undefine([Ac_cachevar])dnl
])# PGAC_SSE42_CRC32_INTRINSICS
+# PGAC_AVX512_PCLMUL_INTRINSICS
+# ---------------------------
+# Check if the compiler supports AVX-512 carryless multiplication
+# and three-way exclusive-or instructions used for computing CRC.
+# AVX-512F is assumed to be supported if the above are.
+#
+# If the intrinsics are supported, sets pgac_avx512_pclmul_intrinsics.
+AC_DEFUN([PGAC_AVX512_PCLMUL_INTRINSICS],
+[define([Ac_cachevar], [AS_TR_SH([pgac_cv_avx512_pclmul_intrinsics])])dnl
+AC_CACHE_CHECK([for _mm512_clmulepi64_epi128], [Ac_cachevar],
+[AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <immintrin.h>
+ __m512i x;
+ __m512i y;
+
+ #if defined(__has_attribute) && __has_attribute (target)
+ __attribute__((target("vpclmulqdq,avx512vl")))
+ #endif
+ static int avx512_pclmul_test(void)
+ {
+ __m128i z;
+
+ y = _mm512_clmulepi64_epi128(x, y, 0);
+ z = _mm_ternarylogic_epi64(
+ _mm512_castsi512_si128(y),
+ _mm512_extracti32x4_epi32(y, 1),
+ _mm512_extracti32x4_epi32(y, 2),
+ 0x96);
+ return _mm_crc32_u64(0, _mm_extract_epi64(z, 0));
+ }],
+ [return avx512_pclmul_test();])],
+ [Ac_cachevar=yes],
+ [Ac_cachevar=no])])
+if test x"$Ac_cachevar" = x"yes"; then
+ pgac_avx512_pclmul_intrinsics=yes
+fi
+undefine([Ac_cachevar])dnl
+])# PGAC_AVX512_PCLMUL_INTRINSICS
# PGAC_ARMV8_CRC32C_INTRINSICS
# ----------------------------
# Select CRC-32C implementation.
#
-# If we are targeting a processor that has Intel SSE 4.2 instructions, we can
-# use the special CRC instructions for calculating CRC-32C. If we're not
-# targeting such a processor, but we can nevertheless produce code that uses
-# the SSE intrinsics, compile both implementations and select which one to use
-# at runtime, depending on whether SSE 4.2 is supported by the processor we're
-# running on.
+# There are three methods of calculating CRC, in order of increasing
+# performance:
#
-# Similarly, if we are targeting an ARM processor that has the CRC
-# instructions that are part of the ARMv8 CRC Extension, use them. And if
-# we're not targeting such a processor, but can nevertheless produce code that
-# uses the CRC instructions, compile both, and select at runtime.
+# 1. The fallback using a lookup table, called slicing-by-8
+# 2. CRC-32C instructions (found in e.g. Intel SSE 4.2 and ARMv8 CRC Extension)
+# 3. Algorithms using carryless multiplication instructions
+# (e.g. Intel PCLMUL and Arm PMULL)
+#
+# If we can produce code (via function attributes or additional compiler
+# flags) that uses #2 (and possibly #3), we compile all implementations
+# and select which one to use at runtime, depending on what is supported
+# by the processor we're running on.
+#
+# If we are targeting a processor that has #2, we can use that without
+# runtime selection.
#
# Note that we do not use __attribute__((target("..."))) for the ARM CRC
# instructions because until clang 16, using the ARM intrinsics still requires
$as_echo "#define USE_SSE42_CRC32C 1" >>confdefs.h
- PG_CRC32C_OBJS="pg_crc32c_sse42.o"
+ PG_CRC32C_OBJS="pg_crc32c_sse42.o pg_crc32c_sse42_choose.o"
{ $as_echo "$as_me:${as_lineno-$LINENO}: result: SSE 4.2" >&5
$as_echo "SSE 4.2" >&6; }
else
fi
+# Check for carryless multiplication intrinsics to do vectorized CRC calculations.
