On 12/20/14, 2:13 PM, Jim Nasby wrote:
On 12/20/14, 11:51 AM, Tom Lane wrote:
Andres Freund <and...@2ndquadrant.com> writes:
On 2014-12-19 22:03:55 -0600, Jim Nasby wrote:
What I am thinking is not using all of those fields in their raw form to
calculate the hash value. IE: something analogous to:
hash_any(SharedBufHash, (rot(forkNum, 2) | dbNode) ^ relNode) << 32 | blockNum)
perhaps that actual code wouldn't work, but I don't see why we couldn't do
something similar... am I missing something?
I don't think that'd improve anything. Jenkin's hash does have a quite
mixing properties, I don't believe that the above would improve the
quality of the hash.
I think what Jim is suggesting is to intentionally degrade the quality of
the hash in order to let it be calculated a tad faster. We could do that
but I doubt it would be a win, especially in systems with lots of buffers.
IIRC, when we put in Jenkins hashing to replace the older homebrew hash
function, it improved performance even though the hash itself was slower.
Right. Now that you mention it, I vaguely recall the discussions about changing
the hash function to reduce collisions.
I'll still take a look at fash-hash, but it's looking like there may not be
anything we can do here unless we change how we identify relation files
(combining dbid, tablespace id, fork number and file id, at least for
searching). If we had 64bit hash support then maybe that'd be a significant
win, since you wouldn't need to hash at all. But that certainly doesn't seem to
be low-hanging fruit to me...
I've taken a look at a number of different hash algorithms, testing them with
initially with SMHasher [1] and then with pgbench.
It's worth noting that a lot of work has been done in the area of hash algo's
since we last updated the hash_any algorithm in 2009 [2]. It's probably worth
revisiting this every other release or so.
Most of my SMHasher results are at [3]. I suspect SpookyHash is close to what
we currently have, so that's what I used for a baseline. I determined that
fash-hash (called superfast in results) was faster than Spooky, but not as fast
as CityHash64[4] or xxhash[5]. CityHash and xxhash had similar performance, but
xxhash seems to have slightly better characteristics according to SMHasher, and
more important, it's in C, not C++. However, CityHash has been replaced by
farmhash[7], which might be faster than xxhash.
I did a quick hack at using xxhash ONLY for shared buffer lookup [6]. I've
attached the full patch, as well as a version that omits the new files. Note
that currently xxhash is setup in such a way that we'd get different results
depending on endian-ness, so we couldn't just drop this in as-is across the
board. Of course, there's also the question of if we'd want to force a REINDEX
on hash indexes.
pgbench results are below. Select-only testing was done first, then read-write.
There were several select-only runs on both to warm shared_buffers (set to
512MB for this test, and fsync is off). Database initialized with bin/pgbench
-i -F 100 -s 10.
pgbench -S -T10 -c 4 -j 4
master:
tps = 9556.356145 (excluding connections establishing)
tps = 9897.324917 (excluding connections establishing)
tps = 9287.286907 (excluding connections establishing)
tps = 10210.130833 (excluding connections establishing)
XXH32:
tps = 32462.754437 (excluding connections establishing)
tps = 33232.144511 (excluding connections establishing)
tps = 33082.436760 (excluding connections establishing)
tps = 33597.904532 (excluding connections establishing)
pgbench -T10 -c 4 -j 4
master:
tps = 2299.314145 (excluding connections establishing)
tps = 2029.956749 (excluding connections establishing)
tps = 2067.462362 (excluding connections establishing)
XXH32:
tps = 2653.919321 (excluding connections establishing)
tps = 2615.764370 (excluding connections establishing)
tps = 2952.144461 (excluding connections establishing)
Questions:
Do we want to do what we've previously done and cut/paste/modify this code into
our repo? Given how rapidly hash algorithms seem to be changing I'm inclined to
minimize the amount of effort required to pull a new one in...
Can someone with a big-endian CPU see what the impact of
XXH_FORCE_NATIVE_FORMAT 1 vs 0? If there's a notable difference we might want
to do different things for on-disk vs in-memory hashes.
For that matter, assuming we adopt this, do we want to replace the index hash
functions too? SMHasher shows that CityHash is ~50% faster than XXHash for
262144 byte keys. Even SpookyHash is about 17% faster on that key size. So if
we want to do something with hash indexes, we'd probably be better off with
City or Farm hash than XXHash.
[1] https://code.google.com/p/smhasher/
[2]
https://github.com/postgres/postgres/commit/8205258fa675115439017b626c4932d5fefe2ea8
[3] https://github.com/decibel/hash_testing/tree/master/results
[4] https://code.google.com/p/cityhash/
[5] https://code.google.com/p/xxhash/
[6]
https://github.com/decibel/postgres/commit/b82e7a3b936b3950b296514f6ee0542132f11e4a
[7] https://code.google.com/p/farmhash/
--
Jim Nasby, Data Architect, Blue Treble Consulting
Data in Trouble? Get it in Treble! http://BlueTreble.com
>From b82e7a3b936b3950b296514f6ee0542132f11e4a Mon Sep 17 00:00:00 2001
From: Jim Nasby <jim.na...@bluetreble.com>
Date: Tue, 23 Dec 2014 23:00:20 -0600
Subject: [PATCH] Fugly hack to test out XXHash
(https://code.google.com/p/xxhash/)
---
src/backend/storage/buffer/buf_table.c | 5 +-
src/backend/utils/hash/Makefile | 2 +-
src/backend/utils/hash/hashfn.c | 12 +
src/backend/utils/hash/xxhash.c | 928 +++++++++++++++++++++++++++++++++
src/include/utils/hsearch.h | 5 +
src/include/utils/xxhash.h | 158 ++++++
6 files changed, 1107 insertions(+), 3 deletions(-)
create mode 100644 src/backend/utils/hash/xxhash.c
create mode 100644 src/include/utils/xxhash.h
diff --git a/src/backend/storage/buffer/buf_table.c
b/src/backend/storage/buffer/buf_table.c
index 0750b63..7592bd9 100644
--- a/src/backend/storage/buffer/buf_table.c
+++ b/src/backend/storage/buffer/buf_table.c
@@ -23,7 +23,7 @@
#include "storage/bufmgr.h"
#include "storage/buf_internals.h"
-
+#include "utils/hsearch.h" /* For XXHash stuff */
/* entry for buffer lookup hashtable */
typedef struct
@@ -60,11 +60,12 @@ InitBufTable(int size)
info.keysize = sizeof(BufferTag);
info.entrysize = sizeof(BufferLookupEnt);
info.num_partitions = NUM_BUFFER_PARTITIONS;
+ info.hash = PGH32;
SharedBufHash = ShmemInitHash("Shared Buffer Lookup Table",
size, size,
&info,
- HASH_ELEM |
HASH_BLOBS | HASH_PARTITION);
+ HASH_ELEM |
HASH_FUNCTION | HASH_PARTITION);
}
/*
diff --git a/src/backend/utils/hash/Makefile b/src/backend/utils/hash/Makefile
index 05d347c..c04f971 100644
--- a/src/backend/utils/hash/Makefile
+++ b/src/backend/utils/hash/Makefile
@@ -12,6 +12,6 @@ subdir = src/backend/utils/hash
top_builddir = ../../../..
