Code cleanup, mostly in the smgr:

Neil Conway · Neil Conway · commit dfc7e7b71d86 · 2004-01-06T18:07:32.000Z
- Update comment in IsReservedName() to the present day

     - Improve some variable &amp; function names in commands/vacuum.c. I
       was planning to rewrite this to avoid lappend(), but since I
       still intend to do the list rewrite, there's no need for that.

     - Update some smgr comments which seemed to imply that we still
       forced all dirty pages to disk at commit-time.

     - Replace some #ifdef DIAGNOSTIC code with assertions.

     - Make the distinction between OS-level file descriptors and
       virtual file descriptors a little clearer in a few comments

     - Other minor comment improvements in the smgr code
diff --git a/src/backend/catalog/catalog.c b/src/backend/catalog/catalog.c
@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/catalog/catalog.c,v 1.50 2003/11/29 19:51:42 pgsql Exp $
+ *	  $PostgreSQL: pgsql/src/backend/catalog/catalog.c,v 1.51 2004/01/06 18:07:31 neilc Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -165,8 +165,9 @@ IsToastNamespace(Oid namespaceId)
  * IsReservedName
  *		True iff name starts with the pg_ prefix.
  *
- *		For some classes of objects, the prefix pg_ is reserved
- *		for system objects only.
+ *		For some classes of objects, the prefix pg_ is reserved for
+ *		system objects only. As of 7.3, this is now only true for
+ *		schema names.
  */
 bool
 IsReservedName(const char *name)
diff --git a/src/backend/commands/analyze.c b/src/backend/commands/analyze.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/analyze.c,v 1.65 2003/11/29 19:51:47 pgsql Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/analyze.c,v 1.66 2004/01/06 18:07:31 neilc Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -204,8 +204,9 @@ analyze_rel(Oid relid, VacuumStmt *vacstmt)
 	}
 
 	/*
-	 * Check that it's a plain table; we used to do this in getrels() but
-	 * seems safer to check after we've locked the relation.
+	 * Check that it's a plain table; we used to do this in
+	 * get_rel_oids() but seems safer to check after we've locked the
+	 * relation.
 	 */
 	if (onerel->rd_rel->relkind != RELKIND_RELATION)
 	{
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
@@ -13,7 +13,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/vacuum.c,v 1.269 2003/11/29 19:51:47 pgsql Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/vacuum.c,v 1.270 2004/01/06 18:07:31 neilc Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -108,7 +108,7 @@ static TransactionId FreezeLimit;
 
 
 /* non-export function prototypes */
-static List *getrels(const RangeVar *vacrel, const char *stmttype);
+static List *get_rel_oids(const RangeVar *vacrel, const char *stmttype);
 static void vac_update_dbstats(Oid dbid,
 				   TransactionId vacuumXID,
 				   TransactionId frozenXID);
@@ -161,7 +161,7 @@ vacuum(VacuumStmt *vacstmt)
 	TransactionId initialOldestXmin = InvalidTransactionId;
 	TransactionId initialFreezeLimit = InvalidTransactionId;
 	bool		all_rels;
-	List	   *vrl,
+	List	   *relations,
 			   *cur;
 
 	if (vacstmt->verbose)
@@ -216,7 +216,7 @@ vacuum(VacuumStmt *vacstmt)
 	all_rels = (vacstmt->relation == NULL);
 
 	/* Build list of relations to process (note this lives in vac_context) */
-	vrl = getrels(vacstmt->relation, stmttype);
+	relations = get_rel_oids(vacstmt->relation, stmttype);
 
 	/*
 	 * Formerly, there was code here to prevent more than one VACUUM from
@@ -282,7 +282,7 @@ vacuum(VacuumStmt *vacstmt)
 	/*
 	 * Loop to process each selected relation.
 	 */
-	foreach(cur, vrl)
+	foreach(cur, relations)
 	{
 		Oid			relid = lfirsto(cur);
 
@@ -383,21 +383,21 @@ vacuum(VacuumStmt *vacstmt)
  * per-relation transactions.
  */
 static List *
-getrels(const RangeVar *vacrel, const char *stmttype)
+get_rel_oids(const RangeVar *vacrel, const char *stmttype)
 {
-	List	   *vrl = NIL;
+	List	   *oid_list = NIL;
 	MemoryContext oldcontext;
 
 	if (vacrel)
 	{
-		/* Process specific relation */
+		/* Process a specific relation */
 		Oid			relid;
 
 		relid = RangeVarGetRelid(vacrel, false);
 
