From f829ae210fc0f6a010cba9c9e4e7772a9b59ae37 Mon Sep 17 00:00:00 2001 From: Maksim Kita Date: Wed, 7 Oct 2020 23:35:56 +0300 Subject: [PATCH] Allow alter type delete value in enum --- src/backend/catalog/pg_enum.c | 69 +++++++++++++++++++++++++++++++++ src/backend/commands/typecmds.c | 8 +++- src/backend/parser/gram.y | 11 ++++++ src/backend/utils/adt/enum.c | 10 +++++ src/include/catalog/pg_enum.h | 2 + 5 files changed, 98 insertions(+), 2 deletions(-) diff --git a/src/backend/catalog/pg_enum.c b/src/backend/catalog/pg_enum.c index 27e4100a6f..907db93cf4 100644 --- a/src/backend/catalog/pg_enum.c +++ b/src/backend/catalog/pg_enum.c @@ -133,6 +133,7 @@ EnumValuesCreate(Oid enumTypeOid, List *vals) values[Anum_pg_enum_enumsortorder - 1] = Float4GetDatum(elemno + 1); namestrcpy(&enumlabel, lab); values[Anum_pg_enum_enumlabel - 1] = NameGetDatum(&enumlabel); + values[Anum_pg_enum_isdropped - 1] = false; tup = heap_form_tuple(RelationGetDescr(pg_enum), values, nulls); @@ -485,6 +486,7 @@ restart: values[Anum_pg_enum_enumsortorder - 1] = Float4GetDatum(newelemorder); namestrcpy(&enumlabel, newVal); values[Anum_pg_enum_enumlabel - 1] = NameGetDatum(&enumlabel); + values[Anum_pg_enum_isdropped - 1] = false; enum_tup = heap_form_tuple(RelationGetDescr(pg_enum), values, nulls); CatalogTupleInsert(pg_enum, enum_tup); heap_freetuple(enum_tup); @@ -583,6 +585,73 @@ RenameEnumLabel(Oid enumTypeOid, table_close(pg_enum, RowExclusiveLock); } +extern void RemoveEnumLabel(Oid enumTypeOid, const char *val) +{ + Relation pg_enum; + HeapTuple enum_tup; + Form_pg_enum en; + CatCList *list; + int nelems; + HeapTuple old_tup; + int i; + + /* check length of new label is ok */ + if (strlen(val) > (NAMEDATALEN - 1)) + ereport(ERROR, + (errcode(ERRCODE_INVALID_NAME), + errmsg("invalid enum label \"%s\"", val), + errdetail("Labels must be %d characters or less.", + NAMEDATALEN - 1))); + + /* + * Acquire a lock on the enum type, which we won't release until commit. + * This ensures that two backends aren't concurrently modifying the same + * enum type. Since we are not changing the type's sort order, this is + * probably not really necessary, but there seems no reason not to take + * the lock to be sure. + */ + LockDatabaseObject(TypeRelationId, enumTypeOid, 0, ExclusiveLock); + + pg_enum = table_open(EnumRelationId, RowExclusiveLock); + + /* Get the list of existing members of the enum */ + list = SearchSysCacheList1(ENUMTYPOIDNAME, + ObjectIdGetDatum(enumTypeOid)); + nelems = list->n_members; + + /* + * Check if the label is in use. (The unique index on pg_enum would catch that anyway, but we + * prefer a friendlier error message.) + */ + for (i = 0; i < nelems; i++) + { + enum_tup = &(list->members[i]->tuple); + en = (Form_pg_enum) GETSTRUCT(enum_tup); + if (strcmp(NameStr(en->enumlabel), val) == 0) + { + old_tup = enum_tup; + break; + } + } + if (!old_tup) + ereport(ERROR, + (errcode(ERRCODE_INVALID_PARAMETER_VALUE), + errmsg("\"%s\" is not an existing enum label", + val))); + + /* OK, make a writable copy of old tuple */ + enum_tup = heap_copytuple(old_tup); + en = (Form_pg_enum) GETSTRUCT(enum_tup); + + ReleaseCatCacheList(list); + + /* Update the pg_enum entry */ + en->isdropped = true; + CatalogTupleUpdate(pg_enum, &enum_tup->t_self, enum_tup); + heap_freetuple(enum_tup); + + table_close(pg_enum, RowExclusiveLock); +} /* * Test if the given enum value is on the blacklist diff --git a/src/backend/commands/typecmds.c b/src/backend/commands/typecmds.c index 483bb65ddc..b9b3e18a94 100644 --- a/src/backend/commands/typecmds.c +++ b/src/backend/commands/typecmds.c @@ -1232,13 +1232,17 @@ AlterEnum(AlterEnumStmt *stmt) ReleaseSysCache(tup); - if (stmt->oldVal) + if (stmt->oldVal && stmt->newVal) { /* Rename an existing label */ RenameEnumLabel(enum_type_oid, stmt->oldVal, stmt->newVal); } - else + else if (stmt->oldVal) { + /* Delete an existing label */ + RemoveEnumLabel(enum_type_oid, stmt->oldVal); + } + else { /* Add a new label */ AddEnumLabel(enum_type_oid, stmt->newVal, stmt->newValNeighbor, stmt->newValIsAfter, diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y index 0d101d8171..82dd5147fa 100644 --- a/src/backend/parser/gram.y +++ b/src/backend/parser/gram.y @@ -5792,6 +5792,17 @@ AlterEnumStmt: n->skipIfNewValExists = false; $$ = (Node *) n; } + | ALTER TYPE_P any_name DELETE_P VALUE_P Sconst + { + AlterEnumStmt *n = makeNode(AlterEnumStmt); + n->typeName = $3; + n->oldVal = $6; + n->newVal = NULL; + n->newValNeighbor = NULL; + n->newValIsAfter = false; + n->skipIfNewValExists = false; + $$ = (Node *) n; + } ; opt_if_not_exists: IF_P NOT EXISTS { $$ = true; } diff --git a/src/backend/utils/adt/enum.c b/src/backend/utils/adt/enum.c index 5ead794e34..397c02fa69 100644 --- a/src/backend/utils/adt/enum.c +++ b/src/backend/utils/adt/enum.c @@ -113,6 +113,7 @@ enum_in(PG_FUNCTION_ARGS) Oid enumtypoid = PG_GETARG_OID(1); Oid enumoid; HeapTuple tup; + Form_pg_enum en; /* must check length to prevent Assert failure within SearchSysCache */ if (strlen(name) >= NAMEDATALEN) @@ -132,6 +133,15 @@ enum_in(PG_FUNCTION_ARGS) format_type_be(enumtypoid), name))); + en = (Form_pg_enum) GETSTRUCT(tup); + + if (en->isdropped) + ereport(ERROR, + (errcode(ERRCODE_INVALID_TEXT_REPRESENTATION), + errmsg("enum value is dropped %s: \"%s\"", + format_type_be(enumtypoid), + name))); + /* check it's safe to use in SQL */ check_safe_enum_use(tup); diff --git a/src/include/catalog/pg_enum.h b/src/include/catalog/pg_enum.h index b28d441ba7..6a7b00ffbe 100644 --- a/src/include/catalog/pg_enum.h +++ b/src/include/catalog/pg_enum.h @@ -34,6 +34,7 @@ CATALOG(pg_enum,3501,EnumRelationId) Oid enumtypid; /* OID of owning enum type */ float4 enumsortorder; /* sort position of this enum value */ NameData enumlabel; /* text representation of enum value */ + bool isdropped; /* is enum value dropped */ } FormData_pg_enum; /* ---------------- @@ -53,6 +54,7 @@ extern void AddEnumLabel(Oid enumTypeOid, const char *newVal, bool skipIfExists); extern void RenameEnumLabel(Oid enumTypeOid, const char *oldVal, const char *newVal); +extern void RemoveEnumLabel(Oid enumTypeOid, const char *val); extern bool EnumBlacklisted(Oid enum_id); extern Size EstimateEnumBlacklistSpace(void); extern void SerializeEnumBlacklist(void *space, Size size); -- 2.25.1