From fe85fd375c89a85a84e47a88f01a9d629a8abb09 Mon Sep 17 00:00:00 2001 From: Bertrand Drouvot Date: Tue, 6 Jan 2026 11:06:31 +0000 Subject: [PATCH v4 3/4] Remove useless calls to flush some stats Now that some stats can be flushed outside of transaction boundaries, remove useless calls to report/flush some stats. Those calls were in place because before commit stats were flushed only at transaction boundaries. Note that: - it reverts 039549d70f6 (it just keeps its tests) - it can't be done for checkpointer and bgworker for example because they don't have a flush callback to call - it can't be done for auxiliary process (walsummarizer for example) because they currently do not register the new timeout handler --- src/backend/replication/walreceiver.c | 10 ------ src/backend/replication/walsender.c | 36 ++------------------ src/backend/utils/activity/pgstat_relation.c | 13 ------- src/test/recovery/t/001_stream_rep.pl | 1 + src/test/subscription/t/001_rep_changes.pl | 1 + 5 files changed, 4 insertions(+), 57 deletions(-) 69.9% src/backend/replication/ 22.8% src/backend/utils/activity/ 3.5% src/test/recovery/t/ 3.6% src/test/subscription/t/ diff --git a/src/backend/replication/walreceiver.c b/src/backend/replication/walreceiver.c index 6970af3f3ff..dcbe3517b46 100644 --- a/src/backend/replication/walreceiver.c +++ b/src/backend/replication/walreceiver.c @@ -565,16 +565,6 @@ WalReceiverMain(const void *startup_data, size_t startup_data_len) */ bool requestReply = false; - /* - * Report pending statistics to the cumulative stats - * system. This location is useful for the report as it - * is not within a tight loop in the WAL receiver, to - * avoid bloating pgstats with requests, while also making - * sure that the reports happen each time a status update - * is sent. - */ - pgstat_report_wal(false); - /* * Check if time since last receive from primary has * reached the configured limit. diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index a0e6a3d200c..74102def9c7 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -94,14 +94,10 @@ #include "utils/lsyscache.h" #include "utils/memutils.h" #include "utils/pg_lsn.h" -#include "utils/pgstat_internal.h" #include "utils/ps_status.h" #include "utils/timeout.h" #include "utils/timestamp.h" -/* Minimum interval used by walsender for stats flushes, in ms */ -#define WALSENDER_STATS_FLUSH_INTERVAL 1000 - /* * Maximum data payload in a WAL data message. Must be >= XLOG_BLCKSZ. * @@ -1825,7 +1821,6 @@ WalSndWaitForWal(XLogRecPtr loc) int wakeEvents; uint32 wait_event = 0; static XLogRecPtr RecentFlushPtr = InvalidXLogRecPtr; - TimestampTz last_flush = 0; /* * Fast path to avoid acquiring the spinlock in case we already know we @@ -1846,7 +1841,6 @@ WalSndWaitForWal(XLogRecPtr loc) { bool wait_for_standby_at_stop = false; long sleeptime; - TimestampTz now; /* Clear any already-pending wakeups */ ResetLatch(MyLatch); @@ -1957,8 +1951,7 @@ WalSndWaitForWal(XLogRecPtr loc) * new WAL to be generated. (But if we have nothing to send, we don't * want to wake on socket-writable.) */ - now = GetCurrentTimestamp(); - sleeptime = WalSndComputeSleeptime(now); + sleeptime = WalSndComputeSleeptime(GetCurrentTimestamp()); wakeEvents = WL_SOCKET_READABLE; @@ -1967,15 +1960,6 @@ WalSndWaitForWal(XLogRecPtr loc) Assert(wait_event != 0); - /* Report IO statistics, if needed */ - if (TimestampDifferenceExceeds(last_flush, now, - WALSENDER_STATS_FLUSH_INTERVAL)) - { - pgstat_flush_io(false); - (void) pgstat_flush_backend(false, PGSTAT_BACKEND_FLUSH_IO); - last_flush = now; - } - WalSndWait(wakeEvents, sleeptime, wait_event); } @@ -2878,8 +2862,6 @@ WalSndCheckTimeOut(void) static void WalSndLoop(WalSndSendDataCallback send_data) { - TimestampTz last_flush = 0; - /* * Initialize the last reply timestamp. That enables timeout processing * from hereon. @@ -2974,9 +2956,6 @@ WalSndLoop(WalSndSendDataCallback send_data) * WalSndWaitForWal() handle any other blocking; idle receivers need * its additional actions. For physical replication, also block if * caught up; its send_data does not block. - * - * The IO statistics are reported in WalSndWaitForWal() for the - * logical WAL senders. */ if ((WalSndCaughtUp && send_data != XLogSendLogical && !streamingDoneSending) || @@ -2984,7 +2963,6 @@ WalSndLoop(WalSndSendDataCallback send_data) { long sleeptime; int wakeEvents; - TimestampTz now; if (!streamingDoneReceiving) wakeEvents = WL_SOCKET_READABLE; @@ -2995,21 +2973,11 @@ WalSndLoop(WalSndSendDataCallback send_data) * Use fresh timestamp, not last_processing, to reduce the chance * of reaching wal_sender_timeout before sending a keepalive. */ - now = GetCurrentTimestamp(); - sleeptime = WalSndComputeSleeptime(now); + sleeptime = WalSndComputeSleeptime(GetCurrentTimestamp()); if (pq_is_send_pending()) wakeEvents |= WL_SOCKET_WRITEABLE; - /* Report IO statistics, if needed */ - if (TimestampDifferenceExceeds(last_flush, now, - WALSENDER_STATS_FLUSH_INTERVAL)) - { - pgstat_flush_io(false); - (void) pgstat_flush_backend(false, PGSTAT_BACKEND_FLUSH_IO); - last_flush = now; - } - /* Sleep until something happens or we time out */ WalSndWait(wakeEvents, sleeptime, WAIT_EVENT_WAL_SENDER_MAIN); } diff --git a/src/backend/utils/activity/pgstat_relation.c b/src/backend/utils/activity/pgstat_relation.c index bc8c43b96aa..feae2ae5f44 100644 --- a/src/backend/utils/activity/pgstat_relation.c +++ b/src/backend/utils/activity/pgstat_relation.c @@ -260,15 +260,6 @@ pgstat_report_vacuum(Relation rel, PgStat_Counter livetuples, } pgstat_unlock_entry(entry_ref); - - /* - * Flush IO statistics now. pgstat_report_stat() will flush IO stats, - * however this will not be called until after an entire autovacuum cycle - * is done -- which will likely vacuum many relations -- or until the - * VACUUM command has processed all tables and committed. - */ - pgstat_flush_io(false); - (void) pgstat_flush_backend(false, PGSTAT_BACKEND_FLUSH_IO); } /* @@ -360,10 +351,6 @@ pgstat_report_analyze(Relation rel, } pgstat_unlock_entry(entry_ref); - - /* see pgstat_report_vacuum() */ - pgstat_flush_io(false); - (void) pgstat_flush_backend(false, PGSTAT_BACKEND_FLUSH_IO); } /* diff --git a/src/test/recovery/t/001_stream_rep.pl b/src/test/recovery/t/001_stream_rep.pl index e9ac67813c7..c058a5f9b1f 100644 --- a/src/test/recovery/t/001_stream_rep.pl +++ b/src/test/recovery/t/001_stream_rep.pl @@ -15,6 +15,7 @@ my $node_primary = PostgreSQL::Test::Cluster->new('primary'); $node_primary->init( allows_streaming => 1, auth_extra => [ '--create-role' => 'repl_role' ]); +$node_primary->append_conf('postgresql.conf', "stats_flush_interval= '1s'"); $node_primary->start; my $backup_name = 'my_backup'; diff --git a/src/test/subscription/t/001_rep_changes.pl b/src/test/subscription/t/001_rep_changes.pl index d7e62e4d488..dda872f7074 100644 --- a/src/test/subscription/t/001_rep_changes.pl +++ b/src/test/subscription/t/001_rep_changes.pl @@ -11,6 +11,7 @@ use Test::More; # Initialize publisher node my $node_publisher = PostgreSQL::Test::Cluster->new('publisher'); $node_publisher->init(allows_streaming => 'logical'); +$node_publisher->append_conf('postgresql.conf', "stats_flush_interval= '1s'"); $node_publisher->start; # Create subscriber node -- 2.34.1