include $(top_builddir)/src/Makefile.global
-OBJS = dynahash.o hashfn.o
+OBJS = dynahash.o hashfn.o xxhash.o
include $(top_srcdir)/src/backend/common.mk
diff --git a/src/backend/utils/hash/hashfn.c b/src/backend/utils/hash/hashfn.c
index adb0bd9..0bdc23b 100644
--- a/src/backend/utils/hash/hashfn.c
+++ b/src/backend/utils/hash/hashfn.c
@@ -22,6 +22,7 @@
#include "postgres.h"
#include "access/hash.h"
+#include "utils/xxhash.h"
/*
@@ -67,6 +68,17 @@ uint32_hash(const void *key, Size keysize)
}
/*
+ * XXhash hackery
+ */
+// #define PGH32(input, length) ((uint32 *) XXH32_no_seed(input, (size_t)
length));
+uint32
+PGH32(const void *key, Size keysize)
+{
+ return (uint32) XXH32_no_seed(key, (size_t) keysize);
+}
+
+
+/*
* bitmap_hash: hash function for keys that are (pointers to) Bitmapsets
*
* Note: don't forget to specify bitmap_match as the match function!
diff --git a/src/backend/utils/hash/xxhash.c b/src/backend/utils/hash/xxhash.c
new file mode 100644
index 0000000..0046533
--- /dev/null
+++ b/src/backend/utils/hash/xxhash.c
@@ -0,0 +1,928 @@
+/*
+xxHash - Fast Hash algorithm
+Copyright (C) 2012-2014, Yann Collet.
+BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+* Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+* Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+You can contact the author at :
+- xxHash source repository : http://code.google.com/p/xxhash/
+- public discussion board : https://groups.google.com/forum/#!forum/lz4c
+*/
+
+
+//**************************************
+// Tuning parameters
+//**************************************
+// Unaligned memory access is automatically enabled for "common" CPU, such as
x86.
+// For others CPU, the compiler will be more cautious, and insert extra code
to ensure aligned access is respected.
+// If you know your target CPU supports unaligned memory access, you want to
force this option manually to improve performance.
+// You can also enable this parameter if you know your input data will always
be aligned (boundaries of 4, for U32).
+#if defined(__ARM_FEATURE_UNALIGNED) || defined(__i386) || defined(_M_IX86) ||
defined(__x86_64__) || defined(_M_X64)
+# define XXH_USE_UNALIGNED_ACCESS 1
+#endif
+
+// XXH_ACCEPT_NULL_INPUT_POINTER :
+// If the input pointer is a null pointer, xxHash default behavior is to
trigger a memory access error, since it is a bad pointer.
+// When this option is enabled, xxHash output for null input pointers will be
the same as a null-length input.
+// This option has a very small performance cost (only measurable on small
inputs).
+// By default, this option is disabled. To enable it, uncomment below define :
+// #define XXH_ACCEPT_NULL_INPUT_POINTER 1
+
+// XXH_FORCE_NATIVE_FORMAT :
+// By default, xxHash library provides endian-independant Hash values, based
on little-endian convention.
+// Results are therefore identical for little-endian and big-endian CPU.
+// This comes at a performance cost for big-endian CPU, since some swapping is
required to emulate little-endian format.
+// Should endian-independance be of no importance for your application, you
may set the #define below to 1.
+// It will improve speed for Big-endian CPU.
+// This option has no impact on Little_Endian CPU.
+#define XXH_FORCE_NATIVE_FORMAT 1
+
+//**************************************
+// Compiler Specific Options
+//**************************************
+// Disable some Visual warning messages
+#ifdef _MSC_VER // Visual Studio
+# pragma warning(disable : 4127) // disable: C4127: conditional
expression is constant
+#endif
+
+#ifdef _MSC_VER // Visual Studio
+# define FORCE_INLINE static __forceinline
+#else
+# ifdef __GNUC__
+# define FORCE_INLINE static inline __attribute__((always_inline))
+# else
+# define FORCE_INLINE static inline
+# endif
+#endif
+
+//**************************************
+// Includes & Memory related functions
+//**************************************
+#include "utils/xxhash.h"
+// Modify the local functions below should you wish to use some other memory
routines
+// for malloc(), free()
+#include <stdlib.h>
+static void* XXH_malloc(size_t s) { return malloc(s); }
+static void XXH_free (void* p) { free(p); }
+// for memcpy()
+#include <string.h>
+static void* XXH_memcpy(void* dest, const void* src, size_t size)
+{
+ return memcpy(dest,src,size);
+}
+
+
+//**************************************
+// Basic Types
+//**************************************
+#if defined (__STDC_VERSION__) && __STDC_VERSION__ >= 199901L // C99
+# include <stdint.h>
+typedef uint8_t BYTE;
+typedef uint16_t U16;
