From 95783a38684976f81bb8ef0a66139d1bd54935ba Mon Sep 17 00:00:00 2001 From: Andres Freund Date: Tue, 4 Oct 2022 16:08:42 -0700 Subject: [PATCH v1 2/2] wip: wal: Encode RelFileLocator and BLockNumber as varints A run of installcheck in a cluster with autovacuum=off, full_page_writes=off (for increased reproducability) shows a decent saving: master: 241106544 - 230 MB varint: 227858640 - 217 MB Could be used in a bunch of additional places too. Author: Reviewed-by: Discussion: https://postgr.es/m/ Backpatch: --- src/backend/access/transam/xloginsert.c | 9 ++++---- src/backend/access/transam/xlogreader.c | 29 +++++++++++++++++++++++-- 2 files changed, 32 insertions(+), 6 deletions(-) diff --git a/src/backend/access/transam/xloginsert.c b/src/backend/access/transam/xloginsert.c index 5ca15ebbf20..a6e95a58966 100644 --- a/src/backend/access/transam/xloginsert.c +++ b/src/backend/access/transam/xloginsert.c @@ -33,6 +33,7 @@ #include "access/xloginsert.h" #include "catalog/pg_control.h" #include "common/pg_lzcompress.h" +#include "common/varint.h" #include "executor/instrument.h" #include "miscadmin.h" #include "pg_trace.h" @@ -807,11 +808,11 @@ XLogRecordAssemble(RmgrId rmid, uint8 info, } if (!samerel) { - memcpy(scratch, ®buf->rlocator, sizeof(RelFileLocator)); - scratch += sizeof(RelFileLocator); + scratch += pg_varint_encode_uint64(regbuf->rlocator.spcOid, (uint8*) scratch); + scratch += pg_varint_encode_uint64(regbuf->rlocator.dbOid, (uint8*) scratch); + scratch += pg_varint_encode_uint64(regbuf->rlocator.relNumber, (uint8*) scratch); } - memcpy(scratch, ®buf->block, sizeof(BlockNumber)); - scratch += sizeof(BlockNumber); + scratch += pg_varint_encode_uint64(regbuf->block, (uint8*) scratch); } /* followed by the record's origin, if any */ diff --git a/src/backend/access/transam/xlogreader.c b/src/backend/access/transam/xlogreader.c index 5a8fe81f826..899b776ed25 100644 --- a/src/backend/access/transam/xlogreader.c +++ b/src/backend/access/transam/xlogreader.c @@ -31,6 +31,7 @@ #include "access/xlogrecord.h" #include "catalog/pg_control.h" #include "common/pg_lzcompress.h" +#include "common/varint.h" #include "replication/origin.h" #ifndef FRONTEND @@ -1853,7 +1854,22 @@ DecodeXLogRecord(XLogReaderState *state, } if (!(fork_flags & BKPBLOCK_SAME_REL)) { - COPY_HEADER_FIELD(&blk->rlocator, sizeof(RelFileLocator)); + int consumed; + + /* FIXME: needs overflow checks from COPY_HEADER_FIELD() */ + + blk->rlocator.spcOid = pg_varint_decode_uint64((uint8*) ptr, &consumed); + ptr += consumed; + remaining -= consumed; + + blk->rlocator.dbOid = pg_varint_decode_uint64((uint8*) ptr, &consumed); + ptr += consumed; + remaining -= consumed; + + blk->rlocator.relNumber = pg_varint_decode_uint64((uint8*) ptr, &consumed); + ptr += consumed; + remaining -= consumed; + rlocator = &blk->rlocator; } else @@ -1868,7 +1884,16 @@ DecodeXLogRecord(XLogReaderState *state, blk->rlocator = *rlocator; } - COPY_HEADER_FIELD(&blk->blkno, sizeof(BlockNumber)); + + + { + int consumed; + + /* FIXME: needs overflow checks from COPY_HEADER_FIELD() */ + blk->blkno = pg_varint_decode_uint64((uint8*) ptr, &consumed); + ptr += consumed; + remaining -= consumed; + } } else { -- 2.37.3.542.gdd3f6c4cae