/* ----------------------------------------------------------------
* ExecEndNestLoop
*
* closes down scans and frees allocated storage
* ----------------------------------------------------------------
*/
void
ExecEndNestLoop(NestLoopState *node)
{
NL1_printf("ExecEndNestLoop: %s\n",
"ending node processing");
/*
* Free the exprcontext
*/
ExecFreeExprContext(&node->js.ps);
/*
* clean out the tuple table
*/
ExecClearTuple(node->js.ps.ps_ResultTupleSlot);
/*
* close down subplans
*/
ExecEndNode(outerPlanState(node));
ExecEndNode(innerPlanState(node));
NL1_printf("ExecEndNestLoop: %s\n",
"node processing ended");
}
/* ----------------------------------------------------------------
* ExecReScanRecursiveUnion
*
* Rescans the relation.
* ----------------------------------------------------------------
*/
void
ExecReScanRecursiveUnion(RecursiveUnionState *node)
{
PlanState *outerPlan = outerPlanState(node);
PlanState *innerPlan = innerPlanState(node);
RecursiveUnion *plan = (RecursiveUnion *) node->ps.plan;
/*
* Set recursive term's chgParam to tell it that we'll modify the working
* table and therefore it has to rescan.
*/
innerPlan->chgParam = bms_add_member(innerPlan->chgParam, plan->wtParam);
/*
* if chgParam of subnode is not null then plan will be re-scanned by
* first ExecProcNode. Because of above, we only have to do this to the
* non-recursive term.
*/
if (outerPlan->chgParam == NULL)
ExecReScan(outerPlan);
/* Release any hashtable storage */
if (node->tableContext)
MemoryContextResetAndDeleteChildren(node->tableContext);
/* And rebuild empty hashtable if needed */
if (plan->numCols > 0)
build_hash_table(node);
/* reset processing state */
node->recursing = false;
node->intermediate_empty = true;
tuplestore_clear(node->working_table);
tuplestore_clear(node->intermediate_table);
}
/* ----------------------------------------------------------------
* ExecEndRecursiveUnionScan
*
* frees any storage allocated through C routines.
* ----------------------------------------------------------------
*/
void
ExecEndRecursiveUnion(RecursiveUnionState *node)
{
/* Release tuplestores */
tuplestore_end(node->working_table);
tuplestore_end(node->intermediate_table);
/* free subsidiary stuff including hashtable */
if (node->tempContext)
MemoryContextDelete(node->tempContext);
if (node->tableContext)
MemoryContextDelete(node->tableContext);
/*
* clean out the upper tuple table
*/
ExecClearTuple(node->ps.ps_ResultTupleSlot);
/*
* close down subplans
*/
ExecEndNode(outerPlanState(node));
ExecEndNode(innerPlanState(node));
}
/* ----------------------------------------------------------------
* ExecRecursiveUnion(node)
*
* Scans the recursive query sequentially and returns the next
* qualifying tuple.
