NULL;
+					n->indexOid = InvalidOid;
+					n->oldNode = InvalidOid;
+					n->primary = false;
+					n->isconstraint = false;
+					n->deferrable = false;
+					n->initdeferred = false;
+					$$ = (Node *)n;
+				}
 		;
 
 opt_unique:
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 12811a8..076ff8d 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -2803,7 +2803,7 @@ getRowSecurity(Archive *fout, TableInfo tblinfo[], int numTables)
 			continue;
 
 		if (g_verbose)
-			write_msg(NULL, "reading row-security enabled for table \"%s\"",
+			write_msg(NULL, "reading row-security enabled for table \"%s\"\n",
 					  tbinfo->dobj.name);
 
 		/*
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index 006b180..098ac7d 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -60,7 +60,8 @@ extern Oid index_create(Relation heapRelation,
 			 bool allow_system_table_mods,
 			 bool skip_build,
 			 bool concurrent,
-			 bool is_internal);
+			 bool is_internal,
+			 bool if_not_exists);
 
 extern void index_constraint_create(Relation heapRelation,
 						Oid indexRelationId,
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index f3aa69e..a326dc4 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -2255,6 +2255,7 @@ typedef struct IndexStmt
 	bool		deferrable;		/* is the constraint DEFERRABLE? */
 	bool		initdeferred;	/* is the constraint INITIALLY DEFERRED? */
 	bool		concurrent;		/* should this be a concurrent index build? */
+	bool		if_not_exists;	/* just do nothing if index already exists */
 } IndexStmt;
 
 /* ----------------------
diff --git a/src/test/regress/expected/create_index.out b/src/test/regress/expected/create_index.out
index a2bef7a..ba60fbd 100644
--- a/src/test/regress/expected/create_index.out
+++ b/src/test/regress/expected/create_index.out
@@ -6,6 +6,12 @@
 -- BTREE
 --
 CREATE INDEX onek_unique1 ON onek USING btree(unique1 int4_ops);
+CREATE INDEX IF NOT EXISTS onek_unique1 ON onek USING btree(unique1 int4_ops);
+NOTICE:  relation "onek_unique1" already exists, skipping
+CREATE INDEX IF NOT EXISTS ON onek USING btree(unique1 int4_ops);
+ERROR:  IF NOT EXISTS requires that you name the index.
+LINE 1: CREATE INDEX IF NOT EXISTS ON onek USING btree(unique1 int4_...
+                     ^
 CREATE INDEX onek_unique2 ON onek USING btree(unique2 int4_ops);
 CREATE INDEX onek_hundred ON onek USING btree(hundred int4_ops);
 CREATE INDEX onek_stringu1 ON onek USING btree(stringu1 name_ops);
@@ -2290,10 +2296,14 @@ create unique index hash_f8_index_3 on hash_f8_heap(random) where seqno > 1000;
 CREATE TABLE concur_heap (f1 text, f2 text);
 -- empty table
 CREATE INDEX CONCURRENTLY concur_index1 ON concur_heap(f2,f1);
+CREATE INDEX CONCURRENTLY IF NOT EXISTS concur_index1 ON concur_heap(f2,f1);
+NOTICE:  relation "concur_index1" already exists, skipping
 INSERT INTO concur_heap VALUES  ('a','b');
 INSERT INTO concur_heap VALUES  ('b','b');
 -- unique index
 CREATE UNIQUE INDEX CONCURRENTLY concur_index2 ON concur_heap(f1);
+CREATE UNIQUE INDEX CONCURRENTLY IF NOT EXISTS concur_index2 ON concur_heap(f1);
+NOTICE:  relation "concur_index2" already exists, skipping
 -- check if constraint is set up properly to be enforced
 INSERT INTO concur_heap VALUES ('b','x');
 ERROR:  duplicate key value violates unique constraint "concur_index2"
diff --git a/src/test/regress/sql/create_index.sql b/src/test/regress/sql/create_index.sql
index d4d24ef..225727c 100644
--- a/src/test/regress/sql/create_index.sql
+++ b/src/test/regress/sql/create_index.sql
@@ -8,6 +8,10 @@
 --
 CREATE INDEX onek_unique1 ON onek USING btree(unique1 int4_ops);
 
+CREATE INDEX IF NOT EXISTS onek_unique1 ON onek USING btree(unique1 int4_ops);
+
+CREATE INDEX IF NOT EXISTS ON onek USING btree(unique1 int4_ops);
+
 CREATE INDEX onek_unique2 ON onek USING btree(unique2 int4_ops);
 
 CREATE INDEX onek_hundred ON onek USING btree(hundred int4_ops);
@@ -711,10 +715,12 @@ create unique index hash_f8_index_3 on hash_f8_heap(random) where seqno > 1000;
 CREATE TABLE concur_heap (f1 text, f2 text);
 -- empty table
 CREATE INDEX CONCURRENTLY concur_index1 ON concur_heap(f2,f1);
+CREATE INDEX CONCURRENTLY IF NOT EXISTS concur_index1 ON concur_heap(f2,f1);
 INSERT INTO concur_heap VALUES  ('a','b');
 INSERT INTO concur_heap VALUES  ('b','b');
 -- unique index
 CREATE UNIQUE INDEX CONCURRENTLY concur_index2 ON concur_heap(f1);
+CREATE UNIQUE INDEX CONCURRENTLY IF NOT EXISTS concur_index2 ON concur_heap(f1);
 -- check if constraint is set up properly to be enforced
 INSERT INTO concur_heap VALUES ('b','x');
 -- check if constraint is enforced properly at build time

From 51b673799ed8b1d04b4a1999ec7622988281785a Mon Sep 17 00:00:00 2001
From: Marti Raudsepp <marti@juffo.org>
Date: Fri, 3 Oct 2014 11:21:19 +0300
Subject: [PATCH] Simplify CREATE INDEX IF NOT EXISTS grammar

---
 src/backend/parser/gram.y                  | 12 +-----------
 src/test/regress/expected/create_index.out |  4 ++--
 2 files changed, 3 insertions(+), 13 deletions(-)

diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 47b0a14..d02b730 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -6452,7 +6452,7 @@ IndexStmt:	CREATE opt_unique INDEX opt_concurrently opt_index_name
 					n->initdeferred = false;
 					$$ = (Node *)n;
 				}
-			| CREATE opt_unique INDEX opt_concurrently IF_P NOT EXISTS opt_index_name
+			| CREATE opt_unique INDEX opt_concurrently IF_P NOT EXISTS index_name
 			ON qualified_name access_method_clause '(' index_params ')'
 			opt_reloptions OptTableSpace where_clause
 				{
@@ -6461,16 +6461,6 @@ IndexStmt:	CREATE opt_unique INDEX opt_concurrently opt_index_name
 					n->concurrent = $4;
 					n->if_not_exists = true;
 					n->idxname = $8;
-
-					/*
-					 * Throw an exception when IF NOT EXISTS is used without an index name
-					 */
-					if (n->idxname == NULL)
-						ereport(ERROR,
-								(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
-								 errmsg("IF NOT EXISTS requires that you name the index."),
-								 parser_errposition(@5)));
-
 					n->relation = $10;
 					n->accessMethod = $11;
 					n->indexParams = $13;
diff --git a/src/test/regress/expected/create_index.out b/src/test/regress/expected/create_index.out
index ba60fbd..ff866de 100644
--- a/src/test/regress/expected/create_index.out
+++ b/src/test/regress/expected/create_index.out
@@ -9,9 +9,9 @@ CREATE INDEX onek_unique1 ON onek USING btree(unique1 int4_ops);
 CREATE INDEX IF NOT EXISTS onek_unique1 ON onek USING btree(unique1 int4_ops);
 NOTICE:  relation "onek_unique1" already exists, skipping
 CREATE INDEX IF NOT EXISTS ON onek USING btree(unique1 int4_ops);
-ERROR:  IF NOT EXISTS requires that you name the index.
+ERROR:  syntax error at or near "ON"
 LINE 1: CREATE INDEX IF NOT EXISTS ON onek USING btree(unique1 int4_...
-                     ^
+                                   ^
 CREATE INDEX onek_unique2 ON onek USING btree(unique2 int4_ops);
 CREATE INDEX onek_hundred ON onek USING btree(hundred int4_ops);
 CREATE INDEX onek_stringu1 ON onek USING btree(stringu1 name_ops);
-- 
2.1.2

diff --git a/doc/src/sgml/ref/create_index.sgml b/doc/src/sgml/ref/create_index.sgml
index e469b17..2dfe2f4 100644
--- a/doc/src/sgml/ref/create_index.sgml
+++ b/doc/src/sgml/ref/create_index.sgml
@@ -21,7 +21,7 @@ PostgreSQL documentation
 
  <refsynopsisdiv>
 <synopsis>
-CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] [ <replaceable class="parameter">name</replaceable> ] ON <replaceable class="parameter">table_name</replaceable> [ USING <replaceable class="parameter">method</replaceable> ]
+CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] [ IF NOT EXISTS <replaceable class="parameter">name</replaceable> | <replaceable class="parameter">name</replaceable> ] ON <replaceable class="parameter">table_name</replaceable> [ USING <replaceable class="parameter">method</replaceable> ]
     ( { <replaceable class="parameter">column_name</replaceable> | ( <replaceable class="parameter">expression</replaceable> ) } [ COLLATE <replaceable class="parameter">collation</replaceable> ] [ <replaceable class="parameter">opclass</replaceable> ] [ ASC | DESC ] [ NULLS { FIRST | LAST } ] [, ...] )
     [ WITH ( <replaceable class="PARAMETER">storage_parameter</replaceable> = <replaceable class="PARAMETER">value</replaceable> [, ... ] ) ]
     [ TABLESPACE <replaceable class="parameter">tablespace_name</replaceable> ]
@@ -99,6 +99,17 @@ CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] [ <replaceable class="parameter">name</
 
     <variablelist>
      <varlistentry>
+      <term><literal>IF NOT EXISTS</literal></term>
+      <listitem>
+       <para>
+        Do not throw an error if the index already exists. A notice is issued
+        in this case. Note that there is no guarantee that the existing index
+        is anything like the one that would have been created.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry>
       <term><literal>UNIQUE</literal></term>
       <listitem>
        <para>
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index ee10594..8905e30 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -697,7 +697,8 @@ index_create(Relation heapRelation,
 			 bool allow_system_table_mods,
 			 bool skip_build,
 			 bool concurrent,
-			 bool is_internal)
+			 bool is_internal,
+			 bool if_not_exists)
 {
 	Oid			heapRelationId = RelationGetRelid(heapRelation);
 	Relation	pg_class;
@@ -773,10 +774,22 @@ index_create(Relation heapRelation,
 		elog(ERROR, "shared relations must be placed in pg_global tablespace");
 
 	if (get_relname_relid(indexRelationName, namespaceId))
+	{
+		if (if_not_exists)
+		{
+			ereport(NOTICE,
+					(errcode(ERRCODE_DUPLICATE_TABLE),
+					 errmsg("relation \"%s\" already exists, skipping",
+							indexRelationName)));
+			heap_close(pg_class, RowExclusiveLock);
+			return InvalidOid;
+		}
+
 		ereport(ERROR,
 				(errcode(ERRCODE_DUPLICATE_TABLE),
 				 errmsg("relation \"%s\" already exists",
 						indexRelationName)));
+	}
 
 	/*
 	 * construct tuple descriptor for index tuples
diff --git a/src/backend/catalog/toasting.c b/src/backend/catalog/toasting.c
index 160f006..5ef6dcc 100644
--- a/src/backend/catalog/toasting.c
+++ b/src/backend/catalog/toasting.c
@@ -342,7 +342,7 @@ create_toast_table(Relation rel, Oid toastOid, Oid toastIndexOid,
 				 rel->rd_rel->reltablespace,
 				 collationObjectId, classObjectId, coloptions, (Datum) 0,
 				 true, false, false, false,
-				 true, false, false, true);
+				 true, false, false, true, false);
 
 	heap_close(toast_rel, NoLock);
 
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 8a1cb4b..a03773b 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -610,7 +610,14 @@ DefineIndex(Oid relationId,
 					 stmt->isconstraint, stmt->deferrable, stmt->initdeferred,
 					 allowSystemTableMods,
 					 skip_build || stmt->concurrent,
-					 stmt->concurrent, !check_rights);
+					 stmt->concurrent, !check_rights,
+					 stmt->if_not_exists);
+
+	if (!OidIsValid(indexRelationId))
+	{
+		heap_close(rel, NoLock);
+		return indexRelationId;
+	}
 
 	/* Add any requested comment */
 	if (stmt->idxcomment != NULL)
diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index 225756c..39b55db 100644
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -2907,6 +2907,7 @@ _copyIndexStmt(const IndexStmt *from)
 	COPY_SCALAR_FIELD(deferrable);
 	COPY_SCALAR_FIELD(initdeferred);
 	COPY_SCALAR_FIELD(concurrent);
+	COPY_SCALAR_FIELD(if_not_exists);
 
 	return newnode;
 }
diff --git a/src/backend/nodes/equalfuncs.c b/src/backend/nodes/equalfuncs.c
index 905468e..4cf91e0 100644
--- a/src/backend/nodes/equalfuncs.c
+++ b/src/backend/nodes/equalfuncs.c
@@ -1210,6 +1210,7 @@ _equalIndexStmt(const IndexStmt *a, const IndexStmt *b)
 	COMPARE_SCALAR_FIELD(deferrable);
 	COMPARE_SCALAR_FIELD(initdeferred);
 	COMPARE_SCALAR_FIELD(concurrent);
+	COMPARE_SCALAR_FIELD(if_not_exists);
 
