Make it possible for loadable modules to add EXPLAIN options.

Modules can use RegisterExtensionExplainOption to register new
EXPLAIN options, and GetExplainExtensionId, GetExplainExtensionState,
and SetExplainExtensionState to store related state inside the
ExplainState object.

Since this substantially increases the amount of code that needs
to handle ExplainState-related tasks, move a few bits of existing
code to a new file explain_state.c and add the rest of this
infrastructure there.

See the comments at the top of explain_state.c for further
explanation of how this mechanism works.

This does not yet provide a way for such such options to do anything
useful. The intention is that we'll add hooks for that purpose in a
separate commit.

Discussion: http://postgr.es/m/CA+TgmoYSzg58hPuBmei46o8D3SKX+SZoO4K_aGQGwiRzvRApLg@mail.gmail.com
Reviewed-by: Srinath Reddy <srinath2133@gmail.com>
Reviewed-by: Andrei Lepikhov <lepihov@gmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Sami Imseih <samimseih@gmail.com>

1 files changed, 5 insertions, 138 deletions

diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 19ffcc2cacb..ab3898ff1eb 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -17,8 +17,10 @@
 #include "catalog/pg_type.h"
 #include "commands/createas.h"
 #include "commands/defrem.h"
+#include "commands/explain.h"
 #include "commands/explain_dr.h"
 #include "commands/explain_format.h"
+#include "commands/explain_state.h"
 #include "commands/prepare.h"
 #include "foreign/fdwapi.h"
 #include "jit/jit.h"
@@ -176,130 +178,11 @@ ExplainQuery(ParseState *pstate, ExplainStmt *stmt,
 	JumbleState *jstate = NULL;
 	Query	   *query;
 	List	   *rewritten;
-	ListCell   *lc;
-	bool		timing_set = false;
-	bool		buffers_set = false;
-	bool		summary_set = false;
-
-	/* Parse options list. */
-	foreach(lc, stmt->options)
-	{
-		DefElem    *opt = (DefElem *) lfirst(lc);
 
-		if (strcmp(opt->defname, "analyze") == 0)
-			es->analyze = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "verbose") == 0)
-			es->verbose = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "costs") == 0)
-			es->costs = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "buffers") == 0)
-		{
-			buffers_set = true;
-			es->buffers = defGetBoolean(opt);
-		}
-		else if (strcmp(opt->defname, "wal") == 0)
-			es->wal = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "settings") == 0)
-			es->settings = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "generic_plan") == 0)
-			es->generic = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "timing") == 0)
-		{
-			timing_set = true;
-			es->timing = defGetBoolean(opt);
-		}
-		else if (strcmp(opt->defname, "summary") == 0)
-		{
-			summary_set = true;
-			es->summary = defGetBoolean(opt);
-		}
-		else if (strcmp(opt->defname, "memory") == 0)
-			es->memory = defGetBoolean(opt);
-		else if (strcmp(opt->defname, "serialize") == 0)
-		{
-			if (opt->arg)
-			{
-				char	   *p = defGetString(opt);
-
-				if (strcmp(p, "off") == 0 || strcmp(p, "none") == 0)
-					es->serialize = EXPLAIN_SERIALIZE_NONE;
-				else if (strcmp(p, "text") == 0)
-					es->serialize = EXPLAIN_SERIALIZE_TEXT;
-				else if (strcmp(p, "binary") == 0)
-					es->serialize = EXPLAIN_SERIALIZE_BINARY;
-				else
-					ereport(ERROR,
-							(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-							 errmsg("unrecognized value for EXPLAIN option \"%s\": \"%s\"",
-									opt->defname, p),
-							 parser_errposition(pstate, opt->location)));
-			}
-			else
-			{
-				/* SERIALIZE without an argument is taken as 'text' */
-				es->serialize = EXPLAIN_SERIALIZE_TEXT;
-			}
-		}
-		else if (strcmp(opt->defname, "format") == 0)
-		{
-			char	   *p = defGetString(opt);
-
-			if (strcmp(p, "text") == 0)
-				es->format = EXPLAIN_FORMAT_TEXT;
-			else if (strcmp(p, "xml") == 0)
-				es->format = EXPLAIN_FORMAT_XML;
-			else if (strcmp(p, "json") == 0)
-				es->format = EXPLAIN_FORMAT_JSON;
-			else if (strcmp(p, "yaml") == 0)
-				es->format = EXPLAIN_FORMAT_YAML;
-			else
-				ereport(ERROR,
-						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-						 errmsg("unrecognized value for EXPLAIN option \"%s\": \"%s\"",
-								opt->defname, p),
-						 parser_errposition(pstate, opt->location)));
-		}
-		else
-			ereport(ERROR,
-					(errcode(ERRCODE_SYNTAX_ERROR),
-					 errmsg("unrecognized EXPLAIN option \"%s\"",
-							opt->defname),
-					 parser_errposition(pstate, opt->location)));
-	}
-
-	/* check that WAL is used with EXPLAIN ANALYZE */
-	if (es->wal && !es->analyze)
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-				 errmsg("EXPLAIN option %s requires ANALYZE", "WAL")));
-
-	/* if the timing was not set explicitly, set default value */
-	es->timing = (timing_set) ? es->timing : es->analyze;
-
-	/* if the buffers was not set explicitly, set default value */
-	es->buffers = (buffers_set) ? es->buffers : es->analyze;
-
-	/* check that timing is used with EXPLAIN ANALYZE */
-	if (es->timing && !es->analyze)
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-				 errmsg("EXPLAIN option %s requires ANALYZE", "TIMING")));
-
-	/* check that serialize is used with EXPLAIN ANALYZE */
-	if (es->serialize != EXPLAIN_SERIALIZE_NONE && !es->analyze)
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-				 errmsg("EXPLAIN option %s requires ANALYZE", "SERIALIZE")));
-
-	/* check that GENERIC_PLAN is not used with EXPLAIN ANALYZE */
-	if (es->generic && es->analyze)
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-				 errmsg("EXPLAIN options ANALYZE and GENERIC_PLAN cannot be used together")));
-
-	/* if the summary was not set explicitly, set default value */
-	es->summary = (summary_set) ? es->summary : es->analyze;
+	/* Configure the ExplainState based on the provided options */
+	ParseExplainOptionList(es, stmt->options, pstate);
 
+	/* Extract the query and, if enabled, jumble it */
 	query = castNode(Query, stmt->query);
 	if (IsQueryIdEnabled())
 		jstate = JumbleQuery(query);
@@ -361,22 +244,6 @@ ExplainQuery(ParseState *pstate, ExplainStmt *stmt,
 }
 
 /*
- * Create a new ExplainState struct initialized with default options.
- */
-ExplainState *
-NewExplainState(void)
-{
-	ExplainState *es = (ExplainState *) palloc0(sizeof(ExplainState));
-
-	/* Set default options (most fields can be left as zeroes). */
-	es->costs = true;
-	/* Prepare output buffer. */
-	es->str = makeStringInfo();
-
-	return es;
-}
-
-/*
  * ExplainResultDesc -
  *	  construct the result tupledesc for an EXPLAIN
  */