From eab041fcd1f4973b03f6bebd37bef3395fe64b4b Mon Sep 17 00:00:00 2001 From: rkhapov Date: Thu, 24 Apr 2025 17:01:54 +0000 Subject: [PATCH] pg_stat_statements.c: cancelable qtext_load_file In the case of a large PGSS_TEXT_FILE, the work time of the qtext_load_file function will be quite long, and the query to the pg_stat_statements table will not be cancellable, as there is no CHECK_FOR_INTERRUPT in the function. Also, the amount of bytes read can reach 1 GB, which leads to a slow read system call that does not allow cancellation of the query. Testing the speed of sequential read using fio with different block sizes shows that there is no significant difference between 16 MB blocks and 1 GB blocks. Therefore, this patch changes the maximum read value from 1 GB to 16 MB and adds CHECK_FOR_INTERRUPTION in the read loop of qtext_load_file to make it cancellable. Signed-off-by: rkhapov --- contrib/pg_stat_statements/pg_stat_statements.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/contrib/pg_stat_statements/pg_stat_statements.c b/contrib/pg_stat_statements/pg_stat_statements.c index 9778407cba3..cd34f1ce248 100644 --- a/contrib/pg_stat_statements/pg_stat_statements.c +++ b/contrib/pg_stat_statements/pg_stat_statements.c @@ -2365,7 +2365,9 @@ qtext_load_file(Size *buffer_size) nread = 0; while (nread < stat.st_size) { - int toread = Min(1024 * 1024 * 1024, stat.st_size - nread); + int toread = Min(32 * 1024 * 1024, stat.st_size - nread); + + CHECK_FOR_INTERRUPTS(); /* * If we get a short read and errno doesn't get set, the reason is -- 2.43.0