Datum
pg_stat_get_db_tuples_returned(PG_FUNCTION_ARGS)
{
Oid dbid = PG_GETARG_OID(0);
int64 result;
PgStat_StatDBEntry *dbentry;
if ((dbentry = pgstat_fetch_stat_dbentry(dbid)) == NULL)
result = 0;
else
result = (int64) (dbentry->n_tuples_returned);
PG_RETURN_INT64(result);
}
Datum
pg_stat_get_db_conflict_startup_deadlock(PG_FUNCTION_ARGS)
{
Oid dbid = PG_GETARG_OID(0);
int64 result;
PgStat_StatDBEntry *dbentry;
if ((dbentry = pgstat_fetch_stat_dbentry(dbid)) == NULL)
result = 0;
else
result = (int64) (dbentry->n_conflict_startup_deadlock);
PG_RETURN_INT64(result);
}
Datum
pg_stat_get_db_temp_bytes(PG_FUNCTION_ARGS)
{
Oid dbid = PG_GETARG_OID(0);
int64 result;
PgStat_StatDBEntry *dbentry;
if ((dbentry = pgstat_fetch_stat_dbentry(dbid)) == NULL)
result = 0;
else
result = dbentry->n_temp_bytes;
PG_RETURN_INT64(result);
}
Datum
pg_stat_get_db_blk_write_time(PG_FUNCTION_ARGS)
{
Oid dbid = PG_GETARG_OID(0);
double result;
PgStat_StatDBEntry *dbentry;
/* convert counter from microsec to millisec for display */
if ((dbentry = pgstat_fetch_stat_dbentry(dbid)) == NULL)
result = 0;
else
result = ((double) dbentry->n_block_write_time) / 1000.0;
PG_RETURN_FLOAT8(result);
}
Datum
pg_stat_get_db_blocks_hit(PG_FUNCTION_ARGS)
{
PgStat_StatDBEntry *dbentry;
Oid dbid;
int64 result;
dbid = PG_GETARG_OID(0);
if ((dbentry = pgstat_fetch_stat_dbentry(dbid)) == NULL)
result = 0;
else
result = (int64) (dbentry->n_blocks_hit);
PG_RETURN_INT64(result);
}
Datum
pg_stat_get_db_numbackends(PG_FUNCTION_ARGS)
{
PgStat_StatDBEntry *dbentry;
Oid dbid;
int32 result;
dbid = PG_GETARG_OID(0);
if ((dbentry = pgstat_fetch_stat_dbentry(dbid)) == NULL)
result = 0;
else
result = (int32) (dbentry->n_backends);
PG_RETURN_INT32(result);
}
Datum
pg_stat_get_db_stat_reset_time(PG_FUNCTION_ARGS)
{
Oid dbid = PG_GETARG_OID(0);
TimestampTz result;
PgStat_StatDBEntry *dbentry;
if ((dbentry = pgstat_fetch_stat_dbentry(dbid)) == NULL)
result = 0;
else
result = dbentry->stat_reset_timestamp;
if (result == 0)
PG_RETURN_NULL();
else
PG_RETURN_TIMESTAMPTZ(result);
}
/*
* AutoVacMain
*/
NON_EXEC_STATIC void
AutoVacMain(int argc, char *argv[])
{
ListCell *cell;
List *dblist;
autovac_dbase *db;
TransactionId xidForceLimit;
bool for_xid_wrap;
sigjmp_buf local_sigjmp_buf;
/* we are a postmaster subprocess now */
IsUnderPostmaster = true;
am_autovacuum = true;
/* MPP-4990: Autovacuum always runs as utility-mode */
Gp_role = GP_ROLE_UTILITY;
/* reset MyProcPid */
MyProcPid = getpid();
/* record Start Time for logging */
MyStartTime = time(NULL);
/* Identify myself via ps */
init_ps_display("autovacuum process", "", "", "");
SetProcessingMode(InitProcessing);
/*
* If possible, make this process a group leader, so that the postmaster
* can signal any child processes too. (autovacuum probably never has
* any child processes, but for consistency we make all postmaster
* child processes do this.)
*/
#ifdef HAVE_SETSID
if (setsid() < 0)
elog(FATAL, "setsid() failed: %m");
#endif
/*
* Set up signal handlers. We operate on databases much like a regular
* backend, so we use the same signal handling. See equivalent code in
* tcop/postgres.c.
*
* Currently, we don't pay attention to postgresql.conf changes that
* happen during a single daemon iteration, so we can ignore SIGHUP.
