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7537f52a00
the visibility map patch that because autovacuum always sets VacuumStmt->freeze_min_age, visibility map was never used for autovacuum, only for manually launched vacuums. This patch introduces a new scan_all field to VacuumStmt, indicating explicitly whether the visibility map should be used, or the whole relation should be scanned, to advance relfrozenxid. Anti-wraparound vacuums still need to scan all pages.
$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)