*
* 1. evaluate non recursive term and assign the result to RT
*
* 2. execute recursive terms
*
* 2.1 WT := RT
* 2.2 while WT is not empty repeat 2.3 to 2.6. if WT is empty returns RT
* 2.3 replace the name of recursive term with WT
* 2.4 evaluate the recursive term and store into WT
* 2.5 append WT to RT
* 2.6 go back to 2.2
* ----------------------------------------------------------------
*/
TupleTableSlot *
ExecRecursiveUnion(RecursiveUnionState *node)
{
PlanState *outerPlan = outerPlanState(node);
PlanState *innerPlan = innerPlanState(node);
RecursiveUnion *plan = (RecursiveUnion *) node->ps.plan;
TupleTableSlot *slot;
RUHashEntry entry;
bool isnew;
/* 1. Evaluate non-recursive term */
if (!node->recursing)
{
for (;;)
{
slot = ExecProcNode(outerPlan);
if (TupIsNull(slot))
break;
if (plan->numCols > 0)
{
/* Find or build hashtable entry for this tuple's group */
entry = (RUHashEntry)
LookupTupleHashEntry(node->hashtable, slot, &isnew);
/* Must reset temp context after each hashtable lookup */
MemoryContextReset(node->tempContext);
/* Ignore tuple if already seen */
if (!isnew)
continue;
}
/* Each non-duplicate tuple goes to the working table ... */
tuplestore_puttupleslot(node->working_table, slot);
/* ... and to the caller */
return slot;
}
node->recursing = true;
}
/* 2. Execute recursive term */
for (;;)
{
slot = ExecProcNode(innerPlan);
if (TupIsNull(slot))
{
/* Done if there's nothing in the intermediate table */
if (node->intermediate_empty)
break;
/* done with old working table ... */
tuplestore_end(node->working_table);
/* intermediate table becomes working table */
node->working_table = node->intermediate_table;
/* create new empty intermediate table */
node->intermediate_table = tuplestore_begin_heap(false, false,
work_mem);
node->intermediate_empty = true;
/* reset the recursive term */
innerPlan->chgParam = bms_add_member(innerPlan->chgParam,
plan->wtParam);
/* and continue fetching from recursive term */
continue;
}
if (plan->numCols > 0)
{
/* Find or build hashtable entry for this tuple's group */
entry = (RUHashEntry)
LookupTupleHashEntry(node->hashtable, slot, &isnew);
/* Must reset temp context after each hashtable lookup */
MemoryContextReset(node->tempContext);
/* Ignore tuple if already seen */
if (!isnew)
continue;
}
/* Else, tuple is good; stash it in intermediate table ... */
node->intermediate_empty = false;
tuplestore_puttupleslot(node->intermediate_table, slot);
/* ... and return it */
return slot;
}
return NULL;
}
/* ----------------------------------------------------------------
* ExecInitRecursiveUnionScan
* ----------------------------------------------------------------
*/
RecursiveUnionState *
ExecInitRecursiveUnion(RecursiveUnion *node, EState *estate, int eflags)
{
RecursiveUnionState *rustate;
ParamExecData *prmdata;
/* check for unsupported flags */
Assert(!(eflags & (EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK)));
/*
* create state structure
*/
rustate = makeNode(RecursiveUnionState);
rustate->ps.plan = (Plan *) node;
rustate->ps.state = estate;
rustate->eqfunctions = NULL;
rustate->hashfunctions = NULL;
rustate->hashtable = NULL;
rustate->tempContext = NULL;
rustate->tableContext = NULL;
/* initialize processing state */
rustate->recursing = false;
rustate->intermediate_empty = true;
rustate->working_table = tuplestore_begin_heap(false, false, work_mem);
rustate->intermediate_table = tuplestore_begin_heap(false, false, work_mem);
/*
* If hashing, we need a per-tuple memory context for comparisons, and a
* longer-lived context to store the hash table. The table can't just be
* kept in the per-query context because we want to be able to throw it
* away when rescanning.
*/
if (node->numCols > 0)
{
rustate->tempContext =
AllocSetContextCreate(CurrentMemoryContext,
"RecursiveUnion",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
rustate->tableContext =
AllocSetContextCreate(CurrentMemoryContext,
"RecursiveUnion hash table",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
}
/*
* Make the state structure available to descendant WorkTableScan nodes
* via the Param slot reserved for it.
*/
prmdata = &(estate->es_param_exec_vals[node->wtParam]);
Assert(prmdata->execPlan == NULL);
prmdata->value = PointerGetDatum(rustate);
prmdata->isnull = false;
/*
* Miscellaneous initialization
*
* RecursiveUnion plans don't have expression contexts because they never
* call ExecQual or ExecProject.
*/
Assert(node->plan.qual == NIL);
/*
* RecursiveUnion nodes still have Result slots, which hold pointers to
* tuples, so we have to initialize them.
*/
ExecInitResultTupleSlot(estate, &rustate->ps);
/*
* Initialize result tuple type and projection info. (Note: we have to
* set up the result type before initializing child nodes, because
* nodeWorktablescan.c expects it to be valid.)
