Add infrastructure to support EphemeralNamedRelation references.

A QueryEnvironment concept is added, which allows new types of
objects to be passed into queries from parsing on through
execution.  At this point, the only thing implemented is a
collection of EphemeralNamedRelation objects -- relations which
can be referenced by name in queries, but do not exist in the
catalogs.  The only type of ENR implemented is NamedTuplestore, but
provision is made to add more types fairly easily.

An ENR can carry its own TupleDesc or reference a relation in the
catalogs by relid.

Although these features can be used without SPI, convenience
functions are added to SPI so that ENRs can easily be used by code
run through SPI.

The initial use of all this is going to be transition tables in
AFTER triggers, but that will be added to each PL as a separate
commit.

An incidental effect of this patch is to produce a more informative
error message if an attempt is made to modify the contents of a CTE
from a referencing DML statement.  No tests previously covered that
possibility, so one is added.

Kevin Grittner and Thomas Munro
Reviewed by Heikki Linnakangas, David Fetter, and Thomas Munro
with valuable comments and suggestions from many others

1 files changed, 21 insertions, 13 deletions

diff --git a/src/backend/tcop/utility.c b/src/backend/tcop/utility.c
index 584f4f13ccc..b610c8e7cee 100644
--- a/src/backend/tcop/utility.c
+++ b/src/backend/tcop/utility.c
@@ -78,6 +78,7 @@ static void ProcessUtilitySlow(ParseState *pstate,
 				   const char *queryString,
 				   ProcessUtilityContext context,
 				   ParamListInfo params,
+				   QueryEnvironment *queryEnv,
 				   DestReceiver *dest,
 				   char *completionTag);
 static void ExecDropStmt(DropStmt *stmt, bool isTopLevel);
@@ -333,6 +334,7 @@ ProcessUtility(PlannedStmt *pstmt,
 			   const char *queryString,
 			   ProcessUtilityContext context,
 			   ParamListInfo params,
+			   QueryEnvironment *queryEnv,
 			   DestReceiver *dest,
 			   char *completionTag)
 {
@@ -347,11 +349,11 @@ ProcessUtility(PlannedStmt *pstmt,
 	 */
 	if (ProcessUtility_hook)
 		(*ProcessUtility_hook) (pstmt, queryString,
-								context, params,
+								context, params, queryEnv,
 								dest, completionTag);
 	else
 		standard_ProcessUtility(pstmt, queryString,
-								context, params,
+								context, params, queryEnv,
 								dest, completionTag);
 }
 
@@ -371,6 +373,7 @@ standard_ProcessUtility(PlannedStmt *pstmt,
 						const char *queryString,
 						ProcessUtilityContext context,
 						ParamListInfo params,
+						QueryEnvironment *queryEnv,
 						DestReceiver *dest,
 						char *completionTag)
 {
@@ -672,7 +675,8 @@ standard_ProcessUtility(PlannedStmt *pstmt,
 			break;
 
 		case T_ExplainStmt:
-			ExplainQuery(pstate, (ExplainStmt *) parsetree, queryString, params, dest);
+			ExplainQuery(pstate, (ExplainStmt *) parsetree, queryString, params,
+						 queryEnv, dest);
 			break;
 
 		case T_AlterSystemStmt:
@@ -819,7 +823,7 @@ standard_ProcessUtility(PlannedStmt *pstmt,
 
 				if (EventTriggerSupportsGrantObjectType(stmt->objtype))
 					ProcessUtilitySlow(pstate, pstmt, queryString,
-									   context, params,
+									   context, params, queryEnv,
 									   dest, completionTag);
 				else
 					ExecuteGrantStmt(stmt);
@@ -832,7 +836,7 @@ standard_ProcessUtility(PlannedStmt *pstmt,
 
 				if (EventTriggerSupportsObjectType(stmt->removeType))
 					ProcessUtilitySlow(pstate, pstmt, queryString,
-									   context, params,
+									   context, params, queryEnv,
 									   dest, completionTag);
 				else
 					ExecDropStmt(stmt, isTopLevel);
@@ -845,7 +849,7 @@ standard_ProcessUtility(PlannedStmt *pstmt,
 
