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, 14 insertions, 8 deletions

diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 3055b483b1a..139c4c0f68c 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -642,7 +642,8 @@ pg_parse_query(const char *query_string)
  */
 List *
 pg_analyze_and_rewrite(RawStmt *parsetree, const char *query_string,
-					   Oid *paramTypes, int numParams)
+					   Oid *paramTypes, int numParams,
+					   QueryEnvironment *queryEnv)
 {
 	Query	   *query;
 	List	   *querytree_list;
@@ -655,7 +656,8 @@ pg_analyze_and_rewrite(RawStmt *parsetree, const char *query_string,
 	if (log_parser_stats)
 		ResetUsage();
 
-	query = parse_analyze(parsetree, query_string, paramTypes, numParams);
+	query = parse_analyze(parsetree, query_string, paramTypes, numParams,
+						  queryEnv);
 
 	if (log_parser_stats)
 		ShowUsage("PARSE ANALYSIS STATISTICS");
@@ -679,7 +681,8 @@ List *
 pg_analyze_and_rewrite_params(RawStmt *parsetree,
 							  const char *query_string,
 							  ParserSetupHook parserSetup,
-							  void *parserSetupArg)
+							  void *parserSetupArg,
+							  QueryEnvironment *queryEnv)
 {
 	ParseState *pstate;
 	Query	   *query;
@@ -697,6 +700,7 @@ pg_analyze_and_rewrite_params(RawStmt *parsetree,
 
 	pstate = make_parsestate(NULL);
 	pstate->p_sourcetext = query_string;
+	pstate->p_queryEnv = queryEnv;
 	(*parserSetup) (pstate, parserSetupArg);
 
 	query = transformTopLevelStmt(pstate, parsetree);
@@ -1024,7 +1028,7 @@ exec_simple_query(const char *query_string)
 		oldcontext = MemoryContextSwitchTo(MessageContext);
 
 		querytree_list = pg_analyze_and_rewrite(parsetree, query_string,
-												NULL, 0);
+												NULL, 0, NULL);
 
 		plantree_list = pg_plan_queries(querytree_list,
 										CURSOR_OPT_PARALLEL_OK, NULL);
@@ -1314,7 +1318,8 @@ exec_parse_message(const char *query_string,	/* string to execute */
 		 * Create the CachedPlanSource before we do parse analysis, since it
 		 * needs to see the unmodified raw parse tree.
 		 */
-		psrc = CreateCachedPlan(raw_parse_tree, query_string, commandTag);
+		psrc = CreateCachedPlan(raw_parse_tree, query_string, commandTag,
+								NULL);
 
 		/*
 		 * Set up a snapshot if parse analysis will need one.
@@ -1366,7 +1371,8 @@ exec_parse_message(const char *query_string,	/* string to execute */
 		/* Empty input string.  This is legal. */
 		raw_parse_tree = NULL;
 		commandTag = NULL;
-		psrc = CreateCachedPlan(raw_parse_tree, query_string, commandTag);
+		psrc = CreateCachedPlan(raw_parse_tree, query_string, commandTag,
+								NULL);
 		querytree_list = NIL;
 	}
 
@@ -1769,7 +1775,7 @@ exec_bind_message(StringInfo input_message)
 	 * will be generated in MessageContext.  The plan refcount will be
 	 * assigned to the Portal, so it will be released at portal destruction.
 	 */
-	cplan = GetCachedPlan(psrc, params, false);
+	cplan = GetCachedPlan(psrc, params, false, NULL);
 
 	/*
 	 * Now we can define the portal.
@@ -2367,7 +2373,7 @@ exec_describe_statement_message(const char *stmt_name)
 		List	   *tlist;
 
 		/* Get the plan's primary targetlist */
-		tlist = CachedPlanGetTargetList(psrc);
+		tlist = CachedPlanGetTargetList(psrc, NULL);
 
 		SendRowDescriptionMessage(psrc->resultDesc, tlist, NULL);
 	}