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Change CRCs in WAL records from 64bit to 32bit for performance reasons.
Instead of a separate CRC on each backup block, include backup blocks in their parent WAL record's CRC; this is important to ensure that the backup block really goes with the WAL record, ie there was not a page tear right at the start of the backup block. Implement a simple form of compression of backup blocks: drop any run of zeroes starting at pd_lower, so as not to store the unused 'hole' that commonly exists in PG heap and index pages. Tweak PageRepairFragmentation and related routines to ensure they keep the unused space zeroed, so that the above compression method remains effective. All per recent discussions.
This commit is contained in:
Tom Lane
@@ -1,14 +1,25 @@
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/*-------------------------------------------------------------------------
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*
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* pg_crc.c
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* PostgreSQL 64-bit CRC support
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* PostgreSQL CRC support
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*
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* See Ross Williams' excellent introduction
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* A PAINLESS GUIDE TO CRC ERROR DETECTION ALGORITHMS, available from
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* ftp://ftp.rocksoft.com/papers/crc_v3.txt or several other net sites.
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*
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* We use a normal (not "reflected", in Williams' terms) CRC, using initial
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* all-ones register contents and a final bit inversion.
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*
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* The 64-bit variant is not used as of PostgreSQL 8.1, but we retain the
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* code for possible future use.
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*
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*
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* Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/utils/hash/pg_crc.c,v 1.12 2004/12/31 22:01:37 pgsql Exp $
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* $PostgreSQL: pgsql/src/backend/utils/hash/pg_crc.c,v 1.13 2005/06/02 05:55:29 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@@ -17,9 +28,96 @@
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#include "utils/pg_crc.h"
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/*
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* This table is based on the polynomial
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* x^32+x^26+x^23+x^22+x^16+x^12+x^11+x^10+x^8+x^7+x^5+x^4+x^2+x+1.
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* (This is the same polynomial used in Ethernet checksums, for instance.)
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*/
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const uint32 pg_crc32_table[256] = {
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0x00000000, 0x77073096, 0xEE0E612C, 0x990951BA,
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0x076DC419, 0x706AF48F, 0xE963A535, 0x9E6495A3,
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0x0EDB8832, 0x79DCB8A4, 0xE0D5E91E, 0x97D2D988,
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0x09B64C2B, 0x7EB17CBD, 0xE7B82D07, 0x90BF1D91,
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0x1DB71064, 0x6AB020F2, 0xF3B97148, 0x84BE41DE,
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0x1ADAD47D, 0x6DDDE4EB, 0xF4D4B551, 0x83D385C7,
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0x136C9856, 0x646BA8C0, 0xFD62F97A, 0x8A65C9EC,
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0x14015C4F, 0x63066CD9, 0xFA0F3D63, 0x8D080DF5,
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0x3B6E20C8, 0x4C69105E, 0xD56041E4, 0xA2677172,
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0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B,
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0x35B5A8FA, 0x42B2986C, 0xDBBBC9D6, 0xACBCF940,
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0x32D86CE3, 0x45DF5C75, 0xDCD60DCF, 0xABD13D59,
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0x26D930AC, 0x51DE003A, 0xC8D75180, 0xBFD06116,
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0x21B4F4B5, 0x56B3C423, 0xCFBA9599, 0xB8BDA50F,
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0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924,
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0x2F6F7C87, 0x58684C11, 0xC1611DAB, 0xB6662D3D,
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0x76DC4190, 0x01DB7106, 0x98D220BC, 0xEFD5102A,
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0x71B18589, 0x06B6B51F, 0x9FBFE4A5, 0xE8B8D433,
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0x7807C9A2, 0x0F00F934, 0x9609A88E, 0xE10E9818,
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0x7F6A0DBB, 0x086D3D2D, 0x91646C97, 0xE6635C01,
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0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E,
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0x6C0695ED, 0x1B01A57B, 0x8208F4C1, 0xF50FC457,
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0x65B0D9C6, 0x12B7E950, 0x8BBEB8EA, 0xFCB9887C,
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0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3, 0xFBD44C65,
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0x4DB26158, 0x3AB551CE, 0xA3BC0074, 0xD4BB30E2,
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0x4ADFA541, 0x3DD895D7, 0xA4D1C46D, 0xD3D6F4FB,
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0x4369E96A, 0x346ED9FC, 0xAD678846, 0xDA60B8D0,
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0x44042D73, 0x33031DE5, 0xAA0A4C5F, 0xDD0D7CC9,
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0x5005713C, 0x270241AA, 0xBE0B1010, 0xC90C2086,
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0x5768B525, 0x206F85B3, 0xB966D409, 0xCE61E49F,
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0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4,
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0x59B33D17, 0x2EB40D81, 0xB7BD5C3B, 0xC0BA6CAD,
