From a45c70acf35e43257d86313dcbb7bb0e5201fab1 Mon Sep 17 00:00:00 2001
From: Heikki Linnakangas <heikki.linnakangas@iki.fi>
Date: Sun, 28 Jun 2015 21:59:29 +0300
Subject: [PATCH] Fix double-XLogBeginInsert call in GIN page splits.
If data checksums or wal_log_hints is on, and a GIN page is split, the code
to find a new, empty, block was called after having already called
XLogBeginInsert(). That causes an assertion failure or PANIC, if finding the
new block involves updating a FSM page that had not been modified since last
checkpoint, because that update is WAL-logged, which calls XLogBeginInsert
again. Nested XLogBeginInsert calls are not supported.
To fix, rearrange GIN code so that XLogBeginInsert is called later, after
finding the victim buffers.
Reported by Jeff Janes.
---
src/backend/access/gin/ginbtree.c | 15 ++++++---------
src/backend/access/gin/gindatapage.c | 4 ++++
src/backend/access/gin/ginentrypage.c | 1 +
3 files changed, 11 insertions(+), 9 deletions(-)
diff --git a/src/backend/access/gin/ginbtree.c b/src/backend/access/gin/ginbtree.c
index 3f92c56d3c0..f0ff91aba2f 100644
--- a/src/backend/access/gin/ginbtree.c
+++ b/src/backend/access/gin/ginbtree.c
@@ -358,20 +358,15 @@ ginPlaceToPage(GinBtree btree, GinBtreeStack *stack,
* placeToPage can register some data to the WAL record.
*
* If placeToPage returns INSERTED, placeToPage has already called
- * START_CRIT_SECTION(), and we're responsible for calling
- * END_CRIT_SECTION. When it returns INSERTED, it is also responsible for
- * registering any data required to replay the operation with
- * XLogRegisterData(0, ...). It may only add data to block index 0; the
- * main data of the WAL record is reserved for this function.
+ * START_CRIT_SECTION() and XLogBeginInsert(), and registered any data
+ * required to replay the operation, in block index 0. We're responsible
+ * for filling in the main data portion of the WAL record, calling
+ * XLogInsert(), and END_CRIT_SECTION.
*
* If placeToPage returns SPLIT, we're wholly responsible for WAL logging.
* Splits happen infrequently, so we just make a full-page image of all
* the pages involved.
*/
-
- if (RelationNeedsWAL(btree->index))
- XLogBeginInsert();
-
rc = btree->placeToPage(btree, stack->buffer, stack,
insertdata, updateblkno,
&newlpage, &newrpage);
@@ -558,6 +553,8 @@ ginPlaceToPage(GinBtree btree, GinBtreeStack *stack,
{
XLogRecPtr recptr;
+ XLogBeginInsert();
+
/*
* We just take full page images of all the split pages. Splits
* are uncommon enough that it's not worth complicating the code
diff --git a/src/backend/access/gin/gindatapage.c b/src/backend/access/gin/gindatapage.c
index 8e81f6c8687..ec8c94bcbd1 100644
--- a/src/backend/access/gin/gindatapage.c
+++ b/src/backend/access/gin/gindatapage.c
@@ -600,7 +600,10 @@ dataPlaceToPageLeaf(GinBtree btree, Buffer buf, GinBtreeStack *stack,
*/
MemoryContextSwitchTo(oldCxt);
if (RelationNeedsWAL(btree->index))
+ {
+ XLogBeginInsert();
registerLeafRecompressWALData(buf, leaf);
+ }
START_CRIT_SECTION();
dataPlaceToPageLeafRecompress(buf, leaf);
@@ -1120,6 +1123,7 @@ dataPlaceToPageInternal(GinBtree btree, Buffer buf, GinBtreeStack *stack,
data.offset = off;
data.newitem = *pitem;
+ XLogBeginInsert();
XLogRegisterBuffer(0, buf, REGBUF_STANDARD);
XLogRegisterBufData(0, (char *) &data,
sizeof(ginxlogInsertDataInternal));
diff --git a/src/backend/access/gin/ginentrypage.c b/src/backend/access/gin/ginentrypage.c
index 9997eae1bcd..c912e60a112 100644
--- a/src/backend/access/gin/ginentrypage.c
+++ b/src/backend/access/gin/ginentrypage.c
@@ -557,6 +557,7 @@ entryPlaceToPage(GinBtree btree, Buffer buf, GinBtreeStack *stack,
data.isDelete = insertData->isDelete;
data.offset = off;
+ XLogBeginInsert();
XLogRegisterBuffer(0, buf, REGBUF_STANDARD);
XLogRegisterBufData(0, (char *) &data,
offsetof(ginxlogInsertEntry, tuple));
--
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