postgresql/contrib/vacuumlo/vacuumlo.c
Tom Lane 64c604898e Improve the -l (limit) option recently added to contrib/vacuumlo.
Instead of just stopping after removing an arbitrary subset of orphaned
large objects, commit and start a new transaction after each -l objects.
This is just as effective as the original patch at limiting the number of
locks used, and it doesn't require doing the OID collection process
repeatedly to get everything.  Since the option no longer changes the
fundamental behavior of vacuumlo, and it avoids a known server-side
limitation, enable it by default (with a default limit of 1000 LOs per
transaction).

In passing, be more careful about properly quoting the names of tables
and fields, and do some other cosmetic cleanup.
2012-03-20 19:05:44 -04:00

507 lines
12 KiB
C

/*-------------------------------------------------------------------------
*
* vacuumlo.c
* This removes orphaned large objects from a database.
*
* Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* contrib/vacuumlo/vacuumlo.c
*
*-------------------------------------------------------------------------
*/
#include "postgres_fe.h"
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#ifdef HAVE_TERMIOS_H
#include <termios.h>
#endif
#include "libpq-fe.h"
#define atooid(x) ((Oid) strtoul((x), NULL, 10))
#define BUFSIZE 1024
extern char *optarg;
extern int optind,
opterr;
enum trivalue
{
TRI_DEFAULT,
TRI_NO,
TRI_YES
};
struct _param
{
char *pg_user;
enum trivalue pg_prompt;
char *pg_port;
char *pg_host;
int verbose;
int dry_run;
long transaction_limit;
};
static int vacuumlo(const char *database, const struct _param * param);
static void usage(const char *progname);
/*
* This vacuums LOs of one database. It returns 0 on success, -1 on failure.
*/
static int
vacuumlo(const char *database, const struct _param * param)
{
PGconn *conn;
PGresult *res,
*res2;
char buf[BUFSIZE];
long matched;
long deleted;
int i;
static char *password = NULL;
bool new_pass;
bool success = true;
/* Note: password can be carried over from a previous call */
if (param->pg_prompt == TRI_YES && password == NULL)
password = simple_prompt("Password: ", 100, false);
/*
* Start the connection. Loop until we have a password if requested by
* backend.
*/
do
{
new_pass = false;
conn = PQsetdbLogin(param->pg_host,
param->pg_port,
NULL,
NULL,
database,
param->pg_user,
password);
if (!conn)
{
fprintf(stderr, "Connection to database \"%s\" failed\n",
database);
return -1;
}
if (PQstatus(conn) == CONNECTION_BAD &&
PQconnectionNeedsPassword(conn) &&
password == NULL &&
param->pg_prompt != TRI_NO)
{
PQfinish(conn);
password = simple_prompt("Password: ", 100, false);
new_pass = true;
}
} while (new_pass);
/* check to see that the backend connection was successfully made */
if (PQstatus(conn) == CONNECTION_BAD)
{
fprintf(stderr, "Connection to database \"%s\" failed:\n%s",
database, PQerrorMessage(conn));
PQfinish(conn);
return -1;
}
if (param->verbose)
{
fprintf(stdout, "Connected to database \"%s\"\n", database);
if (param->dry_run)
fprintf(stdout, "Test run: no large objects will be removed!\n");
}
/*
* Don't get fooled by any non-system catalogs
*/
res = PQexec(conn, "SET search_path = pg_catalog");
if (PQresultStatus(res) != PGRES_COMMAND_OK)
{
fprintf(stderr, "Failed to set search_path:\n");
fprintf(stderr, "%s", PQerrorMessage(conn));
PQclear(res);
PQfinish(conn);
return -1;
}
PQclear(res);
/*
* First we create and populate the LO temp table
*/
buf[0] = '\0';
strcat(buf, "CREATE TEMP TABLE vacuum_l AS ");
if (PQserverVersion(conn) >= 90000)
strcat(buf, "SELECT oid AS lo FROM pg_largeobject_metadata");
else
strcat(buf, "SELECT DISTINCT loid AS lo FROM pg_largeobject");
res = PQexec(conn, buf);
if (PQresultStatus(res) != PGRES_COMMAND_OK)
{
fprintf(stderr, "Failed to create temp table:\n");
fprintf(stderr, "%s", PQerrorMessage(conn));
PQclear(res);
PQfinish(conn);
return -1;
}
PQclear(res);
/*
* Analyze the temp table so that planner will generate decent plans for
* the DELETEs below.
