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authorNathan Bossart2023-12-04 17:55:18 +0000
committerNathan Bossart2023-12-04 17:55:18 +0000
commitb14b1eb4da4c97afec24cf8956e842b98ebb2a51 (patch)
tree621b51a60c7c4863686a42cf97b67718ea22ca46
parente7c6efe305afff030b50fe6f792af48deff5cf3e (diff)
Teach convert() and friends to avoid copying when possible.
Presently, pg_convert() allocates a new bytea and copies the result regardless of whether any conversion actually happened. This commit adjusts this function to return the source pointer as-is if no conversion occurred. This optimization isn't expected to make a tremendous difference, but it still seems worthwhile to avoid unnecessary memory allocations. Author: Yurii Rashkovskii Reviewed-by: Bertrand Drouvot Discussion: https://postgr.es/m/CA%2BRLCQyknBPSWXRBQGOi6aYEcdQ9RpH9Kch4GjoeY8dQ3D%2Bvhw%40mail.gmail.com
-rw-r--r--src/backend/utils/mb/mbutils.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/src/backend/utils/mb/mbutils.c b/src/backend/utils/mb/mbutils.c
index 67a1ab2ab23..10eb6cd6fa7 100644
--- a/src/backend/utils/mb/mbutils.c
+++ b/src/backend/utils/mb/mbutils.c
@@ -585,19 +585,19 @@ pg_convert(PG_FUNCTION_ARGS)
src_encoding,
dest_encoding);
- /* update len if conversion actually happened */
- if (dest_str != src_str)
- len = strlen(dest_str);
+
+ /* return source string if no conversion happened */
+ if (dest_str == src_str)
+ PG_RETURN_BYTEA_P(string);
/*
* build bytea data type structure.
*/
+ len = strlen(dest_str);
retval = (bytea *) palloc(len + VARHDRSZ);
SET_VARSIZE(retval, len + VARHDRSZ);
memcpy(VARDATA(retval), dest_str, len);
-
- if (dest_str != src_str)
- pfree(dest_str);
+ pfree(dest_str);
/* free memory if allocated by the toaster */
PG_FREE_IF_COPY(string, 0);