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Update vacuumlo to be properly schema-aware. Improve documentation.

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This commit is contained in:
Tom Lane 2003-08-04 22:03:39 +00:00
parent 98bf004421
commit 77489f4523
2 changed files with 31 additions and 20 deletions
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20
contrib/vacuumlo/README.vacuumlo
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@ -1,4 +1,4 @@
$Header: /cvsroot/pgsql/contrib/vacuumlo/Attic/README.vacuumlo,v 1.2 2000/11/21 17:54:21 tgl Exp $
$Header: /cvsroot/pgsql/contrib/vacuumlo/Attic/README.vacuumlo,v 1.3 2003/08/04 22:03:39 tgl Exp $
This is a simple utility that will remove any orphaned large objects out of a
PostgreSQL database. An orphaned LO is considered to be any LO whose OID
@ -14,19 +14,27 @@ Simply run make. A single executable "vacuumlo" is created.
Usage
-----
vacuumlo [-v] database [db2 ... dbn]
vacuumlo [options] database [database2 ... databasen]
The -v flag outputs some progress messages to stdout.
All databases named on the command line are processed. Available options
include:
-v Write a lot of progress messages
-n Don't remove large objects, just show what would be done
-U username Username to connect as
-W Prompt for password
-h hostname Database server host
-p port Database server port
Method
------
First, it builds a temporary table which contains all of the oid's of the
First, it builds a temporary table which contains all of the OIDs of the
large objects in that database.
It then scans through all columns in the database that are of type 'oid',
and removes any matching entries from the temporary table.
It then scans through all columns in the database that are of type "oid"
or "lo", and removes matching entries from the temporary table.
The remaining entries in the temp table identify orphaned LOs. These are
removed.

31
contrib/vacuumlo/vacuumlo.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/contrib/vacuumlo/vacuumlo.c,v 1.21 2003/08/04 02:39:56 momjian Exp $
* $Header: /cvsroot/pgsql/contrib/vacuumlo/vacuumlo.c,v 1.22 2003/08/04 22:03:39 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -256,8 +256,9 @@ vacuumlo(char *database, struct _param * param)
/*
* Now find any candidate tables who have columns of type oid.
*
* NOTE: the temp table formed above is ignored, because its real table
* name will be pg_something. Also, pg_largeobject will be ignored.
* NOTE: we ignore system tables and temp tables by the expedient of
* rejecting tables in schemas named 'pg_*'. In particular, the temp
* table formed above is ignored, and pg_largeobject will be too.
* If either of these were scanned, obviously we'd end up with nothing
* to delete...
*
@ -266,14 +267,14 @@ vacuumlo(char *database, struct _param * param)
*/
buf[0] = '\0';
strcat(buf, "SELECT c.relname, a.attname ");
strcat(buf, "FROM pg_class c, pg_attribute a, pg_type t ");
strcat(buf, "FROM pg_class c, pg_attribute a, pg_namespace s, pg_type t ");
strcat(buf, "WHERE a.attnum > 0 ");
strcat(buf, " AND a.attrelid = c.oid ");
strcat(buf, " AND a.atttypid = t.oid ");
strcat(buf, " AND c.relnamespace = s.oid ");
strcat(buf, " AND t.typname in ('oid', 'lo') ");
strcat(buf, " AND c.relkind = 'r'");
strcat(buf, " AND c.relname NOT LIKE 'pg_%'");
strcat(buf, " AND c.relname != 'vacuum_l'");
strcat(buf, " AND s.nspname NOT LIKE 'pg\\\\_%'");
res = PQexec(conn, buf);
if (PQresultStatus(res) != PGRES_TUPLES_OK)
{
@ -296,12 +297,14 @@ vacuumlo(char *database, struct _param * param)
fprintf(stdout, "Checking %s in %s\n", field, table);
/*
* We use a DELETE with implicit join for efficiency. This is a
* Postgres-ism and not portable to other DBMSs, but then this
* whole program is a Postgres-ism.
* The "IN" construct used here was horribly inefficient before
* Postgres 7.4, but should be now competitive if not better than
* the bogus join we used before.
*/
snprintf(buf, BUFSIZE, "DELETE FROM vacuum_l WHERE lo = \"%s\".\"%s\" ",
table, field);
snprintf(buf, BUFSIZE,
"DELETE FROM vacuum_l "
"WHERE lo IN (SELECT \"%s\" FROM \"%s\")",
field, table);
res2 = PQexec(conn, buf);
if (PQresultStatus(res2) != PGRES_COMMAND_OK)
{
@ -388,10 +391,10 @@ void
usage(void)
{
fprintf(stdout, "vacuumlo removes unreferenced large objects from databases\n\n");
fprintf(stdout, "Usage:\n vacuumlo [options] dbname [dbnames...]\n\n");
fprintf(stdout, "Usage:\n vacuumlo [options] dbname [dbname ...]\n\n");
fprintf(stdout, "Options:\n");
fprintf(stdout, " -v\t\tWrite a lot of output\n");
fprintf(stdout, " -n\t\tDon't remove any large object, just show what would be done\n");
fprintf(stdout, " -v\t\tWrite a lot of progress messages\n");
fprintf(stdout, " -n\t\tDon't remove large objects, just show what would be done\n");
fprintf(stdout, " -U username\tUsername to connect as\n");
fprintf(stdout, " -W\t\tPrompt for password\n");
fprintf(stdout, " -h hostname\tDatabase server host\n");