diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/postmaster/pgstat.c | 244 | ||||
| -rw-r--r-- | src/include/pgstat.h | 20 |
2 files changed, 203 insertions, 61 deletions
diff --git a/src/backend/postmaster/pgstat.c b/src/backend/postmaster/pgstat.c index 990b10e8ff4..d3455cee192 100644 --- a/src/backend/postmaster/pgstat.c +++ b/src/backend/postmaster/pgstat.c @@ -13,7 +13,7 @@ * * Copyright (c) 2001-2008, PostgreSQL Global Development Group * - * $PostgreSQL: pgsql/src/backend/postmaster/pgstat.c,v 1.181 2008/08/25 18:55:43 mha Exp $ + * $PostgreSQL: pgsql/src/backend/postmaster/pgstat.c,v 1.182 2008/11/03 01:17:08 tgl Exp $ * ---------- */ #include "postgres.h" @@ -75,8 +75,14 @@ * Timer definitions. * ---------- */ -#define PGSTAT_STAT_INTERVAL 500 /* How often to write the status file; - * in milliseconds. */ +#define PGSTAT_STAT_INTERVAL 500 /* Minimum time between stats file + * updates; in milliseconds. */ + +#define PGSTAT_RETRY_DELAY 10 /* How long to wait between statistics + * update requests; in milliseconds. */ + +#define PGSTAT_MAX_WAIT_TIME 5000 /* Maximum time to wait for a stats + * file update; in milliseconds. */ #define PGSTAT_RESTART_INTERVAL 60 /* How often to attempt to restart a * failed statistics collector; in @@ -85,6 +91,8 @@ #define PGSTAT_SELECT_TIMEOUT 2 /* How often to check for postmaster * death; in seconds. */ +#define PGSTAT_POLL_LOOP_COUNT (PGSTAT_MAX_WAIT_TIME / PGSTAT_RETRY_DELAY) + /* ---------- * The initial size hints for the hash tables used in the collector. @@ -159,6 +167,12 @@ static TabStatusArray *pgStatTabList = NULL; static HTAB *pgStatFunctions = NULL; /* + * Indicates if backend has some function stats that it hasn't yet + * sent to the collector. + */ +static bool have_function_stats = false; + +/* * Tuple insertion/deletion counts for an open transaction can't be propagated * into PgStat_TableStatus counters until we know if it is going to commit * or abort. Hence, we keep these counts in per-subxact structs that live @@ -201,8 +215,12 @@ static int localNumBackends = 0; */ static PgStat_GlobalStats globalStats; +/* Last time the collector successfully wrote the stats file */ +static TimestampTz last_statwrite; +/* Latest statistics request time from backends */ +static TimestampTz last_statrequest; + static volatile bool need_exit = false; -static volatile bool need_statwrite = false; static volatile bool got_SIGHUP = false; /* @@ -223,7 +241,6 @@ static pid_t pgstat_forkexec(void); NON_EXEC_STATIC void PgstatCollectorMain(int argc, char *argv[]); static void pgstat_exit(SIGNAL_ARGS); -static void force_statwrite(SIGNAL_ARGS); static void pgstat_beshutdown_hook(int code, Datum arg); static void pgstat_sighup_handler(SIGNAL_ARGS); @@ -244,6 +261,7 @@ static void pgstat_setup_memcxt(void); static void pgstat_setheader(PgStat_MsgHdr *hdr, StatMsgType mtype); static void pgstat_send(void *msg, int len); +static void pgstat_recv_inquiry(PgStat_MsgInquiry *msg, int len); static void pgstat_recv_tabstat(PgStat_MsgTabstat *msg, int len); static void pgstat_recv_tabpurge(PgStat_MsgTabpurge *msg, int len); static void pgstat_recv_dropdb(PgStat_MsgDropdb *msg, int len); @@ -655,9 +673,8 @@ pgstat_report_stat(bool force) int i; /* Don't expend a clock check if nothing to do */ - /* Note: we ignore pending function stats in this test ... OK? */ - if (pgStatTabList == NULL || - pgStatTabList->tsa_used == 0) + if ((pgStatTabList == NULL || pgStatTabList->tsa_used == 0) + && !have_function_stats) return; /* @@ -823,6 +840,8 @@ pgstat_send_funcstats(void) if (msg.m_nentries > 0) pgstat_send(&msg, offsetof(PgStat_MsgFuncstat, m_entry[0]) + msg.m_nentries * sizeof(PgStat_FunctionEntry)); + + have_function_stats = false; } @@ -1242,6 +1261,24 @@ pgstat_ping(void) pgstat_send(&msg, sizeof(msg)); } +/* ---------- + * pgstat_send_inquiry() - + * + * Notify collector that we need fresh data. + * ts specifies the minimum acceptable timestamp for the stats file. + * ---------- + */ +static void +pgstat_send_inquiry(TimestampTz ts) +{ + PgStat_MsgInquiry msg; + + pgstat_setheader(&msg.m_hdr, PGSTAT_MTYPE_INQUIRY); + msg.inquiry_time = ts; + pgstat_send(&msg, sizeof(msg)); +} + + /* * Initialize function call usage data. * Called by the executor before invoking a function. @@ -1341,6 +1378,9 @@ pgstat_end_function_usage(PgStat_FunctionCallUsage *fcu, bool finalize) fs->f_numcalls++; fs->f_time = f_total; INSTR_TIME_ADD(fs->f_time_self, f_self); + + /* indicate that we have something to send */ + have_function_stats = true; } @@ -2538,8 +2578,6 @@ pgstat_send_bgwriter(void) NON_EXEC_STATIC void PgstatCollectorMain(int argc, char *argv[]) { - struct itimerval write_timeout; - bool need_timer = false; int len; PgStat_Msg msg; @@ -2571,13 +2609,13 @@ PgstatCollectorMain(int argc, char *argv[]) /* * Ignore all signals usually bound to some action in the postmaster, - * except SIGQUIT and SIGALRM. + * except SIGQUIT. */ pqsignal(SIGHUP, pgstat_sighup_handler); pqsignal(SIGINT, SIG_IGN); pqsignal(SIGTERM, SIG_IGN); pqsignal(SIGQUIT, pgstat_exit); - pqsignal(SIGALRM, force_statwrite); + pqsignal(SIGALRM, SIG_IGN); pqsignal(SIGPIPE, SIG_IGN); pqsignal(SIGUSR1, SIG_IGN); pqsignal(SIGUSR2, SIG_IGN); @@ -2596,12 +2634,8 @@ PgstatCollectorMain(int argc, char *argv[]) /* * Arrange to write the initial status file right away */ - need_statwrite = true; - - /* Preset the delay between status file writes */ - MemSet(&write_timeout, 0, sizeof(struct itimerval)); - write_timeout.it_value.tv_sec = PGSTAT_STAT_INTERVAL / 1000; - write_timeout.it_value.tv_usec = (PGSTAT_STAT_INTERVAL % 1000) * 1000; + last_statrequest = GetCurrentTimestamp(); + last_statwrite = last_statrequest - 1; /* * Read in an existing statistics stats file or initialize the stats to @@ -2623,8 +2657,9 @@ PgstatCollectorMain(int argc, char *argv[]) * death of our parent postmaster. * * For performance reasons, we don't want to do a PostmasterIsAlive() test - * after every message; instead, do it at statwrite time and if - * select()/poll() is interrupted by timeout. + * after every message; instead, do it only when select()/poll() is + * interrupted by timeout. In essence, we'll stay alive as long as + * backends keep sending us stuff often, even if the postmaster is gone. */ for (;;) { @@ -2638,32 +2673,19 @@ PgstatCollectorMain(int argc, char *argv[]) /* * Reload configuration if we got SIGHUP from the postmaster. - * Also, signal a new write of the file, so we drop a new file as - * soon as possible of the directory for it changes. */ if (got_SIGHUP) { ProcessConfigFile(PGC_SIGHUP); got_SIGHUP = false; - need_statwrite = true; } /* - * If time to write the stats file, do so. Note that the alarm - * interrupt isn't re-enabled immediately, but only after we next - * receive a stats message; so no cycles are wasted when there is - * nothing going on. + * Write the stats file if a new request has arrived that is not + * satisfied by existing file. */ - if (need_statwrite) - { - /* Check for postmaster death; if so we'll write file below */ - if (!PostmasterIsAlive(true)) - break; - + if (last_statwrite < last_statrequest) pgstat_write_statsfile(false); - need_statwrite = false; - need_timer = true; - } /* * Wait for a message to arrive; but not for more than @@ -2756,6 +2778,10 @@ PgstatCollectorMain(int argc, char *argv[]) case PGSTAT_MTYPE_DUMMY: break; + case PGSTAT_MTYPE_INQUIRY: + pgstat_recv_inquiry((PgStat_MsgInquiry *) &msg, len); + break; + case PGSTAT_MTYPE_TABSTAT: pgstat_recv_tabstat((PgStat_MsgTabstat *) &msg, len); break; @@ -2800,19 +2826,6 @@ PgstatCollectorMain(int argc, char *argv[]) default: break; } - - /* - * If this is the first message after we wrote the stats file the - * last time, enable the alarm interrupt to make it be written - * again later. - */ - if (need_timer) - { - if (setitimer(ITIMER_REAL, &write_timeout, NULL)) - ereport(ERROR, - (errmsg("could not set statistics collector timer: %m"))); - need_timer = false; - } } else { @@ -2841,13 +2854,6 @@ pgstat_exit(SIGNAL_ARGS) need_exit = true; } -/* SIGALRM signal handler for collector process */ -static void -force_statwrite(SIGNAL_ARGS) -{ - need_statwrite = true; -} - /* SIGHUP handler for collector process */ static void pgstat_sighup_handler(SIGNAL_ARGS) @@ -2943,7 +2949,7 @@ pgstat_write_statsfile(bool permanent) /* * Open the statistics temp file to write out the current values. */ - fpout = fopen(tmpfile, PG_BINARY_W); + fpout = AllocateFile(tmpfile, PG_BINARY_W); if (fpout == NULL) { ereport(LOG, @@ -2954,6 +2960,11 @@ pgstat_write_statsfile(bool permanent) } /* + * Set the timestamp of the stats file. + */ + globalStats.stats_timestamp = GetCurrentTimestamp(); + + /* * Write the file header --- currently just a format ID. */ format_id = PGSTAT_FILE_FORMAT_ID; @@ -3017,10 +3028,10 @@ pgstat_write_statsfile(bool permanent) (errcode_for_file_access(), errmsg("could not write temporary statistics file \"%s\": %m", tmpfile))); - fclose(fpout); + FreeFile(fpout); unlink(tmpfile); } - else if (fclose(fpout) < 0) + else if (FreeFile(fpout) < 0) { ereport(LOG, (errcode_for_file_access(), @@ -3036,6 +3047,22 @@ pgstat_write_statsfile(bool permanent) tmpfile, statfile))); unlink(tmpfile); } + else + { + /* + * Successful write, so update last_statwrite. + */ + last_statwrite = globalStats.stats_timestamp; + + /* + * It's not entirely clear whether there could be clock skew between + * backends and the collector; but just in case someone manages to + * send us a stats request time that's far in the future, reset it. + * This ensures that no inquiry message can cause more than one stats + * file write to occur. + */ + last_statrequest = last_statwrite; + } if (permanent) unlink(pgstat_stat_filename); @@ -3289,6 +3316,52 @@ done: return dbhash; } +/* ---------- + * pgstat_read_statsfile_timestamp() - + * + * Attempt to fetch the timestamp of an existing stats file. + * Returns TRUE if successful (timestamp is stored at *ts). + * ---------- + */ +static bool +pgstat_read_statsfile_timestamp(bool permanent, TimestampTz *ts) +{ + PgStat_GlobalStats myGlobalStats; + FILE *fpin; + int32 format_id; + const char *statfile = permanent?PGSTAT_STAT_PERMANENT_FILENAME:pgstat_stat_filename; + + /* + * Try to open the status file. + */ + if ((fpin = AllocateFile(statfile, PG_BINARY_R)) == NULL) + return false; + + /* + * Verify it's of the expected format. + */ + if (fread(&format_id, 1, sizeof(format_id), fpin) != sizeof(format_id) + || format_id != PGSTAT_FILE_FORMAT_ID) + { + FreeFile(fpin); + return false; + } + + /* + * Read global stats struct + */ + if (fread(&myGlobalStats, 1, sizeof(myGlobalStats), fpin) != sizeof(myGlobalStats)) + { + FreeFile(fpin); + return false; + } + + *ts = myGlobalStats.stats_timestamp; + + FreeFile(fpin); + return true; +} + /* * If not already done, read the statistics collector stats file into * some hash tables. The results will be kept until pgstat_clear_snapshot() @@ -3297,11 +3370,50 @@ done: static void backend_read_statsfile(void) { + TimestampTz