From: Kyotaro Horiguchi <horiguchi.kyotaro@lab.ntt.co.jp>
Date: Tue, 26 Mar 2019 14:48:26 +0900
Subject: [PATCH 8/8] Optimize WAL-logging on btree bulk insertion

Likewise the heap case, bulk insertion into btree can be optimized to
omit WAL-logging on certain conditions.
---
 src/backend/access/heap/heapam.c      | 13 +++++++++++++
 src/backend/access/nbtree/nbtinsert.c |  5 ++++-
 src/backend/access/nbtree/nbtsort.c   | 23 +++++++----------------
 3 files changed, 24 insertions(+), 17 deletions(-)

diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index 00416c4a99..c28b479141 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -8870,6 +8870,8 @@ heap_mask(char *pagedata, BlockNumber blkno)
 void
 heap_register_sync(Relation rel)
 {
+	ListCell   *indlist;
+
 	/* non-WAL-logged tables never need fsync */
 	if (!RelationNeedsWAL(rel))
 		return;
@@ -8883,4 +8885,15 @@ heap_register_sync(Relation rel)
 		RecordWALSkipping(toastrel);
 		heap_close(toastrel, AccessShareLock);
 	}
+
+	/* Do the same to all index relations */
+	foreach(indlist, RelationGetIndexList(rel))
+	{
+		Oid			indexId = lfirst_oid(indlist);
+		Relation	indexRel;
+
+		indexRel = index_open(indexId, AccessShareLock);
+		RecordWALSkipping(indexRel);
+		index_close(indexRel, NoLock);
+	}
 }
diff --git a/src/backend/access/nbtree/nbtinsert.c b/src/backend/access/nbtree/nbtinsert.c
index 96b7593fc1..fadcc09cb1 100644
--- a/src/backend/access/nbtree/nbtinsert.c
+++ b/src/backend/access/nbtree/nbtinsert.c
@@ -20,6 +20,7 @@
 #include "access/tableam.h"
 #include "access/transam.h"
 #include "access/xloginsert.h"
+#include "catalog/storage.h"
 #include "miscadmin.h"
 #include "storage/lmgr.h"
 #include "storage/predicate.h"
@@ -1096,7 +1097,9 @@ _bt_insertonpg(Relation rel,
 			cachedBlock = BufferGetBlockNumber(buf);
 
 		/* XLOG stuff */
-		if (RelationNeedsWAL(rel))
+		if (BufferNeedsWAL(rel, buf) ||
+			(!P_ISLEAF(lpageop) && BufferNeedsWAL(rel, cbuf)) ||
+			(BufferIsValid(metabuf) && BufferNeedsWAL(rel, metabuf)))
 		{
 			xl_btree_insert xlrec;
 			xl_btree_metadata xlmeta;
diff --git a/src/backend/access/nbtree/nbtsort.c b/src/backend/access/nbtree/nbtsort.c
index e65d4aab0f..90a5d6ae13 100644
--- a/src/backend/access/nbtree/nbtsort.c
+++ b/src/backend/access/nbtree/nbtsort.c
@@ -66,6 +66,7 @@
 #include "access/xlog.h"
 #include "access/xloginsert.h"
 #include "catalog/index.h"
+#include "catalog/storage.h"
 #include "miscadmin.h"
 #include "pgstat.h"
 #include "storage/smgr.h"
@@ -264,7 +265,6 @@ typedef struct BTWriteState
 	Relation	heap;
 	Relation	index;
 	BTScanInsert inskey;		/* generic insertion scankey */
-	bool		btws_use_wal;	/* dump pages to WAL? */
 	BlockNumber btws_pages_alloced; /* # pages allocated */
 	BlockNumber btws_pages_written; /* # pages written out */
 	Page		btws_zeropage;	/* workspace for filling zeroes */
@@ -334,6 +334,10 @@ btbuild(Relation heap, Relation index, IndexInfo *indexInfo)
 
 	reltuples = _bt_spools_heapscan(heap, index, &buildstate, indexInfo);
 
+	/* Skip WAL-logging if wal_level = minimal */
+	if (!XLogIsNeeded())
+		RecordWALSkipping(index);
+
 	/*
 	 * Finish the build by (1) completing the sort of the spool file, (2)
 	 * inserting the sorted tuples into btree pages and (3) building the upper
@@ -543,12 +547,6 @@ _bt_leafbuild(BTSpool *btspool, BTSpool *btspool2)
 	wstate.index = btspool->index;
 	wstate.inskey = _bt_mkscankey(wstate.index, NULL);
 
-	/*
-	 * We need to log index creation in WAL iff WAL archiving/streaming is
-	 * enabled UNLESS the index isn't WAL-logged anyway.
-	 */
-	wstate.btws_use_wal = XLogIsNeeded() && RelationNeedsWAL(wstate.index);
-
 	/* reserve the metapage */
 	wstate.btws_pages_alloced = BTREE_METAPAGE + 1;
 	wstate.btws_pages_written = 0;
@@ -622,15 +620,8 @@ _bt_blwritepage(BTWriteState *wstate, Page page, BlockNumber blkno)
 	/* Ensure rd_smgr is open (could have been closed by relcache flush!) */
 	RelationOpenSmgr(wstate->index);
 
-	/* XLOG stuff
-	 *
-	 * Even if minimal mode, WAL is required here if truncation happened after
-	 * being created in the same transaction. It is not needed otherwise but
-	 * we don't bother identifying the case precisely.
-	 */
-	if (wstate->btws_use_wal ||
-		(RelationNeedsWAL(wstate->index) &&
-		 (blkno == BTREE_METAPAGE && BTPageGetMeta(page)->btm_root == 0)))
+	/* XLOG stuff */
+	if (BlockNeedsWAL(wstate->index, blkno))
 	{
 		/* We use the heap NEWPAGE record type for this */
 		log_newpage(&wstate->index->rd_node, MAIN_FORKNUM, blkno, page, true);
-- 
2.16.3


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