postgresql/contrib/vacuumlo/vacuumlo.c
Robert Haas b69f2e3640 Teach vacuumlo to limit number of removals, via new -l option.
Also, handle failure better: don't just blindly keep trying to delete
stuff after the transaction has already failed.

Tim Lewis, reviewed by Josh Kupershmidt, with further hacking by me.
2011-08-08 09:16:45 -04:00

451 lines
10 KiB
C

/*-------------------------------------------------------------------------
*
* vacuumlo.c
* This removes orphaned large objects from a database.
*
* Portions Copyright (c) 1996-2011, 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"
#include "libpq/libpq-fs.h"
#define atooid(x) ((Oid) strtoul((x), NULL, 10))
#define BUFSIZE 1024
extern char *optarg;
extern int optind,
opterr,
optopt;
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;
};
int vacuumlo(char *, struct _param *);
void usage(const char *progname);
/*
* This vacuums LOs of one database. It returns 0 on success, -1 on failure.
*/
int
vacuumlo(char *database, 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;
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 %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);
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);
}
PQclear(res);
/*
* Run the actual deletes in a single transaction. Note that this would
* be a bad idea in pre-7.1 Postgres releases (since rolling back a table
* delete used to cause problems), but it should be safe now.
*/
res = PQexec(conn, "begin");
PQclear(res);
/*
* Finally, those entries remaining in vacuum_l are orphans.
*/
buf[0] = '\0';
strcat(buf, "SELECT lo ");
strcat(buf, "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)
break;
}
PQclear(res);
/*
* That's all folks!
*/
res = PQexec(conn, "end");
PQclear(res);
PQfinish(conn);
if (param->verbose)
{
if (param->dry_run)
fprintf(stdout, "\rWould remove %ld large objects from %s.\n",
deleted, database);
else if (success)
fprintf(stdout,
"\rSuccessfully removed %ld large objects from %s.\n",
deleted, database);
else
fprintf(stdout, "\rRemoval from %s failed at object %ld of %ld.\n",
database, deleted, matched);
}
return ((param->dry_run || success) ? 0 : -1);
}
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 stop after removing 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]);
/* Parameter handling */
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 = 0;
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 '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 '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 '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 'vacuumlo -?' for help.\n");
exit(1);
}
for (c = optind; c < argc; c++)
{
/* Work on selected database */
rc += (vacuumlo(argv[c], &param) != 0);
}
return rc;
}