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a45adc747e
If a view references a foreign table, and the foreign table has a BEFORE INSERT trigger, then it's possible for a tuple inserted or updated through the view to be changed such that it violates the view's WITH CHECK OPTION constraint. Before this commit, postgres_fdw handled this case inconsistently. A RETURNING clause on the INSERT or UPDATE statement targeting the view would cause the finally-inserted tuple to be read back, and the WITH CHECK OPTION violation would throw an error. But without a RETURNING clause, postgres_fdw would not read the final tuple back, and WITH CHECK OPTION would not throw an error for the violation (or may throw an error when there is no real violation). AFTER ROW triggers on the foreign table had a similar effect as a RETURNING clause on the INSERT or UPDATE statement. To fix, this commit retrieves the attributes needed to enforce the WITH CHECK OPTION constraint along with the attributes needed for the RETURNING clause (if any) from the remote side. Thus, the WITH CHECK OPTION constraint is always evaluated against the final tuple after any triggers on the remote side. This fix may be considered inconsistent with CHECK constraints declared on foreign tables, which are not enforced locally at all (because the constraint is on a remote object). The discussion concluded that this difference is reasonable, because the WITH CHECK OPTION is a constraint on the local view (not any remote object); therefore it only makes sense to enforce its WITH CHECK OPTION constraint locally. Author: Etsuro Fujita Reviewed-by: Arthur Zakirov, Stephen Frost Discussion: https://www.postgresql.org/message-id/7eb58fab-fd3b-781b-ac33-f7cfec96021f%40lab.ntt.co.jp
190 lines
6.2 KiB
C
190 lines
6.2 KiB
C
/*-------------------------------------------------------------------------
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*
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* postgres_fdw.h
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* Foreign-data wrapper for remote PostgreSQL servers
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*
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* Portions Copyright (c) 2012-2018, PostgreSQL Global Development Group
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*
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* IDENTIFICATION
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* contrib/postgres_fdw/postgres_fdw.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef POSTGRES_FDW_H
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#define POSTGRES_FDW_H
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#include "foreign/foreign.h"
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#include "lib/stringinfo.h"
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#include "nodes/relation.h"
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#include "utils/relcache.h"
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#include "libpq-fe.h"
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/*
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* FDW-specific planner information kept in RelOptInfo.fdw_private for a
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* postgres_fdw foreign table. For a baserel, this struct is created by
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* postgresGetForeignRelSize, although some fields are not filled till later.
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* postgresGetForeignJoinPaths creates it for a joinrel, and
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* postgresGetForeignUpperPaths creates it for an upperrel.
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*/
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typedef struct PgFdwRelationInfo
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{
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/*
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* True means that the relation can be pushed down. Always true for simple
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* foreign scan.
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*/
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bool pushdown_safe;
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/*
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* Restriction clauses, divided into safe and unsafe to pushdown subsets.
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* All entries in these lists should have RestrictInfo wrappers; that
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* improves efficiency of selectivity and cost estimation.
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*/
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List *remote_conds;
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List *local_conds;
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/* Actual remote restriction clauses for scan (sans RestrictInfos) */
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List *final_remote_exprs;
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/* Bitmap of attr numbers we need to fetch from the remote server. */
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Bitmapset *attrs_used;
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/* Cost and selectivity of local_conds. */
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QualCost local_conds_cost;
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Selectivity local_conds_sel;
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/* Selectivity of join conditions */
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Selectivity joinclause_sel;
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/* Estimated size and cost for a scan or join. */
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double rows;
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int width;
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Cost startup_cost;
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Cost total_cost;
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/* Costs excluding costs for transferring data from the foreign server */
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Cost rel_startup_cost;
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Cost rel_total_cost;
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/* Options extracted from catalogs. */
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bool use_remote_estimate;
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Cost fdw_startup_cost;
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Cost fdw_tuple_cost;
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List *shippable_extensions; /* OIDs of whitelisted extensions */
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/* Cached catalog information. */
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ForeignTable *table;
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ForeignServer *server;
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UserMapping *user; /* only set in use_remote_estimate mode */
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int fetch_size; /* fetch size for this remote table */
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/*
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* Name of the relation while EXPLAINing ForeignScan. It is used for join
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* relations but is set for all relations. For join relation, the name
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* indicates which foreign tables are being joined and the join type used.