 	return true;
 }
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 77d2f29..d02b730 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -6434,6 +6434,7 @@ IndexStmt:	CREATE opt_unique INDEX opt_concurrently opt_index_name
 					IndexStmt *n = makeNode(IndexStmt);
 					n->unique = $2;
 					n->concurrent = $4;
+					n->if_not_exists = false;
 					n->idxname = $5;
 					n->relation = $7;
 					n->accessMethod = $8;
@@ -6451,6 +6452,31 @@ IndexStmt:	CREATE opt_unique INDEX opt_concurrently opt_index_name
 					n->initdeferred = false;
 					$$ = (Node *)n;
 				}
+			| CREATE opt_unique INDEX opt_concurrently IF_P NOT EXISTS index_name
+			ON qualified_name access_method_clause '(' index_params ')'
+			opt_reloptions OptTableSpace where_clause
+				{
+					IndexStmt *n = makeNode(IndexStmt);
+					n->unique = $2;
+					n->concurrent = $4;
+					n->if_not_exists = true;
+					n->idxname = $8;
+					n->relation = $10;
+					n->accessMethod = $11;
+					n->indexParams = $13;
+					n->options = $15;
+					n->tableSpace = $16;
+					n->whereClause = $17;
+					n->excludeOpNames = NIL;
+					n->idxcomment = NULL;
+					n->indexOid = InvalidOid;
+					n->oldNode = InvalidOid;
+					n->primary = false;
+					n->isconstraint = false;
+					n->deferrable = false;
+					n->initdeferred = false;
+					$$ = (Node *)n;
+				}
 		;
 
 opt_unique:
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index 12811a8..076ff8d 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -2803,7 +2803,7 @@ getRowSecurity(Archive *fout, TableInfo tblinfo[], int numTables)
 			continue;
 
 		if (g_verbose)
-			write_msg(NULL, "reading row-security enabled for table \"%s\"",
+			write_msg(NULL, "reading row-security enabled for table \"%s\"\n",
 					  tbinfo->dobj.name);
 
 		/*
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index 006b180..098ac7d 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -60,7 +60,8 @@ extern Oid index_create(Relation heapRelation,
 			 bool allow_system_table_mods,
 			 bool skip_build,
 			 bool concurrent,
-			 bool is_internal);
+			 bool is_internal,
+			 bool if_not_exists);
 
 extern void index_constraint_create(Relation heapRelation,
 						Oid indexRelationId,
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index f3aa69e..a326dc4 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -2255,6 +2255,7 @@ typedef struct IndexStmt
 	bool		deferrable;		/* is the constraint DEFERRABLE? */
 	bool		initdeferred;	/* is the constraint INITIALLY DEFERRED? */
 	bool		concurrent;		/* should this be a concurrent index build? */
+	bool		if_not_exists;	/* just do nothing if index already exists */
 } IndexStmt;
 
 /* ----------------------
diff --git a/src/test/regress/expected/create_index.out b/src/test/regress/expected/create_index.out
index a2bef7a..ff866de 100644
--- a/src/test/regress/expected/create_index.out
+++ b/src/test/regress/expected/create_index.out
@@ -6,6 +6,12 @@
 -- BTREE
 --
 CREATE INDEX onek_unique1 ON onek USING btree(unique1 int4_ops);
+CREATE INDEX IF NOT EXISTS onek_unique1 ON onek USING btree(unique1 int4_ops);
+NOTICE:  relation "onek_unique1" already exists, skipping
+CREATE INDEX IF NOT EXISTS ON onek USING btree(unique1 int4_ops);
+ERROR:  syntax error at or near "ON"
+LINE 1: CREATE INDEX IF NOT EXISTS ON onek USING btree(unique1 int4_...
+                                   ^
 CREATE INDEX onek_unique2 ON onek USING btree(unique2 int4_ops);
 CREATE INDEX onek_hundred ON onek USING btree(hundred int4_ops);
 CREATE INDEX onek_stringu1 ON onek USING btree(stringu1 name_ops);
@@ -2290,10 +2296,14 @@ create unique index hash_f8_index_3 on hash_f8_heap(random) where seqno > 1000;
 CREATE TABLE concur_heap (f1 text, f2 text);
 -- empty table
 CREATE INDEX CONCURRENTLY concur_index1 ON concur_heap(f2,f1);
+CREATE INDEX CONCURRENTLY IF NOT EXISTS concur_index1 ON concur_heap(f2,f1);
+NOTICE:  relation "concur_index1" already exists, skipping
 INSERT INTO concur_heap VALUES  ('a','b');
 INSERT INTO concur_heap VALUES  ('b','b');
 -- unique index
 CREATE UNIQUE INDEX CONCURRENTLY concur_index2 ON concur_heap(f1);
+CREATE UNIQUE INDEX CONCURRENTLY IF NOT EXISTS concur_index2 ON concur_heap(f1);
+NOTICE:  relation "concur_index2" already exists, skipping
 -- check if constraint is set up properly to be enforced
 INSERT INTO concur_heap VALUES ('b','x');
 ERROR:  duplicate key value violates unique constraint "concur_index2"
diff --git a/src/test/regress/sql/create_index.sql b/src/test/regress/sql/create_index.sql
index d4d24ef..225727c 100644
--- a/src/test/regress/sql/create_index.sql
+++ b/src/test/regress/sql/create_index.sql
@@ -8,6 +8,10 @@
 --
 CREATE INDEX onek_unique1 ON onek USING btree(unique1 int4_ops);
 
+CREATE INDEX IF NOT EXISTS onek_unique1 ON onek USING btree(unique1 int4_ops);
+
+CREATE INDEX IF NOT EXISTS ON onek USING btree(unique1 int4_ops);
+
 CREATE INDEX onek_unique2 ON onek USING btree(unique2 int4_ops);
 
 CREATE INDEX onek_hundred ON onek USING btree(hundred int4_ops);
@@ -711,10 +715,12 @@ create unique index hash_f8_index_3 on hash_f8_heap(random) where seqno > 1000;
 CREATE TABLE concur_heap (f1 text, f2 text);
 -- empty table
 CREATE INDEX CONCURRENTLY concur_index1 ON concur_heap(f2,f1);
+CREATE INDEX CONCURRENTLY IF NOT EXISTS concur_index1 ON concur_heap(f2,f1);
 INSERT INTO concur_heap VALUES  ('a','b');
 INSERT INTO concur_heap VALUES  ('b','b');
 -- unique index
 CREATE UNIQUE INDEX CONCURRENTLY concur_index2 ON concur_heap(f1);
+CREATE UNIQUE INDEX CONCURRENTLY IF NOT EXISTS concur_index2 ON concur_heap(f1);
 -- check if constraint is set up properly to be enforced
 INSERT INTO concur_heap VALUES ('b','x');
 -- check if constraint is enforced properly at build time

diff --git a/doc/src/sgml/ref/create_index.sgml b/doc/src/sgml/ref/create_index.sgml
index e469b17..9b3f3a3 100644
--- a/doc/src/sgml/ref/create_index.sgml
+++ b/doc/src/sgml/ref/create_index.sgml
@@ -21,7 +21,7 @@ PostgreSQL documentation
 
