Check for interrupts in pg_trgm word similarity

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 
Reviewed-by: Tom Lane 
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
index 49b3609de93b4fbb88557891ad49e2b58a8ed334..c140fcdbbe8ba5e7fb22dcb9278d30d7a8e8e802 100644 (file)
--- 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])