/* ---------- * pgstat.c * * All the statistics collector stuff hacked up in one big, ugly file. * * TODO: - Separate collector, postmaster and backend stuff * into different files. * * - Add some automatic call for pgstat vacuuming. * * - Add a pgstat config column to pg_database, so this * entire thing can be enabled/disabled on a per db basis. * * Copyright (c) 2001-2005, PostgreSQL Global Development Group * * $PostgreSQL: pgsql/src/backend/postmaster/pgstat.c,v 1.99 2005/07/04 04:51:47 tgl Exp $ * ---------- */ #include "postgres.h" #include #include #include #include #include #include #include #include #include #include #include "pgstat.h" #include "access/heapam.h" #include "access/xact.h" #include "catalog/pg_database.h" #include "libpq/libpq.h" #include "libpq/pqsignal.h" #include "mb/pg_wchar.h" #include "miscadmin.h" #include "postmaster/fork_process.h" #include "postmaster/postmaster.h" #include "storage/backendid.h" #include "storage/fd.h" #include "storage/ipc.h" #include "storage/pg_shmem.h" #include "storage/pmsignal.h" #include "tcop/tcopprot.h" #include "utils/hsearch.h" #include "utils/memutils.h" #include "utils/ps_status.h" #include "utils/rel.h" #include "utils/syscache.h" /* ---------- * Paths for the statistics files (relative to installation's $PGDATA). * ---------- */ #define PGSTAT_STAT_FILENAME "global/pgstat.stat" #define PGSTAT_STAT_TMPFILE "global/pgstat.tmp" /* ---------- * Timer definitions. * ---------- */ #define PGSTAT_STAT_INTERVAL 500 /* How often to write the status * file; in milliseconds. */ #define PGSTAT_DESTROY_DELAY 10000 /* How long to keep destroyed * objects known, to give delayed * UDP packets time to arrive; in * milliseconds. */ #define PGSTAT_DESTROY_COUNT (PGSTAT_DESTROY_DELAY / PGSTAT_STAT_INTERVAL) #define PGSTAT_RESTART_INTERVAL 60 /* How often to attempt to restart * a failed statistics collector; * in seconds. */ /* ---------- * Amount of space reserved in pgstat_recvbuffer(). * ---------- */ #define PGSTAT_RECVBUFFERSZ ((int) (1024 * sizeof(PgStat_Msg))) /* ---------- * The initial size hints for the hash tables used in the collector. * ---------- */ #define PGSTAT_DB_HASH_SIZE 16 #define PGSTAT_BE_HASH_SIZE 512 #define PGSTAT_TAB_HASH_SIZE 512 /* ---------- * GUC parameters * ---------- */ bool pgstat_collect_startcollector = true; bool pgstat_collect_resetonpmstart = true; bool pgstat_collect_querystring = false; bool pgstat_collect_tuplelevel = false; bool pgstat_collect_blocklevel = false; /* ---------- * Local data * ---------- */ NON_EXEC_STATIC int pgStatSock = -1; NON_EXEC_STATIC int pgStatPipe[2] = {-1,-1}; static struct sockaddr_storage pgStatAddr; static pid_t pgStatCollectorPid = 0; static time_t last_pgstat_start_time; static long pgStatNumMessages = 0; static bool pgStatRunningInCollector = FALSE; static int pgStatTabstatAlloc = 0; static int pgStatTabstatUsed = 0; static PgStat_MsgTabstat **pgStatTabstatMessages = NULL; #define TABSTAT_QUANTUM 4 /* we alloc this many at a time */ static int pgStatXactCommit = 0; static int pgStatXactRollback = 0; static TransactionId pgStatDBHashXact = InvalidTransactionId; static HTAB *pgStatDBHash = NULL; static HTAB *pgStatBeDead = NULL; static PgStat_StatBeEntry *pgStatBeTable = NULL; static int pgStatNumBackends = 0; /* ---------- * Local function forward declarations * ---------- */ #ifdef EXEC_BACKEND typedef enum STATS_PROCESS_TYPE { STAT_PROC_BUFFER, STAT_PROC_COLLECTOR } STATS_PROCESS_TYPE; static pid_t pgstat_forkexec(STATS_PROCESS_TYPE procType); static void pgstat_parseArgs(int argc, char *argv[]); #endif NON_EXEC_STATIC void PgstatBufferMain(int argc, char *argv[]); NON_EXEC_STATIC void PgstatCollectorMain(int argc, char *argv[]); static void pgstat_recvbuffer(void); static void pgstat_exit(SIGNAL_ARGS); static void pgstat_die(SIGNAL_ARGS); static void pgstat_beshutdown_hook(int code, Datum arg); static PgStat_StatDBEntry *pgstat_get_db_entry(Oid databaseid); static int pgstat_add_backend(PgStat_MsgHdr *msg); static void pgstat_sub_backend(int procpid); static void pgstat_drop_database(Oid databaseid); static void pgstat_write_statsfile(void); static void pgstat_read_statsfile(HTAB **dbhash, Oid onlydb, PgStat_StatBeEntry **betab, int *numbackends); static void backend_read_statsfile(void); static void pgstat_setheader(PgStat_MsgHdr *hdr, int mtype); static void pgstat_send(void *msg, int len); static void pgstat_recv_bestart(PgStat_MsgBestart *msg, int len); static void pgstat_recv_beterm(PgStat_MsgBeterm *msg, int len); static void pgstat_recv_activity(PgStat_MsgActivity *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); static void pgstat_recv_resetcounter(PgStat_MsgResetcounter *msg, int len); /* ------------------------------------------------------------ * Public functions called from postmaster follow * ------------------------------------------------------------ */ /* ---------- * pgstat_init() - * * Called from postmaster at startup. Create the resources required * by the statistics collector process. If unable to do so, do not * fail --- better to let the postmaster start with stats collection * disabled. * ---------- */ void pgstat_init(void) { ACCEPT_TYPE_ARG3 alen; struct addrinfo *addrs = NULL, *addr, hints; int ret; fd_set rset; struct timeval tv; char test_byte; int sel_res; #define TESTBYTEVAL ((char) 199) /* * Force start of collector daemon if something to collect */ if (pgstat_collect_querystring || pgstat_collect_tuplelevel || pgstat_collect_blocklevel) pgstat_collect_startcollector = true; /* * If we don't have to start a collector or should reset the collected * statistics on postmaster start, simply remove the stats file. */ if (!pgstat_collect_startcollector || pgstat_collect_resetonpmstart) unlink(PGSTAT_STAT_FILENAME); /* * Nothing else required if collector will not get started */ if (!pgstat_collect_startcollector) return; /* * Create the UDP socket for sending and receiving statistic messages */ hints.ai_flags = AI_PASSIVE; hints.ai_family = PF_UNSPEC; hints.ai_socktype = SOCK_DGRAM; hints.ai_protocol = 0; hints.ai_addrlen = 0; hints.ai_addr = NULL; hints.ai_canonname = NULL; hints.ai_next = NULL; ret = getaddrinfo_all("localhost", NULL, &hints, &addrs); if (ret || !addrs) { ereport(LOG, (errmsg("could not resolve \"localhost\": %s", gai_strerror(ret)))); goto startup_failed; } /* * On some platforms, getaddrinfo_all() may return multiple addresses * only one of which will actually work (eg, both IPv6 and IPv4 * addresses when kernel will reject IPv6). Worse, the failure may * occur at the bind() or perhaps even connect() stage. So we must * loop through the results till we find a working combination. We * will generate LOG messages, but no error, for bogus combinations. */ for (addr = addrs; addr; addr = addr->ai_next) { #ifdef HAVE_UNIX_SOCKETS /* Ignore AF_UNIX sockets, if any are returned. */ if (addr->ai_family == AF_UNIX) continue; #endif /* * Create the socket. */ if ((pgStatSock = socket(addr->ai_family, SOCK_DGRAM, 0)) < 0) { ereport(LOG, (errcode_for_socket_access(), errmsg("could not create socket for statistics collector: %m"))); continue; } /* * Bind it to a kernel assigned port on localhost and get the * assigned port via getsockname(). */ if (bind(pgStatSock, addr->ai_addr, addr->ai_addrlen) < 0) { ereport(LOG, (errcode_for_socket_access(), errmsg("could not bind socket for statistics collector: %m"))); closesocket(pgStatSock); pgStatSock = -1; continue; } alen = sizeof(pgStatAddr); if (getsockname(pgStatSock, (struct sockaddr *) & pgStatAddr, &alen) < 0) { ereport(LOG, (errcode_for_socket_access(), errmsg("could not get address of socket for statistics collector: %m"))); closesocket(pgStatSock); pgStatSock = -1; continue; } /* * Connect the socket to its own address. This saves a few cycles * by not having to respecify the target address on every send. * This also provides a kernel-level check that only packets from * this same address will be received. */ if (connect(pgStatSock, (struct sockaddr *) & pgStatAddr, alen) < 0) { ereport(LOG, (errcode_for_socket_access(), errmsg("could not connect socket for statistics collector: %m"))); closesocket(pgStatSock); pgStatSock = -1; continue; } /* * Try to send and receive a one-byte test message on the socket. * This is to catch situations where the socket can be created but * will not actually pass data (for instance, because kernel * packet filtering rules prevent it). */ test_byte = TESTBYTEVAL; if (send(pgStatSock, &test_byte, 1, 0) != 1) { ereport(LOG, (errcode_for_socket_access(), errmsg("could not send test message on socket for statistics collector: %m"))); closesocket(pgStatSock); pgStatSock = -1; continue; } /* * There could possibly be a little delay before the message can * be received. We arbitrarily allow up to half a second before * deciding it's broken. */ for (;;) /* need a loop to handle EINTR */ { FD_ZERO(&rset); FD_SET(pgStatSock, &rset); tv.tv_sec = 0; tv.tv_usec = 500000; sel_res = select(pgStatSock + 1, &rset, NULL, NULL, &tv); if (sel_res >= 0 || errno != EINTR) break; } if (sel_res < 0) { ereport(LOG, (errcode_for_socket_access(), errmsg("select() failed in statistics collector: %m"))); closesocket(pgStatSock); pgStatSock = -1; continue; } if (sel_res == 0 || !FD_ISSET(pgStatSock, &rset)) { /* * This is the case we actually think is likely, so take pains * to give a specific message for it. * * errno will not be set meaningfully here, so don't use it. */ ereport(LOG, (errcode(ERRCODE_CONNECTION_FAILURE), errmsg("test message did not get through on socket for statistics collector"))); closesocket(pgStatSock); pgStatSock = -1; continue; } test_byte++; /* just make sure variable is changed */ if (recv(pgStatSock, &test_byte, 1, 0) != 1) { ereport(LOG, (errcode_for_socket_access(), errmsg("could not receive test message on socket for statistics collector: %m"))); closesocket(pgStatSock); pgStatSock = -1; continue; } if (test_byte != TESTBYTEVAL) /* strictly paranoia ... */ { ereport(LOG, (errcode(ERRCODE_INTERNAL_ERROR), errmsg("incorrect test message transmission on socket for statistics collector"))); closesocket(pgStatSock); pgStatSock = -1; continue; } /* If we get here, we have a working socket */ break; } /* Did we find a working address? */ if (!addr || pgStatSock < 0) goto startup_failed; /* * Set the socket to non-blocking IO. This ensures that if the * collector falls behind (despite the buffering process), statistics * messages will be discarded; backends won't block waiting to send * messages to the collector. */ if (!pg_set_noblock(pgStatSock)) { ereport(LOG, (errcode_for_socket_access(), errmsg("could not set statistics collector socket to nonblocking mode: %m"))); goto startup_failed; } freeaddrinfo_all(hints.ai_family, addrs); return; startup_failed: ereport(LOG, (errmsg("disabling statistics collector for lack of working socket"))); if (addrs) freeaddrinfo_all(hints.ai_family, addrs); if (pgStatSock >= 0) closesocket(pgStatSock); pgStatSock = -1; /* Adjust GUC variables to suppress useless activity */ pgstat_collect_startcollector = false; pgstat_collect_querystring = false; pgstat_collect_tuplelevel = false; pgstat_collect_blocklevel = false; } #ifdef EXEC_BACKEND /* * pgstat_forkexec() - * * Format up the arglist for, then fork and exec, statistics * (buffer and collector) processes */ static pid_t pgstat_forkexec(STATS_PROCESS_TYPE procType) { char *av[10]; int ac = 0, bufc = 0, i; char pgstatBuf[2][32]; av[ac++] = "postgres"; switch (procType) { case STAT_PROC_BUFFER: av[ac++] = "-forkbuf"; break; case STAT_PROC_COLLECTOR: av[ac++] = "-forkcol"; break; default: Assert(false); } av[ac++] = NULL; /* filled in by postmaster_forkexec */ /* postgres_exec_path is not passed by write_backend_variables */ av[ac++] = postgres_exec_path; /* Add to the arg list */ Assert(bufc <= lengthof(pgstatBuf)); for (i = 0; i < bufc; i++) av[ac++] = pgstatBuf[i]; av[ac] = NULL; Assert(ac < lengthof(av)); return postmaster_forkexec(ac, av); } /* * pgstat_parseArgs() - * * Extract data from the arglist for exec'ed statistics * (buffer and collector) processes */ static void pgstat_parseArgs(int argc, char *argv[]) { Assert(argc == 4); argc = 3; StrNCpy(postgres_exec_path, argv[argc++], MAXPGPATH); } #endif /* EXEC_BACKEND */ /* ---------- * pgstat_start() - * * Called from postmaster at startup or after an existing collector * died. Attempt to fire up a fresh statistics collector. * * Returns PID of child process, or 0 if fail. * * Note: if fail, we will be called again from the postmaster main loop. * ---------- */ int pgstat_start(void) { time_t curtime; pid_t pgStatPid; /* * Do nothing if no collector needed */ if (!pgstat_collect_startcollector) return 0; /* * Do nothing if too soon since last collector start. This is a * safety valve to protect against continuous respawn attempts if the * collector is dying immediately at launch. Note that since we will * be re-called from the postmaster main loop, we will get another * chance later. */ curtime = time(NULL); if ((unsigned int) (curtime - last_pgstat_start_time) < (unsigned int) PGSTAT_RESTART_INTERVAL) return 0; last_pgstat_start_time = curtime; /* * Check that the socket is there, else pgstat_init failed. */ if (pgStatSock < 0) { ereport(LOG, (errmsg("statistics collector startup skipped"))); /* * We can only get here if someone tries to manually turn * pgstat_collect_startcollector on after it had been off. */ pgstat_collect_startcollector = false; return 0; } /* * Okay, fork off the collector. */ #ifdef EXEC_BACKEND switch ((pgStatPid = pgstat_forkexec(STAT_PROC_BUFFER))) #else switch ((pgStatPid = fork_process())) #endif { case -1: ereport(LOG, (errmsg("could not fork statistics buffer: %m"))); return 0; #ifndef EXEC_BACKEND case 0: /* in postmaster child ... */ /* Close the postmaster's sockets */ ClosePostmasterPorts(false); /* Drop our connection to postmaster's shared memory, as well */ PGSharedMemoryDetach(); PgstatBufferMain(0, NULL); break; #endif default: return (int) pgStatPid; } /* shouldn't get here */ return 0; } /* ---------- * pgstat_beterm() - * * Called from postmaster to tell collector a backend terminated. * ---------- */ void pgstat_beterm(int pid) { PgStat_MsgBeterm msg; if (pgStatSock < 0) return; MemSet(&(msg.m_hdr), 0, sizeof(msg.m_hdr)); msg.m_hdr.m_type = PGSTAT_MTYPE_BETERM; msg.m_hdr.m_procpid = pid; pgstat_send(&msg, sizeof(msg)); } /* ------------------------------------------------------------ * Public functions used by backends follow *------------------------------------------------------------ */ /* ---------- * pgstat_bestart() - * * Tell the collector that this new backend is soon ready to process * queries. Called from tcop/postgres.c before entering the mainloop. * ---------- */ void pgstat_bestart(void) { PgStat_MsgBestart msg; if (pgStatSock < 0) return; pgstat_setheader(&msg.m_hdr, PGSTAT_MTYPE_BESTART); msg.m_databaseid = MyDatabaseId; msg.m_userid = GetSessionUserId(); memcpy(&msg.m_clientaddr, &MyProcPort->raddr, sizeof(msg.m_clientaddr)); pgstat_send(&msg, sizeof(msg)); /* * Set up a process-exit hook to ensure we flush the last batch