v11-0003-Use-fasthash32-for-pgstat_hash_hash_key.patch
text/x-patch
Filename: v11-0003-Use-fasthash32-for-pgstat_hash_hash_key.patch
Type: text/x-patch
Part: 0
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Format: format-patch
Series: patch v11-0003
Subject: Use fasthash32 for pgstat_hash_hash_key
| File | + | − |
|---|---|---|
| src/include/utils/pgstat_internal.h | 2 | 7 |
From 9999aecbc51780ada4634855727c50e3b85a8f7f Mon Sep 17 00:00:00 2001
From: John Naylor <john.naylor@postgresql.org>
Date: Sat, 9 Dec 2023 16:24:56 +0700
Subject: [PATCH v11 3/5] Use fasthash32 for pgstat_hash_hash_key
Currently this calls the 32-bit Murmur finalizer on the three elements,
then joined with hash_combine(). This is simpler and has better
collision guarantees.
WIP: Make sure performance is at least comparable.
WIP: We may not need the full 32-bit finalizer reducing step.
It would be slightly cheaper to just use fasthash64 and then take
the lower 32 bits.
Discussion: (none yet, buried in a related patchset)
---
src/include/utils/pgstat_internal.h | 9 ++-------
1 file changed, 2 insertions(+), 7 deletions(-)
diff --git a/src/include/utils/pgstat_internal.h b/src/include/utils/pgstat_internal.h
index 60fbf9394b..ecc46bef04 100644
--- a/src/include/utils/pgstat_internal.h
+++ b/src/include/utils/pgstat_internal.h
@@ -14,7 +14,7 @@
#define PGSTAT_INTERNAL_H
-#include "common/hashfn.h"
+#include "common/hashfn_unstable.h"
#include "lib/dshash.h"
#include "lib/ilist.h"
#include "pgstat.h"
@@ -777,15 +777,10 @@ static inline uint32
pgstat_hash_hash_key(const void *d, size_t size, void *arg)
{
const PgStat_HashKey *key = (PgStat_HashKey *) d;
- uint32 hash;
Assert(size == sizeof(PgStat_HashKey) && arg == NULL);
- hash = murmurhash32(key->kind);
- hash = hash_combine(hash, murmurhash32(key->dboid));
- hash = hash_combine(hash, murmurhash32(key->objoid));
-
- return hash;
+ return fasthash32((const char *) key, size, 0);
}
/*
--
2.43.0