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Use setitimer() for stats file write, rather than do a gettimeofday()

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call for every stats packet read to adjust select() timeout.  Other
stylistic improvements.
This commit is contained in:
Bruce Momjian 2006-01-03 16:42:17 +00:00
parent fd924b2988
commit 447450df71
1 changed files with 39 additions and 76 deletions
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115
src/backend/postmaster/pgstat.c
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@ -13,7 +13,7 @@
*
* Copyright (c) 2001-2005, PostgreSQL Global Development Group
*
* $PostgreSQL: pgsql/src/backend/postmaster/pgstat.c,v 1.116 2006/01/02 00:58:00 momjian Exp $
* $PostgreSQL: pgsql/src/backend/postmaster/pgstat.c,v 1.117 2006/01/03 16:42:17 momjian Exp $
* ----------
*/
#include "postgres.h"
@ -117,7 +117,7 @@ static time_t last_pgstat_start_time;
static long pgStatNumMessages = 0;
static bool pgStatRunningInCollector = FALSE;
static bool pgStatRunningInCollector = false;
/*
* Place where backends store per-table info to be sent to the collector.
@ -145,6 +145,7 @@ static HTAB *pgStatBeDead = NULL;
static PgStat_StatBeEntry *pgStatBeTable = NULL;
static int pgStatNumBackends = 0;
static volatile bool need_statwrite;
/* ----------
* Local function forward declarations
@ -164,6 +165,7 @@ static void pgstat_parseArgs(int argc, char *argv[]);
NON_EXEC_STATIC void PgstatBufferMain(int argc, char *argv[]);
NON_EXEC_STATIC void PgstatCollectorMain(int argc, char *argv[]);
static void force_statwrite(SIGNAL_ARGS);
static void pgstat_recvbuffer(void);
static void pgstat_exit(SIGNAL_ARGS);
static void pgstat_die(SIGNAL_ARGS);
@ -1548,13 +1550,11 @@ PgstatCollectorMain(int argc, char *argv[])
PgStat_Msg msg;
fd_set rfds;
int readPipe;
int nready;
int len = 0;
struct timeval timeout;
struct timeval next_statwrite;
bool need_statwrite;
struct itimerval timeval;
HASHCTL hash_ctl;
bool need_timer = false;
MyProcPid = getpid(); /* reset MyProcPid */
/*
@ -1572,7 +1572,7 @@ PgstatCollectorMain(int argc, char *argv[])
/* kluge to allow buffer process to kill collector; FIXME */
pqsignal(SIGQUIT, pgstat_exit);
#endif
pqsignal(SIGALRM, SIG_IGN);
pqsignal(SIGALRM, force_statwrite);
pqsignal(SIGPIPE, SIG_IGN);
pqsignal(SIGUSR1, SIG_IGN);
pqsignal(SIGUSR2, SIG_IGN);
@ -1597,17 +1597,17 @@ PgstatCollectorMain(int argc, char *argv[])
init_ps_display("stats collector process", "", "");
set_ps_display("");
/*
* Arrange to write the initial status file right away
*/
gettimeofday(&next_statwrite, NULL);
need_statwrite = TRUE;
need_statwrite = true;
MemSet(&timeval, 0, sizeof(struct itimerval));
timeval.it_value.tv_sec = PGSTAT_STAT_INTERVAL / 1000;
timeval.it_value.tv_usec = PGSTAT_STAT_INTERVAL % 1000;
/*
* Read in an existing statistics stats file or initialize the stats to
* zero.
*/
pgStatRunningInCollector = TRUE;
pgStatRunningInCollector = true;
pgstat_read_statsfile(&pgStatDBHash, InvalidOid, NULL, NULL);
/*
@ -1634,34 +1634,11 @@ PgstatCollectorMain(int argc, char *argv[])
*/
for (;;)
{
/*
* If we need to write the status file again (there have been changes
* in the statistics since we wrote it last) calculate the timeout
* until we have to do so.