  <refsynopsisdiv>
 <synopsis>
-CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] [ <replaceable class="parameter">name</replaceable> ] ON <replaceable class="parameter">table_name</replaceable> [ USING <replaceable class="parameter">method</replaceable> ]
+CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] [ IF NOT EXISTS [ <replaceable class="parameter">name</replaceable> ] ] ON <replaceable class="parameter">table_name</replaceable> [ USING <replaceable class="parameter">method</replaceable> ]
     ( { <replaceable class="parameter">column_name</replaceable> | ( <replaceable class="parameter">expression</replaceable> ) } [ COLLATE <replaceable class="parameter">collation</replaceable> ] [ <replaceable class="parameter">opclass</replaceable> ] [ ASC | DESC ] [ NULLS { FIRST | LAST } ] [, ...] )
     [ WITH ( <replaceable class="PARAMETER">storage_parameter</replaceable> = <replaceable class="PARAMETER">value</replaceable> [, ... ] ) ]
     [ TABLESPACE <replaceable class="parameter">tablespace_name</replaceable> ]
@@ -99,6 +99,18 @@ CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] [ <replaceable class="parameter">name</
 
     <variablelist>
      <varlistentry>
+      <term><literal>IF NOT EXISTS</literal></term>
+      <listitem>
+       <para>
+        Do not throw an error if the index already exists. A notice is issued
+        in this case. Note that there is no guarantee that the existing index
+        is anything like the one that would have been created.
+        Index name is required when IF NOT EXISTS is specified.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry>
       <term><literal>UNIQUE</literal></term>
       <listitem>
        <para>
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index ee10594..8905e30 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -697,7 +697,8 @@ index_create(Relation heapRelation,
 			 bool allow_system_table_mods,
 			 bool skip_build,
 			 bool concurrent,
-			 bool is_internal)
+			 bool is_internal,
+			 bool if_not_exists)
 {
 	Oid			heapRelationId = RelationGetRelid(heapRelation);
 	Relation	pg_class;
@@ -773,10 +774,22 @@ index_create(Relation heapRelation,
 		elog(ERROR, "shared relations must be placed in pg_global tablespace");
 
 	if (get_relname_relid(indexRelationName, namespaceId))
+	{
+		if (if_not_exists)
+		{
+			ereport(NOTICE,
+					(errcode(ERRCODE_DUPLICATE_TABLE),
+					 errmsg("relation \"%s\" already exists, skipping",
+							indexRelationName)));
+			heap_close(pg_class, RowExclusiveLock);
+			return InvalidOid;
+		}
+
 		ereport(ERROR,
 				(errcode(ERRCODE_DUPLICATE_TABLE),
 				 errmsg("relation \"%s\" already exists",
 						indexRelationName)));
+	}
 
 	/*
 	 * construct tuple descriptor for index tuples
diff --git a/src/backend/catalog/toasting.c b/src/backend/catalog/toasting.c
index 160f006..5ef6dcc 100644
--- a/src/backend/catalog/toasting.c
+++ b/src/backend/catalog/toasting.c
@@ -342,7 +342,7 @@ create_toast_table(Relation rel, Oid toastOid, Oid toastIndexOid,
 				 rel->rd_rel->reltablespace,
 				 collationObjectId, classObjectId, coloptions, (Datum) 0,
 				 true, false, false, false,
-				 true, false, false, true);
+				 true, false, false, true, false);
 
 	heap_close(toast_rel, NoLock);
 
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 8a1cb4b..a03773b 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -610,7 +610,14 @@ DefineIndex(Oid relationId,
 					 stmt->isconstraint, stmt->deferrable, stmt->initdeferred,
 					 allowSystemTableMods,
 					 skip_build || stmt->concurrent,
-					 stmt->concurrent, !check_rights);
+					 stmt->concurrent, !check_rights,
+					 stmt->if_not_exists);
+
+	if (!OidIsValid(indexRelationId))
+	{
+		heap_close(rel, NoLock);
+		return indexRelationId;
+	}
 
 	/* Add any requested comment */
 	if (stmt->idxcomment != NULL)
diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index 225756c..39b55db 100644
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -2907,6 +2907,7 @@ _copyIndexStmt(const IndexStmt *from)
 	COPY_SCALAR_FIELD(deferrable);
 	COPY_SCALAR_FIELD(initdeferred);
 	COPY_SCALAR_FIELD(concurrent);
+	COPY_SCALAR_FIELD(if_not_exists);
 
 	return newnode;
 }
diff --git a/src/backend/nodes/equalfuncs.c b/src/backend/nodes/equalfuncs.c
index 905468e..4cf91e0 100644
--- a/src/backend/nodes/equalfuncs.c
+++ b/src/backend/nodes/equalfuncs.c
@@ -1210,6 +1210,7 @@ _equalIndexStmt(const IndexStmt *a, const IndexStmt *b)
 	COMPARE_SCALAR_FIELD(deferrable);
 	COMPARE_SCALAR_FIELD(initdeferred);
 	COMPARE_SCALAR_FIELD(concurrent);
+	COMPARE_SCALAR_FIELD(if_not_exists);
 
 	return true;
 }
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 77d2f29..09f17aa 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -6449,6 +6449,32 @@ IndexStmt:	CREATE opt_unique INDEX opt_concurrently opt_index_name
 					n->isconstraint = false;
 					n->deferrable = false;
 					n->initdeferred = false;
+					n->if_not_exists = false;
+					$$ = (Node *)n;
+				}
+			| CREATE opt_unique INDEX opt_concurrently IF_P NOT EXISTS index_name
+			ON qualified_name access_method_clause '(' index_params ')'
+			opt_reloptions OptTableSpace where_clause
+				{
+					IndexStmt *n = makeNode(IndexStmt);
+					n->unique = $2;
+					n->concurrent = $4;
+					n->idxname = $8;
+					n->relation = $10;
+					n->accessMethod = $11;
+					n->indexParams = $13;
+					n->options = $15;
+					n->tableSpace = $16;
+					n->whereClause = $17;
+					n->excludeOpNames = NIL;
+					n->idxcomment = NULL;
+					n->indexOid = InvalidOid;
+					n->oldNode = InvalidOid;
+					n->primary = false;
+					n->isconstraint = false;
+					n->deferrable = false;
+					n->initdeferred = false;
+					n->if_not_exists = true;
 					$$ = (Node *)n;
 				}
 		;
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index 006b180..098ac7d 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -60,7 +60,8 @@ extern Oid index_create(Relation heapRelation,
 			 bool allow_system_table_mods,
 			 bool skip_build,
 			 bool concurrent,
-			 bool is_internal);
+			 bool is_internal,
+			 bool if_not_exists);
 
 extern void index_constraint_create(Relation heapRelation,
 						Oid indexRelationId,
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index f3aa69e..a326dc4 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -2255,6 +2255,7 @@ typedef struct IndexStmt
 	bool		deferrable;		/* is the constraint DEFERRABLE? */
 	bool		initdeferred;	/* is the constraint INITIALLY DEFERRED? */
 	bool		concurrent;		/* should this be a concurrent index build? */
+	bool		if_not_exists;	/* just do nothing if index already exists */
 } IndexStmt;
 
 /* ----------------------
diff --git a/src/test/regress/expected/create_index.out b/src/test/regress/expected/create_index.out
index a2bef7a..ff866de 100644
--- a/src/test/regress/expected/create_index.out
+++ b/src/test/regress/expected/create_index.out
@@ -6,6 +6,12 @@
 -- BTREE
 --
 CREATE INDEX onek_unique1 ON onek USING btree(unique1 int4_ops);
+CREATE INDEX IF NOT EXISTS onek_unique1 ON onek USING btree(unique1 int4_ops);
+NOTICE:  relation "onek_unique1" already exists, skipping
+CREATE INDEX IF NOT EXISTS ON onek USING btree(unique1 int4_ops);
+ERROR:  syntax error at or near "ON"
+LINE 1: CREATE INDEX IF NOT EXISTS ON onek USING btree(unique1 int4_...
+                                   ^
 CREATE INDEX onek_unique2 ON onek USING btree(unique2 int4_ops);
 CREATE INDEX onek_hundred ON onek USING btree(hundred int4_ops);
 CREATE INDEX onek_stringu1 ON onek USING btree(stringu1 name_ops);
@@ -2290,10 +2296,14 @@ create unique index hash_f8_index_3 on hash_f8_heap(random) where seqno > 1000;
 CREATE TABLE concur_heap (f1 text, f2 text);
 -- empty table
 CREATE INDEX CONCURRENTLY concur_index1 ON concur_heap(f2,f1);
+CREATE INDEX CONCURRENTLY IF NOT EXISTS concur_index1 ON concur_heap(f2,f1);
+NOTICE:  relation "concur_index1" already exists, skipping
 INSERT INTO concur_heap VALUES  ('a','b');
 INSERT INTO concur_heap VALUES  ('b','b');
 -- unique index
 CREATE UNIQUE INDEX CONCURRENTLY concur_index2 ON concur_heap(f1);
+CREATE UNIQUE INDEX CONCURRENTLY IF NOT EXISTS concur_index2 ON concur_heap(f1);
+NOTICE:  relation "concur_index2" already exists, skipping
 -- check if constraint is set up properly to be enforced
 INSERT INTO concur_heap VALUES ('b','x');
 ERROR:  duplicate key value violates unique constraint "concur_index2"
diff --git a/src/test/regress/sql/create_index.sql b/src/test/regress/sql/create_index.sql
index d4d24ef..225727c 100644
--- a/src/test/regress/sql/create_index.sql
+++ b/src/test/regress/sql/create_index.sql
@@ -8,6 +8,10 @@
 --
 CREATE INDEX onek_unique1 ON onek USING btree(unique1 int4_ops);
 
+CREATE INDEX IF NOT EXISTS onek_unique1 ON onek USING btree(unique1 int4_ops);
+
+CREATE INDEX IF NOT EXISTS ON onek USING btree(unique1 int4_ops);
+
 CREATE INDEX onek_unique2 ON onek USING btree(unique2 int4_ops);
 
 CREATE INDEX onek_hundred ON onek USING btree(hundred int4_ops);
@@ -711,10 +715,12 @@ create unique index hash_f8_index_3 on hash_f8_heap(random) where seqno > 1000;
 CREATE TABLE concur_heap (f1 text, f2 text);
 -- empty table
 CREATE INDEX CONCURRENTLY concur_index1 ON concur_heap(f2,f1);
+CREATE INDEX CONCURRENTLY IF NOT EXISTS concur_index1 ON concur_heap(f2,f1);
 INSERT INTO concur_heap VALUES  ('a','b');
 INSERT INTO concur_heap VALUES  ('b','b');
 -- unique index
 CREATE UNIQUE INDEX CONCURRENTLY concur_index2 ON concur_heap(f1);
+CREATE UNIQUE INDEX CONCURRENTLY IF NOT EXISTS concur_index2 ON concur_heap(f1);
 -- check if constraint is set up properly to be enforced
 INSERT INTO concur_heap VALUES ('b','x');
 -- check if constraint is enforced properly at build time

diff --git a/doc/src/sgml/ref/create_index.sgml b/doc/src/sgml/ref/create_index.sgml
index e469b17..ecebcbf 100644
--- a/doc/src/sgml/ref/create_index.sgml
+++ b/doc/src/sgml/ref/create_index.sgml
@@ -21,7 +21,7 @@ PostgreSQL documentation
 
  <refsynopsisdiv>
 <synopsis>
-CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] [ <replaceable class="parameter">name</replaceable> ] ON <replaceable class="parameter">table_name</replaceable> [ USING <replaceable class="parameter">method</replaceable> ]
+CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] [ [ IF NOT EXISTS ] <replaceable class="parameter">name</replaceable> ] ON <replaceable class="parameter">table_name</replaceable> [ USING <replaceable class="parameter">method</replaceable> ]
     ( { <replaceable class="parameter">column_name</replaceable> | ( <replaceable class="parameter">expression</replaceable> ) } [ COLLATE <replaceable class="parameter">collation</replaceable> ] [ <replaceable class="parameter">opclass</replaceable> ] [ ASC | DESC ] [ NULLS { FIRST | LAST } ] [, ...] )
     [ WITH ( <replaceable class="PARAMETER">storage_parameter</replaceable> = <replaceable class="PARAMETER">value</replaceable> [, ... ] ) ]
     [ TABLESPACE <replaceable class="parameter">tablespace_name</replaceable> ]
@@ -99,6 +99,18 @@ CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] [ <replaceable class="parameter">name</
 
     <variablelist>
      <varlistentry>
+      <term><literal>IF NOT EXISTS</literal></term>
+      <listitem>
+       <para>
+        Do not throw an error if the index already exists. A notice is issued
+        in this case. Note that there is no guarantee that the existing index
+        is anything like the one that would have been created.
+        Index name is required when IF NOT EXISTS is specified.
+       </para>
+      </listitem>
+     </varlistentry>
+
+     <varlistentry>
       <term><literal>UNIQUE</literal></term>
       <listitem>
        <para>
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index ee10594..8905e30 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -697,7 +697,8 @@ index_create(Relation heapRelation,
 			 bool allow_system_table_mods,
 			 bool skip_build,
 			 bool concurrent,
-			 bool is_internal)
+			 bool is_internal,
+			 bool if_not_exists)
 {
 	Oid			heapRelationId = RelationGetRelid(heapRelation);
 	Relation	pg_class;
@@ -773,10 +774,22 @@ index_create(Relation heapRelation,
 		elog(ERROR, "shared relations must be placed in pg_global tablespace");
 
 	if (get_relname_relid(indexRelationName, namespaceId))
+	{
+		if (if_not_exists)
+		{
+			ereport(NOTICE,
+					(errcode(ERRCODE_DUPLICATE_TABLE),
+					 errmsg("relation \"%s\" already exists, skipping",
+							indexRelationName)));
+			heap_close(pg_class, RowExclusiveLock);
+			return InvalidOid;
+		}
+
 		ereport(ERROR,
 				(errcode(ERRCODE_DUPLICATE_TABLE),
 				 errmsg("relation \"%s\" already exists",
 						indexRelationName)));
+	}
 
