From c0fda304df276606e6b3c9ce5c63c187fe775602 Mon Sep 17 00:00:00 2001 From: Andres Freund Date: Fri, 22 Sep 2017 13:38:42 -0700 Subject: [PATCH] Backport: Add inline murmurhash32(uint32) function. The function already existed in tidbitmap.c but more users requiring fast hashing of 32bit ints are coming up. Author: Andres Freund Discussion: https://postgr.es/m/20170914061207.zxotvyopetm7lrrp@alap3.anarazel.de https://postgr.es/m/15ae5ae2-bc74-ebef-f9d6-34b16423cc04@blackducksoftware.com Original-Commit: 791961f59b792fbd4f0a992d3ccab47298e79103 --- src/backend/nodes/tidbitmap.c | 20 ++------------------ src/include/utils/hashutils.h | 27 +++++++++++++++++++++++++++ 2 files changed, 29 insertions(+), 18 deletions(-) create mode 100644 src/include/utils/hashutils.h diff --git a/src/backend/nodes/tidbitmap.c b/src/backend/nodes/tidbitmap.c index c4e53adb0c..01d6bc5c11 100644 --- a/src/backend/nodes/tidbitmap.c +++ b/src/backend/nodes/tidbitmap.c @@ -45,6 +45,7 @@ #include "nodes/tidbitmap.h" #include "storage/lwlock.h" #include "utils/dsa.h" +#include "utils/hashutils.h" /* * The maximum number of tuples per page is not large (typically 256 with @@ -237,30 +238,13 @@ static int tbm_comparator(const void *left, const void *right); static int tbm_shared_comparator(const void *left, const void *right, void *arg); -/* - * Simple inline murmur hash implementation for the exact width required, for - * performance. - */ -static inline uint32 -hash_blockno(BlockNumber b) -{ - uint32 h = b; - - h ^= h >> 16; - h *= 0x85ebca6b; - h ^= h >> 13; - h *= 0xc2b2ae35; - h ^= h >> 16; - return h; -} - /* define hashtable mapping block numbers to PagetableEntry's */ #define SH_USE_NONDEFAULT_ALLOCATOR #define SH_PREFIX pagetable #define SH_ELEMENT_TYPE PagetableEntry #define SH_KEY_TYPE BlockNumber #define SH_KEY blockno -#define SH_HASH_KEY(tb, key) hash_blockno(key) +#define SH_HASH_KEY(tb, key) murmurhash32(key) #define SH_EQUAL(tb, a, b) a == b #define SH_SCOPE static inline #define SH_DEFINE diff --git a/src/include/utils/hashutils.h b/src/include/utils/hashutils.h new file mode 100644 index 0000000000..636d33271d --- /dev/null +++ b/src/include/utils/hashutils.h @@ -0,0 +1,27 @@ +/* + * Utilities for working with hash values. + * + * Portions Copyright (c) 2017, PostgreSQL Global Development Group + */ + +#ifndef HASHUTILS_H +#define HASHUTILS_H + +/* + * Simple inline murmur hash implementation hashing a 32 bit ingeger, for + * performance. + */ +static inline uint32 +murmurhash32(uint32 data) +{ + uint32 h = data; + + h ^= h >> 16; + h *= 0x85ebca6b; + h ^= h >> 13; + h *= 0xc2b2ae35; + h ^= h >> 16; + return h; +} + +#endif /* HASHUTILS_H */ -- 2.40.0