Change internal RelFileNode references to RelFileNumber or RelFileLocator.

We have been using the term RelFileNode to refer to either (1) the
integer that is used to name the sequence of files for a certain relation
within the directory set aside for that tablespace/database combination;
or (2) that value plus the OIDs of the tablespace and database; or
occasionally (3) the whole series of files created for a relation
based on those values. Using the same name for more than one thing is
confusing.

Replace RelFileNode with RelFileNumber when we're talking about just the
single number, i.e. (1) from above, and with RelFileLocator when we're
talking about all the things that are needed to locate a relation's files
on disk, i.e. (2) from above. In the places where we refer to (3) as
a relfilenode, instead refer to "relation storage".

Since there is a ton of SQL code in the world that knows about
pg_class.relfilenode, don't change the name of that column, or of other
SQL-facing things that derive their name from it.

On the other hand, do adjust closely-related internal terminology. For
example, the structure member names dbNode and spcNode appear to be
derived from the fact that the structure itself was called RelFileNode,
so change those to dbOid and spcOid. Likewise, various variables with
names like rnode and relnode get renamed appropriately, according to
how they're being used in context.

Hopefully, this is clearer than before. It is also preparation for
future patches that intend to widen the relfilenumber fields from its
current width of 32 bits. Variables that store a relfilenumber are now
declared as type RelFileNumber rather than type Oid; right now, these
are the same, but that can now more easily be changed.

Dilip Kumar, per an idea from me. Reviewed also by Andres Freund.
I fixed some whitespace issues, changed a couple of words in a
comment, and made one other minor correction.

Discussion: http://postgr.es/m/CA+TgmoamOtXbVAQf9hWFzonUo6bhhjS6toZQd7HZ-pmojtAmag@mail.gmail.com
Discussion: http://postgr.es/m/CA+Tgmobp7+7kmi4gkq7Y+4AM9fTvL+O1oQ4-5gFTT+6Ng-dQ=g@mail.gmail.com
Discussion: http://postgr.es/m/CAFiTN-vTe79M8uDH1yprOU64MNFE+R3ODRuA+JWf27JbhY4hJw@mail.gmail.com

1 files changed, 37 insertions, 36 deletions

diff --git a/src/backend/access/transam/xlogutils.c b/src/backend/access/transam/xlogutils.c
index 48516694f08..0cda22597fe 100644
--- a/src/backend/access/transam/xlogutils.c
+++ b/src/backend/access/transam/xlogutils.c
@@ -67,7 +67,7 @@ HotStandbyState standbyState = STANDBY_DISABLED;
  */
 typedef struct xl_invalid_page_key
 {
-	RelFileNode node;			/* the relation */
+	RelFileLocator locator;		/* the relation */
 	ForkNumber	forkno;			/* the fork number */
 	BlockNumber blkno;			/* the page */
 } xl_invalid_page_key;
@@ -86,10 +86,10 @@ static int	read_local_xlog_page_guts(XLogReaderState *state, XLogRecPtr targetPa
 
 /* Report a reference to an invalid page */
 static void
-report_invalid_page(int elevel, RelFileNode node, ForkNumber forkno,
+report_invalid_page(int elevel, RelFileLocator locator, ForkNumber forkno,
 					BlockNumber blkno, bool present)
 {
-	char	   *path = relpathperm(node, forkno);
+	char	   *path = relpathperm(locator, forkno);
 
 	if (present)
 		elog(elevel, "page %u of relation %s is uninitialized",
@@ -102,7 +102,7 @@ report_invalid_page(int elevel, RelFileNode node, ForkNumber forkno,
 
