Limit to_tsvector_byid's initial array allocation to something sane.

tglsfdc · tglsfdc · commit 0fb91ed2b0af · 2023-09-25T11:50:28.000-04:00
The initial estimate of the number of distinct ParsedWords is just that: an estimate. Don't let it exceed what palloc is willing to allocate. If in fact we need more entries, we'll eventually fail trying to enlarge the array. But if we don't, this allows success on inputs that currently draw "invalid memory alloc request size". Per bug #18080 from Uwe Binder. Back-patch to all supported branches. Discussion: https://postgr.es/m/18080-d5c5e58fef8c99b7@postgresql.org
diff --git a/src/backend/tsearch/to_tsany.c b/src/backend/tsearch/to_tsany.c
@@ -242,6 +242,8 @@ to_tsvector_byid(PG_FUNCTION_ARGS)
 												 * number */
 	if (prs.lenwords < 2)
 		prs.lenwords = 2;
+	else if (prs.lenwords > MaxAllocSize / sizeof(ParsedWord))
+		prs.lenwords = MaxAllocSize / sizeof(ParsedWord);
 	prs.curwords = 0;
 	prs.pos = 0;
 	prs.words = (ParsedWord *) palloc(sizeof(ParsedWord) * prs.lenwords);
