[pgpool-hackers: 4290] minimal parser and multi-statement query

[Tatsuo Ishii]

Hi Usama,

While taking care of this:
https://www.pgpool.net/mantisbt/view.php?id=780

I realized that pgpool fails to judge whether a query is
multi-statement or not, if clustering mode is streaming/logical
replication and the multi-statement query includes INSERT or UPDATE
statements. This is because our minimal-parser returns single parse
tree for multi-statement queries including INSERT/UPDATE statements.

gram_minimal.y:

InsertStmtShort:
			opt_with_clause INSERT INTO insert_target
			{
				InsertStmt *insert = makeNode(InsertStmt);
				insert->relation = $4;
				$$ = (Node *) insert;
				/*
				 * Assign the node directly to the parsetree and exit the scanner
				 * we don't want to keep parsing for information we don't need
				 */
				pg_yyget_extra(yyscanner)->parsetree = list_make1(makeRawStmt($$, 0));
				YYACCEPT;
			}
		;

As a result, the test below in SimpleQuery() fails to set
is_multi_statement to true even if the query is a multi-statement
query.

		if (parse_tree_list && list_length(parse_tree_list) > 1)
		{
			query_context->is_multi_statement = true;
		}
		else
		{
			query_context->is_multi_statement = false;
		}

We could avoid this without using the minimal parser but it will take
more time to parse lengthy INSERT/UPDATE queries.

Is there any workaround for this?

Best reagards,
--
Tatsuo Ishii
SRA OSS LLC
English: http://www.sraoss.co.jp/index_en/
Japanese:http://www.sraoss.co.jp