+#
+if test x"$host_cpu" = x"x86_64"; then
+ { $as_echo "$as_me:${as_lineno-$LINENO}: checking for _mm512_clmulepi64_epi128" >&5
+$as_echo_n "checking for _mm512_clmulepi64_epi128... " >&6; }
+if ${pgac_cv_avx512_pclmul_intrinsics+:} false; then :
+ $as_echo_n "(cached) " >&6
+else
+ cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h. */
+#include <immintrin.h>
+ __m512i x;
+ __m512i y;
+
+ #if defined(__has_attribute) && __has_attribute (target)
+ __attribute__((target("vpclmulqdq,avx512vl")))
+ #endif
+ static int avx512_pclmul_test(void)
+ {
+ __m128i z;
+
+ y = _mm512_clmulepi64_epi128(x, y, 0);
+ z = _mm_ternarylogic_epi64(
+ _mm512_castsi512_si128(y),
+ _mm512_extracti32x4_epi32(y, 1),
+ _mm512_extracti32x4_epi32(y, 2),
+ 0x96);
+ return _mm_crc32_u64(0, _mm_extract_epi64(z, 0));
+ }
+int
+main ()
+{
+return avx512_pclmul_test();
+ ;
+ return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+ pgac_cv_avx512_pclmul_intrinsics=yes
+else
+ pgac_cv_avx512_pclmul_intrinsics=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+ conftest$ac_exeext conftest.$ac_ext
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $pgac_cv_avx512_pclmul_intrinsics" >&5
+$as_echo "$pgac_cv_avx512_pclmul_intrinsics" >&6; }
+if test x"$pgac_cv_avx512_pclmul_intrinsics" = x"yes"; then
+ pgac_avx512_pclmul_intrinsics=yes
+fi
+
+fi
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for vectorized CRC-32C" >&5
+$as_echo_n "checking for vectorized CRC-32C... " >&6; }
+if test x"$pgac_avx512_pclmul_intrinsics" = x"yes"; then
+
+$as_echo "#define USE_AVX512_CRC32C_WITH_RUNTIME_CHECK 1" >>confdefs.h
+
+ { $as_echo "$as_me:${as_lineno-$LINENO}: result: AVX-512 with runtime check" >&5
+$as_echo "AVX-512 with runtime check" >&6; }
+else
+ { $as_echo "$as_me:${as_lineno-$LINENO}: result: none" >&5
+$as_echo "none" >&6; }
+fi
# Select semaphore implementation type.
if test "$PORTNAME" != "win32"; then
# Select CRC-32C implementation.
#
-# If we are targeting a processor that has Intel SSE 4.2 instructions, we can
-# use the special CRC instructions for calculating CRC-32C. If we're not
-# targeting such a processor, but we can nevertheless produce code that uses
-# the SSE intrinsics, compile both implementations and select which one to use
-# at runtime, depending on whether SSE 4.2 is supported by the processor we're
-# running on.
-#
-# Similarly, if we are targeting an ARM processor that has the CRC
-# instructions that are part of the ARMv8 CRC Extension, use them. And if
-# we're not targeting such a processor, but can nevertheless produce code that
-# uses the CRC instructions, compile both, and select at runtime.
+# There are three methods of calculating CRC, in order of increasing
+# performance:
+#
+# 1. The fallback using a lookup table, called slicing-by-8
+# 2. CRC-32C instructions (found in e.g. Intel SSE 4.2 and ARMv8 CRC Extension)
+# 3. Algorithms using carryless multiplication instructions
+# (e.g. Intel PCLMUL and Arm PMULL)
+#
+# If we can produce code (via function attributes or additional compiler
+# flags) that uses #2 (and possibly #3), we compile all implementations
+# and select which one to use at runtime, depending on what is supported
+# by the processor we're running on.
+#
+# If we are targeting a processor that has #2, we can use that without
+# runtime selection.
#
# Note that we do not use __attribute__((target("..."))) for the ARM CRC
# instructions because until clang 16, using the ARM intrinsics still requires
AC_MSG_CHECKING([which CRC-32C implementation to use])
if test x"$USE_SSE42_CRC32C" = x"1"; then
AC_DEFINE(USE_SSE42_CRC32C, 1, [Define to 1 use Intel SSE 4.2 CRC instructions.])
- PG_CRC32C_OBJS="pg_crc32c_sse42.o"
+ PG_CRC32C_OBJS="pg_crc32c_sse42.o pg_crc32c_sse42_choose.o"
AC_MSG_RESULT(SSE 4.2)
else
if test x"$USE_SSE42_CRC32C_WITH_RUNTIME_CHECK" = x"1"; then
fi
AC_SUBST(PG_CRC32C_OBJS)
+# Check for carryless multiplication intrinsics to do vectorized CRC calculations.
