Ensure that we retry rather than erroring out when send() or recv() return
EINTR; the stats code was failing to do this and so were a couple of places in the postmaster. The stats code assumed that recv() could not return EINTR if a preceding select() showed the socket to be read-ready, but this is demonstrably false with our Windows implementation of recv(), and it may not be the case on all Unix variants either. I think this explains the intermittent stats regression test failures we've been seeing, as well as reports of stats collector instability under high load on Windows. Backpatch as far as 8.0.
This commit is contained in:
parent
a420818d67
commit
e96373aae5
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@ -13,7 +13,7 @@
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*
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* Copyright (c) 2001-2006, PostgreSQL Global Development Group
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*
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* $PostgreSQL: pgsql/src/backend/postmaster/pgstat.c,v 1.135 2006/07/14 14:52:22 momjian Exp $
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* $PostgreSQL: pgsql/src/backend/postmaster/pgstat.c,v 1.136 2006/07/16 18:17:14 tgl Exp $
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* ----------
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*/
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#include "postgres.h"
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@ -323,8 +323,12 @@ pgstat_init(void)
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* rules prevent it).
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*/
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test_byte = TESTBYTEVAL;
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retry1:
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if (send(pgStatSock, &test_byte, 1, 0) != 1)
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{
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if (errno == EINTR)
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goto retry1; /* if interrupted, just retry */
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ereport(LOG,
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(errcode_for_socket_access(),
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errmsg("could not send test message on socket for statistics collector: %m")));
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@ -375,8 +379,11 @@ pgstat_init(void)
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test_byte++; /* just make sure variable is changed */
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retry2:
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if (recv(pgStatSock, &test_byte, 1, 0) != 1)
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{
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if (errno == EINTR)
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goto retry2; /* if interrupted, just retry */
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ereport(LOG,
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(errcode_for_socket_access(),
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errmsg("could not receive test message on socket for statistics collector: %m")));
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@ -1533,17 +1540,23 @@ pgstat_setheader(PgStat_MsgHdr *hdr, StatMsgType mtype)
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static void
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pgstat_send(void *msg, int len)
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{
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int rc;
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if (pgStatSock < 0)
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return;
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((PgStat_MsgHdr *) msg)->m_size = len;
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/* We'll retry after EINTR, but ignore all other failures */
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do
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{
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rc = send(pgStatSock, msg, len, 0);
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} while (rc < 0 && errno == EINTR);
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#ifdef USE_ASSERT_CHECKING
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if (send(pgStatSock, msg, len, 0) < 0)
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/* In debug builds, log send failures ... */
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if (rc < 0)
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elog(LOG, "could not send to statistics collector: %m");
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#else
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send(pgStatSock, msg, len, 0);
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/* We deliberately ignore any error from send() */
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#endif
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}
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@ -1718,9 +1731,13 @@ PgstatCollectorMain(int argc, char *argv[])
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len = recv(pgStatSock, (char *) &msg,
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sizeof(PgStat_Msg), 0);
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if (len < 0)
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{
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if (errno == EINTR)
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continue;
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ereport(ERROR,
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(errcode_for_socket_access(),
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errmsg("could not read statistics message: %m")));
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}
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/*
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* We ignore messages that are smaller than our common header
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@ -37,7 +37,7 @@
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/postmaster/postmaster.c,v 1.494 2006/07/15 15:47:17 tgl Exp $
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* $PostgreSQL: pgsql/src/backend/postmaster/postmaster.c,v 1.495 2006/07/16 18:17:14 tgl Exp $
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*
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* NOTES
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*
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@ -1374,8 +1374,12 @@ ProcessStartupPacket(Port *port, bool SSLdone)
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#else
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SSLok = 'N'; /* No support for SSL */
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#endif
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retry1:
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if (send(port->sock, &SSLok, 1, 0) != 1)
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{
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if (errno == EINTR)
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goto retry1; /* if interrupted, just retry */
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ereport(COMMERROR,
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(errcode_for_socket_access(),
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errmsg("failed to send SSL negotiation response: %m")));
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report_fork_failure_to_client(Port *port, int errnum)
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{
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char buffer[1000];
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int rc;
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/* Format the error message packet (always V2 protocol) */
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snprintf(buffer, sizeof(buffer), "E%s%s\n",
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if (!pg_set_noblock(port->sock))
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return;
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send(port->sock, buffer, strlen(buffer) + 1, 0);
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/* We'll retry after EINTR, but ignore all other failures */
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do
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{
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rc = send(port->sock, buffer, strlen(buffer) + 1, 0);
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} while (rc < 0 && errno == EINTR);
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}
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