static bool
DynamicIndexScan_ReMapColumns(DynamicIndexScanState *scanState, Oid newOid)
{
Assert(OidIsValid(newOid));
IndexScan *indexScan = (IndexScan *) scanState->indexScanState.ss.ps.plan;
if (!isDynamicScan(&indexScan->scan))
{
return false;
}
Oid oldOid = scanState->columnLayoutOid;
if (!OidIsValid(oldOid))
{
/* Very first partition */
oldOid = rel_partition_get_root(newOid);
}
Assert(OidIsValid(oldOid));
if (oldOid == newOid)
{
/*
* If we have only one partition and we are rescanning
* then we can have this scenario.
*/
return false;
}
AttrNumber *attMap = IndexScan_GetColumnMapping(oldOid, newOid);
scanState->columnLayoutOid = newOid;
if (attMap)
{
IndexScan_MapLogicalIndexInfo(indexScan->logicalIndexInfo, attMap, indexScan->scan.scanrelid);
change_varattnos_of_a_varno((Node*)indexScan->scan.plan.targetlist, attMap, indexScan->scan.scanrelid);
change_varattnos_of_a_varno((Node*)indexScan->scan.plan.qual, attMap, indexScan->scan.scanrelid);
change_varattnos_of_a_varno((Node*)indexScan->indexqual, attMap, indexScan->scan.scanrelid);
pfree(attMap);
return true;
}
else
{
return false;
}
}
/*
* DynamicScan_RemapExpression
* Re-maps the expression using the provided attMap.
*/
bool
DynamicScan_RemapExpression(ScanState *scanState, AttrNumber *attMap, Node *expr)
{
if (!isDynamicScan((Scan *)scanState->ps.plan))
{
return false;
}
if (NULL != attMap)
{
change_varattnos_of_a_varno((Node*)expr, attMap, ((Scan *)scanState->ps.plan)->scanrelid);
return true;
}
return false;
}
/*
* initNextTableToScan
* Find the next table to scan and initiate the scan if the previous table
* is finished.
*
* If scanning on the current table is not finished, or a new table is found,
* this function returns true.
* If no more table is found, this function returns false.
*/
static bool
initNextTableToScan(DynamicTableScanState *node)
{
ScanState *scanState = (ScanState *)node;
if (scanState->scan_state == SCAN_INIT ||
scanState->scan_state == SCAN_DONE)
{
Oid *pid = hash_seq_search(&node->pidStatus);
if (pid == NULL)
{
node->shouldCallHashSeqTerm = false;
return false;
}
/* Collect number of partitions scanned in EXPLAIN ANALYZE */
if (NULL != scanState->ps.instrument)
{
Instrumentation *instr = scanState->ps.instrument;
instr->numPartScanned ++;
}
/*
* Inside ExecInitScanTupleSlot() we set the tuple table slot's oid
* to range table entry's relid, which for partitioned table always set
* to parent table's oid. In queries where we need to read table oids
* (MPP-20736) we use the tuple table slot's saved oid (refer to slot_getsysattr()).
* This wrongly returns parent oid, instead of partition oid. Therefore,
* to return correct partition oid, we need to update
* our tuple table slot's oid to reflect the partition oid.
*/
scanState->ss_ScanTupleSlot->tts_tableOid = *pid;
scanState->ss_currentRelation = OpenScanRelationByOid(*pid);
Relation lastScannedRel = OpenScanRelationByOid(node->lastRelOid);
TupleDesc lastTupDesc = RelationGetDescr(lastScannedRel);
CloseScanRelation(lastScannedRel);
TupleDesc partTupDesc = RelationGetDescr(scanState->ss_currentRelation);
ExecAssignScanType(scanState, partTupDesc);
AttrNumber *attMap = NULL;
attMap = varattnos_map(lastTupDesc, partTupDesc);
/* If attribute remapping is not necessary, then do not change the varattno */
if (attMap)
{
change_varattnos_of_a_varno((Node*)scanState->ps.plan->qual, attMap, node->scanrelid);
change_varattnos_of_a_varno((Node*)scanState->ps.plan->targetlist, attMap, node->scanrelid);
/*
* Now that the varattno mapping has been changed, change the relation that
* the new varnos correspond to
*/
node->lastRelOid = *pid;
}
/*
* For the very first partition, the targetlist of planstate is set to null. So, we must
* initialize quals and targetlist, regardless of remapping requirements. For later
* partitions, we only initialize quals and targetlist if a column re-mapping is necessary.
*/
if (attMap || node->firstPartition)
{
node->firstPartition = false;
MemoryContextReset(node->partitionMemoryContext);
MemoryContext oldCxt = MemoryContextSwitchTo(node->partitionMemoryContext);
/* Initialize child expressions */
scanState->ps.qual = (List *)ExecInitExpr((Expr *)scanState->ps.plan->qual, (PlanState*)scanState);
scanState->ps.targetlist = (List *)ExecInitExpr((Expr *)scanState->ps.plan->targetlist, (PlanState*)scanState);
MemoryContextSwitchTo(oldCxt);
}
if (attMap)
{
pfree(attMap);
}
ExecAssignScanProjectionInfo(scanState);
scanState->tableType = getTableType(scanState->ss_currentRelation);
BeginTableScanRelation(scanState);
}
return true;
}