+#
+if test x"$host_cpu" = x"x86_64"; then
+ PGAC_AVX512_PCLMUL_INTRINSICS()
+fi
+
+AC_MSG_CHECKING([for vectorized CRC-32C])
+if test x"$pgac_avx512_pclmul_intrinsics" = x"yes"; then
+ AC_DEFINE(USE_AVX512_CRC32C_WITH_RUNTIME_CHECK, 1, [Define to 1 to use AVX-512 CRC algorithms with a runtime check.])
+ AC_MSG_RESULT(AVX-512 with runtime check)
+else
+ AC_MSG_RESULT(none)
+fi
# Select semaphore implementation type.
if test "$PORTNAME" != "win32"; then
###############################################################
# Select CRC-32C implementation.
#
-# If we are targeting a processor that has Intel SSE 4.2 instructions, we can
-# use the special CRC instructions for calculating CRC-32C. If we're not
-# targeting such a processor, but we can nevertheless produce code that uses
-# the SSE intrinsics, compile both implementations and select which one to use
-# at runtime, depending on whether SSE 4.2 is supported by the processor we're
-# running on.
+# There are three methods of calculating CRC, in order of increasing
+# performance:
#
-# Similarly, if we are targeting an ARM processor that has the CRC
-# instructions that are part of the ARMv8 CRC Extension, use them. And if
-# we're not targeting such a processor, but can nevertheless produce code that
-# uses the CRC instructions, compile both, and select at runtime.
+# 1. The fallback using a lookup table, called slicing-by-8
+# 2. CRC-32C instructions (found in e.g. Intel SSE 4.2 and ARMv8 CRC Extension)
+# 3. Algorithms using carryless multiplication instructions
+# (e.g. Intel PCLMUL and Arm PMULL)
+#
+# If we can produce code (via function attributes or additional compiler
+# flags) that uses #2 (and possibly #3), we compile all implementations
+# and select which one to use at runtime, depending on what is supported
+# by the processor we're running on.
+#
+# If we are targeting a processor that has #2, we can use that without
+# runtime selection.
#
# Note that we do not use __attribute__((target("..."))) for the ARM CRC
# instructions because until clang 16, using the ARM intrinsics still requires
}
'''
- if not cc.links(prog, name: '_mm_crc32_u8 and _mm_crc32_u32',
+ if not cc.links(prog, name: 'SSE 4.2 CRC32C',
args: test_c_args)
# Do not use Intel SSE 4.2
elif (cc.get_define('__SSE4_2__') != '')
have_optimized_crc = true
endif
+ # Check if the compiler supports AVX-512 carryless multiplication
+ # and three-way exclusive-or instructions used for computing CRC.
+ # AVX-512F is assumed to be supported if the above are.
+ prog = '''
+#include <immintrin.h>
+__m512i x;
+__m512i y;
+
+#if defined(__has_attribute) && __has_attribute (target)
+__attribute__((target("vpclmulqdq,avx512vl")))
+#endif
+int main(void)
+{
+ __m128i z;
+
+ y = _mm512_clmulepi64_epi128(x, y, 0);
+ z = _mm_ternarylogic_epi64(
+ _mm512_castsi512_si128(y),
+ _mm512_extracti32x4_epi32(y, 1),
+ _mm512_extracti32x4_epi32(y, 2),
+ 0x96);
+ /* return computed value, to prevent the above being optimized away */
+ return _mm_crc32_u64(0, _mm_extract_epi64(z, 0));
+}
+'''
+
+ if cc.links(prog,
+ name: 'AVX-512 CRC32C',
+ args: test_c_args)
+ cdata.set('USE_AVX512_CRC32C_WITH_RUNTIME_CHECK', 1)
+ endif
+
endif
elif host_cpu == 'arm' or host_cpu == 'aarch64'
/* Define to 1 to build with assertion checks. (--enable-cassert) */
#undef USE_ASSERT_CHECKING
+/* Define to 1 to use AVX-512 CRC algorithms with a runtime check. */
+#undef USE_AVX512_CRC32C_WITH_RUNTIME_CHECK
+
/* Define to 1 to use AVX-512 popcount instructions with a runtime check. */
#undef USE_AVX512_POPCNT_WITH_RUNTIME_CHECK
#define EQ_CRC32C(c1, c2) ((c1) == (c2))
#if defined(USE_SSE42_CRC32C)
-/* Use Intel SSE4.2 instructions. */
+/*
+ * Use either Intel SSE 4.2 or AVX-512 instructions. We don't need a runtime check
+ * for SSE 4.2, so we can inline those in some cases.