of * statistics to the collector. */ on_proc_exit(pgstat_beshutdown_hook, 0); } /* * Flush any remaining statistics counts out to the collector at process * exit. Without this, operations triggered during backend exit (such as * temp table deletions) won't be counted. This is an on_proc_exit hook, * not on_shmem_exit, so that everything interesting must have happened * already. */ static void pgstat_beshutdown_hook(int code, Datum arg) { pgstat_report_tabstat(); } /* ---------- * pgstat_report_activity() - * * Called from tcop/postgres.c to tell the collector what the backend * is actually doing (usually "" or the start of the query to * be executed). * ---------- */ void pgstat_report_activity(const char *what) { PgStat_MsgActivity msg; int len; if (!pgstat_collect_querystring || pgStatSock < 0) return; len = strlen(what); len = pg_mbcliplen((const unsigned char *) what, len, PGSTAT_ACTIVITY_SIZE - 1); memcpy(msg.m_what, what, len); msg.m_what[len] = '\0'; len += offsetof(PgStat_MsgActivity, m_what) +1; pgstat_setheader(&msg.m_hdr, PGSTAT_MTYPE_ACTIVITY); pgstat_send(&msg, len); } /* ---------- * pgstat_report_tabstat() - * * Called from tcop/postgres.c to send the so far collected * per table access statistics to the collector. * ---------- */ void pgstat_report_tabstat(void) { int i; if (pgStatSock < 0 || !(pgstat_collect_querystring || pgstat_collect_tuplelevel || pgstat_collect_blocklevel)) { /* Not reporting stats, so just flush whatever we have */ pgStatTabstatUsed = 0; return; } /* * For each message buffer used during the last query set the header * fields and send it out. */ for (i = 0; i < pgStatTabstatUsed; i++) { PgStat_MsgTabstat *tsmsg = pgStatTabstatMessages[i]; int n; int len; n = tsmsg->m_nentries; len = offsetof(PgStat_MsgTabstat, m_entry[0]) + n * sizeof(PgStat_TableEntry); tsmsg->m_xact_commit = pgStatXactCommit; tsmsg->m_xact_rollback = pgStatXactRollback; pgStatXactCommit = 0; pgStatXactRollback = 0; pgstat_setheader(&tsmsg->m_hdr, PGSTAT_MTYPE_TABSTAT); tsmsg->m_databaseid = MyDatabaseId; pgstat_send(tsmsg, len); } pgStatTabstatUsed = 0; } /* ---------- * pgstat_vacuum_tabstat() - * * Will tell the collector about objects he can get rid of. * ---------- */ int pgstat_vacuum_tabstat(void) { Relation dbrel; HeapScanDesc dbscan; HeapTuple dbtup; Oid *dbidlist; int dbidalloc; int dbidused; HASH_SEQ_STATUS hstat; PgStat_StatDBEntry *dbentry; PgStat_StatTabEntry *tabentry; HeapTuple reltup; int nobjects = 0; PgStat_MsgTabpurge msg; int len; int i; if (pgStatSock < 0) return 0; /* * If not done for this transaction, read the statistics collector * stats file into some hash tables. */ backend_read_statsfile(); /* * Lookup our own database entry */ dbentry = (PgStat_StatDBEntry *) hash_search(pgStatDBHash, (void *) &MyDatabaseId, HASH_FIND, NULL); if (dbentry == NULL) return -1; if (dbentry->tables == NULL) return 0; /* * Initialize our messages table counter to zero */ msg.m_nentries = 0; /* * Check for all tables if they still exist. */ hash_seq_init(&hstat, dbentry->tables); while ((tabentry = (PgStat_StatTabEntry *) hash_seq_search(&hstat)) != NULL) { /* * Check if this relation is still alive by looking up it's * pg_class tuple in the system catalog cache. */ reltup = SearchSysCache(RELOID, ObjectIdGetDatum(tabentry->tableid), 0, 0, 0); if (HeapTupleIsValid(reltup)) { ReleaseSysCache(reltup); continue; } /* * Add this table's Oid to the message */ msg.m_tableid[msg.m_nentries++] = tabentry->tableid; nobjects++; /* * If the message is full, send it out and reinitialize ot zero */ if (msg.m_nentries >= PGSTAT_NUM_TABPURGE) { len = offsetof(PgStat_MsgTabpurge, m_tableid[0]) +msg.m_nentries * sizeof(Oid); pgstat_setheader(&msg.m_hdr, PGSTAT_MTYPE_TABPURGE); pgstat_send(&msg, len); msg.m_nentries = 0; } } /* * Send the rest */ if (msg.m_nentries > 0) { len = offsetof(PgStat_MsgTabpurge, m_tableid[0]) +msg.m_nentries * sizeof(Oid); pgstat_setheader(&msg.m_hdr, PGSTAT_MTYPE_TABPURGE); msg.m_databaseid = MyDatabaseId; pgstat_send(&msg, len); } /* * Read pg_database and remember the Oid's of all existing databases */ dbidalloc = 256; dbidused = 0; dbidlist = (Oid *) palloc(sizeof(Oid) * dbidalloc); dbrel = heap_open(DatabaseRelationId, AccessShareLock); dbscan = heap_beginscan(dbrel, SnapshotNow, 0, NULL); while ((dbtup = heap_getnext(dbscan, ForwardScanDirection)) != NULL) { if (dbidused >= dbidalloc) { dbidalloc *= 2; dbidlist = (Oid *) repalloc((char *) dbidlist, sizeof(Oid) * dbidalloc); } dbidlist[dbidused++] = HeapTupleGetOid(dbtup); } heap_endscan(dbscan); heap_close(dbrel, AccessShareLock); /* * Search the database hash table for dead databases and tell the * collector to drop them as well. */ hash_seq_init(&hstat, pgStatDBHash); while ((dbentry = (PgStat_StatDBEntry *) hash_seq_search(&hstat)) != NULL) { Oid dbid = dbentry->databaseid; for (i = 0; i < dbidused; i++) { if (dbidlist[i] == dbid) { dbid = InvalidOid; break; } } if (dbid != InvalidOid) { nobjects++; pgstat_drop_database(dbid); } } /* * Free the dbid list. */ pfree(dbidlist); /* * Tell the caller how many removeable objects we found */ return nobjects; } /* ---------- * pgstat_drop_database() - * * Tell the collector that we just dropped a database. * This is the only message that shouldn't get lost in space. Otherwise * the collector will keep the statistics for the dead DB until his * stats file got removed while the postmaster is down. * ---------- */ static void pgstat_drop_database(Oid databaseid) { PgStat_MsgDropdb msg; if (pgStatSock < 0) return; pgstat_setheader(&msg.m_hdr, PGSTAT_MTYPE_DROPDB); msg.m_databaseid = databaseid; pgstat_send(&msg, sizeof(msg)); } /* ---------- * pgstat_reset_counters() - * * Tell the statistics collector to reset counters for our database. * ---------- */ void pgstat_reset_counters(void) { PgStat_MsgResetcounter msg; if (pgStatSock < 0) return; if (!superuser()) ereport(ERROR, (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE), errmsg("must be superuser to reset statistics counters"))); pgstat_setheader(&msg.m_hdr, PGSTAT_MTYPE_RESETCOUNTER); msg.m_databaseid = MyDatabaseId; pgstat_send(&msg, sizeof(msg)); } /* ---------- * pgstat_ping() - * * Send some junk data to the collector to increase traffic. * ---------- */ void pgstat_ping(void) { PgStat_MsgDummy msg; if (pgStatSock < 0) return; pgstat_setheader(&msg.m_hdr, PGSTAT_MTYPE_DUMMY); pgstat_send(&msg, sizeof(msg)); } /* * Create or enlarge the pgStatTabstatMessages array */ static void more_tabstat_space(void) { PgStat_MsgTabstat *newMessages; PgStat_MsgTabstat **msgArray; int newAlloc = pgStatTabstatAlloc + TABSTAT_QUANTUM; int i; /* Create (another) quantum of message buffers */ newMessages = (PgStat_MsgTabstat *) MemoryContextAllocZero(TopMemoryContext, sizeof(PgStat_MsgTabstat) * TABSTAT_QUANTUM); /* Create or enlarge the pointer array */ if (pgStatTabstatMessages == NULL) msgArray = (PgStat_MsgTabstat **) MemoryContextAlloc(TopMemoryContext, sizeof(PgStat_MsgTabstat *) * newAlloc); else msgArray = (PgStat_MsgTabstat **) repalloc(pgStatTabstatMessages, sizeof(PgStat_MsgTabstat *) * newAlloc); for (i = 0; i < TABSTAT_QUANTUM; i++) msgArray[pgStatTabstatAlloc + i] = newMessages++; pgStatTabstatMessages = msgArray; pgStatTabstatAlloc = newAlloc; Assert(pgStatTabstatUsed < pgStatTabstatAlloc); } /* ---------- * pgstat_initstats() - * * Called from various places usually dealing with initialization * of Relation or Scan structures. The data placed into these * structures from here tell where later to count for buffer reads, * scans and tuples fetched. * ---------- */ void pgstat_initstats(PgStat_Info *stats, Relation rel) { Oid rel_id = rel->rd_id; PgStat_TableEntry *useent; PgStat_MsgTabstat *tsmsg; int mb; int i; /* * Initialize data not to count at all. */ stats->tabentry = NULL; stats->no_stats = FALSE; stats->heap_scan_counted = FALSE; stats->index_scan_counted = FALSE; if (pgStatSock < 0 || !