+typedef uint32_t U32;
+typedef int32_t S32;
+typedef uint64_t U64;
+#else
+typedef unsigned char BYTE;
+typedef unsigned short U16;
+typedef unsigned int U32;
+typedef signed int S32;
+typedef unsigned long long U64;
+#endif
+
+#if defined(__GNUC__) && !defined(XXH_USE_UNALIGNED_ACCESS)
+# define _PACKED __attribute__ ((packed))
+#else
+# define _PACKED
+#endif
+
+#if !defined(XXH_USE_UNALIGNED_ACCESS) && !defined(__GNUC__)
+# ifdef __IBMC__
+# pragma pack(1)
+# else
+# pragma pack(push, 1)
+# endif
+#endif
+
+typedef struct _U32_S
+{
+ U32 v;
+} _PACKED U32_S;
+typedef struct _U64_S
+{
+ U64 v;
+} _PACKED U64_S;
+
+#if !defined(XXH_USE_UNALIGNED_ACCESS) && !defined(__GNUC__)
+# pragma pack(pop)
+#endif
+
+#define A32(x) (((U32_S *)(x))->v)
+#define A64(x) (((U64_S *)(x))->v)
+
+
+//***************************************
+// Compiler-specific Functions and Macros
+//***************************************
+#define GCC_VERSION (__GNUC__ * 100 + __GNUC_MINOR__)
+
+// Note : although _rotl exists for minGW (GCC under windows), performance
seems poor
+#if defined(_MSC_VER)
+# define XXH_rotl32(x,r) _rotl(x,r)
+# define XXH_rotl64(x,r) _rotl64(x,r)
+#else
+# define XXH_rotl32(x,r) ((x << r) | (x >> (32 - r)))
+# define XXH_rotl64(x,r) ((x << r) | (x >> (64 - r)))
+#endif
+
+#if defined(_MSC_VER) // Visual Studio
+# define XXH_swap32 _byteswap_ulong
+# define XXH_swap64 _byteswap_uint64
+#elif GCC_VERSION >= 403
+# define XXH_swap32 __builtin_bswap32
+# define XXH_swap64 __builtin_bswap64
+#else
+static inline U32 XXH_swap32 (U32 x)
+{
+ return ((x << 24) & 0xff000000 ) |
+ ((x << 8) & 0x00ff0000 ) |
+ ((x >> 8) & 0x0000ff00 ) |
+ ((x >> 24) & 0x000000ff );
+}
+static inline U64 XXH_swap64 (U64 x)
+{
+ return ((x << 56) & 0xff00000000000000ULL) |
+ ((x << 40) & 0x00ff000000000000ULL) |
+ ((x << 24) & 0x0000ff0000000000ULL) |
+ ((x << 8) & 0x000000ff00000000ULL) |
+ ((x >> 8) & 0x00000000ff000000ULL) |
+ ((x >> 24) & 0x0000000000ff0000ULL) |
+ ((x >> 40) & 0x000000000000ff00ULL) |
+ ((x >> 56) & 0x00000000000000ffULL);
+}
+#endif
+
+
+//**************************************
+// Constants
+//**************************************
+#define PRIME32_1 2654435761U
+#define PRIME32_2 2246822519U
+#define PRIME32_3 3266489917U
+#define PRIME32_4 668265263U
+#define PRIME32_5 374761393U
+
+#define PRIME64_1 11400714785074694791ULL
+#define PRIME64_2 14029467366897019727ULL
+#define PRIME64_3 1609587929392839161ULL
+#define PRIME64_4 9650029242287828579ULL
+#define PRIME64_5 2870177450012600261ULL
+
+//**************************************
+// Architecture Macros
+//**************************************
+typedef enum { XXH_bigEndian=0, XXH_littleEndian=1 } XXH_endianess;
+#ifndef XXH_CPU_LITTLE_ENDIAN // It is possible to define
XXH_CPU_LITTLE_ENDIAN externally, for example using a compiler switch
+static const int one = 1;
+# define XXH_CPU_LITTLE_ENDIAN (*(char*)(&one))
+#endif
+
+
+//**************************************
+// Macros
+//**************************************
+#define XXH_STATIC_ASSERT(c) { enum { XXH_static_assert = 1/(!!(c)) }; }
// use only *after* variable declarations
+
+
+//****************************
+// Memory reads
+//****************************
+typedef enum { XXH_aligned, XXH_unaligned } XXH_alignment;
+
+FORCE_INLINE U32 XXH_readLE32_align(const void* ptr, XXH_endianess endian,
XXH_alignment align)
+{
+ if (align==XXH_unaligned)
+ return endian==XXH_littleEndian ? A32(ptr) : XXH_swap32(A32(ptr));
+ else
+ return endian==XXH_littleEndian ? *(U32*)ptr : XXH_swap32(*(U32*)ptr);
+}
+
+FORCE_INLINE U32 XXH_readLE32(const void* ptr, XXH_endianess endian)
+{
+ return XXH_readLE32_align(ptr, endian, XXH_unaligned);
+}
+
+FORCE_INLINE U64 XXH_readLE64_align(const void* ptr, XXH_endianess endian,
XXH_alignment align)
+{
+ if (align==XXH_unaligned)
+ return endian==XXH_littleEndian ? A64(ptr) : XXH_swap64(A64(ptr));
+ else
+ return endian==XXH_littleEndian ? *(U64*)ptr : XXH_swap64(*(U64*)ptr);
+}
+
+FORCE_INLINE U64 XXH_readLE64(const void* ptr, XXH_endianess endian)
+{
+ return XXH_readLE64_align(ptr, endian, XXH_unaligned);
+}
+
+
+//****************************
+// Simple Hash Functions
+//****************************
+FORCE_INLINE U32 XXH32_endian_align(const void* input, size_t len, U32 seed,
XXH_endianess endian, XXH_alignment align)
+{
+ const BYTE* p = (const BYTE*)input;
+ const BYTE* bEnd = p + len;
+ U32 h32;
+#define XXH_get32bits(p) XXH_readLE32_align(p, endian, align)
+
+#ifdef XXH_ACCEPT_NULL_INPUT_POINTER
+ if (p==NULL)
+ {
+ len=0;
+ bEnd=p=(const BYTE*)(size_t)16;
