Commit the reasonably uncontroversial parts of J.R. Nield's PITR patch, to

wit: Add a header record to each WAL segment file so that it can be reliably
identified.  Avoid splitting WAL records across segment files (this is not
strictly necessary, but makes it simpler to incorporate the header records).
Make WAL entries for file creation, deletion, and truncation (as foreseen but
never implemented by Vadim).  Also, add support for making XLOG_SEG_SIZE
configurable at compile time, similarly to BLCKSZ.  Fix a couple bugs I
introduced in WAL replay during recent smgr API changes.  initdb is forced
due to changes in pg_control contents.

Author: tglsfdc

src/backend/access/transam/xact.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.163 2004/02/10 03:42:43 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/access/transam/xact.c,v 1.164 2004/02/11 22:55:24 tgl Exp $
  *
  * NOTES
  *		Transaction aborts can now occur two ways:
@@ -519,19 +519,32 @@ RecordTransactionCommit(void)
 		if (MyLastRecPtr.xrecoff != 0)
 		{
 			/* Need to emit a commit record */
-			XLogRecData rdata;
+			XLogRecData rdata[2];
 			xl_xact_commit xlrec;
+			int			nrels;
+			RelFileNode *rptr;
+
+			nrels = smgrGetPendingDeletes(true, &rptr);
 
 			xlrec.xtime = time(NULL);
-			rdata.buffer = InvalidBuffer;
-			rdata.data = (char *) (&xlrec);
-			rdata.len = SizeOfXactCommit;
-			rdata.next = NULL;
+			rdata[0].buffer = InvalidBuffer;
+			rdata[0].data = (char *) (&xlrec);
+			rdata[0].len = MinSizeOfXactCommit;
+			if (nrels > 0)
+			{
+				rdata[0].next = &(rdata[1]);
+				rdata[1].buffer = InvalidBuffer;
+				rdata[1].data = (char *) rptr;
+				rdata[1].len = nrels * sizeof(RelFileNode);
+				rdata[1].next = NULL;
+			}
+			else
+				rdata[0].next = NULL;
 
-			/*
-			 * XXX SHOULD SAVE ARRAY OF RELFILENODE-s TO DROP
-			 */
-			recptr = XLogInsert(RM_XACT_ID, XLOG_XACT_COMMIT, &rdata);
+			recptr = XLogInsert(RM_XACT_ID, XLOG_XACT_COMMIT, rdata);
+
+			if (rptr)
+				pfree(rptr);
 		}
 		else
 		{
@@ -689,26 +702,42 @@ RecordTransactionAbort(void)
 		 * We only need to log the abort in XLOG if the transaction made
 		 * any transaction-controlled XLOG entries.  (Otherwise, its XID
 		 * appears nowhere in permanent storage, so no one else will ever
-		 * care if it committed.)  We do not flush XLOG to disk in any
-		 * case, since the default assumption after a crash would be that
-		 * we aborted, anyway.
+		 * care if it committed.)  We do not flush XLOG to disk unless
+		 * deleting files, since the default assumption after a crash
+		 * would be that we aborted, anyway.
 		 */
 		if (MyLastRecPtr.xrecoff != 0)
 		{
-			XLogRecData rdata;
+			XLogRecData rdata[2];
 			xl_xact_abort xlrec;
+			int			nrels;
+			RelFileNode *rptr;
 			XLogRecPtr	recptr;
 
+			nrels = smgrGetPendingDeletes(false, &rptr);
+
 			xlrec.xtime = time(NULL);
-			rdata.buffer = InvalidBuffer;
-			rdata.data = (char *) (&xlrec);
-			rdata.len = SizeOfXactAbort;
-			rdata.next = NULL;
+			rdata[0].buffer = InvalidBuffer;
+			rdata[0].data = (char *) (&xlrec);
+			rdata[0].len = MinSizeOfXactAbort;
+			if (nrels > 0)
+			{
+				rdata[0].next = &(rdata[1]);
+				rdata[1].buffer = InvalidBuffer;
+				rdata[1].data = (char *) rptr;
+				rdata[1].len = nrels * sizeof(RelFileNode);
+				rdata[1].next = NULL;
+			}
+			else
+				rdata[0].next = NULL;
 
-			/*
-			 * SHOULD SAVE ARRAY OF RELFILENODE-s TO DROP
-			 */
-			recptr = XLogInsert(RM_XACT_ID, XLOG_XACT_ABORT, &rdata);
+			recptr = XLogInsert(RM_XACT_ID, XLOG_XACT_ABORT, rdata);
+
+			if (nrels > 0)
+				XLogFlush(recptr);
+
+			if (rptr)
+				pfree(rptr);
 		}
 
 		/*
@@ -1774,13 +1803,33 @@ xact_redo(XLogRecPtr lsn, XLogRecord *record)
 
 	if (info == XLOG_XACT_COMMIT)
 	{
+		xl_xact_commit *xlrec = (xl_xact_commit *) XLogRecGetData(record);
+		int		nfiles;
+		int		i;
+
 		TransactionIdCommit(record->xl_xid);
-		/* SHOULD REMOVE FILES OF ALL DROPPED RELATIONS */
+		/* Make sure files supposed to be dropped are dropped */
+		nfiles = (record->xl_len - MinSizeOfXactCommit) / sizeof(RelFileNode);
+		for (i = 0; i < nfiles; i++)
+		{
+			XLogCloseRelation(xlrec->xnodes[i]);
+			smgrdounlink(smgropen(xlrec->xnodes[i]), false, true);
+		}
 	}
 	else if (info == XLOG_XACT_ABORT)
 	{
+		xl_xact_abort *xlrec = (xl_xact_abort *) XLogRecGetData(record);
+		int		nfiles;
+		int		i;
+
 		TransactionIdAbort(record->xl_xid);
-		/* SHOULD REMOVE FILES OF ALL FAILED-TO-BE-CREATED RELATIONS */
+		/* Make sure files supposed to be dropped are dropped */
+		nfiles = (record->xl_len - MinSizeOfXactAbort) / sizeof(RelFileNode);
+		for (i = 0; i < nfiles; i++)
+		{
+			XLogCloseRelation(xlrec->xnodes[i]);
+			smgrdounlink(smgropen(xlrec->xnodes[i]), false, true);
+		}
 	}
 	else
 		elog(PANIC, "xact_redo: unknown op code %u", info);
@@ -1810,6 +1859,7 @@ xact_desc(char *buf, uint8 xl_info, char *rec)
 		sprintf(buf + strlen(buf), "commit: %04u-%02u-%02u %02u:%02u:%02u",
 				tm->tm_year + 1900, tm->tm_mon + 1, tm->tm_mday,
 				tm->tm_hour, tm->tm_min, tm->tm_sec);
+		/* XXX can't show RelFileNodes for lack of access to record length */
 	}
 	else if (info == XLOG_XACT_ABORT)
 	{
@@ -1819,6 +1869,7 @@ xact_desc(char *buf, uint8 xl_info, char *rec)
 		sprintf(buf + strlen(buf), "abort: %04u-%02u-%02u %02u:%02u:%02u",
 				tm->tm_year + 1900, tm->tm_mon + 1, tm->tm_mday,
 				tm->tm_hour, tm->tm_min, tm->tm_sec);
+		/* XXX can't show RelFileNodes for lack of access to record length */
 	}
 	else
 		strcat(buf, "UNKNOWN");