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commit    f84c2a6345367bd6aee05b87dd5e573be724f715
Author:   Tatsuo Ishii <ishii@postgresql.org>
Date:     Thu Oct 17 04:59:17 2024 +0000

    Fix bug in pcp_invalidate_query_cache.
    
    Buildfarm reported 006.memqcache failure. This was caused by a mistake
    in the test script (test.sh). It executes pcp_invalidate_query_cache
    then compares the results of a query calling current_timestamp which
    is already in query cache (using /*FORCE QUERY CACHE*/ comment). Since
    pcp_invalidate_query_cache just places an invalidation request and
    next query processes it, comparing the result right after execution of
    "SELECT current_timestamp" with the previous cached result indeed
    returns an equality and the test failed. To fix this, after
    pcp_invalidate_query_cache, executes a different query.
    
    Also I found the test not only fails, but sometimes causes timeout at
    my local environment. Inspecting the remaining child process showed
    that it is likely the SIGINT handler was not executed (variable
    exit_request was not set). I suspect this is because
    pool_clear_memory_cache(), which is responsible for actually clearing
    the query cache, blocks all signal including SIGINT. I think this is
    the reason why the signal handler for SIGINT is not executed. Since
    pool_clear_memory_cache() already uses pool_shmem_lock() to protect
    the operation on query cache, the signal blocking is not necessary. In
    this commit I just removed calls to POOL_SETMASK2 and POOL_SETMASK.


 src/query_cache/pool_memqcache.c                | 4 ----
 src/test/regression/tests/006.memqcache/test.sh | 1 +
 2 files changed, 1 insertion(+), 4 deletions(-)

diff --git a/src/query_cache/pool_memqcache.c b/src/query_cache/pool_memqcache.c
index de50729d1..4c55f0fc4 100644
--- a/src/query_cache/pool_memqcache.c
+++ b/src/query_cache/pool_memqcache.c
@@ -2126,9 +2126,7 @@ void
 pool_clear_memory_cache(void)
 {
 	size_t		size;
-	pool_sigset_t oldmask;
 
-	POOL_SETMASK2(&BlockSig, &oldmask);
 	pool_shmem_lock(POOL_MEMQ_EXCLUSIVE_LOCK);
 
 	PG_TRY();
@@ -2148,13 +2146,11 @@ pool_clear_memory_cache(void)
 	PG_CATCH();
 	{
 		pool_shmem_unlock();
-		POOL_SETMASK(&oldmask);
 		PG_RE_THROW();
 	}
 	PG_END_TRY();
 
 	pool_shmem_unlock();
-	POOL_SETMASK(&oldmask);
 }
 
 #ifdef USE_MEMCACHED
diff --git a/src/test/regression/tests/006.memqcache/test.sh b/src/test/regression/tests/006.memqcache/test.sh
index e915d8c5d..4b218e197 100755
--- a/src/test/regression/tests/006.memqcache/test.sh
+++ b/src/test/regression/tests/006.memqcache/test.sh
@@ -482,6 +482,7 @@ EOF
 	    exit 1
 	fi
 	# make sure query cache has gone
+	$PSQL -t -c "SELECT 1" test	# this query processes query cache invalidation request
 	res1=`$PSQL -t -c "/*FORCE QUERY CACHE*/SELECT current_timestamp" test`
 	if [ "$res1" = "$res2" ];then
 	    echo "query cache was not invalidated"


[parent: 7008d9ffb781]