+ }
+#endif
+
+ if (len>=16)
+ {
+ const BYTE* const limit = bEnd - 16;
+ U32 v1 = seed + PRIME32_1 + PRIME32_2;
+ U32 v2 = seed + PRIME32_2;
+ U32 v3 = seed + 0;
+ U32 v4 = seed - PRIME32_1;
+
+ do
+ {
+ v1 += XXH_get32bits(p) * PRIME32_2;
+ v1 = XXH_rotl32(v1, 13);
+ v1 *= PRIME32_1;
+ p+=4;
+ v2 += XXH_get32bits(p) * PRIME32_2;
+ v2 = XXH_rotl32(v2, 13);
+ v2 *= PRIME32_1;
+ p+=4;
+ v3 += XXH_get32bits(p) * PRIME32_2;
+ v3 = XXH_rotl32(v3, 13);
+ v3 *= PRIME32_1;
+ p+=4;
+ v4 += XXH_get32bits(p) * PRIME32_2;
+ v4 = XXH_rotl32(v4, 13);
+ v4 *= PRIME32_1;
+ p+=4;
+ }
+ while (p<=limit);
+
+ h32 = XXH_rotl32(v1, 1) + XXH_rotl32(v2, 7) + XXH_rotl32(v3, 12) +
XXH_rotl32(v4, 18);
+ }
+ else
+ {
+ h32 = seed + PRIME32_5;
+ }
+
+ h32 += (U32) len;
+
+ while (p+4<=bEnd)
+ {
+ h32 += XXH_get32bits(p) * PRIME32_3;
+ h32 = XXH_rotl32(h32, 17) * PRIME32_4 ;
+ p+=4;
+ }
+
+ while (p<bEnd)
+ {
+ h32 += (*p) * PRIME32_5;
+ h32 = XXH_rotl32(h32, 11) * PRIME32_1 ;
+ p++;
+ }
+
+ h32 ^= h32 >> 15;
+ h32 *= PRIME32_2;
+ h32 ^= h32 >> 13;
+ h32 *= PRIME32_3;
+ h32 ^= h32 >> 16;
+
+ return h32;
+}
+
+
+unsigned int XXH32 (const void* input, size_t len, unsigned seed)
+{
+#if 0
+ // Simple version, good for code maintenance, but unfortunately slow for
small inputs
+ XXH32_state_t state;
+ XXH32_reset(&state, seed);
+ XXH32_update(&state, input, len);
+ return XXH32_digest(&state);
+#else
+ XXH_endianess endian_detected = (XXH_endianess)XXH_CPU_LITTLE_ENDIAN;
+
+# if !defined(XXH_USE_UNALIGNED_ACCESS)
+ if ((((size_t)input) & 3) == 0) // Input is aligned, let's leverage the
speed advantage
+ {
+ if ((endian_detected==XXH_littleEndian) || XXH_FORCE_NATIVE_FORMAT)
+ return XXH32_endian_align(input, len, seed, XXH_littleEndian,
XXH_aligned);
+ else
+ return XXH32_endian_align(input, len, seed, XXH_bigEndian,
XXH_aligned);
+ }
+# endif
+
+ if ((endian_detected==XXH_littleEndian) || XXH_FORCE_NATIVE_FORMAT)
+ return XXH32_endian_align(input, len, seed, XXH_littleEndian,
XXH_unaligned);
+ else
+ return XXH32_endian_align(input, len, seed, XXH_bigEndian,
XXH_unaligned);
+#endif
+}
+
+FORCE_INLINE U64 XXH64_endian_align(const void* input, size_t len, U64 seed,
XXH_endianess endian, XXH_alignment align)
+{
+ const BYTE* p = (const BYTE*)input;
+ const BYTE* bEnd = p + len;
+ U64 h64;
+#define XXH_get64bits(p) XXH_readLE64_align(p, endian, align)
+
+#ifdef XXH_ACCEPT_NULL_INPUT_POINTER
+ if (p==NULL)
+ {
+ len=0;
+ bEnd=p=(const BYTE*)(size_t)32;
+ }
+#endif
+
+ if (len>=32)
+ {
+ const BYTE* const limit = bEnd - 32;
+ U64 v1 = seed + PRIME64_1 + PRIME64_2;
+ U64 v2 = seed + PRIME64_2;
+ U64 v3 = seed + 0;
+ U64 v4 = seed - PRIME64_1;
+
+ do
+ {
+ v1 += XXH_get64bits(p) * PRIME64_2;
+ p+=8;
+ v1 = XXH_rotl64(v1, 31);
+ v1 *= PRIME64_1;
+ v2 += XXH_get64bits(p) * PRIME64_2;
+ p+=8;
+ v2 = XXH_rotl64(v2, 31);
+ v2 *= PRIME64_1;
+ v3 += XXH_get64bits(p) * PRIME64_2;
+ p+=8;
+ v3 = XXH_rotl64(v3, 31);
+ v3 *= PRIME64_1;
+ v4 += XXH_get64bits(p) * PRIME64_2;
+ p+=8;
+ v4 = XXH_rotl64(v4, 31);
+ v4 *= PRIME64_1;
+ }
+ while (p<=limit);
+
+ h64 = XXH_rotl64(v1, 1) + XXH_rotl64(v2, 7) + XXH_rotl64(v3, 12) +
XXH_rotl64(v4, 18);
+
+ v1 *= PRIME64_2;
+ v1 = XXH_rotl64(v1, 31);
+ v1 *= PRIME64_1;
+ h64 ^= v1;
+ h64 = h64 * PRIME64_1 + PRIME64_4;
+
+ v2 *= PRIME64_2;
+ v2 = XXH_rotl64(v2, 31);
+ v2 *= PRIME64_1;
+ h64 ^= v2;
+ h64 = h64 * PRIME64_1 + PRIME64_4;
+
+ v3 *= PRIME64_2;
+ v3 = XXH_rotl64(v3, 31);
+ v3 *= PRIME64_1;
+ h64 ^= v3;
+ h64 = h64 * PRIME64_1 + PRIME64_4;
+
+ v4 *= PRIME64_2;
+ v4 = XXH_rotl64(v4, 31);
+ v4 *= PRIME64_1;
+ h64 ^= v4;
+ h64 = h64 * PRIME64_1 + PRIME64_4;
+ }
+ else
+ {
+ h64 = seed + PRIME64_5;
+ }
+
+ h64 += (U64) len;
+
+ while (p+8<=bEnd)
+ {
+ U64 k1 = XXH_get64bits(p);
+ k1 *= PRIME64_2;
+ k1 = XXH_rotl64(k1,31);
+ k1 *= PRIME64_1;
+ h64 ^= k1;
+ h64 = XXH_rotl64(h64,27) * PRIME64_1 + PRIME64_4;
+ p+=8;
+ }
+
+ if (p+4<=bEnd)
+ {
+ h64 ^= (U64)(XXH_get32bits(p)) * PRIME64_1;
+ h64 = XXH_rotl64(h64, 23) * PRIME64_2 + PRIME64_3;
+ p+=4;
+ }
+
+ while (p<bEnd)
+ {
+ h64 ^= (*p) * PRIME64_5;
+ h64 = XXH_rotl64(h64, 11) * PRIME64_1;
+ p++;
+ }
+
+ h64 ^= h64 >> 33;
+ h64 *= PRIME64_2;
+ h64 ^= h64 >> 29;
+ h64 *= PRIME64_3;
+ h64 ^= h64 >> 32;
+
+ return h64;
+}
+
+
+unsigned long long XXH64 (const void* input, size_t len, unsigned long long
seed)
+{
+#if 0
+ // Simple version, good for code maintenance, but unfortunately slow for
small inputs
+ XXH64_state_t state;
+ XXH64_reset(&state, seed);
+ XXH64_update(&state, input, len);
+ return XXH64_digest(&state);
+#else
+ XXH_endianess endian_detected = (XXH_endianess)XXH_CPU_LITTLE_ENDIAN;
+
+# if !defined(XXH_USE_UNALIGNED_ACCESS)
+ if ((((size_t)input) & 7)==0) // Input is aligned, let's leverage the
speed advantage
+ {
+ if ((endian_detected==XXH_littleEndian) || XXH_FORCE_NATIVE_FORMAT)
+ return XXH64_endian_align(input, len, seed, XXH_littleEndian,
XXH_aligned);
+ else
+ return XXH64_endian_align(input, len, seed, XXH_bigEndian,
XXH_aligned);
+ }
+# endif
+
+ if ((endian_detected==XXH_littleEndian) || XXH_FORCE_NATIVE_FORMAT)
+ return XXH64_endian_align(input, len, seed, XXH_littleEndian,
XXH_unaligned);
+ else
+ return XXH64_endian_align(input, len, seed, XXH_bigEndian,
XXH_unaligned);
+#endif
+}
+
+/****************************************************
+ * Advanced Hash Functions
+****************************************************/
+
+/*** Allocation ***/
+typedef struct
+{
+ U64 total_len;
+ U32 seed;
+ U32 v1;
+ U32 v2;
+ U32 v3;
+ U32 v4;
+ U32 mem32[4]; /* defined as U32 for alignment */
+ U32 memsize;
+} XXH_istate32_t;
+
+typedef struct
+{
+ U64 total_len;
+ U64 seed;
+ U64 v1;
+ U64 v2;
+ U64 v3;
+ U64 v4;
+ U64 mem64[4]; /* defined as U64 for alignment */
+ U32 memsize;
+} XXH_istate64_t;
+
+
+XXH32_state_t* XXH32_createState(void)
+{
+ XXH_STATIC_ASSERT(sizeof(XXH32_state_t) >= sizeof(XXH_istate32_t)); // A
compilation error here means XXH32_state_t is not large enough
+ return (XXH32_state_t*)XXH_malloc(sizeof(XXH32_state_t));
+}
+XXH_errorcode XXH32_freeState(XXH32_state_t* statePtr)
+{
+ XXH_free(statePtr);
+ return XXH_OK;
+};
+
+XXH64_state_t* XXH64_createState(void)
+{
+ XXH_STATIC_ASSERT(sizeof(XXH64_state_t) >= sizeof(XXH_istate64_t)); // A
compilation error here means XXH64_state_t is not large enough
+ return (XXH64_state_t*)XXH_malloc(sizeof(XXH64_state_t));
+}
+XXH_errorcode XXH64_freeState(XXH64_state_t* statePtr)
+{
+ XXH_free(statePtr);
+ return XXH_OK;
+};
+
+
+/*** Hash feed ***/
+
+XXH_errorcode XXH32_reset(XXH32_state_t* state_in, U32 seed)
+{
+ XXH_istate32_t* state = (XXH_istate32_t*) state_in;
+ state->seed = seed;
+ state->v1 = seed + PRIME32_1 + PRIME32_2;
+ state->v2 = seed + PRIME32_2;
+ state->v3 = seed + 0;
+ state->v4 = seed - PRIME32_1;
+ state->total_len = 0;
+ state->memsize = 0;
+ return XXH_OK;
+}
+
+XXH_errorcode XXH64_reset(XXH64_state_t* state_in, unsigned long long seed)
+{
+ XXH_istate64_t* state = (XXH_istate64_t*) state_in;
+ state->seed = seed;
+ state->v1 = seed + PRIME64_1 + PRIME64_2;
+ state->v2 = seed + PRIME64_2;
+ state->v3 = seed + 0;
+ state->v4 = seed - PRIME64_1;
+ state->total_len = 0;
+ state->memsize = 0;
+ return XXH_OK;
+}
+
+
+FORCE_INLINE XXH_errorcode XXH32_update_endian (XXH32_state_t* state_in, const
void* input, size_t len, XXH_endianess endian)
+{
+ XXH_istate32_t* state = (XXH_istate32_t *) state_in;
+ const BYTE* p = (const BYTE*)input;
+ const BYTE* const bEnd = p + len;
+
+#ifdef XXH_ACCEPT_NULL_INPUT_POINTER
+ if (input==NULL) return XXH_ERROR;
+#endif
+
+ state->total_len += len;
+
+ if (state->memsize + len < 16) // fill in tmp buffer
+ {
+ XXH_memcpy((BYTE*)(state->mem32) + state->memsize, input, len);
+ state->memsize += (U32)len;
+ return XXH_OK;
+ }
+
+ if (state->memsize) // some data left from previous update
+ {
+ XXH_memcpy((BYTE*)(state->mem32) + state->memsize, input,
16-state->memsize);
+ {
+ const U32* p32 = state->mem32;
+ state->v1 += XXH_readLE32(p32, endian) * PRIME32_2;
+ state->v1 = XXH_rotl32(state->v1, 13);
+ state->v1 *= PRIME32_1;
+ p32++;
+ state->v2 += XXH_readLE32(p32, endian) * PRIME32_2;
+ state->v2 = XXH_rotl32(state->v2, 13);
+ state->v2 *= PRIME32_1;
+ p32++;
+ state->v3 += XXH_readLE32(p32, endian) * PRIME32_2;
+ state->v3 = XXH_rotl32(state->v3, 13);
+ state->v3 *= PRIME32_1;
+ p32++;
+ state->v4 += XXH_readLE32(p32, endian) * PRIME32_2;
+ state->v4 = XXH_rotl32(state->v4, 13);
+ state->v4 *= PRIME32_1;
+ p32++;
+ }
+ p += 16-state->memsize;
+ state->memsize = 0;
+ }
+
+ if (p <= bEnd-16)
+ {
+ const BYTE* const limit = bEnd - 16;
+ U32 v1 = state->v1;
+ U32 v2 = state->v2;
+ U32 v3 = state->v3;
+ U32 v4 = state->v4;
+
+ do
+ {
+ v1 += XXH_readLE32(p, endian) * PRIME32_2;
+ v1 = XXH_rotl32(v1, 13);
+ v1 *= PRIME32_1;
+ p+=4;
+ v2 += XXH_readLE32(p, endian) * PRIME32_2;
+ v2 = XXH_rotl32(v2, 13);
+ v2 *= PRIME32_1;
+ p+=4;
+ v3 += XXH_readLE32(p, endian) * PRIME32_2;
+ v3 = XXH_rotl32(v3, 13);
+ v3 *= PRIME32_1;
+ p+=4;
+ v4 += XXH_readLE32(p, endian) * PRIME32_2;
+ v4 = XXH_rotl32(v4, 13);
+ v4 *= PRIME32_1;
+ p+=4;
+ }
+ while (p<=limit);
+
+ state->v1 = v1;
+ state->v2 = v2;
