pgq.insert_event: Fix rare crash

If hash_search(HASH_ENTER) succeeds, but make_plan() fails,
due to statement_timeout/deadlock, then HTAB entry will
contain invalid values which leads to crash on next call.

Fix it by always fully initializing struct before calling make_plan().

Debugged-by: Martin Pihlak

1 files changed, 8 insertions, 4 deletions

diff --git a/sql/pgq/lowlevel/insert_event.c b/sql/pgq/lowlevel/insert_event.c
index 7cb0154e..f63890d8 100644
--- a/sql/pgq/lowlevel/insert_event.c
+++ b/sql/pgq/lowlevel/insert_event.c
@@ -166,13 +166,17 @@ static void *load_insert_plan(Datum qname, struct QueueState *state)
 
 	entry = hash_search(insert_cache, &queue_id, HASH_ENTER, &did_exist);
 	if (did_exist) {
-		if (state->cur_table == entry->cur_table)
+		if (entry->plan && state->cur_table == entry->cur_table)
 			goto valid_table;
-		SPI_freeplan(entry->plan);
-	} else {
-		entry->last_xid = 0;
+		if (entry->plan)
+			SPI_freeplan(entry->plan);
 	}
+
 	entry->cur_table = state->cur_table;
+	entry->last_xid = 0;
+	entry->plan = NULL;
+
+	/* this can fail, struct must be valid before */
 	entry->plan = make_plan(state);
 valid_table: