From 819c4409a832e151874b42715257675aecdd746d Mon Sep 17 00:00:00 2001 From: Christoph Berg Date: Fri, 14 Mar 2025 16:29:19 +0100 Subject: [PATCH] Add pg_tablespace_avail() functions This exposes the f_avail value from statvfs() on tablespace directories on the SQL level, allowing monitoring of free disk space from within the server. On windows, GetDiskFreeSpaceEx() is used. Permissions required match those from pg_tablespace_size(). In psql, include a new "Free" column in \db+ output. Add test coverage for pg_tablespace_avail() and the previously not covered pg_tablespace_size() function. --- doc/src/sgml/func.sgml | 21 +++++ doc/src/sgml/ref/psql-ref.sgml | 2 +- src/backend/utils/adt/dbsize.c | 102 +++++++++++++++++++++++ src/bin/psql/describe.c | 11 ++- src/include/catalog/pg_proc.dat | 8 ++ src/test/regress/expected/tablespace.out | 21 +++++ src/test/regress/sql/tablespace.sql | 10 +++ 7 files changed, 171 insertions(+), 4 deletions(-) diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml index 574a544d9fa4..f4f324cf50db 100644 --- a/doc/src/sgml/func.sgml +++ b/doc/src/sgml/func.sgml @@ -30003,6 +30003,27 @@ postgres=# SELECT '0/0'::pg_lsn + pd.segment_number * ps.setting::int + :offset + + + + pg_tablespace_avail + + pg_tablespace_avail ( name ) + bigint + + + pg_tablespace_avail ( oid ) + bigint + + + Returns the available disk space in the tablespace with the + specified name or OID. To use this function, you must + have CREATE privilege on the specified tablespace + or have privileges of the pg_read_all_stats role, + unless it is the default tablespace for the current database. + + + diff --git a/doc/src/sgml/ref/psql-ref.sgml b/doc/src/sgml/ref/psql-ref.sgml index f7c8bc16a7fc..c6ab1a73fab3 100644 --- a/doc/src/sgml/ref/psql-ref.sgml +++ b/doc/src/sgml/ref/psql-ref.sgml @@ -1492,7 +1492,7 @@ SELECT $1 \parse stmt1 If x is appended to the command name, the results are displayed in expanded mode. If + is appended to the command name, each tablespace - is listed with its associated options, on-disk size, permissions and + is listed with its associated options, on-disk size and free disk space, permissions and description. diff --git a/src/backend/utils/adt/dbsize.c b/src/backend/utils/adt/dbsize.c index 25865b660ef8..9bd8667c2d97 100644 --- a/src/backend/utils/adt/dbsize.c +++ b/src/backend/utils/adt/dbsize.c @@ -12,6 +12,12 @@ #include "postgres.h" #include +#ifdef WIN32 +#include +#include +#else +#include +#endif #include "access/htup_details.h" #include "access/relation.h" @@ -316,6 +322,102 @@ pg_tablespace_size_name(PG_FUNCTION_ARGS) } +/* + * Return available disk space of tablespace. Returns -1 if the tablespace + * directory cannot be found. + */ +static int64 +calculate_tablespace_avail(Oid tblspcOid) +{ + char tblspcPath[MAXPGPATH]; + AclResult aclresult; +#ifdef WIN32 + ULARGE_INTEGER lpFreeBytesAvailable; +#else + struct statvfs fst; +#endif + + /* + * User must have privileges of pg_read_all_stats or have CREATE privilege + * for target tablespace, either explicitly granted or implicitly because + * it is default for current database. + */ + if (tblspcOid != MyDatabaseTableSpace && + !has_privs_of_role(GetUserId(), ROLE_PG_READ_ALL_STATS)) + { + aclresult = object_aclcheck(TableSpaceRelationId, tblspcOid, GetUserId(), ACL_CREATE); + if (aclresult != ACLCHECK_OK) + aclcheck_error(aclresult, OBJECT_TABLESPACE, + get_tablespace_name(tblspcOid)); + } + + if (tblspcOid == DEFAULTTABLESPACE_OID) + snprintf(tblspcPath, MAXPGPATH, "base"); + else if (tblspcOid == GLOBALTABLESPACE_OID) + snprintf(tblspcPath, MAXPGPATH, "global"); + else + snprintf(tblspcPath, MAXPGPATH, "%s/%u/%s", PG_TBLSPC_DIR, tblspcOid, + TABLESPACE_VERSION_DIRECTORY); + +#ifdef WIN32 + if (! GetDiskFreeSpaceEx(tblspcPath, &lpFreeBytesAvailable, NULL, NULL)) + elog(ERROR, "GetDiskFreeSpaceEx failed: error code %lu", GetLastError()); + + return lpFreeBytesAvailable.QuadPart; /* ULONGLONG part of ULARGE_INTEGER */ +#else + if (statvfs(tblspcPath, &fst) < 0) + { + if (errno == ENOENT) + return -1; + else + ereport(ERROR, + (errcode_for_file_access(), + errmsg("could not statvfs directory \"%s\": %m", tblspcPath))); + } + + return fst.f_bavail * fst.f_frsize; /* available blocks times fragment size */ +#endif +} + +Datum +pg_tablespace_avail_oid(PG_FUNCTION_ARGS) +{ + Oid tblspcOid = PG_GETARG_OID(0); + int64 avail; + + /* + * Not needed for correctness, but avoid non-user-facing error message + * later if the tablespace doesn't exist. + */ + if (!SearchSysCacheExists1(TABLESPACEOID, ObjectIdGetDatum(tblspcOid))) + ereport(ERROR, + errcode(ERRCODE_UNDEFINED_OBJECT), + errmsg("tablespace with OID %u does not exist", tblspcOid)); + + avail = calculate_tablespace_avail(tblspcOid); + + if (avail < 0) + PG_RETURN_NULL(); + + PG_RETURN_INT64(avail); +} + +Datum +pg_tablespace_avail_name(PG_FUNCTION_ARGS) +{ + Name tblspcName = PG_GETARG_NAME(0); + Oid tblspcOid = get_tablespace_oid(NameStr(*tblspcName), false); + int64 avail; + + avail = calculate_tablespace_avail(tblspcOid); + + if (avail < 0) + PG_RETURN_NULL(); + + PG_RETURN_INT64(avail); +} + + /* * calculate size of (one fork of) a relation * diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c index 1d08268393e3..9ddfd1c09d67 100644 --- a/src/bin/psql/describe.c +++ b/src/bin/psql/describe.c @@ -241,10 +241,15 @@ describeTablespaces(const char *pattern, bool verbose) printACLColumn(&buf, "spcacl"); appendPQExpBuffer(&buf, ",\n spcoptions AS \"%s\"" - ",\n pg_catalog.pg_size_pretty(pg_catalog.pg_tablespace_size(oid)) AS \"%s\"" - ",\n pg_catalog.shobj_description(oid, 'pg_tablespace') AS \"%s\"", + ",\n pg_catalog.pg_size_pretty(pg_catalog.pg_tablespace_size(oid)) AS \"%s\"", gettext_noop("Options"), - gettext_noop("Size"), + gettext_noop("Size")); + if (pset.sversion >= 180000) + appendPQExpBuffer(&buf, + ",\n pg_catalog.pg_size_pretty(pg_catalog.pg_tablespace_avail(oid)) AS \"%s\"", + gettext_noop("Free")); + appendPQExpBuffer(&buf, + ",\n pg_catalog.shobj_description(oid, 'pg_tablespace') AS \"%s\"", gettext_noop("Description")); } diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat index 62beb71da288..e157f967e22a 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -7733,6 +7733,14 @@ descr => 'total disk space usage for the specified tablespace', proname => 'pg_tablespace_size', provolatile => 'v', prorettype => 'int8', proargtypes => 'name', prosrc => 'pg_tablespace_size_name' }, +{ oid => '6015', + descr => 'disk stats for the specified tablespace', + proname => 'pg_tablespace_avail', provolatile => 'v', prorettype => 'int8', + proargtypes => 'oid', prosrc => 'pg_tablespace_avail_oid' }, +{ oid => '6016', + descr => 'disk stats for the specified tablespace', + proname => 'pg_tablespace_avail', provolatile => 'v', prorettype => 'int8', + proargtypes => 'name', prosrc => 'pg_tablespace_avail_name' }, { oid => '2324', descr => 'total disk space usage for the specified database', proname => 'pg_database_size', provolatile => 'v', prorettype => 'int8', proargtypes => 'oid', prosrc => 'pg_database_size_oid' }, diff --git a/src/test/regress/expected/tablespace.out b/src/test/regress/expected/tablespace.out index a90e39e57382..6709ed794df1 100644 --- a/src/test/regress/expected/tablespace.out +++ b/src/test/regress/expected/tablespace.out @@ -20,6 +20,27 @@ SELECT spcoptions FROM pg_tablespace WHERE spcname = 'regress_tblspacewith'; {random_page_cost=3.0} (1 row) +-- check size functions +SELECT pg_tablespace_size('pg_default') BETWEEN 1_000_000 and 10_000_000_000, -- rough sanity check + pg_tablespace_size('pg_global') BETWEEN 100_000 and 10_000_000, + pg_tablespace_size('regress_tblspacewith'); -- empty + ?column? | ?column? | pg_tablespace_size +----------+----------+-------------------- + t | t | 0 +(1 row) + +SELECT pg_tablespace_size('missing'); +ERROR: tablespace "missing" does not exist +SELECT pg_tablespace_avail('pg_default') > 1_000_000, + pg_tablespace_avail('pg_global') > 1_000_000, + pg_tablespace_avail('regress_tblspacewith') > 1_000_000; + ?column? | ?column? | ?column? +----------+----------+---------- + t | t | t +(1 row) + +SELECT pg_tablespace_avail('missing'); +ERROR: tablespace "missing" does not exist -- drop the tablespace so we can re-use the location DROP TABLESPACE regress_tblspacewith; -- This returns a relative path as of an effect of allow_in_place_tablespaces, diff --git a/src/test/regress/sql/tablespace.sql b/src/test/regress/sql/tablespace.sql index dfe3db096e28..3fcd4bb00ff6 100644 --- a/src/test/regress/sql/tablespace.sql +++ b/src/test/regress/sql/tablespace.sql @@ -17,6 +17,16 @@ CREATE TABLESPACE regress_tblspacewith LOCATION '' WITH (random_page_cost = 3.0) -- check to see the parameter was used SELECT spcoptions FROM pg_tablespace WHERE spcname = 'regress_tblspacewith'; +-- check size functions +SELECT pg_tablespace_size('pg_default') BETWEEN 1_000_000 and 10_000_000_000, -- rough sanity check + pg_tablespace_size('pg_global') BETWEEN 100_000 and 10_000_000, + pg_tablespace_size('regress_tblspacewith'); -- empty +SELECT pg_tablespace_size('missing'); +SELECT pg_tablespace_avail('pg_default') > 1_000_000, + pg_tablespace_avail('pg_global') > 1_000_000, + pg_tablespace_avail('regress_tblspacewith') > 1_000_000; +SELECT pg_tablespace_avail('missing'); + -- drop the tablespace so we can re-use the location DROP TABLESPACE regress_tblspacewith;