*/
ExecAssignResultTypeFromTL(&rustate->ps);
rustate->ps.ps_ProjInfo = NULL;
/*
* initialize child nodes
*/
outerPlanState(rustate) = ExecInitNode(outerPlan(node), estate, eflags);
innerPlanState(rustate) = ExecInitNode(innerPlan(node), estate, eflags);
/*
* If hashing, precompute fmgr lookup data for inner loop, and create the
* hash table.
*/
if (node->numCols > 0)
{
execTuplesHashPrepare(node->numCols,
node->dupOperators,
&rustate->eqfunctions,
&rustate->hashfunctions);
build_hash_table(rustate);
}
return rustate;
}
/* ----------------------------------------------------------------
* ExecNestLoop(node)
*
* old comments
* Returns the tuple joined from inner and outer tuples which
* satisfies the qualification clause.
*
* It scans the inner relation to join with current outer tuple.
*
* If none is found, next tuple from the outer relation is retrieved
* and the inner relation is scanned from the beginning again to join
* with the outer tuple.
*
* NULL is returned if all the remaining outer tuples are tried and
* all fail to join with the inner tuples.
*
* NULL is also returned if there is no tuple from inner relation.
*
* Conditions:
* -- outerTuple contains current tuple from outer relation and
* the right son(inner relation) maintains "cursor" at the tuple
* returned previously.
* This is achieved by maintaining a scan position on the outer
* relation.
*
* Initial States:
* -- the outer child and the inner child
* are prepared to return the first tuple.
* ----------------------------------------------------------------
*/
TupleTableSlot *
ExecNestLoop(NestLoopState *node)
{
PlanState *innerPlan;
PlanState *outerPlan;
TupleTableSlot *outerTupleSlot;
TupleTableSlot *innerTupleSlot;
List *joinqual;
List *otherqual;
ExprContext *econtext;
/*
* get information from the node
*/
ENL1_printf("getting info from node");
joinqual = node->js.joinqual;
otherqual = node->js.ps.qual;
outerPlan = outerPlanState(node);
innerPlan = innerPlanState(node);
econtext = node->js.ps.ps_ExprContext;
/*
* get the current outer tuple
*/
outerTupleSlot = node->js.ps.ps_OuterTupleSlot;
econtext->ecxt_outertuple = outerTupleSlot;
/*
* Check to see if we're still projecting out tuples from a previous join
* tuple (because there is a function-returning-set in the projection
* expressions). If so, try to project another one.
*/
if (node->js.ps.ps_TupFromTlist)
{
TupleTableSlot *result;
ExprDoneCond isDone;
result = ExecProject(node->js.ps.ps_ProjInfo, &isDone);
if (isDone == ExprMultipleResult)
return result;
/* Done with that source tuple... */
node->js.ps.ps_TupFromTlist = false;
}
/*
* If we're doing an IN join, we want to return at most one row per outer
* tuple; so we can stop scanning the inner scan if we matched on the
* previous try.
*/
if (node->js.jointype == JOIN_IN &&
node->nl_MatchedOuter)
node->nl_NeedNewOuter = true;
/*
* Reset per-tuple memory context to free any expression evaluation
* storage allocated in the previous tuple cycle. Note this can't happen
* until we're done projecting out tuples from a join tuple.
*/
ResetExprContext(econtext);
/*
* Ok, everything is setup for the join so now loop until we return a
* qualifying join tuple.
*/
ENL1_printf("entering main loop");
for (;;)
{
/*
* If we don't have an outer tuple, get the next one and reset the
* inner scan.
*/
if (node->nl_NeedNewOuter)
{
ENL1_printf("getting new outer tuple");
outerTupleSlot = ExecProcNode(outerPlan);
/*
* if there are no more outer tuples, then the join is complete..
*/
if (TupIsNull(outerTupleSlot))
{
ENL1_printf("no outer tuple, ending join");
return NULL;
}
ENL1_printf("saving new outer tuple information");
node->js.ps.ps_OuterTupleSlot = outerTupleSlot;
econtext->ecxt_outertuple = outerTupleSlot;
node->nl_NeedNewOuter = false;
node->nl_MatchedOuter = false;
/*
* now rescan the inner plan
*/
ENL1_printf("rescanning inner plan");
/*
* The scan key of the inner plan might depend on the current
* outer tuple (e.g. in index scans), that's why we pass our expr
* context.
*/
ExecReScan(innerPlan, econtext);
}
/*
* we have an outerTuple, try to get the next inner tuple.
*/
ENL1_printf("getting new inner tuple");
innerTupleSlot = ExecProcNode(innerPlan);
econtext->ecxt_innertuple = innerTupleSlot;
if (TupIsNull(innerTupleSlot))
{
ENL1_printf("no inner tuple, need new outer tuple");
node->nl_NeedNewOuter = true;
if (!node->nl_MatchedOuter &&
node->js.jointype == JOIN_LEFT)
{
/*
* We are doing an outer join and there were no join matches
* for this outer tuple. Generate a fake join tuple with
* nulls for the inner tuple, and return it if it passes the
* non-join quals.
*/
econtext->ecxt_innertuple = node->nl_NullInnerTupleSlot;
ENL1_printf("testing qualification for outer-join tuple");
if (ExecQual(otherqual, econtext, false))
{
/*
* qualification was satisfied so we project and return
* the slot containing the result tuple using
* ExecProject().
*/
TupleTableSlot *result;
ExprDoneCond isDone;
ENL1_printf("qualification succeeded, projecting tuple");
result = ExecProject(node->js.ps.ps_ProjInfo, &isDone);
if (isDone != ExprEndResult)
{
node->js.ps.ps_TupFromTlist =
(isDone == ExprMultipleResult);
return result;
}
}
}
/*
* Otherwise just return to top of loop for a new outer tuple.
*/
continue;
}
/*
* at this point we have a new pair of inner and outer tuples so we
* test the inner and outer tuples to see if they satisfy the node's
* qualification.
*
* Only the joinquals determine MatchedOuter status, but all quals
* must pass to actually return the tuple.
*/
ENL1_printf("testing qualification");
if (ExecQual(joinqual, econtext, false))
{
node->nl_MatchedOuter = true;
if (otherqual == NIL || ExecQual(otherqual, econtext, false))
{
/*
* qualification was satisfied so we project and return the
* slot containing the result tuple using ExecProject().
*/
TupleTableSlot *result;
ExprDoneCond isDone;
ENL1_printf("qualification succeeded, projecting tuple");
result = ExecProject(node->js.ps.ps_ProjInfo, &isDone);
if (isDone != ExprEndResult)
{
node->js.ps.ps_TupFromTlist =
(isDone == ExprMultipleResult);
return result;
}
}
/* If we didn't return a tuple, may need to set NeedNewOuter */
if (node->js.jointype == JOIN_IN)
node->nl_NeedNewOuter = true;
}
/*
* Tuple fails qual, so free per-tuple memory and try again.
*/
ResetExprContext(econtext);
ENL1_printf("qualification failed, looping");
}
}
/* ----------------------------------------------------------------
* ExecInitNestLoop
* ----------------------------------------------------------------
*/
NestLoopState *
ExecInitNestLoop(NestLoop *node, EState *estate, int eflags)
{
NestLoopState *nlstate;
/* check for unsupported flags */
Assert(!(eflags & (EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK)));
NL1_printf("ExecInitNestLoop: %s\n",
"initializing node");
/*
* create state structure
*/
nlstate = makeNode(NestLoopState);
nlstate->js.ps.plan = (Plan *) node;
nlstate->js.ps.state = estate;
/*
* Miscellaneous initialization
*
* create expression context for node
*/
ExecAssignExprContext(estate, &nlstate->js.ps);
/*
* initialize child expressions
*/
nlstate->js.ps.targetlist = (List *)
ExecInitExpr((Expr *) node->join.plan.targetlist,
(PlanState *) nlstate);
nlstate->js.ps.qual = (List *)
ExecInitExpr((Expr *) node->join.plan.qual,
(PlanState *) nlstate);
nlstate->js.jointype = node->join.jointype;
nlstate->js.joinqual = (List *)
ExecInitExpr((Expr *) node->join.joinqual,
(PlanState *) nlstate);
/*
* initialize child nodes
*
* Tell the inner child that cheap rescans would be good. (This is
* unnecessary if we are doing nestloop with inner indexscan, because the
* rescan will always be with a fresh parameter --- but since
* nodeIndexscan doesn't actually care about REWIND, there's no point in
* dealing with that refinement.)
