From: Robert Haas <rhaas@postgresql.org>
Date: Fri, 17 Jun 2011 18:28:45 +0000 (-0400)
Subject: Add overflow checks to int4 and int8 versions of generate_series().
X-Git-Tag: REL9_0_5~91
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=51328d56a412578480bad0fb65b7cf58816d71b8;p=postgresql

Add overflow checks to int4 and int8 versions of generate_series().

The previous code went into an infinite loop after overflow.  In fact,
an overflow is not really an error; it just means that the current
value is the last one we need to return.  So, just arrange to stop
immediately when overflow is detected.

Back-patch all the way.
---

diff --git a/src/backend/utils/adt/int.c b/src/backend/utils/adt/int.c
index 609c3a7fc4..a51f8a9c2c 100644
--- a/src/backend/utils/adt/int.c
+++ b/src/backend/utils/adt/int.c
@@ -1381,6 +1381,10 @@ generate_series_step_int4(PG_FUNCTION_ARGS)
 		/* increment current in preparation for next iteration */
 		fctx->current += fctx->step;
 
+		/* if next-value computation overflows, this is the final result */
+		if (SAMESIGN(result, fctx->step) && !SAMESIGN(result, fctx->current))
+			fctx->step = 0;
+
 		/* do when there is more left to send */
 		SRF_RETURN_NEXT(funcctx, Int32GetDatum(result));
 	}
diff --git a/src/backend/utils/adt/int8.c b/src/backend/utils/adt/int8.c
index cde9313fdf..de9b29893b 100644
--- a/src/backend/utils/adt/int8.c
+++ b/src/backend/utils/adt/int8.c
@@ -1412,6 +1412,10 @@ generate_series_step_int8(PG_FUNCTION_ARGS)
 		/* increment current in preparation for next iteration */
 		fctx->current += fctx->step;
 
+		/* if next-value computation overflows, this is the final result */
+		if (SAMESIGN(result, fctx->step) && !SAMESIGN(result, fctx->current))
+			fctx->step = 0;
+
 		/* do when there is more left to send */
 		SRF_RETURN_NEXT(funcctx, Int64GetDatum(result));
 	}