Nested transactions. There is still much left to do, especially on the

performance front, but with feature freeze upon us I think it's time to
drive a stake in the ground and say that this will be in 7.5.

Alvaro Herrera, with some help from Tom Lane.

8 files changed, 71 insertions, 28 deletions

diff --git a/src/include/utils/catcache.h b/src/include/utils/catcache.h
index 9c8d3053fec..3ce54b99a25 100644
--- a/src/include/utils/catcache.h
+++ b/src/include/utils/catcache.h
@@ -13,7 +13,7 @@
  * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/utils/catcache.h,v 1.48 2003/11/29 22:41:15 pgsql Exp $
+ * $PostgreSQL: pgsql/src/include/utils/catcache.h,v 1.49 2004/07/01 00:51:44 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -101,6 +101,9 @@ typedef struct catctup
 	 * and negative entries is identical.
 	 */
 	int			refcount;		/* number of active references */
+	int		   *prev_refcount;	/* refcounts for upper subtransactions */
+	int			numpushes;		/* number of used refcounts in the array */
+	int			numalloc;		/* allocated size of array */
 	bool		dead;			/* dead but not yet removed? */
 	bool		negative;		/* negative cache entry? */
 	uint32		hash_value;		/* hash value for this tuple's keys */
@@ -139,6 +142,9 @@ typedef struct catclist
 	 */
 	Dlelem		cache_elem;		/* list member of per-catcache list */
 	int			refcount;		/* number of active references */
+	int		   *prev_refcount;	/* refcounts for upper subtransactions */
+	int			numpushes;		/* number of used refcounts in the array */
+	int			numalloc;		/* allocated size of array */
 	bool		dead;			/* dead but not yet removed? */
 	bool		ordered;		/* members listed in index order? */
 	short		nkeys;			/* number of lookup keys specified */
@@ -163,6 +169,8 @@ extern DLLIMPORT MemoryContext CacheMemoryContext;
 
 extern void CreateCacheMemoryContext(void);
 extern void AtEOXact_CatCache(bool isCommit);
+extern void AtSubStart_CatCache(void);
+extern void AtEOSubXact_CatCache(bool isCommit);
 
 extern CatCache *InitCatCache(int id, const char *relname, const char *indname,
 			 int reloidattr,
diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h
index b91682af88f..0a510cd6653 100644
--- a/src/include/utils/guc.h
+++ b/src/include/utils/guc.h
@@ -7,7 +7,7 @@
  * Copyright (c) 2000-2003, PostgreSQL Global Development Group
  * Written by Peter Eisentraut <peter_e@gmx.net>.
  *
- * $PostgreSQL: pgsql/src/include/utils/guc.h,v 1.47 2004/05/28 05:13:32 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/utils/guc.h,v 1.48 2004/07/01 00:51:44 tgl Exp $
  *--------------------------------------------------------------------
  */
 #ifndef GUC_H
@@ -175,14 +175,14 @@ extern void DefineCustomStringVariable(
 	GucStringAssignHook assign_hook,
 	GucShowHook show_hook);
 
-extern void EmittWarningsOnPlaceholders(const char* className);
+extern void EmitWarningsOnPlaceholders(const char* className);
 
 extern const char *GetConfigOption(const char *name);
 extern const char *GetConfigOptionResetString(const char *name);
 extern void ProcessConfigFile(GucContext context);
 extern void InitializeGUCOptions(void);
 extern void ResetAllOptions(void);
-extern void AtEOXact_GUC(bool isCommit);
+extern void AtEOXact_GUC(bool isCommit, bool isSubXact);
 extern void BeginReportingGUCOptions(void);
 extern void ParseLongOption(const char *string, char **name, char **value);
 extern bool set_config_option(const char *name, const char *value,
diff --git a/src/include/utils/guc_tables.h b/src/include/utils/guc_tables.h
index 62d2d571b29..d522f6d5e94 100644
--- a/src/include/utils/guc_tables.h
+++ b/src/include/utils/guc_tables.h
@@ -7,12 +7,31 @@
  *
  * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
  *
- *	  $PostgreSQL: pgsql/src/include/utils/guc_tables.h,v 1.11 2004/05/26 15:07:41 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/include/utils/guc_tables.h,v 1.12 2004/07/01 00:51:44 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
-#ifndef GUC_TABLES
-#define GUC_TABLES 1
+#ifndef GUC_TABLES_H
+#define GUC_TABLES_H 1
+
+/*
+ * GUC supports these types of variables:
+ */
+enum config_type
+{
+	PGC_BOOL,
+	PGC_INT,
+	PGC_REAL,
+	PGC_STRING
+};
+
+union config_var_value
+{
+	bool		boolval;
+	int			intval;
+	double		realval;
+	char	   *stringval;
+};
 