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0xEDB88320, 0x9ABFB3B6, 0x03B6E20C, 0x74B1D29A,
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0xEAD54739, 0x9DD277AF, 0x04DB2615, 0x73DC1683,
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0xE3630B12, 0x94643B84, 0x0D6D6A3E, 0x7A6A5AA8,
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0xE40ECF0B, 0x9309FF9D, 0x0A00AE27, 0x7D079EB1,
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0xF00F9344, 0x8708A3D2, 0x1E01F268, 0x6906C2FE,
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0xF762575D, 0x806567CB, 0x196C3671, 0x6E6B06E7,
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0xFED41B76, 0x89D32BE0, 0x10DA7A5A, 0x67DD4ACC,
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0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5,
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0xD6D6A3E8, 0xA1D1937E, 0x38D8C2C4, 0x4FDFF252,
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0xD1BB67F1, 0xA6BC5767, 0x3FB506DD, 0x48B2364B,
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0xD80D2BDA, 0xAF0A1B4C, 0x36034AF6, 0x41047A60,
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0xDF60EFC3, 0xA867DF55, 0x316E8EEF, 0x4669BE79,
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0xCB61B38C, 0xBC66831A, 0x256FD2A0, 0x5268E236,
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0xCC0C7795, 0xBB0B4703, 0x220216B9, 0x5505262F,
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0xC5BA3BBE, 0xB2BD0B28, 0x2BB45A92, 0x5CB36A04,
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0xC2D7FFA7, 0xB5D0CF31, 0x2CD99E8B, 0x5BDEAE1D,
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0x9B64C2B0, 0xEC63F226, 0x756AA39C, 0x026D930A,
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0x9C0906A9, 0xEB0E363F, 0x72076785, 0x05005713,
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0x95BF4A82, 0xE2B87A14, 0x7BB12BAE, 0x0CB61B38,
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0x92D28E9B, 0xE5D5BE0D, 0x7CDCEFB7, 0x0BDBDF21,
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0x86D3D2D4, 0xF1D4E242, 0x68DDB3F8, 0x1FDA836E,
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0x81BE16CD, 0xF6B9265B, 0x6FB077E1, 0x18B74777,
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0x88085AE6, 0xFF0F6A70, 0x66063BCA, 0x11010B5C,
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0x8F659EFF, 0xF862AE69, 0x616BFFD3, 0x166CCF45,
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0xA00AE278, 0xD70DD2EE, 0x4E048354, 0x3903B3C2,
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0xA7672661, 0xD06016F7, 0x4969474D, 0x3E6E77DB,
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0xAED16A4A, 0xD9D65ADC, 0x40DF0B66, 0x37D83BF0,
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0xA9BCAE53, 0xDEBB9EC5, 0x47B2CF7F, 0x30B5FFE9,
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0xBDBDF21C, 0xCABAC28A, 0x53B39330, 0x24B4A3A6,
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0xBAD03605, 0xCDD70693, 0x54DE5729, 0x23D967BF,
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0xB3667A2E, 0xC4614AB8, 0x5D681B02, 0x2A6F2B94,
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0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B, 0x2D02EF8D
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};
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#ifdef PROVIDE_64BIT_CRC
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/*
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* This table is based on the polynomial
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*
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* x^64 + x^62 + x^57 + x^55 + x^54 + x^53 + x^52 + x^47 + x^46 + x^45 +
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* x^40 + x^39 + x^38 + x^37 + x^35 + x^33 + x^32 + x^31 + x^29 + x^27 +
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* x^24 + x^23 + x^22 + x^21 + x^19 + x^17 + x^13 + x^12 + x^10 + x^9 +
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* x^7 + x^4 + x + 1
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*
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* which is borrowed from the DLT1 spec
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* (ECMA-182, available from http://www.ecma.ch/ecma1/STAND/ECMA-182.HTM)
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*/
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#ifdef INT64_IS_BUSTED
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const uint32 crc_table0[256] = {
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const uint32 pg_crc64_table0[256] = {
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0x00000000, 0xA9EA3693,
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0x53D46D26, 0xFA3E5BB5,
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0x0E42ECDF, 0xA7A8DA4C,
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@@ -150,7 +248,7 @@ const uint32 crc_table0[256] = {
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0x676F8394, 0xCE85B507
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};
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const uint32 crc_table1[256] = {
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const uint32 pg_crc64_table1[256] = {
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0x00000000, 0x42F0E1EB,
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0x85E1C3D7, 0xC711223C,
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0x49336645, 0x0BC387AE,
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@@ -283,7 +381,7 @@ const uint32 crc_table1[256] = {
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#else /* int64 works */
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const uint64 crc_table[256] = {
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const uint64 pg_crc64_table[256] = {
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UINT64CONST(0x0000000000000000), UINT64CONST(0x42F0E1EBA9EA3693),
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UINT64CONST(0x85E1C3D753D46D26), UINT64CONST(0xC711223CFA3E5BB5),
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UINT64CONST(0x493366450E42ECDF), UINT64CONST(0x0BC387AEA7A8DA4C),
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@@ -415,3 +513,5 @@ const uint64 crc_table[256] = {
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};
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#endif /* INT64_IS_BUSTED */
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#endif /* PROVIDE_64BIT_CRC */
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