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Columnar: use proper generic WAL interface. (#5543) 

Previously, we cheated by using the RM_GENERIC_ID record type, but not
actually using the generic WAL API. This worked because we always took
a full page image, and saved the extra work of allocating and copying
to a temporary page.

But it introduced complexity, and perhaps fragility, so better to just
use the API properly. The performance penalty for a serial data load
seems to be less than 1%.
pull/5548/head
jeff-davis 2022-01-04 22:42:21 -08:00 committed by GitHub
parent afd53e4c54
commit 1546aa0d9f
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1 changed files with 6 additions and 20 deletions
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26
src/backend/columnar/columnar_storage.c
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@ -38,6 +38,7 @@
#include "safe_lib.h" #include "safe_lib.h"
#include "access/generic_xlog.h"
#include "catalog/storage.h" #include "catalog/storage.h"
#include "miscadmin.h" #include "miscadmin.h"
#include "storage/bufmgr.h" #include "storage/bufmgr.h"
@ -699,9 +700,12 @@ WriteToBlock(Relation rel, BlockNumber blockno, uint32 offset, char *buf,
uint32 len, bool clear) uint32 len, bool clear)
{ {
Buffer buffer = ReadBuffer(rel, blockno); Buffer buffer = ReadBuffer(rel, blockno);
GenericXLogState *state = GenericXLogStart(rel);
LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE); LockBuffer(buffer, BUFFER_LOCK_EXCLUSIVE);
Page page = BufferGetPage(buffer); Page page = GenericXLogRegisterBuffer(state, buffer, GENERIC_XLOG_FULL_IMAGE);
PageHeader phdr = (PageHeader) page; PageHeader phdr = (PageHeader) page;
if (PageIsNew(page) || clear) if (PageIsNew(page) || clear)
{ {
@ -734,28 +738,10 @@ WriteToBlock(Relation rel, BlockNumber blockno, uint32 offset, char *buf,
phdr->pd_lower = offset; phdr->pd_lower = offset;
} }
START_CRIT_SECTION();
memcpy_s(page + phdr->pd_lower, phdr->pd_upper - phdr->pd_lower, buf, len); memcpy_s(page + phdr->pd_lower, phdr->pd_upper - phdr->pd_lower, buf, len);
phdr->pd_lower += len; phdr->pd_lower += len;
MarkBufferDirty(buffer); GenericXLogFinish(state);
if (RelationNeedsWAL(rel))
{
XLogBeginInsert();
/*
* Since columnar will mostly write whole pages we force the transmission of the
* whole image in the buffer
*/
XLogRegisterBuffer(0, buffer, REGBUF_FORCE_IMAGE);
XLogRecPtr recptr = XLogInsert(RM_GENERIC_ID, 0);
PageSetLSN(page, recptr);
}
END_CRIT_SECTION();
UnlockReleaseBuffer(buffer); UnlockReleaseBuffer(buffer);
} }