>From f77a55bdf01c6997428bbf7e1bedac771998a95c Mon Sep 17 00:00:00 2001 From: Andres Freund Date: Tue, 11 Jun 2013 23:25:26 +0200 Subject: [PATCH 05/17] wal_decoding: Add pg_relation_by_filenode to lookup up a relation by (tablespace, filenode) This requires the previously added RELFILENODE syscache and the added RelationMapFilenodeToOid function added in previous two commits. --- doc/src/sgml/func.sgml | 23 ++++++++++++++- src/backend/utils/adt/dbsize.c | 63 ++++++++++++++++++++++++++++++++++++++++++ src/include/catalog/pg_proc.h | 2 ++ src/include/utils/builtins.h | 2 ++ 4 files changed, 89 insertions(+), 1 deletion(-) diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml index 4c5af4b..a8f83e2 100644 --- a/doc/src/sgml/func.sgml +++ b/doc/src/sgml/func.sgml @@ -15726,7 +15726,7 @@ postgres=# SELECT * FROM pg_xlogfile_name_offset(pg_stop_backup()); The functions shown in assist - in identifying the specific disk files associated with database objects. + in identifying the specific disk files associated with database objects or doing the reverse. @@ -15735,6 +15735,9 @@ postgres=# SELECT * FROM pg_xlogfile_name_offset(pg_stop_backup()); pg_relation_filepath + + pg_relation_by_filenode + Database Object Location Functions @@ -15763,6 +15766,15 @@ postgres=# SELECT * FROM pg_xlogfile_name_offset(pg_stop_backup()); File path name of the specified relation + + + pg_relation_by_filenode(tablespace oid, filenode oid) + + regclass + + Find the associated relation of a filenode + +
@@ -15786,6 +15798,15 @@ postgres=# SELECT * FROM pg_xlogfile_name_offset(pg_stop_backup()); the relation. + + pg_relation_by_filenode is the reverse of + pg_relation_filenode. Given a tablespace OID and + a filenode it returns the associated relation. The default + tablespace for user tables can be replaced with 0. Check the + documentation of pg_relation_filenode for an explanation why + this cannot always easily answered by querying pg_class. + + diff --git a/src/backend/utils/adt/dbsize.c b/src/backend/utils/adt/dbsize.c index 4c4e1ed..ce5f49e 100644 --- a/src/backend/utils/adt/dbsize.c +++ b/src/backend/utils/adt/dbsize.c @@ -746,6 +746,69 @@ pg_relation_filenode(PG_FUNCTION_ARGS) } /* + * Get the relation via (reltablespace, relfilenode) + * + * This is expected to be used when somebody wants to match an individual file + * on the filesystem back to its table. Thats not trivially possible via + * pg_class because that doesn't contain the relfilenodes of shared and nailed + * tables. + * + * We don't fail but return NULL if we cannot find a mapping. + * + * Instead of knowing DEFAULTTABLESPACE_OID you can pass 0. + */ +Datum +pg_relation_by_filenode(PG_FUNCTION_ARGS) +{ + Oid reltablespace = PG_GETARG_OID(0); + Oid relfilenode = PG_GETARG_OID(1); + Oid lookup_tablespace; + Oid heaprel = InvalidOid; + HeapTuple tuple; + + if (reltablespace == 0) + reltablespace = DEFAULTTABLESPACE_OID; + + /* in global tablespace, has to be a shared table */ + if (reltablespace == GLOBALTABLESPACE_OID) + { + heaprel = RelationMapFilenodeToOid(relfilenode, true); + } + else + { + /* + * relations in the default tablespace are stored with InvalidOid as + * pg_class."reltablespace". + */ + if (reltablespace == DEFAULTTABLESPACE_OID) + lookup_tablespace = InvalidOid; + else + lookup_tablespace = reltablespace; + + + tuple = SearchSysCache2(RELFILENODE, + lookup_tablespace, + relfilenode); + /* ok, found it */ + if (HeapTupleIsValid(tuple)) + { + heaprel = HeapTupleHeaderGetOid(tuple->t_data); + ReleaseSysCache(tuple); + } + /* has to be nonexistant or a nailed table, but not shared */ + else + { + heaprel = RelationMapFilenodeToOid(relfilenode, false); + } + } + + if (!OidIsValid(heaprel)) + PG_RETURN_NULL(); + else + PG_RETURN_OID(heaprel); +} + +/* * Get the pathname (relative to $PGDATA) of a relation * * See comments for pg_relation_filenode. diff --git a/src/include/catalog/pg_proc.h b/src/include/catalog/pg_proc.h index 6d3d702..8d268dd 100644 --- a/src/include/catalog/pg_proc.h +++ b/src/include/catalog/pg_proc.h @@ -3446,6 +3446,8 @@ DATA(insert OID = 2998 ( pg_indexes_size PGNSP PGUID 12 1 0 0 0 f f f f t f v 1 DESCR("disk space usage for all indexes attached to the specified table"); DATA(insert OID = 2999 ( pg_relation_filenode PGNSP PGUID 12 1 0 0 0 f f f f t f s 1 0 26 "2205" _null_ _null_ _null_ _null_ pg_relation_filenode _null_ _null_ _null_ )); DESCR("filenode identifier of relation"); +DATA(insert OID = 3454 ( pg_relation_by_filenode PGNSP PGUID 12 1 0 0 0 f f f f t f s 2 0 2205 "26 26" _null_ _null_ _null_ _null_ pg_relation_by_filenode _null_ _null_ _null_ )); +DESCR("filenode identifier of relation"); DATA(insert OID = 3034 ( pg_relation_filepath PGNSP PGUID 12 1 0 0 0 f f f f t f s 1 0 25 "2205" _null_ _null_ _null_ _null_ pg_relation_filepath _null_ _null_ _null_ )); DESCR("file path of relation"); diff --git a/src/include/utils/builtins.h b/src/include/utils/builtins.h index 667c58b..ddbedea 100644 --- a/src/include/utils/builtins.h +++ b/src/include/utils/builtins.h @@ -459,8 +459,10 @@ extern Datum pg_size_pretty(PG_FUNCTION_ARGS); extern Datum pg_size_pretty_numeric(PG_FUNCTION_ARGS); extern Datum pg_table_size(PG_FUNCTION_ARGS); extern Datum pg_indexes_size(PG_FUNCTION_ARGS); +extern Datum pg_relation_by_filenode(PG_FUNCTION_ARGS); extern Datum pg_relation_filenode(PG_FUNCTION_ARGS); extern Datum pg_relation_filepath(PG_FUNCTION_ARGS); +extern Datum pg_relation_is_scannable(PG_FUNCTION_ARGS); /* genfile.c */ extern bytea *read_binary_file(const char *filename, -- 1.8.2.rc2.4.g7799588.dirty