 /*
  * Groupings to help organize all the run-time options for display
@@ -56,15 +75,19 @@ enum config_group
 };
 
 /*
- * GUC supports these types of variables:
+ * Stack entry for saving the state of a variable prior to the current
+ * transaction
  */
-enum config_type
+typedef struct guc_stack
 {
-	PGC_BOOL,
-	PGC_INT,
-	PGC_REAL,
-	PGC_STRING
-};
+	struct guc_stack *prev;		/* previous stack item, if any */
+	int			nest_level;		/* nesting depth of cur transaction */
+	int			status;			/* previous status bits, see below */
+	GucSource	tentative_source;		/* source of the tentative_value */
+	GucSource	source;			/* source of the actual value */
+	union config_var_value tentative_val;	/* previous tentative val */
+	union config_var_value value;			/* previous actual value */
+} GucStack;
 
 /*
  * Generic fields applicable to all types of variables
@@ -86,9 +109,9 @@ struct config_generic
 	enum config_type vartype;	/* type of variable (set only at startup) */
 	int			status;			/* status bits, see below */
 	GucSource	reset_source;	/* source of the reset_value */
-	GucSource	session_source; /* source of the session_value */
 	GucSource	tentative_source;		/* source of the tentative_value */
 	GucSource	source;			/* source of the current actual value */
+	GucStack   *stack;			/* stacked outside-of-transaction states */
 };
 
 /* bit values in flags field */
@@ -104,6 +127,7 @@ struct config_generic
 /* bit values in status field */
 #define GUC_HAVE_TENTATIVE	0x0001		/* tentative value is defined */
 #define GUC_HAVE_LOCAL		0x0002		/* a SET LOCAL has been executed */
+#define GUC_HAVE_STACK		0x0004		/* we have stacked prior value(s) */
 
 
 /* GUC records for specific variable types */
@@ -118,7 +142,6 @@ struct config_bool
 	GucBoolAssignHook assign_hook;
 	GucShowHook show_hook;
 	/* variable fields, initialized at runtime: */
-	bool		session_val;
 	bool		tentative_val;
 };
 
@@ -134,7 +157,6 @@ struct config_int
 	GucIntAssignHook assign_hook;
 	GucShowHook show_hook;
 	/* variable fields, initialized at runtime: */
-	int			session_val;
 	int			tentative_val;
 };
 
@@ -150,7 +172,6 @@ struct config_real
 	GucRealAssignHook assign_hook;
 	GucShowHook show_hook;
 	/* variable fields, initialized at runtime: */
-	double		session_val;
 	double		tentative_val;
 };
 
@@ -165,7 +186,6 @@ struct config_string
 	GucShowHook show_hook;
 	/* variable fields, initialized at runtime: */
 	char	   *reset_val;
-	char	   *session_val;
 	char	   *tentative_val;
 };
 
@@ -180,4 +200,4 @@ extern struct config_generic **get_guc_variables(void);
 
 extern void build_guc_variables(void);
 
-#endif
+#endif /* GUC_TABLES_H */
diff --git a/src/include/utils/inval.h b/src/include/utils/inval.h
index a2bad9cd06c..add5ca83c71 100644
--- a/src/include/utils/inval.h
+++ b/src/include/utils/inval.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/utils/inval.h,v 1.31 2004/05/06 16:10:57 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/utils/inval.h,v 1.32 2004/07/01 00:51:44 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -22,9 +22,15 @@ typedef void (*CacheCallbackFunction) (Datum arg, Oid relid);
 
 extern void AcceptInvalidationMessages(void);
 
