From 30863c010421affd737977dbfe21ea08f18a43cb Mon Sep 17 00:00:00 2001 From: Matthias van de Meent Date: Tue, 7 Jan 2025 10:07:38 +0100 Subject: [PATCH] libpagestore: timeout = max(0, difference), not min(0, difference) (#10274) Using `min(0, ...)` causes us to fail to wait in most situations, so a lack of data would be a hot wait loop, which is bad. ## Problem We noticed high CPU usage in some situations --- pgxn/neon/libpagestore.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/pgxn/neon/libpagestore.c b/pgxn/neon/libpagestore.c index 88d0a5292b..fa2a570ea8 100644 --- a/pgxn/neon/libpagestore.c +++ b/pgxn/neon/libpagestore.c @@ -680,7 +680,7 @@ call_PQgetCopyData(shardno_t shard_no, char **buffer) * but in the cases that take exceptionally long, it's useful to log the * exact timestamps. */ -#define LOG_INTERVAL_US UINT64CONST(10 * 1000000) +#define LOG_INTERVAL_MS INT64CONST(10 * 1000) INSTR_TIME_SET_CURRENT(now); start_ts = last_log_ts = now; @@ -694,7 +694,7 @@ retry: WaitEvent event; long timeout; - timeout = Min(0, LOG_INTERVAL_US - INSTR_TIME_GET_MICROSEC(since_last_log)); + timeout = Max(0, LOG_INTERVAL_MS - INSTR_TIME_GET_MILLISEC(since_last_log)); /* Sleep until there's something to do */ (void) WaitEventSetWait(shard->wes_read, timeout, &event, 1, @@ -723,7 +723,7 @@ retry: INSTR_TIME_SET_CURRENT(now); since_last_log = now; INSTR_TIME_SUBTRACT(since_last_log, last_log_ts); - if (INSTR_TIME_GET_MICROSEC(since_last_log) >= LOG_INTERVAL_US) + if (INSTR_TIME_GET_MILLISEC(since_last_log) >= LOG_INTERVAL_MS) { since_start = now; INSTR_TIME_SUBTRACT(since_start, start_ts);