+ */
#include <nmmintrin.h>
((crc) = pg_comp_crc32c_dispatch((crc), (data), (len)))
#define FIN_CRC32C(crc) ((crc) ^= 0xFFFFFFFF)
+extern pg_crc32c (*pg_comp_crc32c) (pg_crc32c crc, const void *data, size_t len);
extern pg_crc32c pg_comp_crc32c_sse42(pg_crc32c crc, const void *data, size_t len);
+#ifdef USE_AVX512_CRC32C_WITH_RUNTIME_CHECK
+extern pg_crc32c pg_comp_crc32c_avx512(pg_crc32c crc, const void *data, size_t len);
+#endif
/*
* We can only get here if the host compiler targets SSE 4.2, but on some
return crc;
}
else
- return pg_comp_crc32c_sse42(crc, data, len);
+ /* Otherwise, use a runtime check for AVX-512 instructions. */
+ return pg_comp_crc32c(crc, data, len);
}
+#elif defined(USE_SSE42_CRC32C_WITH_RUNTIME_CHECK)
+
+/*
+ * Use Intel SSE 4.2 or AVX-512 instructions, but perform a runtime check first
+ * to check that they are available.
+ */
+#define COMP_CRC32C(crc, data, len) \
+ ((crc) = pg_comp_crc32c((crc), (data), (len)))
+#define FIN_CRC32C(crc) ((crc) ^= 0xFFFFFFFF)
+
+extern pg_crc32c pg_comp_crc32c_sb8(pg_crc32c crc, const void *data, size_t len);
+extern PGDLLIMPORT pg_crc32c (*pg_comp_crc32c) (pg_crc32c crc, const void *data, size_t len);
+extern pg_crc32c pg_comp_crc32c_sse42(pg_crc32c crc, const void *data, size_t len);
+#ifdef USE_AVX512_CRC32C_WITH_RUNTIME_CHECK
+extern pg_crc32c pg_comp_crc32c_avx512(pg_crc32c crc, const void *data, size_t len);
+#endif
+
#elif defined(USE_ARMV8_CRC32C)
/* Use ARMv8 CRC Extension instructions. */
extern pg_crc32c pg_comp_crc32c_loongarch(pg_crc32c crc, const void *data, size_t len);
-#elif defined(USE_SSE42_CRC32C_WITH_RUNTIME_CHECK) || defined(USE_ARMV8_CRC32C_WITH_RUNTIME_CHECK)
+#elif defined(USE_ARMV8_CRC32C_WITH_RUNTIME_CHECK)
/*
- * Use Intel SSE 4.2 or ARMv8 instructions, but perform a runtime check first
+ * Use ARMv8 instructions, but perform a runtime check first
* to check that they are available.
*/
#define COMP_CRC32C(crc, data, len) \
extern pg_crc32c pg_comp_crc32c_sb8(pg_crc32c crc, const void *data, size_t len);
extern pg_crc32c (*pg_comp_crc32c) (pg_crc32c crc, const void *data, size_t len);
-
-#ifdef USE_SSE42_CRC32C_WITH_RUNTIME_CHECK
-extern pg_crc32c pg_comp_crc32c_sse42(pg_crc32c crc, const void *data, size_t len);
-#endif
-#ifdef USE_ARMV8_CRC32C_WITH_RUNTIME_CHECK
extern pg_crc32c pg_comp_crc32c_armv8(pg_crc32c crc, const void *data, size_t len);
-#endif
#else
/*
# x86/x64
['pg_crc32c_sse42', 'USE_SSE42_CRC32C'],
['pg_crc32c_sse42', 'USE_SSE42_CRC32C_WITH_RUNTIME_CHECK'],
+ ['pg_crc32c_sse42_choose', 'USE_SSE42_CRC32C'],
['pg_crc32c_sse42_choose', 'USE_SSE42_CRC32C_WITH_RUNTIME_CHECK'],
['pg_crc32c_sb8', 'USE_SSE42_CRC32C_WITH_RUNTIME_CHECK'],
/*-------------------------------------------------------------------------
*
* pg_crc32c_sse42.c
- * Compute CRC-32C checksum using Intel SSE 4.2 instructions.