*/
buf[0] = '\0';
strcat(buf, "ANALYZE vacuum_l");
res = PQexec(conn, buf);
if (PQresultStatus(res) != PGRES_COMMAND_OK)
{
fprintf(stderr, "Failed to vacuum temp table:\n");
fprintf(stderr, "%s", PQerrorMessage(conn));
PQclear(res);
PQfinish(conn);
return -1;
}
PQclear(res);
/*
* Now find any candidate tables that have columns of type oid.
*
* 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...
*
* NOTE: the system oid column is ignored, as it has attnum < 1. This
* shouldn't matter for correctness, but it saves time.
*/
buf[0] = '\0';
strcat(buf, "SELECT s.nspname, c.relname, a.attname ");
strcat(buf, "FROM pg_class c, pg_attribute a, pg_namespace s, pg_type t ");
strcat(buf, "WHERE a.attnum > 0 AND NOT a.attisdropped ");
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 s.nspname !~ '^pg_'");
res = PQexec(conn, buf);
if (PQresultStatus(res) != PGRES_TUPLES_OK)
{
fprintf(stderr, "Failed to find OID columns:\n");
fprintf(stderr, "%s", PQerrorMessage(conn));
PQclear(res);
PQfinish(conn);
return -1;
}
for (i = 0; i < PQntuples(res); i++)
{
char *schema,
*table,
*field;
schema = PQgetvalue(res, i, 0);
table = PQgetvalue(res, i, 1);
field = PQgetvalue(res, i, 2);
if (param->verbose)
fprintf(stdout, "Checking %s in %s.%s\n", field, schema, table);
schema = PQescapeIdentifier(conn, schema, strlen(schema));
table = PQescapeIdentifier(conn, table, strlen(table));
field = PQescapeIdentifier(conn, field, strlen(field));
if (!schema || !table || !field)
{
fprintf(stderr, "Out of memory\n");
PQclear(res);
PQfinish(conn);
return -1;
}
snprintf(buf, BUFSIZE,
"DELETE FROM vacuum_l "
"WHERE lo IN (SELECT %s FROM %s.%s)",
field, schema, table);
res2 = PQexec(conn, buf);
if (PQresultStatus(res2) != PGRES_COMMAND_OK)
{
fprintf(stderr, "Failed to check %s in table %s.%s:\n",
field, schema, table);
fprintf(stderr, "%s", PQerrorMessage(conn));
PQclear(res2);
PQclear(res);
PQfinish(conn);
return -1;
}
PQclear(res2);
PQfreemem(schema);
PQfreemem(table);
PQfreemem(field);
}
PQclear(res);
/*
* Now, those entries remaining in vacuum_l are orphans. Delete 'em.
*
* We don't want to run each delete as an individual transaction, because
* the commit overhead would be high. However, since 9.0 the backend will
* acquire a lock per deleted LO, so deleting too many LOs per transaction
* risks running out of room in the shared-memory lock table.
* Accordingly, we delete up to transaction_limit LOs per transaction.
*/
res = PQexec(conn, "begin");
if (PQresultStatus(res) != PGRES_COMMAND_OK)
{
fprintf(stderr, "Failed to start transaction:\n");
fprintf(stderr, "%s", PQerrorMessage(conn));
PQclear(res);
PQfinish(conn);
return -1;
}
PQclear(res);
buf[0] = '\0';
strcat(buf, "SELECT lo FROM vacuum_l");
res = PQexec(conn, buf);
if (PQresultStatus(res) != PGRES_TUPLES_OK)
{
fprintf(stderr, "Failed to read temp table:\n");
fprintf(stderr, "%s", PQerrorMessage(conn));
PQclear(res);
PQfinish(conn);
return -1;
}
matched = PQntuples(res);
deleted = 0;
for (i = 0; i < matched; i++)
{
Oid lo = atooid(PQgetvalue(res, i, 0));
if (param->verbose)
{
fprintf(stdout, "\rRemoving lo %6u ", lo);
fflush(stdout);
}
if (param->dry_run == 0)
{
if (lo_unlink(conn, lo) < 0)
{
fprintf(stderr, "\nFailed to remove lo %u: ", lo);
fprintf(stderr, "%s", PQerrorMessage(conn));
if (PQtransactionStatus(conn) == PQTRANS_INERROR)
{
success = false;
break;
}
}
else
deleted++;
}
else
deleted++;
if (param->transaction_limit > 0 &&
(deleted % param->transaction_limit) == 0)
{
res2 = PQexec(conn, "commit");
if (PQresultStatus(res2) != PGRES_COMMAND_OK)
{
fprintf(stderr, "Failed to commit transaction:\n");
fprintf(stderr, "%s", PQerrorMessage(conn));
PQclear(res2);
PQclear(res);
PQfinish(conn);
return -1;
}
PQclear(res2);
res2 = PQexec(conn, "begin");
if (PQresultStatus(res2) != PGRES_COMMAND_OK)
{
fprintf(stderr, "Failed to start transaction:\n");
fprintf(stderr, "%s", PQerrorMessage(conn));
PQclear(res2);
PQclear(res);
PQfinish(conn);
return -1;
}
PQclear(res2);
}
}
PQclear(res);
/*
* That's all folks!