min_ts; + int count; + /* already read it? */ if (pgStatDBHash) return; Assert(!pgStatRunningInCollector); + /* + * We set the minimum acceptable timestamp to PGSTAT_STAT_INTERVAL msec + * before now. This indirectly ensures that the collector needn't write + * the file more often than PGSTAT_STAT_INTERVAL. + * + * Note that we don't recompute min_ts after sleeping; so we might end up + * accepting a file a bit older than PGSTAT_STAT_INTERVAL. In practice + * that shouldn't happen, though, as long as the sleep time is less than + * PGSTAT_STAT_INTERVAL; and we don't want to lie to the collector about + * what our cutoff time really is. + */ + min_ts = TimestampTzPlusMilliseconds(GetCurrentTimestamp(), + -PGSTAT_STAT_INTERVAL); + + /* + * Loop until fresh enough stats file is available or we ran out of time. + * The stats inquiry message is sent repeatedly in case collector drops it. + */ + for (count = 0; count < PGSTAT_POLL_LOOP_COUNT; count++) + { + TimestampTz file_ts; + + CHECK_FOR_INTERRUPTS(); + + if (pgstat_read_statsfile_timestamp(false, &file_ts) && + file_ts >= min_ts) + break; + + /* Not there or too old, so kick the collector and wait a bit */ + pgstat_send_inquiry(min_ts); + pg_usleep(PGSTAT_RETRY_DELAY * 1000L); + } + + if (count >= PGSTAT_POLL_LOOP_COUNT) + elog(WARNING, "pgstat wait timeout"); + /* Autovacuum launcher wants stats about all databases */ if (IsAutoVacuumLauncherProcess()) pgStatDBHash = pgstat_read_statsfile(InvalidOid, false); @@ -3354,6 +3466,20 @@ pgstat_clear_snapshot(void) /* ---------- + * pgstat_recv_inquiry() - + * + * Process stat inquiry requests. + * ---------- + */ +static void +pgstat_recv_inquiry(PgStat_MsgInquiry *msg, int len) +{ + if (msg->inquiry_time > last_statrequest) + last_statrequest = msg->inquiry_time; +} + + +/* ---------- * pgstat_recv_tabstat() - * * Count what the backend has done. diff --git a/src/include/pgstat.h b/src/include/pgstat.h index 8c2d39e4c55..119d7b6966d 100644 --- a/src/include/pgstat.h +++ b/src/include/pgstat.h @@ -5,7 +5,7 @@ * * Copyright (c) 2001-2008, PostgreSQL Global Development Group * - * $PostgreSQL: pgsql/src/include/pgstat.h,v 1.78 2008/08/15 08:37:40 mha Exp $ + * $PostgreSQL: pgsql/src/include/pgstat.h,v 1.79 2008/11/03 01:17:08 tgl Exp $ * ---------- */ #ifndef PGSTAT_H @@ -33,6 +33,7 @@ typedef enum TrackFunctionsLevel typedef enum StatMsgType { PGSTAT_MTYPE_DUMMY, + PGSTAT_MTYPE_INQUIRY, PGSTAT_MTYPE_TABSTAT, PGSTAT_MTYPE_TABPURGE, PGSTAT_MTYPE_DROPDB, @@ -174,6 +175,19 @@ typedef struct PgStat_MsgDummy /* ---------- + * PgStat_MsgInquiry Sent by a backend to ask the collector + * to write the stats file. + * ---------- + */ + +typedef struct PgStat_MsgInquiry +{ + PgStat_MsgHdr m_hdr; + TimestampTz inquiry_time; /* minimum acceptable file timestamp */ +} PgStat_MsgInquiry; + + +/* ---------- * PgStat_TableEntry Per-table info in a MsgTabstat * ---------- */ @@ -392,6 +406,7 @@ typedef union PgStat_Msg { PgStat_MsgHdr msg_hdr; PgStat_MsgDummy msg_dummy; + PgStat_MsgInquiry msg_inquiry; PgStat_MsgTabstat msg_tabstat; PgStat_MsgTabpurge msg_tabpurge; PgStat_MsgDropdb msg_dropdb; @@ -413,7 +428,7 @@ typedef union PgStat_Msg * ------------------------------------------------------------ */ -#define PGSTAT_FILE_FORMAT_ID 0x01A5BC97 +#define PGSTAT_FILE_FORMAT_ID 0x01A5BC98 /* ---------- * PgStat_StatDBEntry The collector's data per database @@ -494,6 +509,7 @@ typedef struct PgStat_StatFuncEntry */ typedef struct PgStat_GlobalStats { + TimestampTz stats_timestamp; /* time of stats file update */ PgStat_Counter timed_checkpoints; PgStat_Counter requested_checkpoints; PgStat_Counter buf_written_checkpoints; |