From 43434ed94d80b4a181d5d9dc6bda585a9267eb1e Mon Sep 17 00:00:00 2001
From: Noah Misch <noah@leadboat.com>
Date: Sat, 21 Mar 2020 09:38:33 -0700
Subject: [PATCH] Back-patch log_newpage_range().
Back-patch a subset of commit 9155580fd5fc2a0cbb23376dfca7cd21f59c2c7b
to v11, v10, 9.6, and 9.5. Include the latest repairs to this function.
Use a new XLOG_FPI_MULTI value instead of reusing XLOG_FPI. That way,
if an older server reads WAL from this function, that server will PANIC
instead of applying just one page of the record. The next commit adds a
call to this function.
Discussion: https://postgr.es/m/20200304.162919.898938381201316571.horikyota.ntt@gmail.com
---
src/backend/access/rmgrdesc/xlogdesc.c | 6 +-
src/backend/access/transam/xlog.c | 23 ++++---
src/backend/access/transam/xloginsert.c | 88 ++++++++++++++++++++++++
src/backend/replication/logical/decode.c | 1 +
src/include/access/xloginsert.h | 3 +
src/include/catalog/pg_control.h | 1 +
6 files changed, 113 insertions(+), 9 deletions(-)
diff --git a/src/backend/access/rmgrdesc/xlogdesc.c b/src/backend/access/rmgrdesc/xlogdesc.c
index f72f0760173..563fae5ebfa 100644
--- a/src/backend/access/rmgrdesc/xlogdesc.c
+++ b/src/backend/access/rmgrdesc/xlogdesc.c
@@ -78,7 +78,8 @@ xlog_desc(StringInfo buf, XLogReaderState *record)
appendStringInfoString(buf, xlrec->rp_name);
}
- else if (info == XLOG_FPI || info == XLOG_FPI_FOR_HINT)
+ else if (info == XLOG_FPI || info == XLOG_FPI_FOR_HINT ||
+ info == XLOG_FPI_MULTI)
{
/* no further information to print */
}
@@ -182,6 +183,9 @@ xlog_identify(uint8 info)
case XLOG_FPI_FOR_HINT:
id = "FPI_FOR_HINT";
break;
+ case XLOG_FPI_MULTI:
+ id = "FPI_MULTI";
+ break;
}
return id;
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index f4b059aa2e8..ec66b99b325 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -9721,7 +9721,7 @@ xlog_redo(XLogReaderState *record)
/* in XLOG rmgr, backup blocks are only used by XLOG_FPI records */
Assert(info == XLOG_FPI || info == XLOG_FPI_FOR_HINT ||
- !XLogRecHasAnyBlockRefs(record));
+ info == XLOG_FPI_MULTI || !XLogRecHasAnyBlockRefs(record));
if (info == XLOG_NEXTOID)
{
@@ -9924,14 +9924,16 @@ xlog_redo(XLogReaderState *record)
{
/* nothing to do here */
}
- else if (info == XLOG_FPI || info == XLOG_FPI_FOR_HINT)
+ else if (info == XLOG_FPI || info == XLOG_FPI_FOR_HINT ||
+ info == XLOG_FPI_MULTI)
{
- Buffer buffer;
+ uint8 block_id;
/*
* Full-page image (FPI) records contain nothing else but a backup
- * block. The block reference must include a full-page image -
- * otherwise there would be no point in this record.
+ * block (or multiple backup blocks). Every block reference must
+ * include a full-page image - otherwise there would be no point in
+ * this record.
*
* No recovery conflicts are generated by these generic records - if a
* resource manager needs to generate conflicts, it has to define a
@@ -9943,9 +9945,14 @@ xlog_redo(XLogReaderState *record)
* XLOG_FPI and XLOG_FPI_FOR_HINT records, they use a different info
* code just to distinguish them for statistics purposes.
*/
- if (XLogReadBufferForRedo(record, 0, &buffer) != BLK_RESTORED)
- elog(ERROR, "unexpected XLogReadBufferForRedo result when restoring backup block");
- UnlockReleaseBuffer(buffer);
+ for (block_id = 0; block_id <= record->max_block_id; block_id++)
+ {
+ Buffer buffer;
+
+ if (XLogReadBufferForRedo(record, block_id, &buffer) != BLK_RESTORED)
+ elog(ERROR, "unexpected XLogReadBufferForRedo result when restoring backup block");
+ UnlockReleaseBuffer(buffer);
+ }
}
else if (info == XLOG_BACKUP_END)
{
diff --git a/src/backend/access/transam/xloginsert.c b/src/backend/access/transam/xloginsert.c
index 1f86c907598..579d8de7759 100644
--- a/src/backend/access/transam/xloginsert.c
+++ b/src/backend/access/transam/xloginsert.c
@@ -1021,6 +1021,94 @@ log_newpage_buffer(Buffer buffer, bool page_std)
return log_newpage(&rnode, forkNum, blkno, page, page_std);
}
+/*
+ * WAL-log a range of blocks in a relation.
+ *
+ * An image of all pages with block numbers 'startblk' <= X < 'endblk' is
+ * written to the WAL. If the range is large, this is done in multiple WAL
+ * records.