*/
pqsignal(SIGHUP, SIG_IGN);
/*
* SIGINT is used to signal cancelling the current table's vacuum; SIGTERM
* means abort and exit cleanly, and SIGQUIT means abandon ship.
*/
pqsignal(SIGINT, StatementCancelHandler);
pqsignal(SIGTERM, die);
pqsignal(SIGQUIT, quickdie);
pqsignal(SIGALRM, handle_sig_alarm);
pqsignal(SIGPIPE, SIG_IGN);
pqsignal(SIGUSR1, procsignal_sigusr1_handler);
/* We don't listen for async notifies */
pqsignal(SIGUSR2, SIG_IGN);
pqsignal(SIGFPE, FloatExceptionHandler);
pqsignal(SIGCHLD, SIG_DFL);
/* Early initialization */
BaseInit();
/*
* Create a per-backend PGPROC struct in shared memory, except in the
* EXEC_BACKEND case where this was done in SubPostmasterMain. We must do
* this before we can use LWLocks (and in the EXEC_BACKEND case we already
* had to do some stuff with LWLocks).
*/
#ifndef EXEC_BACKEND
InitProcess();
#endif
/*
* If an exception is encountered, processing resumes here.
*
* See notes in postgres.c about the design of this coding.
*/
if (sigsetjmp(local_sigjmp_buf, 1) != 0)
{
/* Prevents interrupts while cleaning up */
HOLD_INTERRUPTS();
/* Report the error to the server log */
EmitErrorReport();
/*
* We can now go away. Note that because we called InitProcess, a
* callback was registered to do ProcKill, which will clean up
* necessary state.
*/
proc_exit(0);
}
/* We can now handle ereport(ERROR) */
PG_exception_stack = &local_sigjmp_buf;
PG_SETMASK(&UnBlockSig);
/*
* Force zero_damaged_pages OFF in the autovac process, even if it is set
* in postgresql.conf. We don't really want such a dangerous option being
* applied non-interactively.
*/
SetConfigOption("zero_damaged_pages", "false", PGC_SUSET, PGC_S_OVERRIDE);
/* Get a list of databases */
dblist = autovac_get_database_list();
/*
* Determine the oldest datfrozenxid/relfrozenxid that we will allow
* to pass without forcing a vacuum. (This limit can be tightened for
* particular tables, but not loosened.)
*/
recentXid = ReadNewTransactionId();
xidForceLimit = recentXid - autovacuum_freeze_max_age;
/* ensure it's a "normal" XID, else TransactionIdPrecedes misbehaves */
if (xidForceLimit < FirstNormalTransactionId)
xidForceLimit -= FirstNormalTransactionId;
/*
* Choose a database to connect to. We pick the database that was least
* recently auto-vacuumed, or one that needs vacuuming to prevent Xid
* wraparound-related data loss. If any db at risk of wraparound is
* found, we pick the one with oldest datfrozenxid,
* independently of autovacuum times.
*
* Note that a database with no stats entry is not considered, except for
* Xid wraparound purposes. The theory is that if no one has ever
* connected to it since the stats were last initialized, it doesn't need
* vacuuming.
*
* XXX This could be improved if we had more info about whether it needs
* vacuuming before connecting to it. Perhaps look through the pgstats
* data for the database's tables? One idea is to keep track of the
* number of new and dead tuples per database in pgstats. However it
* isn't clear how to construct a metric that measures that and not cause
* starvation for less busy databases.
*/
db = NULL;
for_xid_wrap = false;
foreach(cell, dblist)
{
autovac_dbase *tmp = lfirst(cell);
/* Find pgstat entry if any */
tmp->entry = pgstat_fetch_stat_dbentry(tmp->oid);
/* Check to see if this one is at risk of wraparound */
if (TransactionIdPrecedes(tmp->frozenxid, xidForceLimit))
{
if (db == NULL ||
TransactionIdPrecedes(tmp->frozenxid, db->frozenxid))
db = tmp;
for_xid_wrap = true;
continue;
}
else if (for_xid_wrap)
continue; /* ignore not-at-risk DBs */
/*
* Otherwise, skip a database with no pgstat entry; it means it
* hasn't seen any activity.
*/
if (!tmp->entry)
continue;
/*
* Remember the db with oldest autovac time. (If we are here,
* both tmp->entry and db->entry must be non-null.)
*/
if (db == NULL ||
tmp->entry->last_autovac_time < db->entry->last_autovac_time)
db = tmp;
}
