From 3350b3740e5960da294384ba9c1806f13b72ba6f Mon Sep 17 00:00:00 2001
From: Neil Conway <neilc@samurai.com>
Date: Wed, 23 Feb 2005 22:46:17 +0000
Subject: [PATCH] This patch optimizes the md5_text() function (which is used
to implement the md5() SQL-level function). The old code did the following:
1. de-toast the datum
2. convert it to a cstring via textout()
3. get the length of the cstring via strlen()
Since we are treating the datum context as a blob of binary data,
the latter two steps are unnecessary. Once the data has been
detoasted, we can just use it as-is, and derive its length from
the varlena metadata.
This patch improves some run-of-the-mill md5() computations by
just under 10% in my limited tests, and passes the regression tests.
I also noticed that md5_text() wasn't checking the return value
of md5_hash(); encountering OOM at precisely the right moment
could result in returning a random md5 hash. This patch corrects
that. A better fix would be to make md5_hash() only return on
success (and/or allocate via palloc()), but since it's used in
the frontend as well I don't see an easy way to do that.
---
src/backend/libpq/md5.c | 6 +++---
src/backend/utils/adt/varlena.c | 14 ++++++++++----
2 files changed, 13 insertions(+), 7 deletions(-)
diff --git a/src/backend/libpq/md5.c b/src/backend/libpq/md5.c
index 16649abe24f..3c7fcd69127 100644
--- a/src/backend/libpq/md5.c
+++ b/src/backend/libpq/md5.c
@@ -14,7 +14,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/libpq/md5.c,v 1.27 2004/12/31 21:59:50 pgsql Exp $
+ * $PostgreSQL: pgsql/src/backend/libpq/md5.c,v 1.28 2005/02/23 22:46:17 neilc Exp $
*/
@@ -289,8 +289,8 @@ bytesToHex(uint8 b[16], char *s)
* characters. you thus need to provide an array
* of 33 characters, including the trailing '\0'.
*
- * RETURNS 0 on failure (out of memory for internal buffers) or
- * non-zero on success.
+ * RETURNS false on failure (out of memory for internal buffers) or
+ * true on success.
*
* STANDARDS MD5 is described in RFC 1321.
*
diff --git a/src/backend/utils/adt/varlena.c b/src/backend/utils/adt/varlena.c
index a2570a66bbe..26fcab20d35 100644
--- a/src/backend/utils/adt/varlena.c
+++ b/src/backend/utils/adt/varlena.c
@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
- * $PostgreSQL: pgsql/src/backend/utils/adt/varlena.c,v 1.118 2004/12/31 22:01:22 pgsql Exp $
+ * $PostgreSQL: pgsql/src/backend/utils/adt/varlena.c,v 1.119 2005/02/23 22:46:17 neilc Exp $
*
*-------------------------------------------------------------------------
*/
@@ -2310,16 +2310,22 @@ to_hex64(PG_FUNCTION_ARGS)
Datum
md5_text(PG_FUNCTION_ARGS)
{
- char *buff = PG_TEXT_GET_STR(PG_GETARG_TEXT_P(0));
- size_t len = strlen(buff);
+ text *in_text = PG_GETARG_TEXT_P(0);
+ size_t len;
char *hexsum;
text *result_text;
+ /* Calculate the length of the buffer using varlena metadata */
+ len = VARSIZE(in_text) - VARHDRSZ;
+
/* leave room for the terminating '\0' */
hexsum = (char *) palloc(MD5_HASH_LEN + 1);
/* get the hash result */
- md5_hash((void *) buff, len, hexsum);
+ if (md5_hash(VARDATA(in_text), len, hexsum) == false)
+ ereport(ERROR,
+ (errcode(ERRCODE_OUT_OF_MEMORY),
+ errmsg("out of memory")));
/* convert to text and return it */
result_text = PG_STR_GET_TEXT(hexsum);
--
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