Index: src/backend/postmaster/pgstat.c =================================================================== RCS file: /projects/cvsroot/pgsql/src/backend/postmaster/pgstat.c,v retrieving revision 1.181 diff -c -r1.181 pgstat.c *** src/backend/postmaster/pgstat.c 25 Aug 2008 18:55:43 -0000 1.181 --- src/backend/postmaster/pgstat.c 5 Sep 2008 18:36:24 -0000 *************** *** 85,90 **** --- 85,92 ---- #define PGSTAT_SELECT_TIMEOUT 2 /* How often to check for postmaster * death; in seconds. */ + #define PGSTAT_WRITE_TIMEOUT 5 /* How long to wait for the collector + * to finish writing the file; in seconds. */ /* ---------- * The initial size hints for the hash tables used in the collector. *************** *** 94,100 **** #define PGSTAT_TAB_HASH_SIZE 512 #define PGSTAT_FUNCTION_HASH_SIZE 512 - /* ---------- * GUC parameters * ---------- --- 96,101 ---- *************** *** 201,208 **** --- 202,213 ---- */ static PgStat_GlobalStats globalStats; + /* Last time we wrote the stats file */ + static TimestampTz last_statwrite; + static volatile bool need_exit = false; static volatile bool need_statwrite = false; + static volatile bool stats_ready = false; static volatile bool got_SIGHUP = false; /* *************** *** 213,218 **** --- 218,229 ---- static instr_time total_func_time; + #define PGSTAT_MAX_INQUIRIES 16 /* Max number of outstanding stats inquiries */ + + /* List of backends that need notifications */ + static pid_t inquiring_backends[PGSTAT_MAX_INQUIRIES]; + static int num_inquiries = 0; + /* ---------- * Local function forward declarations * ---------- *************** *** 223,229 **** 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); --- 234,240 ---- NON_EXEC_STATIC void PgstatCollectorMain(int argc, char *argv[]); static void pgstat_exit(SIGNAL_ARGS); ! static void pgstat_alarm_handler(SIGNAL_ARGS); static void pgstat_beshutdown_hook(int code, Datum arg); static void pgstat_sighup_handler(SIGNAL_ARGS); *************** *** 254,259 **** --- 265,271 ---- static void pgstat_recv_bgwriter(PgStat_MsgBgWriter *msg, int len); static void pgstat_recv_funcstat(PgStat_MsgFuncstat *msg, int len); static void pgstat_recv_funcpurge(PgStat_MsgFuncpurge *msg, int len); + static void pgstat_recv_inquiry(PgStat_MsgInquiry *msg, int len); /* ------------------------------------------------------------ *************** *** 2463,2468 **** --- 2475,2496 ---- hdr->m_type = mtype; } + /* ---------- + * pgstat_send_inquiry() - + * + * Notify collector that we need fresh data. + * ---------- + */ + static void + pgstat_send_inquiry(void) + { + PgStat_MsgInquiry msg; + + elog(DEBUG1, "pgstat_send_inquiry: I am %u", getpid()); + pgstat_setheader(&msg.m_hdr, PGSTAT_MTYPE_INQUIRY); + msg.m_pid = getpid(); + pgstat_send(&msg, sizeof(msg)); + } /* ---------- * pgstat_send() - *************** *** 2538,2545 **** NON_EXEC_STATIC void PgstatCollectorMain(int argc, char *argv[]) { - struct itimerval write_timeout; - bool need_timer = false; int len; PgStat_Msg msg; --- 2566,2571 ---- *************** *** 2577,2583 **** pqsignal(SIGINT, SIG_IGN); pqsignal(SIGTERM, SIG_IGN); pqsignal(SIGQUIT, pgstat_exit); - pqsignal(SIGALRM, force_statwrite); pqsignal(SIGPIPE, SIG_IGN); pqsignal(SIGUSR1, SIG_IGN); pqsignal(SIGUSR2, SIG_IGN); --- 2603,2608 ---- *************** *** 2598,2608 **** */ 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; - /* * Read in an existing statistics stats file or initialize the stats to * zero. --- 2623,2628 ---- *************** *** 2628,2634 **** */ for (;;) { ! int got_data; /* * Quit if we get SIGQUIT from the postmaster. --- 2648,2654 ---- */ for (;;) { ! int i, got_data; /* * Quit if we get SIGQUIT from the postmaster. *************** *** 2649,2670 **** } /* ! * 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. */ if (need_statwrite) { /* Check for postmaster death; if so we'll write file below */ if (!PostmasterIsAlive(true)) break; ! pgstat_write_statsfile(false); need_statwrite = false; - need_timer = true; } /* * Wait for a message to arrive; but not for more than * PGSTAT_SELECT_TIMEOUT seconds. (This determines how quickly we will --- 2669,2708 ---- } /* ! * If time to write the stats file, do so. */ if (need_statwrite) { + TimestampTz now = GetCurrentTimestamp(); + long sec; + int us; + /* Check for postmaster death; if so we'll write file below */ if (!PostmasterIsAlive(true)) break; ! /* Write the file, but only if enough time has passed since last write */ ! if (TimestampDifferenceExceeds(last_statwrite, now, PGSTAT_STAT_INTERVAL)) ! { ! pgstat_write_statsfile(false); ! last_statwrite = now; ! } ! ! TimestampDifference(now, GetCurrentTimestamp(), &sec, &us); ! elog(DEBUG1, "pgstat_write_statsfile: written in %ldms", ! (long)(sec*1000 + us/1000.0)); ! need_statwrite = false; } + /* Notify inquiring backends that we are done with the file */ + for (i = 0; i < num_inquiries; i++) + { + elog(DEBUG1, "signalling backend %u", (unsigned)inquiring_backends[i]); + kill(inquiring_backends[i], SIGALRM); + } + num_inquiries = 0; + /* * Wait for a message to arrive; but not for more than * PGSTAT_SELECT_TIMEOUT seconds. (This determines how quickly we will *************** *** 2797,2817 **** pgstat_recv_funcpurge((PgStat_MsgFuncpurge *) &msg, len); break; ! 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 --- 2835,2846 ---- pgstat_recv_funcpurge((PgStat_MsgFuncpurge *) &msg, len); break; ! case PGSTAT_MTYPE_INQUIRY: ! pgstat_recv_inquiry((PgStat_MsgInquiry *)&msg, len); break; ! default: ! break; } } else *************** *** 2841,2853 **** 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) --- 2870,2875 ---- *************** *** 2855,2860 **** --- 2877,2888 ---- got_SIGHUP = true; } + /* SIGALRM signal handler for backend process */ + static void + pgstat_alarm_handler(SIGNAL_ARGS) + { + stats_ready = true; + } /* * Lookup the hash table entry for the specified database. If no hash *************** *** 3297,3307 **** --- 3325,3368 ---- static void backend_read_statsfile(void) { + TimestampTz start; + pqsigfunc oldalarm; + static struct itimerval stat_timeout; + int count = 0; + long sec; + int usec; + /* already read it? */ if (pgStatDBHash) return; Assert(!pgStatRunningInCollector); + start = GetCurrentTimestamp(); + + /* These need only be done once */ + pqsignal(SIGALRM, pgstat_alarm_handler); + stat_timeout.it_value.tv_sec = PGSTAT_WRITE_TIMEOUT; + + stats_ready = false; + if (setitimer(ITIMER_REAL, &stat_timeout, NULL)) + ereport(ERROR, (errmsg("could not set statistics collector poll timer: %m"))); + + while (!stats_ready) + { + CHECK_FOR_INTERRUPTS(); + + pgstat_send_inquiry(); + pg_usleep(5000); + count += 1; + } + + /* Stats ready or timeout - either way we have to proceed */ + + TimestampDifference(start, GetCurrentTimestamp(), &sec, &usec); + elog(DEBUG1, "backend_read_statsfile: %u: waited for %lu ms, looped %d times.", + getpid(), + (unsigned long)(sec*1000 + usec/1000.0), count); + /* Autovacuum launcher wants stats about all databases */ if (IsAutoVacuumLauncherProcess()) pgStatDBHash = pgstat_read_statsfile(InvalidOid, false); *************** *** 3779,3781 **** --- 3840,3870 ---- HASH_REMOVE, NULL); } } + + /* ---------- + * pgstat_recv_inquiry() - + * + * Process stat inquiry requests. + * ---------- + */ + static void + pgstat_recv_inquiry(PgStat_MsgInquiry *msg, int len) + { + int i; + + /* filter out duplicates */ + for (i = 0; i < num_inquiries; i++) + if (inquiring_backends[i] == msg->m_pid) + return; + + if (num_inquiries >= PGSTAT_MAX_INQUIRIES) + { + /* List is full - just drop the message, it'll be resent */ + elog(DEBUG1, "pgstat_recv_inquiry: too many outstanding inquiries - %d", + num_inquiries); + return; + } + inquiring_backends[num_inquiries++] = msg->m_pid; + need_statwrite = true; + } + Index: src/include/pgstat.h =================================================================== RCS file: /projects/cvsroot/pgsql/src/include/pgstat.h,v retrieving revision 1.78 diff -c -r1.78 pgstat.h *** src/include/pgstat.h 15 Aug 2008 08:37:40 -0000 1.78 --- src/include/pgstat.h 5 Sep 2008 18:36:27 -0000 *************** *** 42,48 **** PGSTAT_MTYPE_ANALYZE, PGSTAT_MTYPE_BGWRITER, PGSTAT_MTYPE_FUNCSTAT, ! PGSTAT_MTYPE_FUNCPURGE } StatMsgType; /* ---------- --- 42,49 ---- PGSTAT_MTYPE_ANALYZE, PGSTAT_MTYPE_BGWRITER, PGSTAT_MTYPE_FUNCSTAT, ! PGSTAT_MTYPE_FUNCPURGE, ! PGSTAT_MTYPE_INQUIRY } StatMsgType; /* ---------- *************** *** 385,390 **** --- 386,404 ---- /* ---------- + * PgStat_MsgInquiry Sent by the backend to tell the collector + * to write the stats file. + * ---------- + */ + + typedef struct PgStat_MsgInquiry + { + PgStat_MsgHdr m_hdr; + int m_pid; + } PgStat_MsgInquiry; + + + /* ---------- * PgStat_Msg Union over all possible messages. * ---------- */ *************** *** 402,407 **** --- 416,422 ---- PgStat_MsgBgWriter msg_bgwriter; PgStat_MsgFuncstat msg_funcstat; PgStat_MsgFuncpurge msg_funcpurge; + PgStat_MsgInquiry msg_inquiry; } PgStat_Msg;