 		/* Make a relation list entry for this guy */
 		oldcontext = MemoryContextSwitchTo(vac_context);
-		vrl = lappendo(vrl, relid);
+		oid_list = lappendo(oid_list, relid);
 		MemoryContextSwitchTo(oldcontext);
 	}
 	else
@@ -421,15 +421,15 @@ getrels(const RangeVar *vacrel, const char *stmttype)
 		{
 			/* Make a relation list entry for this guy */
 			oldcontext = MemoryContextSwitchTo(vac_context);
-			vrl = lappendo(vrl, HeapTupleGetOid(tuple));
+			oid_list = lappendo(oid_list, HeapTupleGetOid(tuple));
 			MemoryContextSwitchTo(oldcontext);
 		}
 
 		heap_endscan(scan);
 		heap_close(pgclass, AccessShareLock);
 	}
 
-	return vrl;
+	return oid_list;
 }
 
 /*
@@ -818,8 +818,9 @@ vacuum_rel(Oid relid, VacuumStmt *vacstmt, char expected_relkind)
 	}
 
 	/*
-	 * Check that it's a plain table; we used to do this in getrels() but
-	 * seems safer to check after we've locked the relation.
+	 * Check that it's a plain table; we used to do this in
+	 * get_rel_oids() but seems safer to check after we've locked the
+	 * relation.
 	 */
 	if (onerel->rd_rel->relkind != expected_relkind)
 	{
diff --git a/src/backend/storage/smgr/md.c b/src/backend/storage/smgr/md.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/storage/smgr/md.c,v 1.99 2003/11/29 19:51:57 pgsql Exp $
+ *	  $PostgreSQL: pgsql/src/backend/storage/smgr/md.c,v 1.100 2004/01/06 18:07:31 neilc Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -25,18 +25,15 @@
 #include "utils/inval.h"
 #include "utils/memutils.h"
 
-
-#undef DIAGNOSTIC
-
 /*
- *	The magnetic disk storage manager keeps track of open file descriptors
- *	in its own descriptor pool.  This happens for two reasons.	First, at
- *	transaction boundaries, we walk the list of descriptors and flush
- *	anything that we've dirtied in the current transaction.  Second, we want
- *	to support relations larger than the OS' file size limit (often 2GBytes).
- *	In order to do that, we break relations up into chunks of < 2GBytes
- *	and store one chunk in each of several files that represent the relation.
- *	See the BLCKSZ and RELSEG_SIZE configuration constants in include/pg_config.h.
+ *	The magnetic disk storage manager keeps track of open file
+ *	descriptors in its own descriptor pool.  This is done to make it
+ *	easier to support relations that are larger than the operating
+ *	system's file size limit (often 2GBytes).  In order to do that, we
+ *	we break relations up into chunks of < 2GBytes and store one chunk
+ *	in each of several files that represent the relation.  See the
+ *	BLCKSZ and RELSEG_SIZE configuration constants in
+ *	include/pg_config.h.
  *
  *	The file descriptor stored in the relation cache (see RelationGetFile())
  *	is actually an index into the Md_fdvec array.  -1 indicates not open.
@@ -67,7 +64,7 @@ static MdfdVec *Md_fdvec = (MdfdVec *) NULL;
 static int	Md_Free = -1;		/* head of freelist of unused fdvec
 								 * entries */
 static int	CurFd = 0;			/* first never-used fdvec index */
-static MemoryContext MdCxt;		/* context for all my allocations */
+static MemoryContext MdCxt;		/* context for all md.c allocations */
 
 /* routines declared here */
 static void mdclose_fd(int fd);
@@ -84,11 +81,8 @@ static BlockNumber _mdnblocks(File file, Size blcksz);
 /*
  *	mdinit() -- Initialize private state for magnetic disk storage manager.
  *
- *		We keep a private table of all file descriptors.  Whenever we do
- *		a write to one, we mark it dirty in our table.	Whenever we force
- *		changes to disk, we mark the file descriptor clean.  At transaction
- *		commit, we force changes to disk for all dirty file descriptors.
- *		This routine allocates and initializes the table.
+ *		We keep a private table of all file descriptors.  This routine
+ *		allocates and initializes the table.
  *
  *		Returns SM_SUCCESS or SM_FAIL with errno set as appropriate.
  */
@@ -247,16 +241,13 @@ mdextend(Relation reln, BlockNumber blocknum, char *buffer)
 
 #ifndef LET_OS_MANAGE_FILESIZE
 	seekpos = (long) (BLCKSZ * (blocknum % ((BlockNumber) RELSEG_SIZE)));
-#ifdef DIAGNOSTIC
-	if (seekpos >= BLCKSZ * RELSEG_SIZE)
-		elog(FATAL, "seekpos too big");
-#endif
+	Assert(seekpos < BLCKSZ * RELSEG_SIZE);
 #else
 	seekpos = (long) (BLCKSZ * (blocknum));
 #endif
 