(pgstat_collect_tuplelevel || pgstat_collect_blocklevel)) { stats->no_stats = TRUE; return; } /* * Search the already-used message slots for this relation. */ for (mb = 0; mb < pgStatTabstatUsed; mb++) { tsmsg = pgStatTabstatMessages[mb]; for (i = tsmsg->m_nentries; --i >= 0;) { if (tsmsg->m_entry[i].t_id == rel_id) { stats->tabentry = (void *) &(tsmsg->m_entry[i]); return; } } if (tsmsg->m_nentries >= PGSTAT_NUM_TABENTRIES) continue; /* * Not found, but found a message buffer with an empty slot * instead. Fine, let's use this one. */ i = tsmsg->m_nentries++; useent = &tsmsg->m_entry[i]; MemSet(useent, 0, sizeof(PgStat_TableEntry)); useent->t_id = rel_id; stats->tabentry = (void *) useent; return; } /* * If we ran out of message buffers, we just allocate more. */ if (pgStatTabstatUsed >= pgStatTabstatAlloc) more_tabstat_space(); /* * Use the first entry of the next message buffer. */ mb = pgStatTabstatUsed++; tsmsg = pgStatTabstatMessages[mb]; tsmsg->m_nentries = 1; useent = &tsmsg->m_entry[0]; MemSet(useent, 0, sizeof(PgStat_TableEntry)); useent->t_id = rel_id; stats->tabentry = (void *) useent; } /* ---------- * pgstat_count_xact_commit() - * * Called from access/transam/xact.c to count transaction commits. * ---------- */ void pgstat_count_xact_commit(void) { if (!(pgstat_collect_querystring || pgstat_collect_tuplelevel || pgstat_collect_blocklevel)) return; pgStatXactCommit++; /* * If there was no relation activity yet, just make one existing * message buffer used without slots, causing the next report to tell * new xact-counters. */ if (pgStatTabstatAlloc == 0) more_tabstat_space(); if (pgStatTabstatUsed == 0) { pgStatTabstatUsed++; pgStatTabstatMessages[0]->m_nentries = 0; } } /* ---------- * pgstat_count_xact_rollback() - * * Called from access/transam/xact.c to count transaction rollbacks. * ---------- */ void pgstat_count_xact_rollback(void) { if (!(pgstat_collect_querystring || pgstat_collect_tuplelevel || pgstat_collect_blocklevel)) return; pgStatXactRollback++; /* * If there was no relation activity yet, just make one existing * message buffer used without slots, causing the next report to tell * new xact-counters. */ if (pgStatTabstatAlloc == 0) more_tabstat_space(); if (pgStatTabstatUsed == 0) { pgStatTabstatUsed++; pgStatTabstatMessages[0]->m_nentries = 0; } } /* ---------- * pgstat_fetch_stat_dbentry() - * * Support function for the SQL-callable pgstat* functions. Returns * the collected statistics for one database or NULL. NULL doesn't mean * that the database doesn't exist, it is just not yet known by the * collector, so the caller is better off to report ZERO instead. * ---------- */ PgStat_StatDBEntry * pgstat_fetch_stat_dbentry(Oid dbid) { /* * If not done for this transaction, read the statistics collector * stats file into some hash tables. */ backend_read_statsfile(); /* * Lookup the requested database; return NULL if not found */ return (PgStat_StatDBEntry *) hash_search(pgStatDBHash, (void *) &dbid, HASH_FIND, NULL); } /* ---------- * pgstat_fetch_stat_tabentry() - * * Support function for the SQL-callable pgstat* functions. Returns * the collected statistics for one table or NULL. NULL doesn't mean * that the table doesn't exist, it is just not yet known by the * collector, so the caller is better off to report ZERO instead. * ---------- */ PgStat_StatTabEntry * pgstat_fetch_stat_tabentry(Oid relid) { PgStat_StatDBEntry *dbentry; PgStat_StatTabEntry *tabentry; /* * If not done for this transaction, read the statistics collector * stats file into some hash tables. */ backend_read_statsfile(); /* * Lookup our database. */ dbentry = (PgStat_StatDBEntry *) hash_search(pgStatDBHash, (void *) &MyDatabaseId, HASH_FIND, NULL); if (dbentry == NULL) return NULL; /* * Now inside the DB's table hash table lookup the requested one. */ if (dbentry->tables == NULL) return NULL; tabentry = (PgStat_StatTabEntry *) hash_search(dbentry->tables, (void *) &relid, HASH_FIND, NULL); if (tabentry == NULL) return NULL; return tabentry; } /* ---------- * pgstat_fetch_stat_beentry() - * * Support function for the SQL-callable pgstat* functions. Returns * the actual activity slot of one active backend. The caller is * responsible for a check if the actual user is permitted to see * that info (especially the querystring). * ---------- */ PgStat_StatBeEntry * pgstat_fetch_stat_beentry(int beid) { backend_read_statsfile(); if (beid < 1 || beid > pgStatNumBackends) return NULL; return &pgStatBeTable[beid - 1]; } /* ---------- * pgstat_fetch_stat_numbackends() - * * Support function for the SQL-callable pgstat* functions. Returns * the maximum current backend id. * ---------- */ int pgstat_fetch_stat_numbackends(void) { backend_read_statsfile(); return pgStatNumBackends; } /* ------------------------------------------------------------ * Local support functions follow * ------------------------------------------------------------ */ /* ---------- * pgstat_setheader() - * * Set common header fields in a statistics message * ---------- */ static void pgstat_setheader(PgStat_MsgHdr *hdr, int mtype) { hdr->m_type = mtype; hdr->m_backendid = MyBackendId; hdr->m_procpid = MyProcPid; } /* ---------- * pgstat_send() - * * Send out one statistics message to the collector * ---------- */ static void pgstat_send(void *msg, int len) { if (pgStatSock < 0) return; ((PgStat_MsgHdr *) msg)->m_size = len; send(pgStatSock, msg, len, 0); /* We deliberately ignore any error from send() */ } /* ---------- * PgstatBufferMain() - * * Start up the statistics buffer process. This is the body of the * postmaster child process. * * The argc/argv parameters are valid only in EXEC_BACKEND case. * ---------- */ NON_EXEC_STATIC void PgstatBufferMain(int argc, char *argv[]) { IsUnderPostmaster = true; /* we are a postmaster subprocess now */ MyProcPid = getpid(); /* reset MyProcPid */ /* Lose the postmaster's on-exit routines */ on_exit_reset(); /* * Ignore all signals usually bound to some action in the postmaster, * except for SIGCHLD and SIGQUIT --- see pgstat_recvbuffer. */ pqsignal(SIGHUP, SIG_IGN); pqsignal(SIGINT, SIG_IGN); pqsignal(SIGTERM, SIG_IGN); pqsignal(SIGQUIT, pgstat_exit); pqsignal(SIGALRM, SIG_IGN); pqsignal(SIGPIPE, SIG_IGN); pqsignal(SIGUSR1, SIG_IGN); pqsignal(SIGUSR2, SIG_IGN); pqsignal(SIGCHLD, pgstat_die); pqsignal(SIGTTIN, SIG_DFL); pqsignal(SIGTTOU, SIG_DFL); pqsignal(SIGCONT, SIG_DFL); pqsignal(SIGWINCH, SIG_DFL); /* unblock will happen in pgstat_recvbuffer */ #ifdef EXEC_BACKEND pgstat_parseArgs(argc, argv); #endif /* * Start a buffering process to read from the socket, so we have a * little more time to process incoming messages. * * NOTE: the process structure is: postmaster is parent of buffer process * is parent of collector process. This way, the buffer can detect * collector failure via SIGCHLD, whereas otherwise it wouldn't notice * collector failure until it tried to write on the pipe. That would * mean that after the postmaster started a new collector, we'd have * two buffer processes competing to read from the UDP socket --- not * good. */ if (pgpipe(pgStatPipe) < 0) ereport(ERROR, (errcode_for_socket_access(), errmsg("could not create pipe for statistics buffer: %m"))); /* child becomes collector