From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Sat, 7 Oct 2006 00:12:12 +0000 (+0000)
Subject: Fix string_to_array() to correctly handle the case where there are
X-Git-Url: http://git.postgresql.org/gitweb/static/gitweb.js?a=commitdiff_plain;h=b0d6fbe1303aabe8f3a5e8a40bdd1abca1ded864;p=users%2Fbernd%2Fpostgres.git

Fix string_to_array() to correctly handle the case where there are
overlapping possible matches for the separator string, such as
string_to_array('123xx456xxx789', 'xx').
Also, revise the logic of replace(), split_part(), and string_to_array()
to avoid O(N^2) work from redundant searches and conversions to pg_wchar
format when there are N matches to the separator string.
Backpatched the full patch as far as 8.0.  7.4 also has the bug, but the
code has diverged a lot, so I just went for a quick-and-dirty fix of the
bug itself in that branch.
---

diff --git a/src/backend/utils/adt/varlena.c b/src/backend/utils/adt/varlena.c
index 88a6b8a92c..9133ebac81 100644
--- a/src/backend/utils/adt/varlena.c
+++ b/src/backend/utils/adt/varlena.c
@@ -779,6 +779,8 @@ text_position(Datum str, Datum search_str, int matchnum)
 					pos = p + 1;
 					break;
 				}
+				p1 += len2 - 1;
+				p += len2 - 1;
 			}
 			p1++;
 		}
@@ -809,6 +811,8 @@ text_position(Datum str, Datum search_str, int matchnum)
 					pos = p + 1;
 					break;
 				}
+				p1 += len2 - 1;
+				p += len2 - 1;
 			}
 			p1++;
 		}