From 0bd624d63b056205fda17a2d694d91db16468e3f Mon Sep 17 00:00:00 2001
From: Heikki Linnakangas <heikki.linnakangas@iki.fi>
Date: Mon, 24 Nov 2014 10:43:32 +0200
Subject: [PATCH] Distinguish XLOG_FPI records generated for hint-bit updates.
Add a new XLOG_FPI_FOR_HINT record type, and use that for full-page images
generated for hint bit updates, when checksums are enabled. The new record
type is replayed exactly the same as XLOG_FPI, but allows them to be tallied
separately e.g. in pg_xlogdump.
---
src/backend/access/rmgrdesc/xlogdesc.c | 5 ++++-
src/backend/access/transam/xlog.c | 18 +++++++++++-------
src/backend/access/transam/xloginsert.c | 2 +-
src/backend/replication/logical/decode.c | 1 +
src/include/catalog/pg_control.h | 3 ++-
5 files changed, 19 insertions(+), 10 deletions(-)
diff --git a/src/backend/access/rmgrdesc/xlogdesc.c b/src/backend/access/rmgrdesc/xlogdesc.c
index 4088ba99b7f..eba046d1fa9 100644
--- a/src/backend/access/rmgrdesc/xlogdesc.c
+++ b/src/backend/access/rmgrdesc/xlogdesc.c
@@ -74,7 +74,7 @@ xlog_desc(StringInfo buf, XLogReaderState *record)
appendStringInfo(buf, "%s", xlrec->rp_name);
}
- else if (info == XLOG_FPI)
+ else if (info == XLOG_FPI || info == XLOG_FPI_FOR_HINT)
{
/* no further information to print */
}
@@ -170,6 +170,9 @@ xlog_identify(uint8 info)
case XLOG_FPI:
id = "FPI";
break;
+ case XLOG_FPI_FOR_HINT:
+ id = "FPI_FOR_HINT";
+ break;
}
return id;
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index 2059bbeda4a..8e712b793f3 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -8545,7 +8545,8 @@ xlog_redo(XLogReaderState *record)
XLogRecPtr lsn = record->EndRecPtr;
/* in XLOG rmgr, backup blocks are only used by XLOG_FPI records */
- Assert(!XLogRecHasAnyBlockRefs(record) || info == XLOG_FPI);
+ Assert(info == XLOG_FPI || info == XLOG_FPI_FOR_HINT ||
+ !XLogRecHasAnyBlockRefs(record));
if (info == XLOG_NEXTOID)
{
@@ -8730,7 +8731,7 @@ xlog_redo(XLogReaderState *record)
{
/* nothing to do here */
}
- else if (info == XLOG_FPI)
+ else if (info == XLOG_FPI || info == XLOG_FPI_FOR_HINT)
{
Buffer buffer;
@@ -8739,12 +8740,15 @@ xlog_redo(XLogReaderState *record)
* block. The block reference must include a full-page image -
* otherwise there would be no point in this record.
*
- * Since the only change in these backup block are hint bits, there
- * are no recovery conflicts generated.
+ * No recovery conflicts are generated by these generic records - if a
+ * resource manager needs to generate conflicts, it has to define a
+ * separate WAL record type and redo routine.
*
- * This also means there is no corresponding API call for this, so an
- * smgr implementation has no need to implement anything. Which means
- * nothing is needed in md.c etc
+ * XLOG_FPI_FOR_HINT records are generated when a page needs to be
+ * WAL- logged because of a hint bit update. They are only generated
+ * when checksums are enabled. There is no difference in handling
+ * 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");
diff --git a/src/backend/access/transam/xloginsert.c b/src/backend/access/transam/xloginsert.c
index fe204313024..34e44e4f235 100644
--- a/src/backend/access/transam/xloginsert.c
+++ b/src/backend/access/transam/xloginsert.c
@@ -786,7 +786,7 @@ XLogSaveBufferForHint(Buffer buffer, bool buffer_std)
BufferGetTag(buffer, &rnode, &forkno, &blkno);
XLogRegisterBlock(0, &rnode, forkno, blkno, copied_buffer, flags);
- recptr = XLogInsert(RM_XLOG_ID, XLOG_FPI);
+ recptr = XLogInsert(RM_XLOG_ID, XLOG_FPI_FOR_HINT);
}
return recptr;
diff --git a/src/backend/replication/logical/decode.c b/src/backend/replication/logical/decode.c
index 1c7dac38fc9..4e81322509f 100644
--- a/src/backend/replication/logical/decode.c
+++ b/src/backend/replication/logical/decode.c
@@ -170,6 +170,7 @@ DecodeXLogOp(LogicalDecodingContext *ctx, XLogRecordBuffer *buf)
case XLOG_PARAMETER_CHANGE:
case XLOG_RESTORE_POINT:
case XLOG_FPW_CHANGE:
+ case XLOG_FPI_FOR_HINT:
case XLOG_FPI:
break;
default:
diff --git a/src/include/catalog/pg_control.h b/src/include/catalog/pg_control.h
index ba79d253ae5..15f81e4a44d 100644
--- a/src/include/catalog/pg_control.h
+++ b/src/include/catalog/pg_control.h
@@ -67,7 +67,8 @@ typedef struct CheckPoint
#define XLOG_RESTORE_POINT 0x70
#define XLOG_FPW_CHANGE 0x80
#define XLOG_END_OF_RECOVERY 0x90
-#define XLOG_FPI 0xA0
+#define XLOG_FPI_FOR_HINT 0xA0
+#define XLOG_FPI 0xB0
/*
--
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