process */ #ifdef EXEC_BACKEND pgStatCollectorPid = pgstat_forkexec(STAT_PROC_COLLECTOR); #else pgStatCollectorPid = fork(); #endif switch (pgStatCollectorPid) { case -1: ereport(ERROR, (errmsg("could not fork statistics collector: %m"))); #ifndef EXEC_BACKEND case 0: /* child becomes collector process */ PgstatCollectorMain(0, NULL); break; #endif default: /* parent becomes buffer process */ closesocket(pgStatPipe[0]); pgstat_recvbuffer(); } exit(0); } /* ---------- * PgstatCollectorMain() - * * Start up the statistics collector itself. This is the body of the * postmaster grandchild process. * * The argc/argv parameters are valid only in EXEC_BACKEND case. * ---------- */ NON_EXEC_STATIC void 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; HASHCTL hash_ctl; MyProcPid = getpid(); /* reset MyProcPid */ /* * Reset signal handling. With the exception of restoring default * SIGCHLD and SIGQUIT handling, this is a no-op in the * non-EXEC_BACKEND case because we'll have inherited these settings * from the buffer process; but it's not a no-op for EXEC_BACKEND. */ pqsignal(SIGHUP, SIG_IGN); pqsignal(SIGINT, SIG_IGN); pqsignal(SIGTERM, SIG_IGN); #ifndef WIN32 pqsignal(SIGQUIT, SIG_IGN); #else /* kluge to allow buffer process to kill collector; FIXME */ pqsignal(SIGQUIT, pgstat_exit); #endif pqsignal(SIGALRM, SIG_IGN); pqsignal(SIGPIPE, SIG_IGN); pqsignal(SIGUSR1, SIG_IGN); pqsignal(SIGUSR2, SIG_IGN); pqsignal(SIGCHLD, SIG_DFL); pqsignal(SIGTTIN, SIG_DFL); pqsignal(SIGTTOU, SIG_DFL); pqsignal(SIGCONT, SIG_DFL); pqsignal(SIGWINCH, SIG_DFL); PG_SETMASK(&UnBlockSig); #ifdef EXEC_BACKEND pgstat_parseArgs(argc, argv); #endif /* Close unwanted files */ closesocket(pgStatPipe[1]); closesocket(pgStatSock); /* * Identify myself via ps */ 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; /* * Read in an existing statistics stats file or initialize the stats * to zero. */ pgStatRunningInCollector = TRUE; pgstat_read_statsfile(&pgStatDBHash, InvalidOid, NULL, NULL); /* * Create the dead backend hashtable */ memset(&hash_ctl, 0, sizeof(hash_ctl)); hash_ctl.keysize = sizeof(int); hash_ctl.entrysize = sizeof(PgStat_StatBeDead); hash_ctl.hash = tag_hash; pgStatBeDead = hash_create("Dead Backends", PGSTAT_BE_HASH_SIZE, &hash_ctl, HASH_ELEM | HASH_FUNCTION); /* * Create the known backends table */ pgStatBeTable = (PgStat_StatBeEntry *) palloc0( sizeof(PgStat_StatBeEntry) * MaxBackends); readPipe = pgStatPipe[0]; /* * Process incoming messages and handle all the reporting stuff until * there are no more messages. */ 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; } } } /* * Setup the descriptor set for select(2) */ FD_ZERO(&rfds); FD_SET(readPipe, &rfds); /* * Now wait for something to do. */ nready = select(readPipe + 1, &rfds, NULL, NULL, (need_statwrite) ? &timeout : NULL); if (nready < 0) { if (errno == EINTR) continue; ereport(ERROR, (errcode_for_socket_access(), 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. */ if (FD_ISSET(readPipe, &rfds)) { /* * We may need to issue multiple read calls in case the buffer * process didn't write the message in a single write, which * is possible since it dumps its buffer bytewise. In any * case, we'd need two reads since we don't know the message * length initially. */ int nread = 0; int targetlen = sizeof(PgStat_MsgHdr); /* initial */ bool pipeEOF = false; while (nread < targetlen) { len = piperead(readPipe, ((char *) &msg) + nread, targetlen - nread); if (len < 0) { if (errno == EINTR) continue; ereport(ERROR, (errcode_for_socket_access(), errmsg("could not read from statistics collector pipe: %m"))); } if (len == 0) /* EOF on the pipe! */ { pipeEOF = true; break; } nread += len; if (nread == sizeof(PgStat_MsgHdr)) { /* we have the header, compute actual msg length */ targetlen = msg.msg_hdr.m_size; if (targetlen < (int) sizeof(PgStat_MsgHdr) || targetlen > (int) sizeof(msg)) { /* * Bogus message length implies that we got out of * sync with the buffer process somehow. Abort so * that we can restart both processes. */ ereport(ERROR, (errmsg("invalid statistics message length"))); } } } /* * EOF on the pipe implies that the buffer process exited. * Fall out of outer loop. */ if (pipeEOF) break; /* * Distribute the message to the specific function handling * it. */ switch (msg.msg_hdr.m_type) { case PGSTAT_MTYPE_DUMMY: break; case PGSTAT_MTYPE_BESTART: pgstat_recv_bestart((PgStat_MsgBestart *) &msg, nread); break; case PGSTAT_MTYPE_BETERM: pgstat_recv_beterm((PgStat_MsgBeterm *) &msg, nread); break; case PGSTAT_MTYPE_TABSTAT: pgstat_recv_tabstat((PgStat_MsgTabstat *) &msg, nread); break; case PGSTAT_MTYPE_TABPURGE: pgstat_recv_tabpurge((PgStat_MsgTabpurge *) &msg, nread); break; case PGSTAT_MTYPE_ACTIVITY: pgstat_recv_activity((PgStat_MsgActivity *) &msg, nread); break; case PGSTAT_MTYPE_DROPDB: pgstat_recv_dropdb((PgStat_MsgDropdb *) &msg, nread); break; case PGSTAT_MTYPE_RESETCOUNTER: pgstat_recv_resetcounter((PgStat_MsgResetcounter *) &msg, nread); break; default: break; } /* * Globally count messages. */ 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) { 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; } } /* * Note that we do NOT check for postmaster exit inside the loop; * only EOF on the buffer pipe causes us to fall out. This * ensures we don't exit prematurely if there are still a few * messages in the buffer or pipe at postmaster shutdown. */ } /* * Okay, we saw EOF on the buffer pipe, so there are no more messages * to process. If the buffer process quit because of postmaster * shutdown, we want to save the final stats to reuse at next startup. * But if the buffer process failed, it seems best not to (there may * even now be a new collector firing up, and we don't want it to read * a partially-rewritten stats file). */ if (!PostmasterIsAlive(false)) pgstat_write_statsfile(); } /* ---------- * pgstat_recvbuffer() - * * This is the body of the separate buffering process. Its only * purpose is to receive messages from the UDP socket as fast as * possible and forward them over a pipe into the collector itself. * If the collector is slow to absorb messages, they are buffered here. * ---------- */ static void pgstat_recvbuffer(void) { fd_set rfds; fd_set wfds; struct timeval timeout; int writePipe = pgStatPipe[1]; int maxfd; int nready; int len; int xfr; int frm; PgStat_Msg input_buffer; char *msgbuffer; int msg_send = 0; /* next send index in buffer */ int msg_recv = 0; /* next receive index */ int msg_have = 0; /* number of bytes stored */ bool overflow = false; /* * Identify myself via ps */ init_ps_display("stats buffer process", "", ""); set_ps_display(""); /* * We want to die if our child collector process does. There are two * ways we might notice that it has died: receive SIGCHLD, or get a * write failure on the pipe leading to the child. We can set SIGPIPE * to kill us here. Our SIGCHLD handler was already set up before we * forked (must do it that way, else it's a race condition). */ pqsignal(SIGPIPE, SIG_DFL); PG_SETMASK(&UnBlockSig); /* * Set the write pipe to nonblock mode, so that we cannot block when * the collector falls behind. */ if (!pg_set_noblock(writePipe)) ereport(ERROR, (errcode_for_socket_access(), errmsg("could not set statistics collector pipe to nonblocking mode: %m"))); /* * Allocate the message buffer */ msgbuffer = (char *) palloc(PGSTAT_RECVBUFFERSZ); /* * Loop forever */ for (;;) { FD_ZERO(&rfds); FD_ZERO(&wfds); maxfd = -1; /* * As long as we have buffer space we add the socket to the read * descriptor set. */ if (msg_have <= (int) (PGSTAT_RECVBUFFERSZ - sizeof(PgStat_Msg))) { FD_SET(pgStatSock, &rfds); maxfd = pgStatSock; overflow = false; } else { if (!overflow) { ereport(LOG, (errmsg("statistics buffer is full"))); overflow = true; } } /* * If we have messages to write out, we add the pipe to the write * descriptor set. */ if (msg_have > 0) { FD_SET(writePipe, &wfds); if (writePipe > maxfd) 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 (errno == EINTR) continue; ereport(ERROR, (errcode_for_socket_access(), errmsg("select() failed in statistics buffer: %m"))); } /* * If there is a message on the socket, read it and check for * validity. */ if (FD_ISSET(pgStatSock, &rfds)) { len = recv(pgStatSock, (char *) &input_buffer, sizeof(PgStat_Msg), 0); if (len < 0) ereport(ERROR, (errcode_for_socket_access(), errmsg("could not read statistics message: %m"))); /* * We ignore messages that are smaller than our common header */ if (len < sizeof(PgStat_MsgHdr)) continue; /* * The received length must match the length in the header */ if (input_buffer.msg_hdr.m_size != len) continue; /* * O.K. - we accept this message. Copy it to the circular * msgbuffer. */ frm = 0; while (len > 0) { xfr = PGSTAT_RECVBUFFERSZ - msg_recv; if (xfr > len) xfr = len; Assert(xfr > 0); memcpy(msgbuffer + msg_recv, ((char *) &input_buffer) + frm, xfr); msg_recv += xfr; if (msg_recv == PGSTAT_RECVBUFFERSZ) msg_recv = 0; msg_have += xfr; frm += xfr; len -= xfr; } } /* * If the collector is ready to receive, write some data into his * pipe. We may or may not be able to write all that we have. * * NOTE: if what we have is less than PIPE_BUF bytes but more than * the space available in the pipe buffer, most kernels will * refuse to write any of it, and will return EAGAIN. This means * we will busy-loop until the situation changes (either because * the collector caught up, or because more data arrives so that * we have more than PIPE_BUF bytes buffered). This is not good, * but is there any way around it? We have no way to tell when * the collector has caught up... */ if (FD_ISSET(writePipe, &wfds)) { xfr = PGSTAT_RECVBUFFERSZ - msg_send; if (xfr > msg_have) xfr = msg_have; Assert(xfr > 0); len = pipewrite(writePipe, msgbuffer + msg_send, xfr); if (len < 0) { if (errno == EINTR || errno == EAGAIN) continue; /* not enough space in pipe */ ereport(ERROR, (errcode_for_socket_access(), errmsg("could not write to statistics collector pipe: %m"))); } /* NB: len < xfr is okay */ msg_send += len; if (msg_send == PGSTAT_RECVBUFFERSZ) msg_send = 0; msg_have -= len; } /* * Make sure we forwarded all messages before we check for * postmaster termination. */ if (msg_have != 0 || FD_ISSET(pgStatSock, &rfds)) continue; /* * If the postmaster has terminated, we die too. (This is no * longer the normal exit path, however.) */ if (!PostmasterIsAlive(true)) exit(0); } } /* SIGQUIT signal handler for buffer process */ static void pgstat_exit(SIGNAL_ARGS) { /* * For now, we just nail the doors shut and get out of town. It might * be cleaner to allow any pending messages to be sent, but that * creates a tradeoff against speed of exit. */ /* * If running in bufferer, kill our collector as well. On some broken * win32 systems, it does not shut down automatically because of issues * with socket inheritance. XXX so why not fix the socket inheritance... */ #ifdef WIN32 if (pgStatCollectorPid > 0) kill(pgStatCollectorPid, SIGQUIT); #endif exit(0); } /* SIGCHLD signal handler for buffer process */ static void pgstat_die(SIGNAL_ARGS) { exit(1); } /* ---------- * pgstat_add_backend() - * * Support function to keep our backend list up to date. * ---------- */ static int pgstat_add_backend(PgStat_MsgHdr *msg) { PgStat_StatBeEntry *beentry; PgStat_StatBeDead *deadbe; /* * Check that the backend ID is valid */ if (msg->m_backendid < 1 || msg->m_backendid > MaxBackends) { ereport(LOG, (errmsg("invalid server process ID %d", msg->m_backendid))); return -1; } /* * Get the slot for this backendid. */ beentry = &pgStatBeTable[msg->m_backendid - 1]; /* * If the slot contains the PID of this backend, everything is * fine and we have nothing to do. Note that all the slots are * zero'd out when the collector is started. We assume that a slot * is "empty" iff procpid == 0. */ if (beentry->procpid > 0 && beentry->procpid == msg->m_procpid) return 0; /* * Lookup if this backend is known to be dead. This can be caused due * to messages arriving in the wrong order - e.g. postmaster's BETERM * message might have arrived before we received all the backends * stats messages, or even a new backend with the same backendid was * faster in sending his BESTART. * * If the backend is known to be dead, we ignore this add. */ deadbe = (PgStat_StatBeDead *) hash_search(pgStatBeDead, (void *) &(msg->m_procpid), HASH_FIND, NULL); if (deadbe) return 1; /* * Backend isn't known to be dead. If it's slot is currently used, we * have to kick out the old backend. */ if (beentry->procpid > 0) pgstat_sub_backend(beentry->procpid); /* Must be able to distinguish between empty and non-empty slots */ Assert(msg->m_procpid > 0); /* Put this new backend into the slot */ beentry->procpid = msg->m_procpid; beentry->start_timestamp = GetCurrentTimestamp(); beentry->activity_start_timestamp = 0; beentry->activity[0] = '\0'; /* * We can't initialize the rest of the data in this slot until we * see the BESTART message. Therefore, we set the database and * user to sentinel values, to indicate "undefined". There is no * easy way to do this for the client address, so make sure to * check that the database or user are defined before accessing * the client address. */ beentry->userid = InvalidOid; beentry->databaseid = InvalidOid; return 0; } /* * Lookup the hash table entry for the specified database. If no hash * table entry exists, initialize it. */ static PgStat_StatDBEntry * pgstat_get_db_entry(Oid databaseid) { PgStat_StatDBEntry *result; bool found; /* Lookup or create the hash table entry for this database */ result = (PgStat_StatDBEntry *) hash_search(pgStatDBHash, &databaseid, HASH_ENTER, &found); /* If not found, initialize the new one. */ if (!found) { HASHCTL hash_ctl; result->tables = NULL; result->n_xact_commit = 0; result->n_xact_rollback = 0; result->n_blocks_fetched = 0; result->n_blocks_hit = 0; result->destroy = 0; memset(&hash_ctl, 0, sizeof(hash_ctl)); hash_ctl.keysize = sizeof(Oid); hash_ctl.entrysize = sizeof(PgStat_StatTabEntry); hash_ctl.hash = oid_hash; result->tables = hash_create("Per-database table", PGSTAT_TAB_HASH_SIZE, &hash_ctl, HASH_ELEM | HASH_FUNCTION); } return result; } /* ---------- * pgstat_sub_backend() - * * Remove a backend from the actual backends list. * ---------- */ static void pgstat_sub_backend(int procpid) { int i; PgStat_StatBeDead *deadbe; bool found; /* * Search in the known-backends table for the slot containing this * PID. */ for (i = 0; i < MaxBackends; i++) { if (pgStatBeTable[i].procpid == procpid) { /* * That's him. Add an entry to the known to be dead backends. * Due to possible misorder in the arrival of UDP packets it's * possible that even if we know the backend is dead, there * could still be messages queued that arrive later. Those * messages must not cause our number of backends statistics * to get screwed up, so we remember for a couple of seconds * that this PID is dead and ignore them (only the counting of * backends, not the table access stats they sent). */ deadbe = (PgStat_StatBeDead *) hash_search(pgStatBeDead, (void *) &procpid, HASH_ENTER, &found); if (!found) { deadbe->backendid = i + 1; deadbe->destroy = PGSTAT_DESTROY_COUNT; } /* * Declare the backend slot empty. */ pgStatBeTable[i].procpid = 0; return; } } /* * No big problem if not found. This can happen if UDP messages arrive * out of order here. */ } /* ---------- * pgstat_write_statsfile() - * * Tell the news. * ---------- */ static void pgstat_write_statsfile(void) { HASH_SEQ_STATUS hstat; HASH_SEQ_STATUS tstat; PgStat_StatDBEntry *dbentry; PgStat_StatTabEntry *tabentry; PgStat_StatBeDead *deadbe; FILE *fpout; int i; /* * Open the statistics temp file to write out the current values. */ fpout = fopen(PGSTAT_STAT_TMPFILE, PG_BINARY_W); if (fpout == NULL) { ereport(LOG, (errcode_for_file_access(), errmsg("could not open temporary statistics file \"%s\": %m", PGSTAT_STAT_TMPFILE))); return; } /* * Walk through the database table. */ hash_seq_init(&hstat, pgStatDBHash); while ((dbentry = (PgStat_StatDBEntry *) hash_seq_search(&hstat)) != NULL) { /* * If this database is marked destroyed, count down and do so if * it reaches 0. */ if (dbentry->destroy > 0) { if (--(dbentry->destroy) == 0) { if (dbentry->tables != NULL) hash_destroy(dbentry->tables); if (hash_search(pgStatDBHash, (void *) &(dbentry->databaseid), HASH_REMOVE, NULL) == NULL) ereport(ERROR, (errmsg("database hash table corrupted " "during cleanup --- abort"))); } /* * Don't include statistics for it. */ continue; } /* * Write out the DB line including the number of life backends. */ fputc('D', fpout); fwrite(dbentry, sizeof(PgStat_StatDBEntry), 1, fpout); /* * Walk through the databases access stats per table. */ hash_seq_init(&tstat, dbentry->tables); while ((tabentry = (PgStat_StatTabEntry *) hash_seq_search(&tstat)) != NULL) { /* * If table entry marked for destruction, same as above for * the database entry. */ if (tabentry->destroy > 0) { if (--(tabentry->destroy) == 0) { if (hash_search(dbentry->tables, (void *) &(tabentry->tableid), HASH_REMOVE, NULL) == NULL) { ereport(ERROR, (errmsg("tables hash table for " "database %u corrupted during " "cleanup --- abort", dbentry->databaseid))); } } continue; } /* * At least we think this is still a life table. Print it's * access stats. */ fputc('T', fpout); fwrite(tabentry, sizeof(PgStat_StatTabEntry), 1, fpout); } /* * Mark the end of this DB */ fputc('d', fpout); } /* * Write out the known running backends to the stats file. */ i = MaxBackends; fputc('M', fpout); fwrite(&i, sizeof(i), 1, fpout); for (i = 0; i < MaxBackends; i++) { if (pgStatBeTable[i].procpid > 0) { fputc('B', fpout); fwrite(&pgStatBeTable[i], sizeof(PgStat_StatBeEntry), 1, fpout); } } /* * No more output to be done. Close the temp file and replace the old * pgstat.stat with it. */ fputc('E', fpout); if (fclose(fpout) < 0) { ereport(LOG, (errcode_for_file_access(), errmsg("could not close temporary statistics file \"%s\": %m", PGSTAT_STAT_TMPFILE))); } else { if (rename(PGSTAT_STAT_TMPFILE, PGSTAT_STAT_FILENAME) < 0) { ereport(LOG, (errcode_for_file_access(), errmsg("could not rename temporary statistics file \"%s\" to \"%s\": %m", PGSTAT_STAT_TMPFILE, PGSTAT_STAT_FILENAME))); } } /* * Clear out the dead backends table */ hash_seq_init(&hstat, pgStatBeDead); while ((deadbe = (PgStat_StatBeDead *) hash_seq_search(&hstat)) != NULL) { /* * Count down the destroy delay and remove entries where it * reaches 0. */ if (--(deadbe->destroy) <= 0) { if (hash_search(pgStatBeDead, (void *) &(deadbe->procpid), HASH_REMOVE, NULL) == NULL) { ereport(ERROR, (errmsg("dead-server-process hash table corrupted " "during cleanup --- abort"))); } } } } /* ---------- * pgstat_read_statsfile() - * * Reads in an existing statistics collector and initializes the * databases hash table (who's entries point to the tables hash tables) * and the current backend table. * ---------- */ static void pgstat_read_statsfile(HTAB **dbhash, Oid onlydb, PgStat_StatBeEntry **betab, int *numbackends) { PgStat_StatDBEntry *dbentry; PgStat_StatDBEntry dbbuf; PgStat_StatTabEntry *tabentry; PgStat_StatTabEntry tabbuf; HASHCTL hash_ctl; HTAB *tabhash = NULL; FILE *fpin; int maxbackends = 0; int havebackends = 0; bool found; MemoryContext use_mcxt; int mcxt_flags; /* * If running in the collector we use the DynaHashCxt memory context. * If running in a backend, we use the TopTransactionContext instead, * so the caller must only know the last XactId when this call * happened to know if his tables are still valid or already gone! */ if (pgStatRunningInCollector) { use_mcxt = NULL; mcxt_flags = 0; } else { use_mcxt = TopTransactionContext; mcxt_flags = HASH_CONTEXT; } /* * Create the DB hashtable */ memset(&hash_ctl, 0, sizeof(hash_ctl)); hash_ctl.keysize = sizeof(Oid); hash_ctl.entrysize = sizeof(PgStat_StatDBEntry); hash_ctl.hash = oid_hash; hash_ctl.hcxt = use_mcxt; *dbhash = hash_create("Databases hash", PGSTAT_DB_HASH_SIZE, &hash_ctl, HASH_ELEM | HASH_FUNCTION | mcxt_flags); /* * Initialize the number of known backends to zero, just in case we do * a silent error return below. */ if (numbackends != NULL) *numbackends = 0; if (betab != NULL) *betab = NULL; /* * Try to open the status file. If it doesn't exist, the backends * simply return zero for anything and the collector simply starts * from scratch with empty counters. */ if ((fpin = AllocateFile(PGSTAT_STAT_FILENAME, PG_BINARY_R)) == NULL) return; /* * We found an existing collector stats file. Read it and put all the * hashtable entries into place. */ for (;;) { switch (fgetc(fpin)) { /* * 'D' A PgStat_StatDBEntry struct describing a database * follows. Subsequently, zero to many 'T' entries will * follow until a 'd' is encountered. */ case 'D': if (fread(&dbbuf, 1, sizeof(dbbuf), fpin) != sizeof(dbbuf)) { ereport(pgStatRunningInCollector ? LOG : WARNING, (errmsg("corrupted pgstat.stat file"))); goto done; } /* * Add to the DB hash */ dbentry = (PgStat_StatDBEntry *) hash_search(*dbhash, (void *) &dbbuf.databaseid, HASH_ENTER, &found); if (found) { ereport(pgStatRunningInCollector ? LOG : WARNING, (errmsg("corrupted pgstat.stat file"))); goto done; } memcpy(dbentry, &dbbuf, sizeof(PgStat_StatDBEntry)); dbentry->tables = NULL; dbentry->destroy = 0; dbentry->n_backends = 0; /* * Don't collect tables if not the requested DB */ if (onlydb != InvalidOid && onlydb != dbbuf.databaseid) break; memset(&hash_ctl, 0, sizeof(hash_ctl)); hash_ctl.keysize = sizeof(Oid); hash_ctl.entrysize = sizeof(PgStat_StatTabEntry); hash_ctl.hash = oid_hash; hash_ctl.hcxt = use_mcxt; dbentry->tables = hash_create("Per-database table", PGSTAT_TAB_HASH_SIZE, &hash_ctl, HASH_ELEM | HASH_FUNCTION | mcxt_flags); /* * Arrange that following 'T's add entries to this * databases tables hash table. */ tabhash = dbentry->tables; break; /* * 'd' End of this database. */ case 'd': tabhash = NULL; break; /* * 'T' A PgStat_StatTabEntry follows. */ case 'T': if (fread(&tabbuf, 1, sizeof(tabbuf), fpin) != sizeof(tabbuf)) { ereport(pgStatRunningInCollector ? LOG : WARNING, (errmsg("corrupted pgstat.stat file"))); goto done; } /* * Skip if table belongs to a not requested database. */ if (tabhash == NULL) break; tabentry = (PgStat_StatTabEntry *) hash_search(tabhash, (void *) &tabbuf.tableid, HASH_ENTER, &found); if (found) { ereport(pgStatRunningInCollector ? LOG : WARNING, (errmsg("corrupted pgstat.stat file"))); goto done; } memcpy(tabentry, &tabbuf, sizeof(tabbuf)); break; /* * 'M' The maximum number of backends to expect follows. */ case 'M': if (betab == NULL || numbackends == NULL) goto done; if (fread(&maxbackends, 1, sizeof(maxbackends), fpin) != sizeof(maxbackends)) { ereport(pgStatRunningInCollector ? LOG : WARNING, (errmsg("corrupted pgstat.stat file"))); goto done; } if (maxbackends == 0) goto done; /* * Allocate space (in TopTransactionContext too) for the * backend table. */ if (use_mcxt == NULL) *betab = (PgStat_StatBeEntry *) palloc( sizeof(PgStat_StatBeEntry) * maxbackends); else *betab = (PgStat_StatBeEntry *) MemoryContextAlloc( use_mcxt, sizeof(PgStat_StatBeEntry) * maxbackends); break; /* * 'B' A PgStat_StatBeEntry follows. */ case 'B': if (betab == NULL || numbackends == NULL || *betab == NULL) goto done; /* * Read it directly into the table. */ if (fread(&(*betab)[havebackends], 1, sizeof(PgStat_StatBeEntry), fpin) != sizeof(PgStat_StatBeEntry)) { ereport(pgStatRunningInCollector ? LOG : WARNING, (errmsg("corrupted pgstat.stat file"))); goto done; } /* * Count backends per database here. */ dbentry = (PgStat_StatDBEntry *) hash_search(*dbhash, (void *) &((*betab)[havebackends].databaseid), HASH_FIND, NULL); if (dbentry) dbentry->n_backends++; havebackends++; if (numbackends != 0) *numbackends = havebackends; if (havebackends >= maxbackends) goto done; break; /* * 'E' The EOF marker of a complete stats file. */ case 'E': goto done; default: ereport(pgStatRunningInCollector ? LOG : WARNING, (errmsg("corrupted pgstat.stat file"))); goto done; } } done: FreeFile(fpin); } /* * If not done for this transaction, read the statistics collector * stats file into some hash tables. * * Because we store the hash tables in TopTransactionContext, the result * is good for the entire current main transaction. */ static void backend_read_statsfile(void) { TransactionId topXid = GetTopTransactionId(); if (!TransactionIdEquals(pgStatDBHashXact, topXid)) { Assert(!pgStatRunningInCollector); pgstat_read_statsfile(&pgStatDBHash, MyDatabaseId, &pgStatBeTable, &pgStatNumBackends); pgStatDBHashXact = topXid; } } /* ---------- * pgstat_recv_bestart() - * * Process a backend startup message. * ---------- */ static void pgstat_recv_bestart(PgStat_MsgBestart *msg, int len) { PgStat_StatBeEntry *entry; /* * If the backend is known dead, we ignore the message -- we don't * want to update the backend entry's state since this BESTART * message refers to an old, dead backend */ if (pgstat_add_backend(&msg->m_hdr) != 0) return; entry = &(pgStatBeTable[msg->m_hdr.m_backendid - 1]); entry->userid = msg->m_userid; memcpy(&entry->clientaddr, &msg->m_clientaddr, sizeof(entry->clientaddr)); entry->databaseid = msg->m_databaseid; } /* ---------- * pgstat_recv_beterm() - * * Process a backend termination message. * ---------- */ static void pgstat_recv_beterm(PgStat_MsgBeterm *msg, int len) { pgstat_sub_backend(msg->m_hdr.m_procpid); } /* ---------- * pgstat_recv_activity() - * * Remember what the backend is doing. * ---------- */ static void pgstat_recv_activity(PgStat_MsgActivity *msg, int len) { PgStat_StatBeEntry *entry; /* * Here we check explicitly for 0 return, since we don't want to * mangle the activity of an active backend by a delayed packet from a * dead one. */ if (pgstat_add_backend(&msg->m_hdr) != 0) return; entry = &(pgStatBeTable[msg->m_hdr.m_backendid - 1]); StrNCpy(entry->activity, msg->m_what, PGSTAT_ACTIVITY_SIZE); entry->activity_start_timestamp = GetCurrentTimestamp(); } /* ---------- * pgstat_recv_tabstat() - * * Count what the backend has done. * ---------- */ static void pgstat_recv_tabstat(PgStat_MsgTabstat *msg, int len) { PgStat_TableEntry *tabmsg = &(msg->m_entry[0]); PgStat_StatDBEntry *dbentry; PgStat_StatTabEntry *tabentry; int i; bool found; /* * Make sure the backend is counted for. */ if (pgstat_add_backend(&msg->m_hdr) < 0) return; dbentry = pgstat_get_db_entry(msg->m_databaseid); /* * If the database is marked for destroy, this is a delayed UDP packet * and not worth being counted. */ if (dbentry->destroy > 0) return; dbentry->n_xact_commit += (PgStat_Counter) (msg->m_xact_commit); dbentry->n_xact_rollback += (PgStat_Counter) (msg->m_xact_rollback); /* * Process all table entries in the message. */ for (i = 0; i < msg->m_nentries; i++) { tabentry = (PgStat_StatTabEntry *) hash_search(dbentry->tables, (void *) &(tabmsg[i].t_id), HASH_ENTER, &found); if (!found) { /* * If it's a new table entry, initialize counters to the * values we just got. */ tabentry->numscans = tabmsg[i].t_numscans; tabentry->tuples_returned = tabmsg[i].t_tuples_returned; tabentry->tuples_fetched = tabmsg[i].t_tuples_fetched; tabentry->tuples_inserted = tabmsg[i].t_tuples_inserted; tabentry->tuples_updated = tabmsg[i].t_tuples_updated; tabentry->tuples_deleted = tabmsg[i].t_tuples_deleted; tabentry->blocks_fetched = tabmsg[i].t_blocks_fetched; tabentry->blocks_hit = tabmsg[i].t_blocks_hit; tabentry->destroy = 0; } else { /* * Otherwise add the values to the existing entry. */ tabentry->numscans += tabmsg[i].t_numscans; tabentry->tuples_returned += tabmsg[i].t_tuples_returned; tabentry->tuples_fetched += tabmsg[i].t_tuples_fetched; tabentry->tuples_inserted += tabmsg[i].t_tuples_inserted; tabentry->tuples_updated += tabmsg[i].t_tuples_updated; tabentry->tuples_deleted += tabmsg[i].t_tuples_deleted; tabentry->blocks_fetched += tabmsg[i].t_blocks_fetched; tabentry->blocks_hit += tabmsg[i].t_blocks_hit; } /* * And add the block IO to the database entry. */ dbentry->n_blocks_fetched += tabmsg[i].t_blocks_fetched; dbentry->n_blocks_hit += tabmsg[i].t_blocks_hit; } } /* ---------- * pgstat_recv_tabpurge() - * * Arrange for dead table removal. * ---------- */ static void pgstat_recv_tabpurge(PgStat_MsgTabpurge *msg, int len) { PgStat_StatDBEntry *dbentry; PgStat_StatTabEntry *tabentry; int i; /* * Make sure the backend is counted for. */ if (pgstat_add_backend(&msg->m_hdr) < 0) return; dbentry = pgstat_get_db_entry(msg->m_databaseid); /* * If the database is marked for destroy, this is a delayed UDP packet * and the tables will go away at DB destruction. */ if (dbentry->destroy > 0) return; /* * Process all table entries in the message. */ for (i = 0; i < msg->m_nentries; i++) { tabentry = (PgStat_StatTabEntry *) hash_search(dbentry->tables, (void *) &(msg->m_tableid[i]), HASH_FIND, NULL); if (tabentry) tabentry->destroy = PGSTAT_DESTROY_COUNT; } } /* ---------- * pgstat_recv_dropdb() - * * Arrange for dead database removal * ---------- */ static void pgstat_recv_dropdb(PgStat_MsgDropdb *msg, int len) { PgStat_StatDBEntry *dbentry; /* * Make sure the backend is counted for. */ if (pgstat_add_backend(&msg->m_hdr) < 0) return; /* * Lookup the database in the hashtable. */ dbentry = pgstat_get_db_entry(msg->m_databaseid); /* * Mark the database for destruction. */ dbentry->destroy = PGSTAT_DESTROY_COUNT; } /* ---------- * pgstat_recv_resetcounter() - * * Reset the statistics for the specified database. * ---------- */ static void pgstat_recv_resetcounter(PgStat_MsgResetcounter *msg, int len) { HASHCTL hash_ctl; PgStat_StatDBEntry *dbentry; /* * Make sure the backend is counted for. */ if (pgstat_add_backend(&msg->m_hdr) < 0) return; /* * Lookup the database in the hashtable. */ dbentry = pgstat_get_db_entry(msg->m_databaseid); /* * We simply throw away all the database's table entries by * recreating a new hash table for them. */ if (dbentry->tables != NULL) hash_destroy(dbentry->tables); dbentry->tables = NULL; dbentry->n_xact_commit = 0; dbentry->n_xact_rollback = 0; dbentry->n_blocks_fetched = 0; dbentry->n_blocks_hit = 0; dbentry->destroy = 0; memset(&hash_ctl, 0, sizeof(hash_ctl)); hash_ctl.keysize = sizeof(Oid); hash_ctl.entrysize = sizeof(PgStat_StatTabEntry); hash_ctl.hash = oid_hash; dbentry->tables = hash_create("Per-database table", PGSTAT_TAB_HASH_SIZE, &hash_ctl, HASH_ELEM | HASH_FUNCTION); }