From db42fdcc5ee3097b3364ec51602d6d58994b2060 Mon Sep 17 00:00:00 2001 From: Christoph Berg Date: Fri, 14 Mar 2025 16:29:19 +0100 Subject: [PATCH v4] 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 51dd8ad6571..0b4456ad958 100644 --- a/doc/src/sgml/func.sgml +++ b/doc/src/sgml/func.sgml @@ -30093,6 +30093,27 @@ 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 cedccc14129..9e1bec0b422 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 25865b660ef..9bd8667c2d9 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 e6cf468ac9e..8c52a126ac1 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 42e427f8fe8..9d64da6bfb8 100644 --- a/src/include/catalog/pg_proc.dat +++ b/src/include/catalog/pg_proc.dat @@ -7680,6 +7680,14 @@ 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 a90e39e5738..6709ed794df 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 dfe3db096e2..3fcd4bb00ff 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; -- 2.47.2