From 73d640cbac5d33c151c24c71613fc89f99a78c97 Mon Sep 17 00:00:00 2001 From: Bharath Rupireddy Date: Wed, 31 Jan 2024 07:48:57 +0000 Subject: [PATCH v22 4/4] Use WALReadFromBuffers() in more places --- src/backend/access/transam/xlogutils.c | 14 +++++++++++++- src/backend/replication/walsender.c | 16 +++++++++++++--- 2 files changed, 26 insertions(+), 4 deletions(-) diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c index aa8667abd1..1740ac3160 100644 --- a/src/backend/access/transam/xlogutils.c +++ b/src/backend/access/transam/xlogutils.c @@ -894,6 +894,8 @@ read_local_xlog_page_guts(XLogReaderState *state, XLogRecPtr targetPagePtr, int count; WALReadError errinfo; TimeLineID currTLI; + Size nbytes; + Size rbytes; loc = targetPagePtr + reqLen; @@ -1006,12 +1008,22 @@ read_local_xlog_page_guts(XLogReaderState *state, XLogRecPtr targetPagePtr, count = read_upto - targetPagePtr; } + /* Attempt to read WAL from WAL buffers first. */ + nbytes = XLOG_BLCKSZ; + rbytes = WALReadFromBuffers(cur_page, targetPagePtr, nbytes, currTLI); + cur_page += rbytes; + targetPagePtr += rbytes; + nbytes -= rbytes; + /* + * Now read the remaining WAL from WAL file. + * * Even though we just determined how much of the page can be validly read * as 'count', read the whole page anyway. It's guaranteed to be * zero-padded up to the page boundary if it's incomplete. */ - if (!WALRead(state, cur_page, targetPagePtr, XLOG_BLCKSZ, tli, + if (nbytes > 0 && + !WALRead(state, cur_page, targetPagePtr, nbytes, tli, &errinfo)) WALReadRaiseError(&errinfo); diff --git a/src/backend/replication/walsender.c b/src/backend/replication/walsender.c index 0551f0f2d8..3f515bbf18 100644 --- a/src/backend/replication/walsender.c +++ b/src/backend/replication/walsender.c @@ -1059,6 +1059,8 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req WALReadError errinfo; XLogSegNo segno; TimeLineID currTLI; + Size nbytes; + Size rbytes; /* * Make sure we have enough WAL available before retrieving the current @@ -1095,11 +1097,19 @@ logical_read_xlog_page(XLogReaderState *state, XLogRecPtr targetPagePtr, int req else count = flushptr - targetPagePtr; /* part of the page available */ - /* now actually read the data, we know it's there */ - if (!WALRead(state, + /* Attempt to read WAL from WAL buffers first. */ + nbytes = XLOG_BLCKSZ; + rbytes = WALReadFromBuffers(cur_page, targetPagePtr, nbytes, currTLI); + cur_page += rbytes; + targetPagePtr += rbytes; + nbytes -= rbytes; + + /* Now read the remaining WAL from WAL file. */ + if (nbytes > 0 && + !WALRead(state, cur_page, targetPagePtr, - XLOG_BLCKSZ, + nbytes, currTLI, /* Pass the current TLI because only * WalSndSegmentOpen controls whether new TLI * is needed. */ -- 2.34.1