*/
res = PQexec(conn, "commit");
if (PQresultStatus(res) != PGRES_COMMAND_OK)
{
fprintf(stderr, "Failed to commit transaction:\n");
fprintf(stderr, "%s", PQerrorMessage(conn));
PQclear(res);
PQfinish(conn);
return -1;
}
PQclear(res);
PQfinish(conn);
if (param->verbose)
{
if (param->dry_run)
fprintf(stdout, "\rWould remove %ld large objects from database \"%s\".\n",
deleted, database);
else if (success)
fprintf(stdout,
"\rSuccessfully removed %ld large objects from database \"%s\".\n",
deleted, database);
else
fprintf(stdout, "\rRemoval from database \"%s\" failed at object %ld of %ld.\n",
database, deleted, matched);
}
return ((param->dry_run || success) ? 0 : -1);
}
static void
usage(const char *progname)
{
printf("%s removes unreferenced large objects from databases.\n\n", progname);
printf("Usage:\n %s [OPTION]... DBNAME...\n\n", progname);
printf("Options:\n");
printf(" -h HOSTNAME database server host or socket directory\n");
printf(" -l LIMIT commit after removing each LIMIT large objects\n");
printf(" -n don't remove large objects, just show what would be done\n");
printf(" -p PORT database server port\n");
printf(" -U USERNAME user name to connect as\n");
printf(" -w never prompt for password\n");
printf(" -W force password prompt\n");
printf(" -v write a lot of progress messages\n");
printf(" --help show this help, then exit\n");
printf(" --version output version information, then exit\n");
printf("\n");
printf("Report bugs to <pgsql-bugs@postgresql.org>.\n");
}
int
main(int argc, char **argv)
{
int rc = 0;
struct _param param;
int c;
int port;
const char *progname;
progname = get_progname(argv[0]);
/* Set default parameter values */
param.pg_user = NULL;
param.pg_prompt = TRI_DEFAULT;
param.pg_host = NULL;
param.pg_port = NULL;
param.verbose = 0;
param.dry_run = 0;
param.transaction_limit = 1000;
/* Process command-line arguments */
if (argc > 1)
{
if (strcmp(argv[1], "--help") == 0 || strcmp(argv[1], "-?") == 0)
{
usage(progname);
exit(0);
}
if (strcmp(argv[1], "--version") == 0 || strcmp(argv[1], "-V") == 0)
{
puts("vacuumlo (PostgreSQL) " PG_VERSION);
exit(0);
}
}
while (1)
{
c = getopt(argc, argv, "h:l:U:p:vnwW");
if (c == -1)
break;
switch (c)
{
case '?':
fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
exit(1);
case ':':
exit(1);
case 'v':
param.verbose = 1;
break;
case 'n':
param.dry_run = 1;
param.verbose = 1;
break;
case 'l':
param.transaction_limit = strtol(optarg, NULL, 10);
if (param.transaction_limit < 0)
{
fprintf(stderr,
"%s: transaction limit must not be negative (0 disables)\n",
progname);
exit(1);
}
break;
case 'U':
param.pg_user = strdup(optarg);
break;
case 'w':
param.pg_prompt = TRI_NO;
break;
case 'W':
param.pg_prompt = TRI_YES;
break;
case 'p':
port = strtol(optarg, NULL, 10);
if ((port < 1) || (port > 65535))
{
fprintf(stderr, "%s: invalid port number: %s\n", progname, optarg);
exit(1);
}
param.pg_port = strdup(optarg);
break;
case 'h':
param.pg_host = strdup(optarg);
break;
}
}
/* No database given? Show usage */
if (optind >= argc)
{
fprintf(stderr, "vacuumlo: missing required argument: database name\n");
fprintf(stderr, _("Try \"%s --help\" for more information.\n"), progname);
exit(1);
}
for (c = optind; c < argc; c++)
{
/* Work on selected database */
rc += (vacuumlo(argv[c], &param) != 0);
}
return rc;
}