 /* Log a reference to an invalid page */
 static void
-log_invalid_page(RelFileNode node, ForkNumber forkno, BlockNumber blkno,
+log_invalid_page(RelFileLocator locator, ForkNumber forkno, BlockNumber blkno,
 				 bool present)
 {
 	xl_invalid_page_key key;
@@ -119,7 +119,7 @@ log_invalid_page(RelFileNode node, ForkNumber forkno, BlockNumber blkno,
 	 */
 	if (reachedConsistency)
 	{
-		report_invalid_page(WARNING, node, forkno, blkno, present);
+		report_invalid_page(WARNING, locator, forkno, blkno, present);
 		elog(ignore_invalid_pages ? WARNING : PANIC,
 			 "WAL contains references to invalid pages");
 	}
@@ -130,7 +130,7 @@ log_invalid_page(RelFileNode node, ForkNumber forkno, BlockNumber blkno,
 	 * something about the XLOG record that generated the reference).
 	 */
 	if (message_level_is_interesting(DEBUG1))
-		report_invalid_page(DEBUG1, node, forkno, blkno, present);
+		report_invalid_page(DEBUG1, locator, forkno, blkno, present);
 
 	if (invalid_page_tab == NULL)
 	{
@@ -147,7 +147,7 @@ log_invalid_page(RelFileNode node, ForkNumber forkno, BlockNumber blkno,
 	}
 
 	/* we currently assume xl_invalid_page_key contains no padding */
-	key.node = node;
+	key.locator = locator;
 	key.forkno = forkno;
 	key.blkno = blkno;
 	hentry = (xl_invalid_page *)
@@ -166,7 +166,8 @@ log_invalid_page(RelFileNode node, ForkNumber forkno, BlockNumber blkno,
 
 /* Forget any invalid pages >= minblkno, because they've been dropped */
 static void
-forget_invalid_pages(RelFileNode node, ForkNumber forkno, BlockNumber minblkno)
+forget_invalid_pages(RelFileLocator locator, ForkNumber forkno,
+					 BlockNumber minblkno)
 {
 	HASH_SEQ_STATUS status;
 	xl_invalid_page *hentry;
@@ -178,13 +179,13 @@ forget_invalid_pages(RelFileNode node, ForkNumber forkno, BlockNumber minblkno)
 
 	while ((hentry = (xl_invalid_page *) hash_seq_search(&status)) != NULL)
 	{
-		if (RelFileNodeEquals(hentry->key.node, node) &&
+		if (RelFileLocatorEquals(hentry->key.locator, locator) &&
 			hentry->key.forkno == forkno &&
 			hentry->key.blkno >= minblkno)
 		{
 			if (message_level_is_interesting(DEBUG2))
 			{
-				char	   *path = relpathperm(hentry->key.node, forkno);
+				char	   *path = relpathperm(hentry->key.locator, forkno);
 
 				elog(DEBUG2, "page %u of relation %s has been dropped",
 					 hentry->key.blkno, path);
@@ -213,11 +214,11 @@ forget_invalid_pages_db(Oid dbid)
 
 	while ((hentry = (xl_invalid_page *) hash_seq_search(&status)) != NULL)
 	{
-		if (hentry->key.node.dbNode == dbid)
+		if (hentry->key.locator.dbOid == dbid)
 		{
 			if (message_level_is_interesting(DEBUG2))
 			{
-				char	   *path = relpathperm(hentry->key.node, hentry->key.forkno);
+				char	   *path = relpathperm(hentry->key.locator, hentry->key.forkno);
 
 				elog(DEBUG2, "page %u of relation %s has been dropped",
 					 hentry->key.blkno, path);
@@ -261,7 +262,7 @@ XLogCheckInvalidPages(void)
 	 */
 	while ((hentry = (xl_invalid_page *) hash_seq_search(&status)) != NULL)
 	{
-		report_invalid_page(WARNING, hentry->key.node, hentry->key.forkno,
+		report_invalid_page(WARNING, hentry->key.locator, hentry->key.forkno,
 							hentry->key.blkno, hentry->present);
 		foundone = true;
 	}
@@ -356,7 +357,7 @@ XLogReadBufferForRedoExtended(XLogReaderState *record,
 							  Buffer *buf)
 {
 	XLogRecPtr	lsn = record->EndRecPtr;
-	RelFileNode rnode;
+	RelFileLocator rlocator;
 	ForkNumber	forknum;
 	BlockNumber blkno;
 	Buffer		prefetch_buffer;
@@ -364,7 +365,7 @@ XLogReadBufferForRedoExtended(XLogReaderState *record,
 	bool		zeromode;
 	bool		willinit;
 
-	if (!XLogRecGetBlockTagExtended(record, block_id, &rnode, &forknum, &blkno,
+	if (!XLogRecGetBlockTagExtended(record, block_id, &rlocator, &forknum, &blkno,
 									&prefetch_buffer))
 	{
 		/* Caller specified a bogus block_id */
@@ -387,7 +388,7 @@ XLogReadBufferForRedoExtended(XLogReaderState *record,
 	if (XLogRecBlockImageApply(record, block_id))
 	{
 		Assert(XLogRecHasBlockImage(record, block_id));
-		*buf = XLogReadBufferExtended(rnode, forknum, blkno,
+		*buf = XLogReadBufferExtended(rlocator, forknum, blkno,
 									  get_cleanup_lock ? RBM_ZERO_AND_CLEANUP_LOCK : RBM_ZERO_AND_LOCK,
 									  prefetch_buffer);
 		page = BufferGetPage(*buf);
@@ -418,7 +419,7 @@ XLogReadBufferForRedoExtended(XLogReaderState *record,
 	}
 	else
 	{
-		*buf = XLogReadBufferExtended(rnode, forknum, blkno, mode, prefetch_buffer);
+		*buf = XLogReadBufferExtended(rlocator, forknum, blkno, mode, prefetch_buffer);
 		if (BufferIsValid(*buf))
 		{
 			if (mode != RBM_ZERO_AND_LOCK && mode != RBM_ZERO_AND_CLEANUP_LOCK)
@@ -468,7 +469,7 @@ XLogReadBufferForRedoExtended(XLogReaderState *record,
  * they will be invisible to tools that need to know which pages are modified.
  */
 Buffer
-XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum,
+XLogReadBufferExtended(RelFileLocator rlocator, ForkNumber forknum,
 					   BlockNumber blkno, ReadBufferMode mode,
 					   Buffer recent_buffer)
 {
@@ -481,14 +482,14 @@ XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum,
 	/* Do we have a clue where the buffer might be already? */
 	if (BufferIsValid(recent_buffer) &&
 		mode == RBM_NORMAL &&
-		ReadRecentBuffer(rnode, forknum, blkno, recent_buffer))
+		ReadRecentBuffer(rlocator, forknum, blkno, recent_buffer))
 	{
 		buffer = recent_buffer;
 		goto recent_buffer_fast_path;
 	}
 
 	/* Open the relation at smgr level */
-	smgr = smgropen(rnode, InvalidBackendId);
+	smgr = smgropen(rlocator, InvalidBackendId);
 
 	/*
 	 * Create the target file if it doesn't already exist.  This lets us cope
@@ -505,7 +506,7 @@ XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum,
 	if (blkno < lastblock)
 	{
 		/* page exists in file */
-		buffer = ReadBufferWithoutRelcache(rnode, forknum, blkno,
+		buffer = ReadBufferWithoutRelcache(rlocator, forknum, blkno,
 										   mode, NULL, true);
 	}
 	else
@@ -513,7 +514,7 @@ XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum,
 		/* hm, page doesn't exist in file */
 		if (mode == RBM_NORMAL)
 		{
-			log_invalid_page(rnode, forknum, blkno, false);
+			log_invalid_page(rlocator, forknum, blkno, false);
 			return InvalidBuffer;
 		}
 		if (mode == RBM_NORMAL_NO_LOG)
@@ -530,7 +531,7 @@ XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum,
 					LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
 				ReleaseBuffer(buffer);
 			}
-			buffer = ReadBufferWithoutRelcache(rnode, forknum,
+			buffer = ReadBufferWithoutRelcache(rlocator, forknum,
 											   P_NEW, mode, NULL, true);
 		}
 		while (BufferGetBlockNumber(buffer) < blkno);
@@ -540,7 +541,7 @@ XLogReadBufferExtended(RelFileNode rnode, ForkNumber forknum,
 			if (mode == RBM_ZERO_AND_LOCK || mode == RBM_ZERO_AND_CLEANUP_LOCK)
 				LockBuffer(buffer, BUFFER_LOCK_UNLOCK);
 			ReleaseBuffer(buffer);
-			buffer = ReadBufferWithoutRelcache(rnode, forknum, blkno,
+			buffer = ReadBufferWithoutRelcache(rlocator, forknum, blkno,
 											   mode, NULL, true);
 		}
 	}
@@ -559,7 +560,7 @@ recent_buffer_fast_path:
 		if (PageIsNew(page))
 		{
 			ReleaseBuffer(buffer);
-			log_invalid_page(rnode, forknum, blkno, true);
+			log_invalid_page(rlocator, forknum, blkno, true);
 			return InvalidBuffer;
 		}
 	}
@@ -594,7 +595,7 @@ typedef FakeRelCacheEntryData *FakeRelCacheEntry;
  * Caller must free the returned entry with FreeFakeRelcacheEntry().
  */
 Relation
-CreateFakeRelcacheEntry(RelFileNode rnode)
+CreateFakeRelcacheEntry(RelFileLocator rlocator)
 {
 	FakeRelCacheEntry fakeentry;
 	Relation	rel;
@@ -604,7 +605,7 @@ CreateFakeRelcacheEntry(RelFileNode rnode)
 	rel = (Relation) fakeentry;
 
 	rel->rd_rel = &fakeentry->pgc;
-	rel->rd_node = rnode;
+	rel->rd_locator = rlocator;
 
 	/*
 	 * We will never be working with temp rels during recovery or while
@@ -615,18 +616,18 @@ CreateFakeRelcacheEntry(RelFileNode rnode)
 	/* It must be a permanent table here */
 	rel->rd_rel->relpersistence = RELPERSISTENCE_PERMANENT;
 
-	/* We don't know the name of the relation; use relfilenode instead */
-	sprintf(RelationGetRelationName(rel), "%u", rnode.relNode);
+	/* We don't know the name of the relation; use relfilenumber instead */
+	sprintf(RelationGetRelationName(rel), "%u", rlocator.relNumber);
 
 	/*
 	 * We set up the lockRelId in case anything tries to lock the dummy
-	 * relation.  Note that this is fairly bogus since relNode may be
+	 * relation.  Note that this is fairly bogus since relNumber may be
 	 * different from the relation's OID.  It shouldn't really matter though.
 	 * In recovery, we are running by ourselves and can't have any lock
 	 * conflicts.  While syncing, we already hold AccessExclusiveLock.
 	 */
-	rel->rd_lockInfo.lockRelId.dbId = rnode.dbNode;
-	rel->rd_lockInfo.lockRelId.relId = rnode.relNode;
+	rel->rd_lockInfo.lockRelId.dbId = rlocator.dbOid;
+	rel->rd_lockInfo.lockRelId.relId = rlocator.relNumber;
 
 	rel->rd_smgr = NULL;
 
@@ -652,9 +653,9 @@ FreeFakeRelcacheEntry(Relation fakerel)
  * any open "invalid-page" records for the relation.
  */
 void
-XLogDropRelation(RelFileNode rnode, ForkNumber forknum)
+XLogDropRelation(RelFileLocator rlocator, ForkNumber forknum)
 {
-	forget_invalid_pages(rnode, forknum, 0);
+	forget_invalid_pages(rlocator, forknum, 0);
 }
 
 /*
@@ -682,10 +683,10 @@ XLogDropDatabase(Oid dbid)
  * We need to clean up any open "invalid-page" records for the dropped pages.
  */
 void
-XLogTruncateRelation(RelFileNode rnode, ForkNumber forkNum,
+XLogTruncateRelation(RelFileLocator rlocator, ForkNumber forkNum,
 					 BlockNumber nblocks)
 {
-	forget_invalid_pages(rnode, forkNum, nblocks);
+	forget_invalid_pages(rlocator, forkNum, nblocks);
 }
 
 /*