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*/
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StringInfo relation_name;
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/* Join information */
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RelOptInfo *outerrel;
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RelOptInfo *innerrel;
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JoinType jointype;
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/* joinclauses contains only JOIN/ON conditions for an outer join */
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List *joinclauses; /* List of RestrictInfo */
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/* Grouping information */
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List *grouped_tlist;
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/* Subquery information */
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bool make_outerrel_subquery; /* do we deparse outerrel as a
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* subquery? */
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bool make_innerrel_subquery; /* do we deparse innerrel as a
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* subquery? */
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Relids lower_subquery_rels; /* all relids appearing in lower
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* subqueries */
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/*
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* Index of the relation. It is used to create an alias to a subquery
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* representing the relation.
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*/
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int relation_index;
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} PgFdwRelationInfo;
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/* in postgres_fdw.c */
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extern int set_transmission_modes(void);
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extern void reset_transmission_modes(int nestlevel);
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/* in connection.c */
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extern PGconn *GetConnection(UserMapping *user, bool will_prep_stmt);
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extern void ReleaseConnection(PGconn *conn);
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extern unsigned int GetCursorNumber(PGconn *conn);
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extern unsigned int GetPrepStmtNumber(PGconn *conn);
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extern PGresult *pgfdw_get_result(PGconn *conn, const char *query);
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extern PGresult *pgfdw_exec_query(PGconn *conn, const char *query);
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extern void pgfdw_report_error(int elevel, PGresult *res, PGconn *conn,
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bool clear, const char *sql);
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/* in option.c */
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extern int ExtractConnectionOptions(List *defelems,
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const char **keywords,
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const char **values);
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extern List *ExtractExtensionList(const char *extensionsString,
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bool warnOnMissing);
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/* in deparse.c */
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extern void classifyConditions(PlannerInfo *root,
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RelOptInfo *baserel,
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List *input_conds,
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List **remote_conds,
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List **local_conds);
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extern bool is_foreign_expr(PlannerInfo *root,
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RelOptInfo *baserel,
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Expr *expr);
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extern void deparseInsertSql(StringInfo buf, RangeTblEntry *rte,
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Index rtindex, Relation rel,
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List *targetAttrs, bool doNothing,
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List *withCheckOptionList, List *returningList,
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List **retrieved_attrs);
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extern void deparseUpdateSql(StringInfo buf, RangeTblEntry *rte,
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Index rtindex, Relation rel,
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List *targetAttrs,
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List *withCheckOptionList, List *returningList,
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List **retrieved_attrs);
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extern void deparseDirectUpdateSql(StringInfo buf, PlannerInfo *root,
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Index rtindex, Relation rel,
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RelOptInfo *foreignrel,
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List *targetlist,
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List *targetAttrs,
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List *remote_conds,
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List **params_list,
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List *returningList,
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List **retrieved_attrs);
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extern void deparseDeleteSql(StringInfo buf, RangeTblEntry *rte,
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Index rtindex, Relation rel,
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List *returningList,
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List **retrieved_attrs);
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extern void deparseDirectDeleteSql(StringInfo buf, PlannerInfo *root,
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Index rtindex, Relation rel,
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RelOptInfo *foreignrel,
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List *remote_conds,
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List **params_list,
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List *returningList,
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List **retrieved_attrs);
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extern void deparseAnalyzeSizeSql(StringInfo buf, Relation rel);
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extern void deparseAnalyzeSql(StringInfo buf, Relation rel,
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List **retrieved_attrs);
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extern void deparseStringLiteral(StringInfo buf, const char *val);
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extern Expr *find_em_expr_for_rel(EquivalenceClass *ec, RelOptInfo *rel);
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extern List *build_tlist_to_deparse(RelOptInfo *foreignrel);
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extern void deparseSelectStmtForRel(StringInfo buf, PlannerInfo *root,
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RelOptInfo *foreignrel, List *tlist,
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List *remote_conds, List *pathkeys, bool is_subquery,
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List **retrieved_attrs, List **params_list);
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extern const char *get_jointype_name(JoinType jointype);
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/* in shippable.c */
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extern bool is_builtin(Oid objectId);
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extern bool is_shippable(Oid objectId, Oid classId, PgFdwRelationInfo *fpinfo);
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#endif /* POSTGRES_FDW_H */
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