+ state->v3 = v3;
+ state->v4 = v4;
+ }
+
+ if (p < bEnd)
+ {
+ XXH_memcpy(state->mem32, p, bEnd-p);
+ state->memsize = (int)(bEnd-p);
+ }
+
+ return XXH_OK;
+}
+
+XXH_errorcode XXH32_update (XXH32_state_t* state_in, const void* input, size_t
len)
+{
+ XXH_endianess endian_detected = (XXH_endianess)XXH_CPU_LITTLE_ENDIAN;
+
+ if ((endian_detected==XXH_littleEndian) || XXH_FORCE_NATIVE_FORMAT)
+ return XXH32_update_endian(state_in, input, len, XXH_littleEndian);
+ else
+ return XXH32_update_endian(state_in, input, len, XXH_bigEndian);
+}
+
+
+
+FORCE_INLINE U32 XXH32_digest_endian (const XXH32_state_t* state_in,
XXH_endianess endian)
+{
+ XXH_istate32_t* state = (XXH_istate32_t*) state_in;
+ const BYTE * p = (const BYTE*)state->mem32;
+ BYTE* bEnd = (BYTE*)(state->mem32) + state->memsize;
+ U32 h32;
+
+ if (state->total_len >= 16)
+ {
+ h32 = XXH_rotl32(state->v1, 1) + XXH_rotl32(state->v2, 7) +
XXH_rotl32(state->v3, 12) + XXH_rotl32(state->v4, 18);
+ }
+ else
+ {
+ h32 = state->seed + PRIME32_5;
+ }
+
+ h32 += (U32) state->total_len;
+
+ while (p+4<=bEnd)
+ {
+ h32 += XXH_readLE32(p, endian) * PRIME32_3;
+ h32 = XXH_rotl32(h32, 17) * PRIME32_4;
+ p+=4;
+ }
+
+ while (p<bEnd)
+ {
+ h32 += (*p) * PRIME32_5;
+ h32 = XXH_rotl32(h32, 11) * PRIME32_1;
+ p++;
+ }
+
+ h32 ^= h32 >> 15;
+ h32 *= PRIME32_2;
+ h32 ^= h32 >> 13;
+ h32 *= PRIME32_3;
+ h32 ^= h32 >> 16;
+
+ return h32;
+}
+
+
+U32 XXH32_digest (const XXH32_state_t* state_in)
+{
+ XXH_endianess endian_detected = (XXH_endianess)XXH_CPU_LITTLE_ENDIAN;
+
+ if ((endian_detected==XXH_littleEndian) || XXH_FORCE_NATIVE_FORMAT)
+ return XXH32_digest_endian(state_in, XXH_littleEndian);
+ else
+ return XXH32_digest_endian(state_in, XXH_bigEndian);
+}
+
+
+FORCE_INLINE XXH_errorcode XXH64_update_endian (XXH64_state_t* state_in, const
void* input, size_t len, XXH_endianess endian)
+{
+ XXH_istate64_t * state = (XXH_istate64_t *) state_in;
+ const BYTE* p = (const BYTE*)input;
+ const BYTE* const bEnd = p + len;
+
+#ifdef XXH_ACCEPT_NULL_INPUT_POINTER
+ if (input==NULL) return XXH_ERROR;
+#endif
+
+ state->total_len += len;
+
+ if (state->memsize + len < 32) // fill in tmp buffer
+ {
+ XXH_memcpy(((BYTE*)state->mem64) + state->memsize, input, len);
+ state->memsize += (U32)len;
+ return XXH_OK;
+ }
+
+ if (state->memsize) // some data left from previous update
+ {
+ XXH_memcpy(((BYTE*)state->mem64) + state->memsize, input,
32-state->memsize);
+ {
+ const U64* p64 = state->mem64;
+ state->v1 += XXH_readLE64(p64, endian) * PRIME64_2;
+ state->v1 = XXH_rotl64(state->v1, 31);
+ state->v1 *= PRIME64_1;
+ p64++;
+ state->v2 += XXH_readLE64(p64, endian) * PRIME64_2;
+ state->v2 = XXH_rotl64(state->v2, 31);
+ state->v2 *= PRIME64_1;
+ p64++;
+ state->v3 += XXH_readLE64(p64, endian) * PRIME64_2;
+ state->v3 = XXH_rotl64(state->v3, 31);
+ state->v3 *= PRIME64_1;
+ p64++;
+ state->v4 += XXH_readLE64(p64, endian) * PRIME64_2;
+ state->v4 = XXH_rotl64(state->v4, 31);
+ state->v4 *= PRIME64_1;
+ p64++;
+ }
+ p += 32-state->memsize;
+ state->memsize = 0;
+ }
+
+ if (p+32 <= bEnd)
+ {
+ const BYTE* const limit = bEnd - 32;
+ U64 v1 = state->v1;
+ U64 v2 = state->v2;
+ U64 v3 = state->v3;
+ U64 v4 = state->v4;
+
+ do
+ {
+ v1 += XXH_readLE64(p, endian) * PRIME64_2;
+ v1 = XXH_rotl64(v1, 31);
+ v1 *= PRIME64_1;
+ p+=8;
+ v2 += XXH_readLE64(p, endian) * PRIME64_2;
+ v2 = XXH_rotl64(v2, 31);
+ v2 *= PRIME64_1;
+ p+=8;
+ v3 += XXH_readLE64(p, endian) * PRIME64_2;
+ v3 = XXH_rotl64(v3, 31);
+ v3 *= PRIME64_1;
+ p+=8;
+ v4 += XXH_readLE64(p, endian) * PRIME64_2;
+ v4 = XXH_rotl64(v4, 31);
+ v4 *= PRIME64_1;
+ p+=8;
+ }
+ while (p<=limit);
+
+ state->v1 = v1;
+ state->v2 = v2;
+ state->v3 = v3;
+ state->v4 = v4;
+ }
+
+ if (p < bEnd)
+ {
+ XXH_memcpy(state->mem64, p, bEnd-p);
+ state->memsize = (int)(bEnd-p);
+ }
+
+ return XXH_OK;
+}
+
+XXH_errorcode XXH64_update (XXH64_state_t* state_in, const void* input, size_t
len)
+{
+ XXH_endianess endian_detected = (XXH_endianess)XXH_CPU_LITTLE_ENDIAN;
+
+ if ((endian_detected==XXH_littleEndian) || XXH_FORCE_NATIVE_FORMAT)
+ return XXH64_update_endian(state_in, input, len, XXH_littleEndian);
+ else
+ return XXH64_update_endian(state_in, input, len, XXH_bigEndian);
+}
+
+
+
+FORCE_INLINE U64 XXH64_digest_endian (const XXH64_state_t* state_in,
XXH_endianess endian)
+{
+ XXH_istate64_t * state = (XXH_istate64_t *) state_in;
+ const BYTE * p = (const BYTE*)state->mem64;
+ BYTE* bEnd = (BYTE*)state->mem64 + state->memsize;
+ U64 h64;
+
+ if (state->total_len >= 32)
+ {
+ U64 v1 = state->v1;
+ U64 v2 = state->v2;
+ U64 v3 = state->v3;
+ U64 v4 = state->v4;
+
+ h64 = XXH_rotl64(v1, 1) + XXH_rotl64(v2, 7) + XXH_rotl64(v3, 12) +
XXH_rotl64(v4, 18);
+
+ v1 *= PRIME64_2;
+ v1 = XXH_rotl64(v1, 31);
+ v1 *= PRIME64_1;
+ h64 ^= v1;
+ h64 = h64*PRIME64_1 + PRIME64_4;
+
+ v2 *= PRIME64_2;
+ v2 = XXH_rotl64(v2, 31);
+ v2 *= PRIME64_1;
+ h64 ^= v2;
+ h64 = h64*PRIME64_1 + PRIME64_4;
+
+ v3 *= PRIME64_2;
+ v3 = XXH_rotl64(v3, 31);
+ v3 *= PRIME64_1;
+ h64 ^= v3;
+ h64 = h64*PRIME64_1 + PRIME64_4;
+
+ v4 *= PRIME64_2;
+ v4 = XXH_rotl64(v4, 31);
+ v4 *= PRIME64_1;
+ h64 ^= v4;
+ h64 = h64*PRIME64_1 + PRIME64_4;
+ }
+ else
+ {
+ h64 = state->seed + PRIME64_5;
+ }
+
+ h64 += (U64) state->total_len;
+
+ while (p+8<=bEnd)
+ {
+ U64 k1 = XXH_readLE64(p, endian);
+ k1 *= PRIME64_2;
+ k1 = XXH_rotl64(k1,31);
+ k1 *= PRIME64_1;
+ h64 ^= k1;
+ h64 = XXH_rotl64(h64,27) * PRIME64_1 + PRIME64_4;
+ p+=8;
+ }
+
+ if (p+4<=bEnd)
+ {
+ h64 ^= (U64)(XXH_readLE32(p, endian)) * PRIME64_1;
+ h64 = XXH_rotl64(h64, 23) * PRIME64_2 + PRIME64_3;
+ p+=4;
+ }
+
+ while (p<bEnd)
+ {
+ h64 ^= (*p) * PRIME64_5;
+ h64 = XXH_rotl64(h64, 11) * PRIME64_1;
+ p++;
+ }
+
+ h64 ^= h64 >> 33;
+ h64 *= PRIME64_2;
+ h64 ^= h64 >> 29;
+ h64 *= PRIME64_3;
+ h64 ^= h64 >> 32;
+
+ return h64;
+}
+
+
+unsigned long long XXH64_digest (const XXH64_state_t* state_in)
+{
+ XXH_endianess endian_detected = (XXH_endianess)XXH_CPU_LITTLE_ENDIAN;
+
+ if ((endian_detected==XXH_littleEndian) || XXH_FORCE_NATIVE_FORMAT)
+ return XXH64_digest_endian(state_in, XXH_littleEndian);
+ else
+ return XXH64_digest_endian(state_in, XXH_bigEndian);
+}
+
+
diff --git a/src/include/utils/hsearch.h b/src/include/utils/hsearch.h
index dfdf658..bc531c7 100644
--- a/src/include/utils/hsearch.h
+++ b/src/include/utils/hsearch.h
@@ -157,4 +157,9 @@ extern int bitmap_match(const void *key1, const void
*key2, Size keysize);
#define oid_hash uint32_hash /* Remove me eventually */
+/*
+ * XXHash hackery
+ */
+extern uint32 PGH32(const void *key, Size keysize);
+
#endif /* HSEARCH_H */
diff --git a/src/include/utils/xxhash.h b/src/include/utils/xxhash.h
new file mode 100644
index 0000000..3e0ab0b
--- /dev/null
+++ b/src/include/utils/xxhash.h
@@ -0,0 +1,158 @@
+/*
+ xxHash - Extremely Fast Hash algorithm
+ Header File
+ Copyright (C) 2012-2014, Yann Collet.
+ BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions are
+ met:
+
+ * Redistributions of source code must retain the above copyright
+ notice, this list of conditions and the following disclaimer.
+ * Redistributions in binary form must reproduce the above
+ copyright notice, this list of conditions and the following disclaimer
+ in the documentation and/or other materials provided with the
+ distribution.
+
+ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+ You can contact the author at :
+ - xxHash source repository : http://code.google.com/p/xxhash/
+*/
+
+/* Notice extracted from xxHash homepage :
+
+xxHash is an extremely fast Hash algorithm, running at RAM speed limits.
+It also successfully passes all tests from the SMHasher suite.
+
+Comparison (single thread, Windows Seven 32 bits, using SMHasher on a Core 2
Duo @3GHz)
+
+Name Speed Q.Score Author
+xxHash 5.4 GB/s 10
+CrapWow 3.2 GB/s 2 Andrew
+MumurHash 3a 2.7 GB/s 10 Austin Appleby
+SpookyHash 2.0 GB/s 10 Bob Jenkins
+SBox 1.4 GB/s 9 Bret Mulvey
+Lookup3 1.2 GB/s 9 Bob Jenkins
+SuperFastHash 1.2 GB/s 1 Paul Hsieh
+CityHash64 1.05 GB/s 10 Pike & Alakuijala
+FNV 0.55 GB/s 5 Fowler, Noll, Vo
+CRC32 0.43 GB/s 9
+MD5-32 0.33 GB/s 10 Ronald L. Rivest
+SHA1-32 0.28 GB/s 10
+
+Q.Score is a measure of quality of the hash function.
+It depends on successfully passing SMHasher test set.
+10 is a perfect score.
+*/
+
+#pragma once
+
+#if defined (__cplusplus)
+extern "C" {
+#endif
+
+
+/*****************************
+ Includes
+*****************************/
+#include <stddef.h> /* size_t */
+
+
+/*****************************
+ Type
+*****************************/
+typedef enum { XXH_OK=0, XXH_ERROR } XXH_errorcode;
+
+
+
+/*****************************
+ Simple Hash Functions
+*****************************/
+
+unsigned int XXH32 (const void* input, size_t length, unsigned seed);
+unsigned long long XXH64 (const void* input, size_t length, unsigned long long
seed);
+
+#define XXH32_no_seed(input, length) (XXH32(input, length, 0));
+
+/*
+XXH32() :
+ Calculate the 32-bits hash of sequence "length" bytes stored at memory
address "input".
+ The memory between input & input+length must be valid (allocated and
read-accessible).
+ "seed" can be used to alter the result predictably.
