fdwapi.h

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/*-------------------------------------------------------------------------
 *
 * fdwapi.h
 *    API for foreign-data wrappers
 *
 * Copyright (c) 2010-2016, PostgreSQL Global Development Group
 *
 * src/include/foreign/fdwapi.h
 *
 *-------------------------------------------------------------------------
 */
#ifndef FDWAPI_H
#define FDWAPI_H

#include "access/parallel.h"
#include "nodes/execnodes.h"
#include "nodes/relation.h"

/* To avoid including explain.h here, reference ExplainState thus: */
struct ExplainState;


/*
 * Callback function signatures --- see fdwhandler.sgml for more info.
 */

typedef void (*GetForeignRelSize_function) (PlannerInfo *root,
                                                        RelOptInfo *baserel,
                                                        Oid foreigntableid);

typedef void (*GetForeignPaths_function) (PlannerInfo *root,
                                                      RelOptInfo *baserel,
                                                      Oid foreigntableid);

typedef ForeignScan *(*GetForeignPlan_function) (PlannerInfo *root,
                                                         RelOptInfo *baserel,
                                                          Oid foreigntableid,
                                                      ForeignPath *best_path,
                                                             List *tlist,
                                                          List *scan_clauses,
                                                           Plan *outer_plan);

typedef void (*BeginForeignScan_function) (ForeignScanState *node,
                                                       int eflags);

typedef TupleTableSlot *(*IterateForeignScan_function) (ForeignScanState *node);

typedef bool (*RecheckForeignScan_function) (ForeignScanState *node,
                                                       TupleTableSlot *slot);

typedef void (*ReScanForeignScan_function) (ForeignScanState *node);

typedef void (*EndForeignScan_function) (ForeignScanState *node);

typedef void (*GetForeignJoinPaths_function) (PlannerInfo *root,
                                                          RelOptInfo *joinrel,
                                                        RelOptInfo *outerrel,
                                                        RelOptInfo *innerrel,
                                                          JoinType jointype,
                                                   JoinPathExtraData *extra);

typedef void (*GetForeignUpperPaths_function) (PlannerInfo *root,
                                               RelOptInfo *scan_join_rel);

typedef void (*AddForeignUpdateTargets_function) (Query *parsetree,
                                                   RangeTblEntry *target_rte,
                                                   Relation target_relation);

typedef List *(*PlanForeignModify_function) (PlannerInfo *root,
                                                         ModifyTable *plan,
                                                         Index resultRelation,
                                                         int subplan_index);

typedef void (*BeginForeignModify_function) (ModifyTableState *mtstate,
                                                         ResultRelInfo *rinfo,
                                                         List *fdw_private,
                                                         int subplan_index,
                                                         int eflags);

typedef TupleTableSlot *(*ExecForeignInsert_function) (EState *estate,
                                                        ResultRelInfo *rinfo,
                                                        TupleTableSlot *slot,
                                                   TupleTableSlot *planSlot);

typedef TupleTableSlot *(*ExecForeignUpdate_function) (EState *estate,
                                                        ResultRelInfo *rinfo,
                                                        TupleTableSlot *slot,
                                                   TupleTableSlot *planSlot);

typedef TupleTableSlot *(*ExecForeignDelete_function) (EState *estate,
                                                        ResultRelInfo *rinfo,
                                                        TupleTableSlot *slot,
                                                   TupleTableSlot *planSlot);

typedef void (*EndForeignModify_function) (EState *estate,
                                                       ResultRelInfo *rinfo);

typedef int (*IsForeignRelUpdatable_function) (Relation rel);

typedef bool (*PlanDirectModify_function) (PlannerInfo *root,
                                           ModifyTable *plan,
                                           Index resultRelation,
                                           int subplan_index);

typedef void (*BeginDirectModify_function) (ForeignScanState *node,
                                            int eflags);

typedef TupleTableSlot *(*IterateDirectModify_function) (ForeignScanState *node);

typedef void (*EndDirectModify_function) (ForeignScanState *node);

typedef RowMarkType (*GetForeignRowMarkType_function) (RangeTblEntry *rte,
                                                LockClauseStrength strength);

typedef HeapTuple (*RefetchForeignRow_function) (EState *estate,
                                                             ExecRowMark *erm,
                                                             Datum rowid,
                                                             bool *updated);

typedef void (*ExplainForeignScan_function) (ForeignScanState *node,
                                                    struct ExplainState *es);

typedef void (*ExplainForeignModify_function) (ModifyTableState *mtstate,
                                                        ResultRelInfo *rinfo,
                                                           List *fdw_private,
                                                           int subplan_index,
                                                    struct ExplainState *es);

typedef void (*ExplainDirectModify_function) (ForeignScanState *node,
                                                    struct ExplainState *es);

