From ffbba6ee1244901b492fe268ea94f72e35aedf38 Mon Sep 17 00:00:00 2001
From: Heikki Linnakangas <heikki.linnakangas@iki.fi>
Date: Sat, 5 Apr 2014 22:02:28 +0300
Subject: [PATCH] Fix another palloc in critical section.
Also add a regression test for a GIN index with enough items with the same
key, so that a GIN posting tree gets created. Apparently none of the
existing GIN tests were large enough for that.
This code is new, no backpatching required.
---
src/backend/access/gin/gindatapage.c | 35 ++++++++++++----------
src/test/regress/expected/create_index.out | 14 +++++++++
src/test/regress/sql/create_index.sql | 14 +++++++++
3 files changed, 48 insertions(+), 15 deletions(-)
diff --git a/src/backend/access/gin/gindatapage.c b/src/backend/access/gin/gindatapage.c
index 21ce79fc0b1..70801bd05cb 100644
--- a/src/backend/access/gin/gindatapage.c
+++ b/src/backend/access/gin/gindatapage.c
@@ -1706,22 +1706,16 @@ createPostingTree(Relation index, ItemPointerData *items, uint32 nitems,
{
BlockNumber blkno;
Buffer buffer;
+ Page tmppage;
Page page;
Pointer ptr;
int nrootitems;
int rootsize;
- /*
- * Create the root page.
- */
- buffer = GinNewBuffer(index);
- page = BufferGetPage(buffer);
- blkno = BufferGetBlockNumber(buffer);
-
- START_CRIT_SECTION();
-
- GinInitPage(page, GIN_DATA | GIN_LEAF | GIN_COMPRESSED, BLCKSZ);
- GinPageGetOpaque(page)->rightlink = InvalidBlockNumber;
+ /* Construct the new root page in memory first. */
+ tmppage = (Page) palloc(BLCKSZ);
+ GinInitPage(tmppage, GIN_DATA | GIN_LEAF | GIN_COMPRESSED, BLCKSZ);
+ GinPageGetOpaque(tmppage)->rightlink = InvalidBlockNumber;
/*
* Write as many of the items to the root page as fit. In segments
@@ -1729,7 +1723,7 @@ createPostingTree(Relation index, ItemPointerData *items, uint32 nitems,
*/
nrootitems = 0;
rootsize = 0;
- ptr = (Pointer) GinDataLeafPageGetPostingList(page);
+ ptr = (Pointer) GinDataLeafPageGetPostingList(tmppage);
while (nrootitems < nitems)
{
GinPostingList *segment;
@@ -1750,10 +1744,19 @@ createPostingTree(Relation index, ItemPointerData *items, uint32 nitems,
nrootitems += npacked;
pfree(segment);
}
- GinDataLeafPageSetPostingListSize(page, rootsize);
- MarkBufferDirty(buffer);
+ GinDataLeafPageSetPostingListSize(tmppage, rootsize);
- elog(DEBUG2, "created GIN posting tree with %d items", nrootitems);
+ /*
+ * All set. Get a new physical page, and copy the in-memory page to it.
+ */
+ buffer = GinNewBuffer(index);
+ page = BufferGetPage(buffer);
+ blkno = BufferGetBlockNumber(buffer);
+
+ START_CRIT_SECTION();
+
+ PageRestoreTempPage(tmppage, page);
+ MarkBufferDirty(buffer);
if (RelationNeedsWAL(index))
{
@@ -1787,6 +1790,8 @@ createPostingTree(Relation index, ItemPointerData *items, uint32 nitems,
if (buildStats)
buildStats->nDataPages++;
+ elog(DEBUG2, "created GIN posting tree with %d items", nrootitems);
+
/*
* Add any remaining TIDs to the newly-created posting tree.
*/
diff --git a/src/test/regress/expected/create_index.out b/src/test/regress/expected/create_index.out
index d10253b9e9b..f13b4f8a08d 100644
--- a/src/test/regress/expected/create_index.out
+++ b/src/test/regress/expected/create_index.out
@@ -2221,6 +2221,20 @@ RESET enable_seqscan;
RESET enable_indexscan;
RESET enable_bitmapscan;
--
+-- Try a GIN index with a lot of items with same key. (GIN creates a posting
+-- tree when there are enough duplicates)
+--
+CREATE TABLE array_gin_test (a int[]);
+INSERT INTO array_gin_test SELECT ARRAY[1, g%5, g] FROM generate_series(1, 10000) g;
+CREATE INDEX array_gin_test_idx ON array_gin_test USING gin (a);
+SELECT COUNT(*) FROM array_gin_test WHERE a @> '{2}';
+ count
+-------
+ 2000
+(1 row)
+
+DROP TABLE array_gin_test;
+--
-- HASH
--
CREATE INDEX hash_i4_index ON hash_i4_heap USING hash (random int4_ops);
diff --git a/src/test/regress/sql/create_index.sql b/src/test/regress/sql/create_index.sql
index 8ac1d1d280f..cd5c58d468c 100644
--- a/src/test/regress/sql/create_index.sql
+++ b/src/test/regress/sql/create_index.sql
@@ -636,6 +636,20 @@ RESET enable_seqscan;
RESET enable_indexscan;
RESET enable_bitmapscan;
+--
+-- Try a GIN index with a lot of items with same key. (GIN creates a posting
+-- tree when there are enough duplicates)
+--
+CREATE TABLE array_gin_test (a int[]);
+
+INSERT INTO array_gin_test SELECT ARRAY[1, g%5, g] FROM generate_series(1, 10000) g;
+
+CREATE INDEX array_gin_test_idx ON array_gin_test USING gin (a);
+
+SELECT COUNT(*) FROM array_gin_test WHERE a @> '{2}';
+
+DROP TABLE array_gin_test;
+
--
-- HASH
--
--
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