*/
outerPlanState(nlstate) = ExecInitNode(outerPlan(node), estate, eflags);
innerPlanState(nlstate) = ExecInitNode(innerPlan(node), estate,
eflags | EXEC_FLAG_REWIND);
#define NESTLOOP_NSLOTS 2
/*
* tuple table initialization
*/
ExecInitResultTupleSlot(estate, &nlstate->js.ps);
switch (node->join.jointype)
{
case JOIN_INNER:
case JOIN_IN:
break;
case JOIN_LEFT:
nlstate->nl_NullInnerTupleSlot =
ExecInitNullTupleSlot(estate,
ExecGetResultType(innerPlanState(nlstate)));
break;
default:
elog(ERROR, "unrecognized join type: %d",
(int) node->join.jointype);
}
/*
* initialize tuple type and projection info
*/
ExecAssignResultTypeFromTL(&nlstate->js.ps);
ExecAssignProjectionInfo(&nlstate->js.ps);
/*
* finally, wipe the current outer tuple clean.
*/
nlstate->js.ps.ps_OuterTupleSlot = NULL;
nlstate->js.ps.ps_TupFromTlist = false;
nlstate->nl_NeedNewOuter = true;
nlstate->nl_MatchedOuter = false;
NL1_printf("ExecInitNestLoop: %s\n",
"node initialized");
return nlstate;
}
/* ----------------------------------------------------------------
* ExecInitNestLoop
* ----------------------------------------------------------------
*/
NestLoopState *
ExecInitNestLoop(NestLoop *node, EState *estate)
{
NestLoopState *nlstate;
NL1_printf("ExecInitNestLoop: %s\n",
"initializing node");
/*
* create state structure
*/
nlstate = makeNode(NestLoopState);
nlstate->js.ps.plan = (Plan *) node;
nlstate->js.ps.state = estate;
/*
* Miscellaneous initialization
*
* create expression context for node
*/
ExecAssignExprContext(estate, &nlstate->js.ps);
/*
* initialize child expressions
*/
nlstate->js.ps.targetlist = (List *)
ExecInitExpr((Expr *) node->join.plan.targetlist,
(PlanState *) nlstate);
nlstate->js.ps.qual = (List *)
ExecInitExpr((Expr *) node->join.plan.qual,
(PlanState *) nlstate);
nlstate->js.jointype = node->join.jointype;
nlstate->js.joinqual = (List *)
ExecInitExpr((Expr *) node->join.joinqual,
(PlanState *) nlstate);
/*
* initialize child nodes
*/
outerPlanState(nlstate) = ExecInitNode(outerPlan(node), estate);
innerPlanState(nlstate) = ExecInitNode(innerPlan(node), estate);
#define NESTLOOP_NSLOTS 2
/*
* tuple table initialization
*/
ExecInitResultTupleSlot(estate, &nlstate->js.ps);
switch (node->join.jointype)
{
case JOIN_INNER:
case JOIN_IN:
break;
case JOIN_LEFT:
nlstate->nl_NullInnerTupleSlot =
ExecInitNullTupleSlot(estate,
ExecGetResultType(innerPlanState(nlstate)));
break;
default:
elog(ERROR, "unrecognized join type: %d",
(int) node->join.jointype);
}
/*
* initialize tuple type and projection info
*/
ExecAssignResultTypeFromTL(&nlstate->js.ps);
ExecAssignProjectionInfo(&nlstate->js.ps);
/*
* finally, wipe the current outer tuple clean.
*/
nlstate->js.ps.ps_OuterTupleSlot = NULL;
nlstate->js.ps.ps_TupFromTlist = false;
nlstate->nl_NeedNewOuter = true;
nlstate->nl_MatchedOuter = false;
NL1_printf("ExecInitNestLoop: %s\n",
"node initialized");
return nlstate;
}