typedef int (*AcquireSampleRowsFunc) (Relation relation, int elevel,
                                               HeapTuple *rows, int targrows,
                                                  double *totalrows,
                                                  double *totaldeadrows);

typedef bool (*AnalyzeForeignTable_function) (Relation relation,
                                                 AcquireSampleRowsFunc *func,
                                                    BlockNumber *totalpages);

typedef List *(*ImportForeignSchema_function) (ImportForeignSchemaStmt *stmt,
                                                           Oid serverOid);

typedef Size (*EstimateDSMForeignScan_function) (ForeignScanState *node,
                                                ParallelContext *pcxt);
typedef void (*InitializeDSMForeignScan_function) (ForeignScanState *node,
                                                   ParallelContext *pcxt,
                                                   void *coordinate);
typedef void (*InitializeWorkerForeignScan_function) (ForeignScanState *node,
                                                      shm_toc *toc,
                                                      void *coordinate);
typedef bool (*IsForeignScanParallelSafe_function) (PlannerInfo *root,
                                                             RelOptInfo *rel,
                                                         RangeTblEntry *rte);

/*
 * FdwRoutine is the struct returned by a foreign-data wrapper's handler
 * function.  It provides pointers to the callback functions needed by the
 * planner and executor.
 *
 * More function pointers are likely to be added in the future.  Therefore
 * it's recommended that the handler initialize the struct with
 * makeNode(FdwRoutine) so that all fields are set to NULL.  This will
 * ensure that no fields are accidentally left undefined.
 */
typedef struct FdwRoutine
{
    NodeTag     type;

    /* Functions for scanning foreign tables */
    GetForeignRelSize_function GetForeignRelSize;
    GetForeignPaths_function GetForeignPaths;
    GetForeignPlan_function GetForeignPlan;
    BeginForeignScan_function BeginForeignScan;
    IterateForeignScan_function IterateForeignScan;
    ReScanForeignScan_function ReScanForeignScan;
    EndForeignScan_function EndForeignScan;

    /*
     * Remaining functions are optional.  Set the pointer to NULL for any that
     * are not provided.
     */

    /* Functions for remote-join planning */
    GetForeignJoinPaths_function GetForeignJoinPaths;

    /* Functions for remote upper-relation (post scan/join) planning */
    GetForeignUpperPaths_function GetForeignUpperPaths;

    /* Functions for updating foreign tables */
    AddForeignUpdateTargets_function AddForeignUpdateTargets;
    PlanForeignModify_function PlanForeignModify;
    BeginForeignModify_function BeginForeignModify;
    ExecForeignInsert_function ExecForeignInsert;
    ExecForeignUpdate_function ExecForeignUpdate;
    ExecForeignDelete_function ExecForeignDelete;
    EndForeignModify_function EndForeignModify;
    IsForeignRelUpdatable_function IsForeignRelUpdatable;
    PlanDirectModify_function PlanDirectModify;
    BeginDirectModify_function BeginDirectModify;
    IterateDirectModify_function IterateDirectModify;
    EndDirectModify_function EndDirectModify;

    /* Functions for SELECT FOR UPDATE/SHARE row locking */
    GetForeignRowMarkType_function GetForeignRowMarkType;
    RefetchForeignRow_function RefetchForeignRow;
    RecheckForeignScan_function RecheckForeignScan;

    /* Support functions for EXPLAIN */
    ExplainForeignScan_function ExplainForeignScan;
    ExplainForeignModify_function ExplainForeignModify;
    ExplainDirectModify_function ExplainDirectModify;

    /* Support functions for ANALYZE */
    AnalyzeForeignTable_function AnalyzeForeignTable;

    /* Support functions for IMPORT FOREIGN SCHEMA */
    ImportForeignSchema_function ImportForeignSchema;

    /* Support functions for parallelism under Gather node */
    IsForeignScanParallelSafe_function IsForeignScanParallelSafe;
    EstimateDSMForeignScan_function EstimateDSMForeignScan;
    InitializeDSMForeignScan_function InitializeDSMForeignScan;
    InitializeWorkerForeignScan_function InitializeWorkerForeignScan;
} FdwRoutine;


/* Functions in foreign/foreign.c */
extern FdwRoutine *GetFdwRoutine(Oid fdwhandler);
extern Oid  GetForeignServerIdByRelId(Oid relid);
extern FdwRoutine *GetFdwRoutineByServerId(Oid serverid);
extern FdwRoutine *GetFdwRoutineByRelId(Oid relid);
extern FdwRoutine *GetFdwRoutineForRelation(Relation relation, bool makecopy);
extern bool IsImportableForeignTable(const char *tablename,
                         ImportForeignSchemaStmt *stmt);
extern Path *GetExistingLocalJoinPath(RelOptInfo *joinrel);

#endif   /* FDWAPI_H */