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for example in WITH w AS (SELECT * FROM foo) SELECT * FROM w, bar ... FOR UPDATE the FOR UPDATE will now affect bar but not foo. This is more useful and consistent than the original 8.4 behavior, which tried to propagate FOR UPDATE into the WITH query but always failed due to assorted implementation restrictions. Even though we are in process of removing those restrictions, it seems correct on philosophical grounds to not let the outer query's FOR UPDATE affect the WITH query. In passing, fix isLockedRel which frequently got things wrong in nested-subquery cases: "FOR UPDATE OF foo" applies to an alias foo in the current query level, not subqueries. This has been broken for a long time, but it doesn't seem worth back-patching further than 8.4 because the actual consequences are minimal. At worst the parser would sometimes get RowShareLock on a relation when it should be AccessShareLock or vice versa. That would only make a difference if someone were using ExclusiveLock concurrently, which no standard operation does, and anyway FOR UPDATE doesn't result in visible changes so it's not clear that the someone would notice any problem. Between that and the fact that FOR UPDATE barely works with subqueries at all in existing releases, I'm not excited about worrying about it.
$PostgreSQL: pgsql/src/backend/parser/README,v 1.10 2008/04/09 01:00:46 momjian Exp $ Parser ====== This directory does more than tokenize and parse SQL queries. It also creates Query structures for the various complex queries that are passed to the optimizer and then executor. parser.c things start here scan.l break query into tokens scansup.c handle escapes in input strings keywords.c turn keywords into specific tokens gram.y parse the tokens and fill query-type-specific structures analyze.c top level of parse analysis for optimizable queries parse_clause.c handle clauses like WHERE, ORDER BY, GROUP BY, ... parse_coerce.c handle coercing expressions to different data types parse_expr.c handle expressions like col, col + 3, x = 3 or x = 4 parse_oper.c handle operators in expressions parse_agg.c handle aggregates, like SUM(col1), AVG(col2), ... parse_func.c handle functions, table.column and column identifiers parse_node.c create nodes for various structures parse_target.c handle the result list of the query parse_relation.c support routines for tables and column handling parse_type.c support routines for data type handling parse_utilcmd.c parse analysis for utility commands (done at execution time)