+ * Compute CRC-32C checksum using Intel SSE 4.2 or AVX-512 instructions.
*
* Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
#include "c.h"
#include <nmmintrin.h>
+#ifdef USE_AVX512_CRC32C_WITH_RUNTIME_CHECK
+#include <immintrin.h>
+#endif
#include "port/pg_crc32c.h"
return crc;
}
+
+#ifdef USE_AVX512_CRC32C_WITH_RUNTIME_CHECK
+
+/*
+ * Note: There is no copyright notice in the following generated code.
+ *
+ * We have modified the output to
+ * - match our function declaration
+ * - match whitespace to our project style
+ * - add a threshold for the alignment stanza
+ */
+
+/* Generated by https://github.com/corsix/fast-crc32/ using: */
+/* ./generate -i avx512_vpclmulqdq -p crc32c -a v1e */
+/* MIT licensed */
+
+#define clmul_lo(a, b) (_mm512_clmulepi64_epi128((a), (b), 0))
+#define clmul_hi(a, b) (_mm512_clmulepi64_epi128((a), (b), 17))
+
+pg_attribute_target("vpclmulqdq,avx512vl")
+pg_crc32c
+pg_comp_crc32c_avx512(pg_crc32c crc, const void *data, size_t length)
+{
+ /* adjust names to match generated code */
+ pg_crc32c crc0 = crc;
+ size_t len = length;
+ const char *buf = data;
+
+ /* Align on cacheline boundary. The threshold is somewhat arbitrary. */
+ if (unlikely(len > 256))
+ {
+ for (; len && ((uintptr_t) buf & 7); --len)
+ crc0 = _mm_crc32_u8(crc0, *buf++);
+ while (((uintptr_t) buf & 56) && len >= 8)
+ {
+ crc0 = _mm_crc32_u64(crc0, *(const uint64_t *) buf);
+ buf += 8;
+ len -= 8;
+ }
+ }
+
+ if (len >= 64)
+ {
+ const char *end = buf + len;
+ const char *limit = buf + len - 64;
+ __m128i z0;
+
+ /* First vector chunk. */
+ __m512i x0 = _mm512_loadu_si512((const void *) buf),
+ y0;
+ __m512i k;
+
+ k = _mm512_broadcast_i32x4(_mm_setr_epi32(0x740eef02, 0, 0x9e4addf8, 0));
+ x0 = _mm512_xor_si512(_mm512_castsi128_si512(_mm_cvtsi32_si128(crc0)), x0);
+ buf += 64;
+
+ /* Main loop. */
+ while (buf <= limit)
+ {
+ y0 = clmul_lo(x0, k), x0 = clmul_hi(x0, k);
+ x0 = _mm512_ternarylogic_epi64(x0, y0,
+ _mm512_loadu_si512((const void *) buf),
+ 0x96);
+ buf += 64;
+ }
+
+ /* Reduce 512 bits to 128 bits. */
+ k = _mm512_setr_epi32(0x1c291d04, 0, 0xddc0152b, 0,
+ 0x3da6d0cb, 0, 0xba4fc28e, 0,
+ 0xf20c0dfe, 0, 0x493c7d27, 0,
+ 0, 0, 0, 0);
+ y0 = clmul_lo(x0, k), k = clmul_hi(x0, k);
+ y0 = _mm512_xor_si512(y0, k);
+ z0 = _mm_ternarylogic_epi64(_mm512_castsi512_si128(y0),
+ _mm512_extracti32x4_epi32(y0, 1),
+ _mm512_extracti32x4_epi32(y0, 2),
+ 0x96);
+ z0 = _mm_xor_si128(z0, _mm512_extracti32x4_epi32(x0, 3));
+
+ /* Reduce 128 bits to 32 bits, and multiply by x^32. */
+ crc0 = _mm_crc32_u64(0, _mm_extract_epi64(z0, 0));
+ crc0 = _mm_crc32_u64(crc0, _mm_extract_epi64(z0, 1));
+ len = end - buf;
+ }
+
+ return pg_comp_crc32c_sse42(crc0, buf, len);
+}
+
+#endif
#include "c.h"
-#ifdef HAVE__GET_CPUID
+#if defined(HAVE__GET_CPUID) || defined(HAVE__GET_CPUID_COUNT)
#include <cpuid.h>
#endif
-#ifdef HAVE__CPUID
+#if defined(HAVE__CPUID) || defined(HAVE__CPUIDEX)
#include <intrin.h>
#endif
+#ifdef HAVE_XSAVE_INTRINSICS
+#include <immintrin.h>
+#endif
+
#include "port/pg_crc32c.h"
+/*
+ * Does XGETBV say the ZMM registers are enabled?
+ *
+ * NB: Caller is responsible for verifying that osxsave is available
+ * before calling this.
+ */
+#ifdef HAVE_XSAVE_INTRINSICS
+pg_attribute_target("xsave")
+#endif
static bool
-pg_crc32c_sse42_available(void)
+zmm_regs_available(void)
{
- unsigned int exx[4] = {0, 0, 0, 0};
-
-#if defined(HAVE__GET_CPUID)
- __get_cpuid(1, &exx[0], &exx[1], &exx[2], &exx[3]);
-#elif defined(HAVE__CPUID)
- __cpuid(exx, 1);
+#ifdef HAVE_XSAVE_INTRINSICS
+ return (_xgetbv(0) & 0xe6) == 0xe6;
#else
-#error cpuid instruction not available
+ return false;
#endif
-
- return (exx[2] & (1 << 20)) != 0; /* SSE 4.2 */
}
/*
static pg_crc32c
pg_comp_crc32c_choose(pg_crc32c crc, const void *data, size_t len)
{
- if (pg_crc32c_sse42_available())
+ unsigned int exx[4] = {0, 0, 0, 0};
+
+ /*
+ * Set fallback. We must guard since slicing-by-8 is not visible
+ * everywhere.
+ */
+#ifdef USE_SSE42_CRC32C_WITH_RUNTIME_CHECK
+ pg_comp_crc32c = pg_comp_crc32c_sb8;
+#endif
+
+#if defined(HAVE__GET_CPUID)
+ __get_cpuid(1, &exx[0], &exx[1], &exx[2], &exx[3]);
+#elif defined(HAVE__CPUID)
+ __cpuid(exx, 1);
+#else
+#error cpuid instruction not available
+#endif
+
+ if ((exx[2] & (1 << 20)) != 0) /* SSE 4.2 */
+ {
pg_comp_crc32c = pg_comp_crc32c_sse42;
- else
- pg_comp_crc32c = pg_comp_crc32c_sb8;
+
+ if (exx[2] & (1 << 27) && /* OSXSAVE */
+ zmm_regs_available())
+ {
+ /* second cpuid call on leaf 7 to check extended AVX-512 support */
+
+ memset(exx, 0, 4 * sizeof(exx[0]));
+
+#if defined(HAVE__GET_CPUID_COUNT)
+ __get_cpuid_count(7, 0, &exx[0], &exx[1], &exx[2], &exx[3]);
+#elif defined(HAVE__CPUIDEX)
+ __cpuidex(exx, 7, 0);
+#endif
+
+#ifdef USE_AVX512_CRC32C_WITH_RUNTIME_CHECK
+ if (exx[2] & (1 << 10) && /* VPCLMULQDQ */
+ exx[1] & (1 << 31)) /* AVX512-VL */
+ pg_comp_crc32c = pg_comp_crc32c_avx512;
+#endif
+ }
+ }
return pg_comp_crc32c(crc, data, len);
}
419469235
(1 row)
+SELECT crc32c(repeat('A', 127)::bytea);
+ crc32c
+-----------
+ 291820082
+(1 row)
+
+SELECT crc32c(repeat('A', 128)::bytea);
+ crc32c
+-----------
+ 816091258
+(1 row)
+
+SELECT crc32c(repeat('A', 129)::bytea);
+ crc32c
+------------
+ 4213642571
+(1 row)
+
+SELECT crc32c(repeat('A', 800)::bytea);
+ crc32c
+------------
+ 3134039419
+(1 row)
+
--
-- encode/decode
--
SELECT crc32c('');
SELECT crc32c('The quick brown fox jumps over the lazy dog.');
+SELECT crc32c(repeat('A', 127)::bytea);
+SELECT crc32c(repeat('A', 128)::bytea);
+SELECT crc32c(repeat('A', 129)::bytea);
+SELECT crc32c(repeat('A', 800)::bytea);
+
--
-- encode/decode
--
projects / postgresql.git / commitdiff