*/
if (need_statwrite)
{
struct timeval now;
gettimeofday(&now, NULL);
/* avoid assuming that tv_sec is signed */
if (now.tv_sec > next_statwrite.tv_sec ||
(now.tv_sec == next_statwrite.tv_sec &&
now.tv_usec >= next_statwrite.tv_usec))
{
timeout.tv_sec = 0;
timeout.tv_usec = 0;
}
else
{
timeout.tv_sec = next_statwrite.tv_sec - now.tv_sec;
timeout.tv_usec = next_statwrite.tv_usec - now.tv_usec;
if (timeout.tv_usec < 0)
{
timeout.tv_sec--;
timeout.tv_usec += 1000000;
}
}
pgstat_write_statsfile();
need_statwrite = false;
need_timer = true;
}
/*
@ -1673,9 +1650,7 @@ PgstatCollectorMain(int argc, char *argv[])
/*
* Now wait for something to do.
*/
nready = select(readPipe + 1, &rfds, NULL, NULL,
(need_statwrite) ? &timeout : NULL);
if (nready < 0)
if (select(readPipe + 1, &rfds, NULL, NULL, NULL) < 0)
{
if (errno == EINTR)
continue;
@ -1684,18 +1659,6 @@ PgstatCollectorMain(int argc, char *argv[])
errmsg("select() failed in statistics collector: %m")));
}
/*
* If there are no descriptors ready, our timeout for writing the
* stats file happened.
*/
if (nready == 0)
{
pgstat_write_statsfile();
need_statwrite = FALSE;
continue;
}
/*
* Check if there is a new statistics message to collect.
*/
@ -1813,17 +1776,12 @@ PgstatCollectorMain(int argc, char *argv[])
*/
pgStatNumMessages++;
/*
* If this is the first message after we wrote the stats file the
* last time, setup the timeout that it'd be written.
*/
if (!need_statwrite)
if (need_timer)
{
gettimeofday(&next_statwrite, NULL);
next_statwrite.tv_usec += ((PGSTAT_STAT_INTERVAL) * 1000);
next_statwrite.tv_sec += (next_statwrite.tv_usec / 1000000);
next_statwrite.tv_usec %= 1000000;
need_statwrite = TRUE;
if (setitimer(ITIMER_REAL, &timeval, NULL))
ereport(ERROR,
(errmsg("unable to set statistics collector timer: %m")));
need_timer = false;
}
}
@ -1848,6 +1806,13 @@ PgstatCollectorMain(int argc, char *argv[])
}
static void
force_statwrite(SIGNAL_ARGS)
{
need_statwrite = true;
}
/* ----------
* pgstat_recvbuffer() -
*
@ -1865,7 +1830,6 @@ pgstat_recvbuffer(void)
struct timeval timeout;
int writePipe = pgStatPipe[1];
int maxfd;
int nready;
int len;
int xfr;
int frm;
@ -1906,6 +1870,14 @@ pgstat_recvbuffer(void)
*/
msgbuffer = (char *) palloc(PGSTAT_RECVBUFFERSZ);
/*
* Wait for some work to do; but not for more than 10 seconds. (This
* determines how quickly we will shut down after an ungraceful
* postmaster termination; so it needn't be very fast.)
*/
timeout.tv_sec = 10;
timeout.tv_usec = 0;
/*
* Loop forever
*/
@ -1946,16 +1918,7 @@ pgstat_recvbuffer(void)
maxfd = writePipe;
}
/*
* Wait for some work to do; but not for more than 10 seconds. (This
* determines how quickly we will shut down after an ungraceful
* postmaster termination; so it needn't be very fast.)
*/
timeout.tv_sec = 10;
timeout.tv_usec = 0;
nready = select(maxfd + 1, &rfds, &wfds, NULL, &timeout);
if (nready < 0)
if (select(maxfd + 1, &rfds, &wfds, NULL, &timeout) < 0)
{
if (errno == EINTR)
continue;