fix_waldump_size_for_wal_switch_v3-1.patch

diff --git a/src/backend/access/rmgrdesc/xlogdesc.c b/src/backend/access/rmgrdesc/xlogdesc.c
index 3200f777f5..04042a50a4 100644
--- a/src/backend/access/rmgrdesc/xlogdesc.c
+++ b/src/backend/access/rmgrdesc/xlogdesc.c
@@ -142,6 +142,31 @@ xlog_desc(StringInfo buf, XLogReaderState *record)
 	}
 }
 
+uint32
+xlog_switch_junk_len(XLogReaderState *record)
+{
+	uint32 		junk_len;
+	XLogSegNo	startSegNo;
+	XLogSegNo	endSegNo;
+
+	XLByteToSeg(record->ReadRecPtr, startSegNo, record->segcxt.ws_segsize);
+	XLByteToSeg(record->EndRecPtr - 1, endSegNo, record->segcxt.ws_segsize);
+
+	junk_len = record->EndRecPtr - record->ReadRecPtr - XLogRecGetTotalLen(record);
+	/*
+	 * If the wal switch record spread on two segments, we should extra minus the
+	 * long page head. I mean the case when the remain size of a wal segment can not
+	 * afford a XLogRecord struct for XLOG_SWITCH.
+	 */
+	if(startSegNo != endSegNo)
+		junk_len -= SizeOfXLogLongPHD;
+
+
+	Assert(junk_len >= 0);
+
+	return junk_len;
+}
+
 const char *
 xlog_identify(uint8 info)
 {
diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c
index 31e99c2a6d..ab4e7c830f 100644
--- a/src/bin/pg_waldump/pg_waldump.c
+++ b/src/bin/pg_waldump/pg_waldump.c
@@ -24,6 +24,7 @@
 #include "common/logging.h"
 #include "getopt_long.h"
 #include "rmgrdesc.h"
+#include "catalog/pg_control.h"
 
 static const char *progname;
 
@@ -66,8 +67,8 @@ typedef struct Stats
 typedef struct XLogDumpStats
 {
 	uint64		count;
-	Stats		rmgr_stats[RM_NEXT_ID];
-	Stats		record_stats[RM_NEXT_ID][MAX_XLINFO_TYPES];
+	Stats		rmgr_stats[RM_NEXT_ID + 1];
+	Stats		record_stats[RM_NEXT_ID + 1][MAX_XLINFO_TYPES];
 } XLogDumpStats;
 
 #define fatal_error(...) do { pg_log_fatal(__VA_ARGS__); exit(EXIT_FAILURE); } while(0)
@@ -441,6 +442,22 @@ XLogDumpCountRecord(XLogDumpConfig *config, XLogDumpStats *stats,
 	stats->record_stats[rmid][recid].count++;
 	stats->record_stats[rmid][recid].rec_len += rec_len;
 	stats->record_stats[rmid][recid].fpi_len += fpi_len;
+
+
+	/* Add junk-space stats for XLOG_SWITCH  */
+	if(rmid == RM_XLOG_ID && XLogRecGetInfo(record) == XLOG_SWITCH)
+	{
+		uint64 junk_len = xlog_switch_junk_len(record);
+
+		rmid = WALDUMP_RM_ID;
+		recid = 0;
+
+		stats->rmgr_stats[rmid].count++;
+		stats->rmgr_stats[rmid].rec_len += junk_len;
+
+		stats->record_stats[rmid][recid].count++;
+		stats->record_stats[rmid][recid].rec_len += junk_len;
+	}
 }
 
 /*
@@ -616,7 +633,7 @@ XLogDumpDisplayStats(XLogDumpConfig *config, XLogDumpStats *stats)
 	 * calculate column totals.
 	 */
 
-	for (ri = 0; ri < RM_NEXT_ID; ri++)
+	for (ri = 0; ri <= RM_NEXT_ID; ri++)
 	{
 		total_count += stats->rmgr_stats[ri].count;
 		total_rec_len += stats->rmgr_stats[ri].rec_len;
@@ -634,7 +651,7 @@ XLogDumpDisplayStats(XLogDumpConfig *config, XLogDumpStats *stats)
 		   "Type", "N", "(%)", "Record size", "(%)", "FPI size", "(%)", "Combined size", "(%)",
 		   "----", "-", "---", "-----------", "---", "--------", "---", "-------------", "---");
 
-	for (ri = 0; ri < RM_NEXT_ID; ri++)
+	for (ri = 0; ri <= RM_NEXT_ID; ri++)
 	{
 		uint64		count,
 					rec_len,
diff --git a/src/bin/pg_waldump/rmgrdesc.c b/src/bin/pg_waldump/rmgrdesc.c
index 852d8ca4b1..efddc70ac1 100644
--- a/src/bin/pg_waldump/rmgrdesc.c
+++ b/src/bin/pg_waldump/rmgrdesc.c
@@ -35,6 +35,18 @@
 #define PG_RMGR(symname,name,redo,desc,identify,startup,cleanup,mask) \
 	{ name, desc, identify},
 
-const RmgrDescData RmgrDescTable[RM_MAX_ID + 1] = {
+static const char *waldump_xlogswitch_identify(uint8 info);
+
+const RmgrDescData RmgrDescTable[RM_MAX_ID + 2] = {
 #include "access/rmgrlist.h"
+	PG_RMGR(WALDUMP_RM_ID, "OTHERS", NULL, NULL, waldump_xlogswitch_identify, NULL, NULL, NULL)
 };
+
+static const char *
+waldump_xlogswitch_identify(uint8 info)
+{
+	if (info == 0)
+		return "XLOG_SWITCH_JUNK";
+	else
+		return NULL;
+}
diff --git a/src/bin/pg_waldump/rmgrdesc.h b/src/bin/pg_waldump/rmgrdesc.h
index 42f8483b48..2a67d1050e 100644
--- a/src/bin/pg_waldump/rmgrdesc.h
+++ b/src/bin/pg_waldump/rmgrdesc.h
@@ -20,4 +20,6 @@ typedef struct RmgrDescData
 
 extern const RmgrDescData RmgrDescTable[];
 
+#define WALDUMP_RM_ID RM_NEXT_ID
+
 #endif							/* RMGRDESC_H */
diff --git a/src/include/access/xlog_internal.h b/src/include/access/xlog_internal.h
index 4146753d47..8cbc309108 100644
--- a/src/include/access/xlog_internal.h
+++ b/src/include/access/xlog_internal.h
@@ -315,6 +315,7 @@ extern XLogRecPtr RequestXLogSwitch(bool mark_unimportant);
 
 extern void GetOldestRestartPoint(XLogRecPtr *oldrecptr, TimeLineID *oldtli);
 
+extern uint32 xlog_switch_junk_len(XLogReaderState *record);
 /*
  * Exported for the functions in timeline.c and xlogarchive.c.  Only valid
  * in the startup process.