 				if (EventTriggerSupportsObjectType(stmt->renameType))
 					ProcessUtilitySlow(pstate, pstmt, queryString,
-									   context, params,
+									   context, params, queryEnv,
 									   dest, completionTag);
 				else
 					ExecRenameStmt(stmt);
@@ -858,7 +862,7 @@ standard_ProcessUtility(PlannedStmt *pstmt,
 
 				if (EventTriggerSupportsObjectType(stmt->objectType))
 					ProcessUtilitySlow(pstate, pstmt, queryString,
-									   context, params,
+									   context, params, queryEnv,
 									   dest, completionTag);
 				else
 					ExecAlterObjectDependsStmt(stmt, NULL);
@@ -871,7 +875,7 @@ standard_ProcessUtility(PlannedStmt *pstmt,
 
 				if (EventTriggerSupportsObjectType(stmt->objectType))
 					ProcessUtilitySlow(pstate, pstmt, queryString,
-									   context, params,
+									   context, params, queryEnv,
 									   dest, completionTag);
 				else
 					ExecAlterObjectSchemaStmt(stmt, NULL);
@@ -884,7 +888,7 @@ standard_ProcessUtility(PlannedStmt *pstmt,
 
 				if (EventTriggerSupportsObjectType(stmt->objectType))
 					ProcessUtilitySlow(pstate, pstmt, queryString,
-									   context, params,
+									   context, params, queryEnv,
 									   dest, completionTag);
 				else
 					ExecAlterOwnerStmt(stmt);
@@ -897,7 +901,7 @@ standard_ProcessUtility(PlannedStmt *pstmt,
 
 				if (EventTriggerSupportsObjectType(stmt->objtype))
 					ProcessUtilitySlow(pstate, pstmt, queryString,
-									   context, params,
+									   context, params, queryEnv,
 									   dest, completionTag);
 				else
 					CommentObject(stmt);
@@ -910,7 +914,7 @@ standard_ProcessUtility(PlannedStmt *pstmt,
 
 				if (EventTriggerSupportsObjectType(stmt->objtype))
 					ProcessUtilitySlow(pstate, pstmt, queryString,
-									   context, params,
+									   context, params, queryEnv,
 									   dest, completionTag);
 				else
 					ExecSecLabelStmt(stmt);
@@ -920,7 +924,7 @@ standard_ProcessUtility(PlannedStmt *pstmt,
 		default:
 			/* All other statement types have event trigger support */
 			ProcessUtilitySlow(pstate, pstmt, queryString,
-							   context, params,
+							   context, params, queryEnv,
 							   dest, completionTag);
 			break;
 	}
@@ -939,6 +943,7 @@ ProcessUtilitySlow(ParseState *pstate,
 				   const char *queryString,
 				   ProcessUtilityContext context,
 				   ParamListInfo params,
+				   QueryEnvironment *queryEnv,
 				   DestReceiver *dest,
 				   char *completionTag)
 {
@@ -1062,6 +1067,7 @@ ProcessUtilitySlow(ParseState *pstate,
 										   queryString,
 										   PROCESS_UTILITY_SUBCOMMAND,
 										   params,
+										   NULL,
 										   None_Receiver,
 										   NULL);
 						}
@@ -1140,6 +1146,7 @@ ProcessUtilitySlow(ParseState *pstate,
 											   queryString,
 											   PROCESS_UTILITY_SUBCOMMAND,
 											   params,
+											   NULL,
 											   None_Receiver,
 											   NULL);
 								EventTriggerAlterTableStart(parsetree);
@@ -1438,7 +1445,8 @@ ProcessUtilitySlow(ParseState *pstate,
 
 			case T_CreateTableAsStmt:
 				address = ExecCreateTableAs((CreateTableAsStmt *) parsetree,
-										 queryString, params, completionTag);
+											queryString, params, queryEnv,
+											completionTag);
 				break;
 
 			case T_RefreshMatViewStmt: