Files
openGauss-server/src/gausskernel/runtime/executor/nodeForeignscan.cpp
2023-02-21 20:30:35 -08:00

326 lines
10 KiB
C++

/* -------------------------------------------------------------------------
*
* nodeForeignscan.cpp
* Routines to support scans of foreign tables
*
* Portions Copyright (c) 2020 Huawei Technologies Co.,Ltd.
* Portions Copyright (c) 1996-2012, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/gausskernel/runtime/executor/nodeForeignscan.cpp
*
* -------------------------------------------------------------------------
*
* INTERFACE ROUTINES
*
* ExecForeignScan scans a foreign table.
* ExecInitForeignScan creates and initializes state info.
* ExecReScanForeignScan rescans the foreign relation.
* ExecEndForeignScan releases any resources allocated.
*/
#include "postgres.h"
#include "knl/knl_variable.h"
#include "executor/executor.h"
#include "executor/node/nodeForeignscan.h"
#include "foreign/fdwapi.h"
#include "foreign/foreign.h"
#include "utils/rel.h"
#include "utils/rel_gs.h"
#include "utils/memutils.h"
#ifdef ENABLE_MOT
#include "storage/mot/jit_exec.h"
#endif
#ifdef PGXC
#include "utils/lsyscache.h"
#include "pgxc/pgxc.h"
#endif
#include "utils/knl_relcache.h"
static TupleTableSlot* ExecForeignScan(PlanState* state);
static TupleTableSlot* ForeignNext(ForeignScanState* node);
static bool ForeignRecheck(ForeignScanState* node, TupleTableSlot* slot);
/* ----------------------------------------------------------------
* ForeignNext
*
* This is a workhorse for ExecForeignScan
* ----------------------------------------------------------------
*/
static TupleTableSlot* ForeignNext(ForeignScanState* node)
{
TupleTableSlot* slot = NULL;
ForeignScan* plan = (ForeignScan*)node->ss.ps.plan;
ExprContext* econtext = node->ss.ps.ps_ExprContext;
MemoryContext oldcontext;
/* Call the Iterate function in short-lived context */
oldcontext = MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
slot = node->fdwroutine->IterateForeignScan(node);
MemoryContextSwitchTo(oldcontext);
/*
* If any system columns are requested, we have to force the tuple into
* physical-tuple form to avoid "cannot extract system attribute from
* virtual tuple" errors later. We also insert a valid value for
* tableoid, which is the only actually-useful system column.
*/
if (plan->fsSystemCol && !TupIsNull(slot)) {
HeapTuple tup = ExecMaterializeSlot(slot);
if (!OidIsValid(tup->t_tableOid))
tup->t_tableOid = RelationGetRelid(node->ss.ss_currentRelation);
tup->t_bucketId = RelationGetBktid(node->ss.ss_currentRelation);
#ifdef PGXC
tup->t_xc_node_id = u_sess->pgxc_cxt.PGXCNodeIdentifier;
#endif
}
return slot;
}
/*
* ForeignRecheck -- access method routine to recheck a tuple in EvalPlanQual
*/
static bool ForeignRecheck(ForeignScanState* node, TupleTableSlot* slot)
{
return true;
}
/* ----------------------------------------------------------------
* ExecForeignScan(node)
*
* Fetches the next tuple from the FDW, checks local quals, and
* returns it.
* We call the ExecScan() routine and pass it the appropriate
* access method functions.
* ----------------------------------------------------------------
*/
static TupleTableSlot* ExecForeignScan(PlanState* state)
{
ForeignScanState* node = castNode(ForeignScanState, state);
return ExecScan((ScanState*)node, (ExecScanAccessMtd)ForeignNext, (ExecScanRecheckMtd)ForeignRecheck);
}
/* ----------------------------------------------------------------
* ExecInitForeignScan
* ----------------------------------------------------------------
*/
ForeignScanState* ExecInitForeignScan(ForeignScan* node, EState* estate, int eflags)
{
ForeignScanState* scanstate = NULL;
Relation currentRelation = NULL;
FdwRoutine* fdwroutine = NULL;
Index scanrelid = node->scan.scanrelid;
int tlistvarno;
errno_t rc;
/* check for unsupported flags */
Assert(!(eflags & (EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK)));
/*
* create state structure
*/
scanstate = makeNode(ForeignScanState);
scanstate->ss.ps.plan = (Plan*)node;
scanstate->ss.ps.state = estate;
scanstate->ss.ps.ExecProcNode = ExecForeignScan;
/*
* Miscellaneous initialization
*
* create expression context for node
*/
#ifdef ENABLE_MOT
if ((estate->mot_jit_context == NULL) || IS_PGXC_COORDINATOR || !JitExec::IsMotCodegenEnabled()) {
#endif
ExecAssignExprContext(estate, &scanstate->ss.ps);
#ifdef ENABLE_MOT
}
#endif
scanstate->ss.ps.ps_TupFromTlist = false;
/*
* This function ExecInitForeignScan will be called by ExecInitVecForeignScan.
* If the node is VecForeignScan, do not need initialize here.
*/
if (!IsA(node, VecForeignScan)) {
/*
* initialize child expressions
*/
scanstate->ss.ps.targetlist = (List*)ExecInitExpr((Expr*)node->scan.plan.targetlist, (PlanState*)scanstate);
scanstate->ss.ps.qual = (List*)ExecInitExpr((Expr*)node->scan.plan.qual, (PlanState*)scanstate);
}
/*
* tuple table initialization
*/
ExecInitResultTupleSlot(estate, &scanstate->ss.ps);
ExecInitScanTupleSlot(estate, &scanstate->ss);
/*
* open the base relation and acquire appropriate lock on it.