 	/*
-	 * Note: because caller obtained blocknum by calling mdnblocks, which
+	 * Note: because caller obtained blocknum by calling _mdnblocks, which
 	 * did a seek(SEEK_END), this seek is often redundant and will be
 	 * optimized away by fd.c.	It's not redundant, however, if there is a
 	 * partial page at the end of the file.  In that case we want to try
@@ -282,10 +273,7 @@ mdextend(Relation reln, BlockNumber blocknum, char *buffer)
 	}
 
 #ifndef LET_OS_MANAGE_FILESIZE
-#ifdef DIAGNOSTIC
-	if (_mdnblocks(v->mdfd_vfd, BLCKSZ) > ((BlockNumber) RELSEG_SIZE))
-		elog(FATAL, "segment too big");
-#endif
+	Assert(_mdnblocks(v->mdfd_vfd, BLCKSZ) <= ((BlockNumber) RELSEG_SIZE));
 #endif
 
 	return SM_SUCCESS;
@@ -335,11 +323,7 @@ mdopen(Relation reln)
 	Md_fdvec[vfd].mdfd_flags = (uint16) 0;
 #ifndef LET_OS_MANAGE_FILESIZE
 	Md_fdvec[vfd].mdfd_chain = (MdfdVec *) NULL;
-
-#ifdef DIAGNOSTIC
-	if (_mdnblocks(fd, BLCKSZ) > ((BlockNumber) RELSEG_SIZE))
-		elog(FATAL, "segment too big");
-#endif
+	Assert(_mdnblocks(fd, BLCKSZ) <= ((BlockNumber) RELSEG_SIZE));
 #endif
 
 	return vfd;
@@ -348,7 +332,7 @@ mdopen(Relation reln)
 /*
  *	mdclose() -- Close the specified relation, if it isn't closed already.
  *
- *		AND FREE fd vector! It may be re-used for other relation!
+ *		AND FREE fd vector! It may be re-used for other relations!
  *		reln should be flushed from cache after closing !..
  *
  *		Returns SM_SUCCESS or SM_FAIL with errno set as appropriate.
@@ -418,11 +402,7 @@ mdread(Relation reln, BlockNumber blocknum, char *buffer)
 
 #ifndef LET_OS_MANAGE_FILESIZE
 	seekpos = (long) (BLCKSZ * (blocknum % ((BlockNumber) RELSEG_SIZE)));
-
-#ifdef DIAGNOSTIC
-	if (seekpos >= BLCKSZ * RELSEG_SIZE)
-		elog(FATAL, "seekpos too big");
-#endif
+	Assert(seekpos < BLCKSZ * RELSEG_SIZE);
 #else
 	seekpos = (long) (BLCKSZ * (blocknum));
 #endif
@@ -466,10 +446,7 @@ mdwrite(Relation reln, BlockNumber blocknum, char *buffer)
 
 #ifndef LET_OS_MANAGE_FILESIZE
 	seekpos = (long) (BLCKSZ * (blocknum % ((BlockNumber) RELSEG_SIZE)));
-#ifdef DIAGNOSTIC
-	if (seekpos >= BLCKSZ * RELSEG_SIZE)
-		elog(FATAL, "seekpos too big");
-#endif
+	Assert(seekpos < BLCKSZ * RELSEG_SIZE);
 #else
 	seekpos = (long) (BLCKSZ * (blocknum));
 #endif
@@ -505,10 +482,7 @@ mdblindwrt(RelFileNode rnode,
 
 #ifndef LET_OS_MANAGE_FILESIZE
 	seekpos = (long) (BLCKSZ * (blkno % ((BlockNumber) RELSEG_SIZE)));
-#ifdef DIAGNOSTIC
-	if (seekpos >= BLCKSZ * RELSEG_SIZE)
-		elog(FATAL, "seekpos too big");
-#endif
+	Assert(seekpos < BLCKSZ * RELSEG_SIZE);
 #else
 	seekpos = (long) (BLCKSZ * (blkno));
 #endif
@@ -722,8 +696,6 @@ mdcommit(void)
 
 /*
  *	mdabort() -- Abort a transaction.
- *
- *		Changes need not be forced to disk at transaction abort.
  */
 int
 mdabort(void)
@@ -748,7 +720,7 @@ mdsync(void)
 }
 
 /*
- *	_fdvec_alloc () -- grab a free (or new) md file descriptor vector.
+ *	_fdvec_alloc() -- Grab a free (or new) md file descriptor vector.
  */
 static int
 _fdvec_alloc(void)
@@ -802,7 +774,7 @@ _fdvec_alloc(void)
 }
 
 /*
- *	_fdvec_free () -- free md file descriptor vector.
+ *	_fdvec_free() -- free md file descriptor vector.
  *
  */
 static
@@ -853,19 +825,18 @@ _mdfd_openseg(Relation reln, BlockNumber segno, int oflags)
 	v->mdfd_flags = (uint16) 0;
 #ifndef LET_OS_MANAGE_FILESIZE
 	v->mdfd_chain = (MdfdVec *) NULL;
-
-#ifdef DIAGNOSTIC
-	if (_mdnblocks(fd, BLCKSZ) > ((BlockNumber) RELSEG_SIZE))
-		elog(FATAL, "segment too big");
-#endif
+	Assert(_mdnblocks(fd, BLCKSZ) <= ((BlockNumber) RELSEG_SIZE));
 #endif
 
 	/* all done */
 	return v;
 }
 
-/* Get the fd for the relation, opening it if it's not already open */
-
+/*
+ *	_mdfd_getrelnfd() -- Get the (virtual) fd for the relation,
+ *						 opening it if it's not already open
+ *
+ */
 static int
 _mdfd_getrelnfd(Relation reln)
 {
@@ -882,8 +853,11 @@ _mdfd_getrelnfd(Relation reln)
 	return fd;
 }
 
-/* Find the segment of the relation holding the specified block */
-
+/*
+ *	_mdfd_getseg() -- Find the segment of the relation holding the
+ *					  specified block
+ *
+ */
 static MdfdVec *
 _mdfd_getseg(Relation reln, BlockNumber blkno)
 {
@@ -942,7 +916,6 @@ _mdfd_getseg(Relation reln, BlockNumber blkno)
  *
  * The return value is the kernel descriptor, or -1 on failure.
  */
-
 static int
 _mdfd_blind_getseg(RelFileNode rnode, BlockNumber blkno)
 {
diff --git a/src/backend/storage/smgr/smgr.c b/src/backend/storage/smgr/smgr.c
diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h

Original file line number	Diff line number	Diff line change
`@@ -9,7 +9,7 @@`
`9`	`9`	`*`
`10`	`10`	`*`
`11`	`11`	`* IDENTIFICATION`
`12`		`- * $PostgreSQL: pgsql/src/backend/catalog/catalog.c,v 1.50 2003/11/29 19:51:42 pgsql Exp $`
	`12`	`+ * $PostgreSQL: pgsql/src/backend/catalog/catalog.c,v 1.51 2004/01/06 18:07:31 neilc Exp $`
`13`	`13`	`*`
`14`	`14`	`*-------------------------------------------------------------------------`
`15`	`15`	`*/`
`@@ -165,8 +165,9 @@ IsToastNamespace(Oid namespaceId)`
`165`	`165`	`* IsReservedName`
`166`	`166`	`* True iff name starts with the pg_ prefix.`
`167`	`167`	`*`
`168`		`- * For some classes of objects, the prefix pg_ is reserved`
`169`		`- * for system objects only.`
	`168`	`+ * For some classes of objects, the prefix pg_ is reserved for`
	`169`	`+ * system objects only. As of 7.3, this is now only true for`
	`170`	`+ * schema names.`
`170`	`171`	`*/`
`171`	`172`	`bool`
`172`	`173`	`IsReservedName(const char *name)`
Original file line number	Diff line number	Diff line change
`@@ -8,7 +8,7 @@`
`8`	`8`	`*`
`9`	`9`	`*`
`10`	`10`	`* IDENTIFICATION`
`11`		`- * $PostgreSQL: pgsql/src/backend/commands/analyze.c,v 1.65 2003/11/29 19:51:47 pgsql Exp $`
	`11`	`+ * $PostgreSQL: pgsql/src/backend/commands/analyze.c,v 1.66 2004/01/06 18:07:31 neilc Exp $`
`12`	`12`	`*`
`13`	`13`	`*-------------------------------------------------------------------------`
`14`	`14`	`*/`
`@@ -204,8 +204,9 @@ analyze_rel(Oid relid, VacuumStmt *vacstmt)`
`204`	`204`	`}`
`205`	`205`
`206`	`206`	`/*`
`207`		`- * Check that it's a plain table; we used to do this in getrels() but`
`208`		`- * seems safer to check after we've locked the relation.`
	`207`	`+ * Check that it's a plain table; we used to do this in`
	`208`	`+ * get_rel_oids() but seems safer to check after we've locked the`
	`209`	`+ * relation.`
`209`	`210`	`*/`
`210`	`211`	`if (onerel->rd_rel->relkind != RELKIND_RELATION)`
`211`	`212`	`{`