postgresql/contrib/postgres_fdw/postgres_fdw.h
Tom Lane 83204e100c Fix contrib/postgres_fdw to handle multiple join conditions properly.
The previous coding supposed that it could consider just a single join
condition in any one parameterized path for the foreign table.  But in
reality, the parameterized-path machinery forces all join clauses that are
"movable to" the foreign table to be evaluated at that node; including
clauses that we might not consider safe to send across.  Such cases would
result in an Assert failure in an assert-enabled build, and otherwise in
sending an unsafe clause to the foreign server, which might result in
errors or silently-wrong answers.  A lesser problem was that the
cost/rowcount estimates generated for the parameterized path failed to
account for any additional join quals that get assigned to the scan.

To fix, rewrite postgresGetForeignPaths so that it correctly collects all
the movable quals for any one outer relation when generating parameterized
paths; we'll now generate just one path per outer relation not one per join
qual.  Also fix bogus assumptions in postgresGetForeignPlan and
estimate_path_cost_size that only safe-to-send join quals will be
presented.

Based on complaint from Etsuro Fujita that the path costs were being
miscalculated, though this is significantly different from his proposed
patch.
2014-03-07 16:36:40 -05:00

78 lines
2.4 KiB
C

/*-------------------------------------------------------------------------
*
* postgres_fdw.h
* Foreign-data wrapper for remote PostgreSQL servers
*
* Portions Copyright (c) 2012-2014, PostgreSQL Global Development Group
*
* IDENTIFICATION
* contrib/postgres_fdw/postgres_fdw.h
*
*-------------------------------------------------------------------------
*/
#ifndef POSTGRES_FDW_H
#define POSTGRES_FDW_H
#include "foreign/foreign.h"
#include "lib/stringinfo.h"
#include "nodes/relation.h"
#include "utils/rel.h"
#include "libpq-fe.h"
/* in postgres_fdw.c */
extern int set_transmission_modes(void);
extern void reset_transmission_modes(int nestlevel);
/* in connection.c */
extern PGconn *GetConnection(ForeignServer *server, UserMapping *user,
bool will_prep_stmt);
extern void ReleaseConnection(PGconn *conn);
extern unsigned int GetCursorNumber(PGconn *conn);
extern unsigned int GetPrepStmtNumber(PGconn *conn);
extern void pgfdw_report_error(int elevel, PGresult *res, PGconn *conn,
bool clear, const char *sql);
/* in option.c */
extern int ExtractConnectionOptions(List *defelems,
const char **keywords,
const char **values);
/* in deparse.c */
extern void classifyConditions(PlannerInfo *root,
RelOptInfo *baserel,
List *input_conds,
List **remote_conds,
List **local_conds);
extern bool is_foreign_expr(PlannerInfo *root,
RelOptInfo *baserel,
Expr *expr);
extern void deparseSelectSql(StringInfo buf,
PlannerInfo *root,
RelOptInfo *baserel,
Bitmapset *attrs_used,
List **retrieved_attrs);
extern void appendWhereClause(StringInfo buf,
PlannerInfo *root,
RelOptInfo *baserel,
List *exprs,
bool is_first,
List **params);
extern void deparseInsertSql(StringInfo buf, PlannerInfo *root,
Index rtindex, Relation rel,
List *targetAttrs, List *returningList,
List **retrieved_attrs);
extern void deparseUpdateSql(StringInfo buf, PlannerInfo *root,
Index rtindex, Relation rel,
List *targetAttrs, List *returningList,
List **retrieved_attrs);
extern void deparseDeleteSql(StringInfo buf, PlannerInfo *root,
Index rtindex, Relation rel,
List *returningList,
List **retrieved_attrs);
extern void deparseAnalyzeSizeSql(StringInfo buf, Relation rel);
extern void deparseAnalyzeSql(StringInfo buf, Relation rel,
List **retrieved_attrs);
#endif /* POSTGRES_FDW_H */