* or it is a foreign join, we should recreate resultdesc and project info
*/
if (scanrelid > 0) {
if (node->rel == NULL) {
currentRelation = ExecOpenScanRelation(estate, node->scan.scanrelid);
} else {
if (node->in_compute_pool == false) {
currentRelation = ExecOpenScanRelation(estate, node->scan.scanrelid);
} else {
currentRelation = get_rel_from_meta(node->rel);
scanstate->options = node->options;
}
}
scanstate->ss.ss_currentRelation = currentRelation;
/*
* Acquire function pointers from the FDW's handler, and init fdw_state.
*/
if (!node->rel) {
fdwroutine = GetFdwRoutineForRelation(currentRelation, true);
} else {
ForeignDataWrapper* fdw = NULL;
if (node->options->stype == T_OBS_SERVER || node->options->stype == T_HDFS_SERVER) {
fdw = GetForeignDataWrapperByName(HDFS_FDW, false);
} else {
fdw = GetForeignDataWrapperByName(DIST_FDW, false);
}
fdwroutine = GetFdwRoutine(fdw->fdwhandler);
/* Save the data for later reuse in LocalMyDBCacheMemCxt */
FdwRoutine* cfdwroutine = (FdwRoutine*)MemoryContextAlloc(LocalMyDBCacheMemCxt(), sizeof(FdwRoutine));
rc = memcpy_s(cfdwroutine, sizeof(FdwRoutine), fdwroutine, sizeof(FdwRoutine));
securec_check(rc, "\0", "\0");
currentRelation->rd_fdwroutine = cfdwroutine;
}
} else {
/* We can't use the relcache, so get fdwroutine the hard way */
fdwroutine = GetFdwRoutineByServerId(node->fs_server);
}
/*
* Determine the scan tuple type. If the FDW provided a targetlist
* describing the scan tuples, use that; else use base relation's rowtype.
*/
if (node->fdw_scan_tlist != NIL || currentRelation == NULL) {
TupleDesc scan_tupdesc;
scan_tupdesc = ExecTypeFromTL(node->fdw_scan_tlist, false);
ExecAssignScanType(&scanstate->ss, scan_tupdesc);
tlistvarno = INDEX_VAR;
} else {
TupleDesc scan_tupdesc;
/* don't trust FDWs to return tuples fulfilling NOT NULL constraints */
scan_tupdesc = CreateTupleDescCopy(RelationGetDescr(currentRelation));
ExecAssignScanType(&scanstate->ss, scan_tupdesc);
/* Node's targetlist will contain Vars with varno = scanrelid */
tlistvarno = scanrelid;
}
/*
* Initialize result tuple type and projection info.
*/
ExecAssignResultTypeFromTL(
&scanstate->ss.ps,
scanstate->ss.ss_ScanTupleSlot->tts_tupleDescriptor->td_tam_ops);
ExecAssignScanProjectionInfoWithVarno(&scanstate->ss, tlistvarno);
scanstate->fdwroutine = fdwroutine;
scanstate->fdw_state = NULL;
/* Initialize any outer plan. */
if (outerPlan(node)) {
outerPlanState(scanstate) = ExecInitNode(outerPlan(node), estate, eflags);
}
#ifdef ENABLE_MOT
if ((estate->mot_jit_context == NULL) || IS_PGXC_COORDINATOR || !JitExec::IsMotCodegenEnabled()) {
#endif
scanstate->scanMcxt = AllocSetContextCreate(CurrentMemoryContext,
"Foreign Scan",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
/*
* Tell the FDW to initiate the scan.
*/
fdwroutine->BeginForeignScan(scanstate, eflags);
#ifdef ENABLE_MOT
}
#endif
return scanstate;
}
/* ----------------------------------------------------------------
* ExecEndForeignScan
*
* frees any storage allocated through C routines.
* ----------------------------------------------------------------
*/
void ExecEndForeignScan(ForeignScanState* node)
{
/* Let the FDW shut down */
#ifdef ENABLE_MOT
if (node->fdw_state != NULL) {
#endif
node->fdwroutine->EndForeignScan(node);
#ifdef ENABLE_MOT
}
#endif
/* Shut down any outer plan. */
if (outerPlanState(node))
ExecEndNode(outerPlanState(node));
/* Free the exprcontext */
ExecFreeExprContext(&node->ss.ps);
/* clean out the tuple table */
(void)ExecClearTuple(node->ss.ps.ps_ResultTupleSlot);
(void)ExecClearTuple(node->ss.ss_ScanTupleSlot);
/* close the relation. */
ForeignScan* scan = (ForeignScan*)node->ss.ps.plan;
if (node->ss.ss_currentRelation != NULL) {
if (NULL == scan->rel) {
ExecCloseScanRelation(node->ss.ss_currentRelation);
} else {
if (false == scan->in_compute_pool) {
ExecCloseScanRelation(node->ss.ss_currentRelation);
}
}
}
/* clear obs sk key */
if (node->options != NULL) {
char* obskey = getFTOptionValue(node->options->fOptions, OPTION_NAME_OBSKEY);
if (obskey != NULL) {
errno_t rc = EOK;
rc = memset_s(obskey, strlen(obskey), 0, strlen(obskey));
securec_check(rc, "\0", "\0");
}
}
}
/* ----------------------------------------------------------------
* ExecReScanForeignScan
*
* Rescans the relation.
* ----------------------------------------------------------------
*/
void ExecReScanForeignScan(ForeignScanState* node)
{
node->fdwroutine->ReScanForeignScan(node);
ExecScanReScan(&node->ss);
}