 	/*
 	 * construct tuple descriptor for index tuples
diff --git a/src/backend/catalog/toasting.c b/src/backend/catalog/toasting.c
index 160f006..5ef6dcc 100644
--- a/src/backend/catalog/toasting.c
+++ b/src/backend/catalog/toasting.c
@@ -342,7 +342,7 @@ create_toast_table(Relation rel, Oid toastOid, Oid toastIndexOid,
 				 rel->rd_rel->reltablespace,
 				 collationObjectId, classObjectId, coloptions, (Datum) 0,
 				 true, false, false, false,
-				 true, false, false, true);
+				 true, false, false, true, false);
 
 	heap_close(toast_rel, NoLock);
 
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 8a1cb4b..a03773b 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -610,7 +610,14 @@ DefineIndex(Oid relationId,
 					 stmt->isconstraint, stmt->deferrable, stmt->initdeferred,
 					 allowSystemTableMods,
 					 skip_build || stmt->concurrent,
-					 stmt->concurrent, !check_rights);
+					 stmt->concurrent, !check_rights,
+					 stmt->if_not_exists);
+
+	if (!OidIsValid(indexRelationId))
+	{
+		heap_close(rel, NoLock);
+		return indexRelationId;
+	}
 
 	/* Add any requested comment */
 	if (stmt->idxcomment != NULL)
diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index 225756c..39b55db 100644
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -2907,6 +2907,7 @@ _copyIndexStmt(const IndexStmt *from)
 	COPY_SCALAR_FIELD(deferrable);
 	COPY_SCALAR_FIELD(initdeferred);
 	COPY_SCALAR_FIELD(concurrent);
+	COPY_SCALAR_FIELD(if_not_exists);
 
 	return newnode;
 }
diff --git a/src/backend/nodes/equalfuncs.c b/src/backend/nodes/equalfuncs.c
index 905468e..4cf91e0 100644
--- a/src/backend/nodes/equalfuncs.c
+++ b/src/backend/nodes/equalfuncs.c
@@ -1210,6 +1210,7 @@ _equalIndexStmt(const IndexStmt *a, const IndexStmt *b)
 	COMPARE_SCALAR_FIELD(deferrable);
 	COMPARE_SCALAR_FIELD(initdeferred);
 	COMPARE_SCALAR_FIELD(concurrent);
+	COMPARE_SCALAR_FIELD(if_not_exists);
 
 	return true;
 }
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 77d2f29..09f17aa 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -6449,6 +6449,32 @@ IndexStmt:	CREATE opt_unique INDEX opt_concurrently opt_index_name
 					n->isconstraint = false;
 					n->deferrable = false;
 					n->initdeferred = false;
+					n->if_not_exists = false;
+					$$ = (Node *)n;
+				}
+			| CREATE opt_unique INDEX opt_concurrently IF_P NOT EXISTS index_name
+			ON qualified_name access_method_clause '(' index_params ')'
+			opt_reloptions OptTableSpace where_clause
+				{
+					IndexStmt *n = makeNode(IndexStmt);
+					n->unique = $2;
+					n->concurrent = $4;
+					n->idxname = $8;
+					n->relation = $10;
+					n->accessMethod = $11;
+					n->indexParams = $13;
+					n->options = $15;
+					n->tableSpace = $16;
+					n->whereClause = $17;
+					n->excludeOpNames = NIL;
+					n->idxcomment = NULL;
+					n->indexOid = InvalidOid;
+					n->oldNode = InvalidOid;
+					n->primary = false;
+					n->isconstraint = false;
+					n->deferrable = false;
+					n->initdeferred = false;
+					n->if_not_exists = true;
 					$$ = (Node *)n;
 				}
 		;
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index 006b180..098ac7d 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -60,7 +60,8 @@ extern Oid index_create(Relation heapRelation,
 			 bool allow_system_table_mods,
 			 bool skip_build,
 			 bool concurrent,
-			 bool is_internal);
+			 bool is_internal,
+			 bool if_not_exists);
 
 extern void index_constraint_create(Relation heapRelation,
 						Oid indexRelationId,
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index f3aa69e..a326dc4 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -2255,6 +2255,7 @@ typedef struct IndexStmt
 	bool		deferrable;		/* is the constraint DEFERRABLE? */
 	bool		initdeferred;	/* is the constraint INITIALLY DEFERRED? */
 	bool		concurrent;		/* should this be a concurrent index build? */
+	bool		if_not_exists;	/* just do nothing if index already exists */
 } IndexStmt;
 
 /* ----------------------
diff --git a/src/test/regress/expected/create_index.out b/src/test/regress/expected/create_index.out
index a2bef7a..ff866de 100644
--- a/src/test/regress/expected/create_index.out
+++ b/src/test/regress/expected/create_index.out
@@ -6,6 +6,12 @@
 -- BTREE
 --
 CREATE INDEX onek_unique1 ON onek USING btree(unique1 int4_ops);
+CREATE INDEX IF NOT EXISTS onek_unique1 ON onek USING btree(unique1 int4_ops);
+NOTICE:  relation "onek_unique1" already exists, skipping
+CREATE INDEX IF NOT EXISTS ON onek USING btree(unique1 int4_ops);
+ERROR:  syntax error at or near "ON"
+LINE 1: CREATE INDEX IF NOT EXISTS ON onek USING btree(unique1 int4_...
+                                   ^
 CREATE INDEX onek_unique2 ON onek USING btree(unique2 int4_ops);
 CREATE INDEX onek_hundred ON onek USING btree(hundred int4_ops);
 CREATE INDEX onek_stringu1 ON onek USING btree(stringu1 name_ops);
@@ -2290,10 +2296,14 @@ create unique index hash_f8_index_3 on hash_f8_heap(random) where seqno > 1000;
 CREATE TABLE concur_heap (f1 text, f2 text);
 -- empty table
 CREATE INDEX CONCURRENTLY concur_index1 ON concur_heap(f2,f1);
+CREATE INDEX CONCURRENTLY IF NOT EXISTS concur_index1 ON concur_heap(f2,f1);
+NOTICE:  relation "concur_index1" already exists, skipping
 INSERT INTO concur_heap VALUES  ('a','b');
 INSERT INTO concur_heap VALUES  ('b','b');
 -- unique index
 CREATE UNIQUE INDEX CONCURRENTLY concur_index2 ON concur_heap(f1);
+CREATE UNIQUE INDEX CONCURRENTLY IF NOT EXISTS concur_index2 ON concur_heap(f1);
+NOTICE:  relation "concur_index2" already exists, skipping
 -- check if constraint is set up properly to be enforced
 INSERT INTO concur_heap VALUES ('b','x');
 ERROR:  duplicate key value violates unique constraint "concur_index2"
diff --git a/src/test/regress/sql/create_index.sql b/src/test/regress/sql/create_index.sql
index d4d24ef..225727c 100644
--- a/src/test/regress/sql/create_index.sql
+++ b/src/test/regress/sql/create_index.sql
@@ -8,6 +8,10 @@
 --
 CREATE INDEX onek_unique1 ON onek USING btree(unique1 int4_ops);
 
+CREATE INDEX IF NOT EXISTS onek_unique1 ON onek USING btree(unique1 int4_ops);
+
+CREATE INDEX IF NOT EXISTS ON onek USING btree(unique1 int4_ops);
+
 CREATE INDEX onek_unique2 ON onek USING btree(unique2 int4_ops);
 
 CREATE INDEX onek_hundred ON onek USING btree(hundred int4_ops);
@@ -711,10 +715,12 @@ create unique index hash_f8_index_3 on hash_f8_heap(random) where seqno > 1000;
 CREATE TABLE concur_heap (f1 text, f2 text);
 -- empty table
 CREATE INDEX CONCURRENTLY concur_index1 ON concur_heap(f2,f1);
+CREATE INDEX CONCURRENTLY IF NOT EXISTS concur_index1 ON concur_heap(f2,f1);
 INSERT INTO concur_heap VALUES  ('a','b');
 INSERT INTO concur_heap VALUES  ('b','b');
 -- unique index
 CREATE UNIQUE INDEX CONCURRENTLY concur_index2 ON concur_heap(f1);
+CREATE UNIQUE INDEX CONCURRENTLY IF NOT EXISTS concur_index2 ON concur_heap(f1);
 -- check if constraint is set up properly to be enforced
 INSERT INTO concur_heap VALUES ('b','x');
 -- check if constraint is enforced properly at build time

diff --git a/doc/src/sgml/ref/create_index.sgml b/doc/src/sgml/ref/create_index.sgml
index 43df32f..0414c26 100644
--- a/doc/src/sgml/ref/create_index.sgml
+++ b/doc/src/sgml/ref/create_index.sgml
@@ -21,7 +21,7 @@ PostgreSQL documentation
 
  <refsynopsisdiv>
 <synopsis>
-CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] [ <replaceable class="parameter">name</replaceable> ] ON <replaceable class="parameter">table_name</replaceable> [ USING <replaceable class="parameter">method</replaceable> ]
+CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] [ [ IF NOT EXISTS ] <replaceable class="parameter">name</replaceable> ] ON <replaceable class="parameter">table_name</replaceable> [ USING <replaceable class="parameter">method</replaceable> ]
     ( { <replaceable class="parameter">column_name</replaceable> | ( <replaceable class="parameter">expression</replaceable> ) } [ COLLATE <replaceable class="parameter">collation</replaceable> ] [ <replaceable class="parameter">opclass</replaceable> ] [ ASC | DESC ] [ NULLS { FIRST | LAST } ] [, ...] )
     [ WITH ( <replaceable class="PARAMETER">storage_parameter</replaceable> = <replaceable class="PARAMETER">value</replaceable> [, ... ] ) ]
     [ TABLESPACE <replaceable class="parameter">tablespace_name</replaceable> ]
@@ -97,7 +97,6 @@ CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] [ <replaceable class="parameter">name</
  <refsect1>
   <title>Parameters</title>
 
-    <variablelist>
      <varlistentry>
       <term><literal>UNIQUE</literal></term>
       <listitem>
@@ -126,6 +125,19 @@ CREATE [ UNIQUE ] INDEX [ CONCURRENTLY ] [ <replaceable class="parameter">name</
       </listitem>
      </varlistentry>
 
+    <variablelist>
+     <varlistentry>
+      <term><literal>IF NOT EXISTS</literal></term>
+      <listitem>
+       <para>
+        Do not throw an error if a relation with the same name already exists.
+        A notice is issued in this case. Note that there is no guarantee that
+        the existing index is anything like the one that would have been created.
+        Index name is required when <literal>IF NOT EXISTS</literal> is specified.
+       </para>
+      </listitem>
+     </varlistentry>
+
      <varlistentry>
       <term><replaceable class="parameter">name</replaceable></term>
       <listitem>
diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 01ed880..c886f74 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -674,6 +674,8 @@ UpdateIndexRelation(Oid indexoid,
  *		will be marked "invalid" and the caller must take additional steps
  *		to fix it up.
  * is_internal: if true, post creation hook for new index
+ * if_not_exists: if true, issue a notice instead an error if the index with
+ *      the same name already exists
  *
  * Returns the OID of the created index.
  */
@@ -697,7 +699,8 @@ index_create(Relation heapRelation,
 			 bool allow_system_table_mods,
 			 bool skip_build,
 			 bool concurrent,
-			 bool is_internal)
+			 bool is_internal,
+			 bool if_not_exists)
 {
 	Oid			heapRelationId = RelationGetRelid(heapRelation);
 	Relation	pg_class;
@@ -773,10 +776,22 @@ index_create(Relation heapRelation,
 		elog(ERROR, "shared relations must be placed in pg_global tablespace");
 
 	if (get_relname_relid(indexRelationName, namespaceId))
+	{
+		if (if_not_exists)
+		{
+			ereport(NOTICE,
+					(errcode(ERRCODE_DUPLICATE_TABLE),
+					 errmsg("relation \"%s\" already exists, skipping",
+							indexRelationName)));
+			heap_close(pg_class, RowExclusiveLock);
+			return InvalidOid;
+		}
+
 		ereport(ERROR,
 				(errcode(ERRCODE_DUPLICATE_TABLE),
 				 errmsg("relation \"%s\" already exists",
 						indexRelationName)));
+	}
 
 	/*
 	 * construct tuple descriptor for index tuples
diff --git a/src/backend/catalog/toasting.c b/src/backend/catalog/toasting.c
index 160f006..5ef6dcc 100644
--- a/src/backend/catalog/toasting.c
+++ b/src/backend/catalog/toasting.c
@@ -342,7 +342,7 @@ create_toast_table(Relation rel, Oid toastOid, Oid toastIndexOid,
 				 rel->rd_rel->reltablespace,
 				 collationObjectId, classObjectId, coloptions, (Datum) 0,
 				 true, false, false, false,
-				 true, false, false, true);
+				 true, false, false, true, false);
 
 	heap_close(toast_rel, NoLock);
 
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 3c1e90e..0205595 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -610,7 +610,14 @@ DefineIndex(Oid relationId,
 					 stmt->isconstraint, stmt->deferrable, stmt->initdeferred,
 					 allowSystemTableMods,
 					 skip_build || stmt->concurrent,
-					 stmt->concurrent, !check_rights);
+					 stmt->concurrent, !check_rights,
+					 stmt->if_not_exists);
+
+	if (!OidIsValid(indexRelationId))
+	{
+		heap_close(rel, NoLock);
+		return indexRelationId;
+	}
 
 	/* Add any requested comment */
 	if (stmt->idxcomment != NULL)
diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index 21b070a..7b51d33 100644
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -2907,6 +2907,7 @@ _copyIndexStmt(const IndexStmt *from)
 	COPY_SCALAR_FIELD(deferrable);
 	COPY_SCALAR_FIELD(initdeferred);
 	COPY_SCALAR_FIELD(concurrent);
+	COPY_SCALAR_FIELD(if_not_exists);
 
 	return newnode;
 }
diff --git a/src/backend/nodes/equalfuncs.c b/src/backend/nodes/equalfuncs.c
index 358395f..d5db71d 100644
--- a/src/backend/nodes/equalfuncs.c
+++ b/src/backend/nodes/equalfuncs.c
@@ -1210,6 +1210,7 @@ _equalIndexStmt(const IndexStmt *a, const IndexStmt *b)
 	COMPARE_SCALAR_FIELD(deferrable);
 	COMPARE_SCALAR_FIELD(initdeferred);
 	COMPARE_SCALAR_FIELD(concurrent);
+	COMPARE_SCALAR_FIELD(if_not_exists);
 
 	return true;
 }
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 0de9584..bd180e7 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -6434,6 +6434,32 @@ IndexStmt:	CREATE opt_unique INDEX opt_concurrently opt_index_name
 					n->isconstraint = false;
 					n->deferrable = false;
 					n->initdeferred = false;
+					n->if_not_exists = false;
+					$$ = (Node *)n;
+				}
+			| CREATE opt_unique INDEX opt_concurrently IF_P NOT EXISTS index_name
+			ON qualified_name access_method_clause '(' index_params ')'
+			opt_reloptions OptTableSpace where_clause
+				{
+					IndexStmt *n = makeNode(IndexStmt);
+					n->unique = $2;
+					n->concurrent = $4;
+					n->idxname = $8;
+					n->relation = $10;
+					n->accessMethod = $11;
+					n->indexParams = $13;
+					n->options = $15;
+					n->tableSpace = $16;
+					n->whereClause = $17;
+					n->excludeOpNames = NIL;
+					n->idxcomment = NULL;
+					n->indexOid = InvalidOid;
+					n->oldNode = InvalidOid;
+					n->primary = false;
+					n->isconstraint = false;
+					n->deferrable = false;
+					n->initdeferred = false;
+					n->if_not_exists = true;
 					$$ = (Node *)n;
 				}
 		;
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index 006b180..098ac7d 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -60,7 +60,8 @@ extern Oid index_create(Relation heapRelation,
 			 bool allow_system_table_mods,
 			 bool skip_build,
 			 bool concurrent,
-			 bool is_internal);
+			 bool is_internal,
+			 bool if_not_exists);
 
 extern void index_constraint_create(Relation heapRelation,
 						Oid indexRelationId,
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index cef9544..3e4f815 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -2256,6 +2256,7 @@ typedef struct IndexStmt
 	bool		deferrable;		/* is the constraint DEFERRABLE? */
 	bool		initdeferred;	/* is the constraint INITIALLY DEFERRED? */
 	bool		concurrent;		/* should this be a concurrent index build? */
+	bool		if_not_exists;	/* just do nothing if index already exists? */
 } IndexStmt;
 
 /* ----------------------
diff --git a/src/test/regress/expected/create_index.out b/src/test/regress/expected/create_index.out
index d903c4b..26d883c 100644
--- a/src/test/regress/expected/create_index.out
+++ b/src/test/regress/expected/create_index.out
@@ -6,6 +6,12 @@
 -- BTREE
 --
 CREATE INDEX onek_unique1 ON onek USING btree(unique1 int4_ops);
+CREATE INDEX IF NOT EXISTS onek_unique1 ON onek USING btree(unique1 int4_ops);
+NOTICE:  relation "onek_unique1" already exists, skipping
+CREATE INDEX IF NOT EXISTS ON onek USING btree(unique1 int4_ops);
+ERROR:  syntax error at or near "ON"
+LINE 1: CREATE INDEX IF NOT EXISTS ON onek USING btree(unique1 int4_...
+                                   ^
 CREATE INDEX onek_unique2 ON onek USING btree(unique2 int4_ops);
 CREATE INDEX onek_hundred ON onek USING btree(hundred int4_ops);
 CREATE INDEX onek_stringu1 ON onek USING btree(stringu1 name_ops);
@@ -2290,10 +2296,14 @@ create unique index hash_f8_index_3 on hash_f8_heap(random) where seqno > 1000;
 CREATE TABLE concur_heap (f1 text, f2 text);
 -- empty table
 CREATE INDEX CONCURRENTLY concur_index1 ON concur_heap(f2,f1);
+CREATE INDEX CONCURRENTLY IF NOT EXISTS concur_index1 ON concur_heap(f2,f1);
+NOTICE:  relation "concur_index1" already exists, skipping
 INSERT INTO concur_heap VALUES  ('a','b');
 INSERT INTO concur_heap VALUES  ('b','b');
 -- unique index
 CREATE UNIQUE INDEX CONCURRENTLY concur_index2 ON concur_heap(f1);
+CREATE UNIQUE INDEX CONCURRENTLY IF NOT EXISTS concur_index2 ON concur_heap(f1);
+NOTICE:  relation "concur_index2" already exists, skipping
 -- check if constraint is set up properly to be enforced
 INSERT INTO concur_heap VALUES ('b','x');
 ERROR:  duplicate key value violates unique constraint "concur_index2"
diff --git a/src/test/regress/sql/create_index.sql b/src/test/regress/sql/create_index.sql
index 989fc97..e08f35e 100644
--- a/src/test/regress/sql/create_index.sql
+++ b/src/test/regress/sql/create_index.sql
@@ -8,6 +8,10 @@
 --
 CREATE INDEX onek_unique1 ON onek USING btree(unique1 int4_ops);
 
+CREATE INDEX IF NOT EXISTS onek_unique1 ON onek USING btree(unique1 int4_ops);
+
+CREATE INDEX IF NOT EXISTS ON onek USING btree(unique1 int4_ops);
+
 CREATE INDEX onek_unique2 ON onek USING btree(unique2 int4_ops);
 
 CREATE INDEX onek_hundred ON onek USING btree(hundred int4_ops);
@@ -711,10 +715,12 @@ create unique index hash_f8_index_3 on hash_f8_heap(random) where seqno > 1000;
 CREATE TABLE concur_heap (f1 text, f2 text);
 -- empty table
 CREATE INDEX CONCURRENTLY concur_index1 ON concur_heap(f2,f1);
+CREATE INDEX CONCURRENTLY IF NOT EXISTS concur_index1 ON concur_heap(f2,f1);
 INSERT INTO concur_heap VALUES  ('a','b');
 INSERT INTO concur_heap VALUES  ('b','b');
 -- unique index
 CREATE UNIQUE INDEX CONCURRENTLY concur_index2 ON concur_heap(f1);
+CREATE UNIQUE INDEX CONCURRENTLY IF NOT EXISTS concur_index2 ON concur_heap(f1);
 -- check if constraint is set up properly to be enforced
 INSERT INTO concur_heap VALUES ('b','x');
 -- check if constraint is enforced properly at build time