+ This function successfully passes all SMHasher tests.
+ Speed on Core 2 Duo @ 3 GHz (single thread, SMHasher benchmark) : 5.4 GB/s
+XXH64() :
+ Calculate the 64-bits hash of sequence of length "len" stored at memory
address "input".
+*/
+
+
+
+/*****************************
+ Advanced Hash Functions
+*****************************/
+typedef struct { long long ll[ 6]; } XXH32_state_t;
+typedef struct { long long ll[11]; } XXH64_state_t;
+
+/*
+These structures allow static allocation of XXH states.
+States must then be initialized using XXHnn_reset() before first use.
+
+If you prefer dynamic allocation, please refer to functions below.
+*/
+
+XXH32_state_t* XXH32_createState(void);
+XXH_errorcode XXH32_freeState(XXH32_state_t* statePtr);
+
+XXH64_state_t* XXH64_createState(void);
+XXH_errorcode XXH64_freeState(XXH64_state_t* statePtr);
+
+/*
+These functions create and release memory for XXH state.
+States must then be initialized using XXHnn_reset() before first use.
+*/
+
+
+XXH_errorcode XXH32_reset (XXH32_state_t* statePtr, unsigned seed);
+XXH_errorcode XXH32_update (XXH32_state_t* statePtr, const void* input, size_t
length);
+unsigned int XXH32_digest (const XXH32_state_t* statePtr);
+
+XXH_errorcode XXH64_reset (XXH64_state_t* statePtr, unsigned long long
seed);
+XXH_errorcode XXH64_update (XXH64_state_t* statePtr, const void* input,
size_t length);
+unsigned long long XXH64_digest (const XXH64_state_t* statePtr);
+
+/*
+These functions calculate the xxHash of an input provided in multiple smaller
packets,
+as opposed to an input provided as a single block.
+
+XXH state space must first be allocated, using either static or dynamic method
provided above.
+
+Start a new hash by initializing state with a seed, using XXHnn_reset().
+
+Then, feed the hash state by calling XXHnn_update() as many times as necessary.
+Obviously, input must be valid, meaning allocated and read accessible.
+The function returns an error code, with 0 meaning OK, and any other value
meaning there is an error.
+
+Finally, you can produce a hash anytime, by using XXHnn_digest().
+This function returns the final nn-bits hash.
+You can nonetheless continue feeding the hash state with more input,
+and therefore get some new hashes, by calling again XXHnn_digest().
+
+When you are done, don't forget to free XXH state space, using typically
XXHnn_freeState().
+*/
+
+
+#if defined (__cplusplus)
+}
+#endif
--
2.1.2
>From b82e7a3b936b3950b296514f6ee0542132f11e4a Mon Sep 17 00:00:00 2001
From: Jim Nasby <jim.na...@bluetreble.com>
Date: Tue, 23 Dec 2014 23:00:20 -0600
Subject: [PATCH] Fugly hack to test out XXHash
(https://code.google.com/p/xxhash/)
---
src/backend/storage/buffer/buf_table.c | 5 +-
src/backend/utils/hash/Makefile | 2 +-
src/backend/utils/hash/hashfn.c | 12 +
src/backend/utils/hash/xxhash.c | 928 +++++++++++++++++++++++++++++++++
src/include/utils/hsearch.h | 5 +
src/include/utils/xxhash.h | 158 ++++++
6 files changed, 1107 insertions(+), 3 deletions(-)
create mode 100644 src/backend/utils/hash/xxhash.c
create mode 100644 src/include/utils/xxhash.h
diff --git a/src/backend/storage/buffer/buf_table.c
b/src/backend/storage/buffer/buf_table.c
index 0750b63..7592bd9 100644
--- a/src/backend/storage/buffer/buf_table.c
+++ b/src/backend/storage/buffer/buf_table.c
@@ -23,7 +23,7 @@
#include "storage/bufmgr.h"
#include "storage/buf_internals.h"
-
+#include "utils/hsearch.h" /* For XXHash stuff */
/* entry for buffer lookup hashtable */
typedef struct
@@ -60,11 +60,12 @@ InitBufTable(int size)
info.keysize = sizeof(BufferTag);
info.entrysize = sizeof(BufferLookupEnt);
info.num_partitions = NUM_BUFFER_PARTITIONS;
+ info.hash = PGH32;
SharedBufHash = ShmemInitHash("Shared Buffer Lookup Table",
size, size,
&info,
- HASH_ELEM |
HASH_BLOBS | HASH_PARTITION);
+ HASH_ELEM |
HASH_FUNCTION | HASH_PARTITION);
}
/*
diff --git a/src/backend/utils/hash/Makefile b/src/backend/utils/hash/Makefile
index 05d347c..c04f971 100644
--- a/src/backend/utils/hash/Makefile
+++ b/src/backend/utils/hash/Makefile
@@ -12,6 +12,6 @@ subdir = src/backend/utils/hash
top_builddir = ../../../..
include $(top_builddir)/src/Makefile.global
-OBJS = dynahash.o hashfn.o
+OBJS = dynahash.o hashfn.o xxhash.o
include $(top_srcdir)/src/backend/common.mk
diff --git a/src/backend/utils/hash/hashfn.c b/src/backend/utils/hash/hashfn.c
index adb0bd9..0bdc23b 100644
--- a/src/backend/utils/hash/hashfn.c
+++ b/src/backend/utils/hash/hashfn.c
@@ -22,6 +22,7 @@
#include "postgres.h"
#include "access/hash.h"
+#include "utils/xxhash.h"
/*
@@ -67,6 +68,17 @@ uint32_hash(const void *key, Size keysize)
}
/*
+ * XXhash hackery
+ */
+// #define PGH32(input, length) ((uint32 *) XXH32_no_seed(input, (size_t)
length));
+uint32
+PGH32(const void *key, Size keysize)
+{
+ return (uint32) XXH32_no_seed(key, (size_t) keysize);
+}
+
+
+/*
* bitmap_hash: hash function for keys that are (pointers to) Bitmapsets
*
* Note: don't forget to specify bitmap_match as the match function!
diff --git a/src/include/utils/hsearch.h b/src/include/utils/hsearch.h
index dfdf658..bc531c7 100644
--- a/src/include/utils/hsearch.h
+++ b/src/include/utils/hsearch.h
@@ -157,4 +157,9 @@ extern int bitmap_match(const void *key1, const void
*key2, Size keysize);
#define oid_hash uint32_hash /* Remove me eventually */
+/*
+ * XXHash hackery
+ */
+extern uint32 PGH32(const void *key, Size keysize);
+
#endif /* HSEARCH_H */
--
2.1.2
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