+ *
+ * If all page follows the standard page layout, with a PageHeader and unused
+ * space between pd_lower and pd_upper, set 'page_std' to true. That allows
+ * the unused space to be left out from the WAL records, making them smaller.
+ *
+ * NOTE: This function acquires exclusive-locks on the pages. Typically, this
+ * is used on a newly-built relation, and the caller is holding a
+ * AccessExclusiveLock on it, so no other backend can be accessing it at the
+ * same time. If that's not the case, you must ensure that this does not
+ * cause a deadlock through some other means.
+ */
+void
+log_newpage_range(Relation rel, ForkNumber forkNum,
+ BlockNumber startblk, BlockNumber endblk,
+ bool page_std)
+{
+ int flags;
+ BlockNumber blkno;
+
+ flags = REGBUF_FORCE_IMAGE;
+ if (page_std)
+ flags |= REGBUF_STANDARD;
+
+ /*
+ * Iterate over all the pages in the range. They are collected into
+ * batches of XLR_MAX_BLOCK_ID pages, and a single WAL-record is written
+ * for each batch.
+ */
+ XLogEnsureRecordSpace(XLR_MAX_BLOCK_ID - 1, 0);
+
+ blkno = startblk;
+ while (blkno < endblk)
+ {
+ Buffer bufpack[XLR_MAX_BLOCK_ID];
+ XLogRecPtr recptr;
+ int nbufs;
+ int i;
+
+ CHECK_FOR_INTERRUPTS();
+
+ /* Collect a batch of blocks. */
+ nbufs = 0;
+ while (nbufs < XLR_MAX_BLOCK_ID && blkno < endblk)
+ {
+ Buffer buf = ReadBufferExtended(rel, forkNum, blkno,
+ RBM_NORMAL, NULL);
+
+ LockBuffer(buf, BUFFER_LOCK_EXCLUSIVE);
+
+ /*
+ * Completely empty pages are not WAL-logged. Writing a WAL record
+ * would change the LSN, and we don't want that. We want the page
+ * to stay empty.
+ */
+ if (!PageIsNew(BufferGetPage(buf)))
+ bufpack[nbufs++] = buf;
+ else
+ UnlockReleaseBuffer(buf);
+ blkno++;
+ }
+
+ /* Write WAL record for this batch. */
+ XLogBeginInsert();
+
+ START_CRIT_SECTION();
+ for (i = 0; i < nbufs; i++)
+ {
+ XLogRegisterBuffer(i, bufpack[i], flags);
+ MarkBufferDirty(bufpack[i]);
+ }
+
+ recptr = XLogInsert(RM_XLOG_ID, XLOG_FPI_MULTI);
+
+ for (i = 0; i < nbufs; i++)
+ {
+ PageSetLSN(BufferGetPage(bufpack[i]), recptr);
+ UnlockReleaseBuffer(bufpack[i]);
+ }
+ END_CRIT_SECTION();
+ }
+}
+
/*
* Allocate working buffers needed for WAL record construction.
*/
diff --git a/src/backend/replication/logical/decode.c b/src/backend/replication/logical/decode.c
index 8274024b6c9..d7a6f5d4687 100644
--- a/src/backend/replication/logical/decode.c
+++ b/src/backend/replication/logical/decode.c
@@ -195,6 +195,7 @@ DecodeXLogOp(LogicalDecodingContext *ctx, XLogRecordBuffer *buf)
case XLOG_FPW_CHANGE:
case XLOG_FPI_FOR_HINT:
case XLOG_FPI:
+ case XLOG_FPI_MULTI:
break;
default:
elog(ERROR, "unexpected RM_XLOG_ID record type: %u", info);
diff --git a/src/include/access/xloginsert.h b/src/include/access/xloginsert.h
index 174c88677f5..09bf94630a4 100644
--- a/src/include/access/xloginsert.h
+++ b/src/include/access/xloginsert.h
@@ -16,6 +16,7 @@
#include "storage/block.h"
#include "storage/buf.h"
#include "storage/relfilenode.h"
+#include "utils/relcache.h"
/*
* The minimum size of the WAL construction working area. If you need to
@@ -54,6 +55,8 @@ extern bool XLogCheckBufferNeedsBackup(Buffer buffer);
extern XLogRecPtr log_newpage(RelFileNode *rnode, ForkNumber forkNum,
BlockNumber blk, char *page, bool page_std);
extern XLogRecPtr log_newpage_buffer(Buffer buffer, bool page_std);
+extern void log_newpage_range(Relation rel, ForkNumber forkNum,
+ BlockNumber startblk, BlockNumber endblk, bool page_std);
extern XLogRecPtr XLogSaveBufferForHint(Buffer buffer, bool buffer_std);
extern void InitXLogInsert(void);
diff --git a/src/include/catalog/pg_control.h b/src/include/catalog/pg_control.h
index 1ec03caf5fb..77b7a5e5299 100644
--- a/src/include/catalog/pg_control.h
+++ b/src/include/catalog/pg_control.h
@@ -76,6 +76,7 @@ typedef struct CheckPoint
#define XLOG_END_OF_RECOVERY 0x90
#define XLOG_FPI_FOR_HINT 0xA0
#define XLOG_FPI 0xB0
+#define XLOG_FPI_MULTI 0xC0
/*