Check for interrupts in pg_trgm word similarity

danielgustafsson · danielgustafsson · commit ae4fc52ae247 · 2022-09-05T11:10:57.000+02:00
Calculating similarity between large strings can be timesconsuming and overrun configured statement timeouts. Check for interrupts in the main loop to ensure query cancellation can be performed. Author: Robins Tharakan <tharakan@gmail.com> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/CAEP4nAxvmfc_XWTz73bqXRhgjONi=1HaX4_NhsopA3L6UvnN1g@mail.gmail.com
diff --git a/contrib/pg_trgm/trgm_op.c b/contrib/pg_trgm/trgm_op.c
@@ -7,6 +7,7 @@
 
 #include "catalog/pg_type.h"
 #include "lib/qunique.h"
+#include "miscadmin.h"
 #include "trgm.h"
 #include "tsearch/ts_locale.h"
 #include "utils/lsyscache.h"
@@ -492,8 +493,12 @@ iterate_word_similarity(int *trg2indexes,
 
 	for (i = 0; i < len2; i++)
 	{
+		int			trgindex;
+
+		CHECK_FOR_INTERRUPTS();
+
 		/* Get index of next trigram */
-		int			trgindex = trg2indexes[i];
+		trgindex = trg2indexes[i];
 
 		/* Update last position of this trigram */
 		if (lower >= 0 || found[trgindex])