-extern void AtEOXactInvalidationMessages(bool isCommit);
+extern void AtStart_Inval(void);
 
-extern void CommandEndInvalidationMessages(bool isCommit);
+extern void AtSubStart_Inval(void);
+
+extern void AtEOXact_Inval(bool isCommit);
+
+extern void AtSubEOXact_Inval(bool isCommit);
+
+extern void CommandEndInvalidationMessages(void);
 
 extern void CacheInvalidateHeapTuple(Relation relation, HeapTuple tuple);
 
diff --git a/src/include/utils/memutils.h b/src/include/utils/memutils.h
index 7865859c062..d2d7d4a9093 100644
--- a/src/include/utils/memutils.h
+++ b/src/include/utils/memutils.h
@@ -10,7 +10,7 @@
  * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/utils/memutils.h,v 1.55 2004/06/05 19:48:09 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/utils/memutils.h,v 1.56 2004/07/01 00:51:44 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -73,6 +73,7 @@ extern DLLIMPORT MemoryContext PostmasterContext;
 extern DLLIMPORT MemoryContext CacheMemoryContext;
 extern DLLIMPORT MemoryContext MessageContext;
 extern DLLIMPORT MemoryContext TopTransactionContext;
+extern DLLIMPORT MemoryContext CurTransactionContext;
 
 /* These two are transient links to contexts owned by other objects: */
 extern DLLIMPORT MemoryContext QueryContext;
diff --git a/src/include/utils/portal.h b/src/include/utils/portal.h
index 2819295e837..3437dc448a3 100644
--- a/src/include/utils/portal.h
+++ b/src/include/utils/portal.h
@@ -39,7 +39,7 @@
  * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/utils/portal.h,v 1.48 2003/11/29 22:41:16 pgsql Exp $
+ * $PostgreSQL: pgsql/src/include/utils/portal.h,v 1.49 2004/07/01 00:51:44 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -167,6 +167,9 @@ extern void EnablePortalManager(void);
 extern void AtCommit_Portals(void);
 extern void AtAbort_Portals(void);
 extern void AtCleanup_Portals(void);
+extern void AtSubCommit_Portals(TransactionId parentXid);
+extern void AtSubAbort_Portals(void);
+extern void AtSubCleanup_Portals(void);
 extern Portal CreatePortal(const char *name, bool allowDup, bool dupSilent);
 extern Portal CreateNewPortal(void);
 extern void PortalDrop(Portal portal, bool isError);
diff --git a/src/include/utils/rel.h b/src/include/utils/rel.h
index e5008e56ea5..b7f85eda68e 100644
--- a/src/include/utils/rel.h
+++ b/src/include/utils/rel.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/utils/rel.h,v 1.74 2004/05/08 19:09:25 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/utils/rel.h,v 1.75 2004/07/01 00:51:44 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -110,6 +110,9 @@ typedef struct RelationData
 	BlockNumber rd_targblock;	/* current insertion target block, or
 								 * InvalidBlockNumber */
 	int			rd_refcnt;		/* reference count */
+	int		   *rd_prevrefcnt;	/* reference count stack */
+	int			rd_numalloc;	/* stack allocated size */
+	int			rd_numpushed;	/* stack used size */
 	bool		rd_isnew;		/* rel was created in current xact */
 
 	/*
diff --git a/src/include/utils/relcache.h b/src/include/utils/relcache.h
index da82f4f6137..47f46190df7 100644
--- a/src/include/utils/relcache.h
+++ b/src/include/utils/relcache.h
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/utils/relcache.h,v 1.40 2004/06/18 06:14:21 tgl Exp $
+ * $PostgreSQL: pgsql/src/include/utils/relcache.h,v 1.41 2004/07/01 00:51:45 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -65,7 +65,9 @@ extern void RelationCacheInvalidateEntry(Oid relationId, RelFileNode *rnode);
 
 extern void RelationCacheInvalidate(void);
 
-extern void AtEOXact_RelationCache(bool commit);
+extern void AtEOXact_RelationCache(bool isCommit);
+extern void AtSubStart_RelationCache(void);
+extern void AtEOSubXact_RelationCache(bool isCommit);
 
 /*
  * Routines to help manage rebuilding of relcache init file