From 4be94504ab11fe44d3a14d0a7a4a64eb7167e6d4 Mon Sep 17 00:00:00 2001 From: "Andrey M. Borodin" Date: Mon, 21 Aug 2023 11:34:55 +0300 Subject: [PATCH v6 2/3] Buffer random numbers This allows to generate uuids 10 times faster --- src/backend/utils/adt/uuid.c | 23 ++++++++++++++++++++--- 1 file changed, 20 insertions(+), 3 deletions(-) diff --git a/src/backend/utils/adt/uuid.c b/src/backend/utils/adt/uuid.c index 7a493016c9..28a79a7590 100644 --- a/src/backend/utils/adt/uuid.c +++ b/src/backend/utils/adt/uuid.c @@ -405,6 +405,24 @@ uuid_hash_extended(PG_FUNCTION_ARGS) return hash_any_extended(key->data, UUID_LEN, PG_GETARG_INT64(1)); } +#define UUID_RND_CACHE_LEN 512 +int rnd_cache_ptr = UUID_RND_CACHE_LEN; +unsigned char random_cache[UUID_RND_CACHE_LEN]; + +static bool +cached_strong_random(void *buf, size_t len) +{ + if (len + rnd_cache_ptr >= UUID_RND_CACHE_LEN) + { + if (!pg_strong_random(random_cache, UUID_RND_CACHE_LEN)) + return false; + rnd_cache_ptr = 0; + } + memcpy(buf, &random_cache[rnd_cache_ptr], len); + rnd_cache_ptr += len; + return true; +} + Datum gen_random_uuid(PG_FUNCTION_ARGS) { @@ -428,7 +446,6 @@ gen_random_uuid(PG_FUNCTION_ARGS) static uint32_t sequence_counter; static uint64_t previous_timestamp = 0; - Datum gen_uuid_v7(PG_FUNCTION_ARGS) { @@ -455,7 +472,7 @@ gen_uuid_v7(PG_FUNCTION_ARGS) tms = previous_timestamp; /* fill everything after the timestamp and counter with random bytes */ - if (!pg_strong_random(&uuid->data[8], UUID_LEN - 8)) + if (!cached_strong_random(&uuid->data[8], UUID_LEN - 8)) ereport(ERROR, (errcode(ERRCODE_INTERNAL_ERROR), errmsg("could not generate random values"))); @@ -470,7 +487,7 @@ gen_uuid_v7(PG_FUNCTION_ARGS) else { /* fill everything after the timestamp with random bytes */ - if (!pg_strong_random(&uuid->data[6], UUID_LEN - 6)) + if (!cached_strong_random(&uuid->data[6], UUID_LEN - 6)) ereport(ERROR, (errcode(ERRCODE_INTERNAL_ERROR), errmsg("could not generate random values"))); -- 2.37.1 (Apple Git-137.1)