*
* nodeMergejoin.cpp
* routines supporting merge joins
*
* 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/nodeMergejoin.cpp
*
* -------------------------------------------------------------------------
*
* INTERFACE ROUTINES
* ExecMergeJoin mergejoin outer and inner relations.
* ExecInitMergeJoin creates and initializes run time states
* ExecEndMergeJoin cleans up the node.
*
* NOTES
*
* Merge-join is done by joining the inner and outer tuples satisfying
* join clauses of the form ((= outerKey innerKey) ...).
* The join clause list is provided by the query planner and may contain
* more than one (= outerKey innerKey) clause (for composite sort key).
*
* However, the query executor needs to know whether an outer
* tuple is "greater/smaller" than an inner tuple so that it can
* "synchronize" the two relations. For example, consider the following
* relations:
*
* outer: (0 ^1 1 2 5 5 5 6 6 7) current tuple: 1
* inner: (1 ^3 5 5 5 5 6) current tuple: 3
*
* To continue the merge-join, the executor needs to scan both inner
* and outer relations till the matching tuples 5. It needs to know
* that currently inner tuple 3 is "greater" than outer tuple 1 and
* therefore it should scan the outer relation first to find a
* matching tuple and so on.
*
* Therefore, rather than directly executing the merge join clauses,
* we evaluate the left and right key expressions separately and then
* compare the columns one at a time (see MJCompare). The planner
* passes us enough information about the sort ordering of the inputs
* to allow us to determine how to make the comparison. We may use the
* appropriate btree comparison function, since Postgres' only notion
* of ordering is specified by btree opfamilies.
*
*
* Consider the above relations and suppose that the executor has
* just joined the first outer "5" with the last inner "5". The
* next step is of course to join the second outer "5" with all
* the inner "5's". This requires repositioning the inner "cursor"
* to point at the first inner "5". This is done by "marking" the
* first inner 5 so we can restore the "cursor" to it before joining
* with the second outer 5. The access method interface provides
* routines to mark and restore to a tuple.
*
*
* Essential operation of the merge join algorithm is as follows:
*
* Join {
* get initial outer and inner tuples INITIALIZE
* do forever {
* while (outer != inner) { SKIP_TEST
* if (outer < inner)
* advance outer SKIPOUTER_ADVANCE
* else
* advance inner SKIPINNER_ADVANCE
* }
* mark inner position SKIP_TEST
* do forever {
* while (outer == inner) {
* join tuples JOINTUPLES
* advance inner position NEXTINNER
* }
* advance outer position NEXTOUTER
* if (outer == mark) TESTOUTER
* restore inner position to mark TESTOUTER
* else
* break // return to top of outer loop
* }
* }
* }
*
* The merge join operation is coded in the fashion
* of a state machine. At each state, we do something and then
* proceed to another state. This state is stored in the node's
* execution state information and is preserved across calls to
* ExecMergeJoin. -cim 10/31/89
*/
#include "postgres.h"
#include "knl/knl_variable.h"
#include "access/nbtree.h"
#include "executor/exec/execdebug.h"
#include "executor/exec/execStream.h"
#include "executor/node/nodeMergejoin.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "executor/node/nodeHashjoin.h"
* Runtime data for each mergejoin clause
*/
typedef struct MergeJoinClauseData {
ExprState* lexpr;
ExprState* rexpr;
* If we have a current left or right input tuple, the values of the
* expressions are loaded into these fields:
*/
Datum ldatum;
Datum rdatum;
bool lisnull;
bool risnull;
* Everything we need to know to compare the left and right values is
* stored here.
*/
SortSupportData ssup;
} MergeJoinClauseData;
typedef enum {
MJEVAL_MATCHABLE,
MJEVAL_NONMATCHABLE,
MJEVAL_ENDOFJOIN
} MJEvalResult;
#define MarkInnerTuple(inner_tuple_slot, merge_state) ExecCopySlot((merge_state)->mj_MarkedTupleSlot, (inner_tuple_slot))
static TupleTableSlot* ExecMergeJoin(PlanState* state);
* MJExamineQuals
*
* This deconstructs the list of mergejoinable expressions, which is given
* to us by the planner in the form of a list of "leftexpr = rightexpr"
* expression trees in the order matching the sort columns of the inputs.
* We build an array of MergeJoinClause structs containing the information
* we will need at runtime. Each struct essentially tells us how to compare
* the two expressions from the original clause.
*
* In addition to the expressions themselves, the planner passes the btree
* opfamily OID, collation OID, btree strategy number (BTLessStrategyNumber or
* BTGreaterStrategyNumber), and nulls-first flag that identify the intended
* sort ordering for each merge key. The mergejoinable operator is an
* equality operator in the opfamily, and the two inputs are guaranteed to be
* ordered in either increasing or decreasing (respectively) order according
* to the opfamily and collation, with nulls at the indicated end of the range.
* This allows us to obtain the needed comparison function from the opfamily.
*/
static MergeJoinClause MJExamineQuals(List* mergeclauses, Oid* mergefamilies, Oid* mergecollations,
const int* mergestrategies, const bool* mergenullsfirst, PlanState* parent)
{
int nClauses = list_length(mergeclauses);
MergeJoinClause clauses = (MergeJoinClause)palloc0(nClauses * sizeof(MergeJoinClauseData));
int iClause = 0;
ListCell* cl = NULL;
foreach (cl, mergeclauses) {
OpExpr* qual = (OpExpr*)lfirst(cl);
MergeJoinClause clause = &clauses[iClause];
Oid opfamily = mergefamilies[iClause];
Oid collation = mergecollations[iClause];
StrategyNumber opstrategy = mergestrategies[iClause];
bool nulls_first = mergenullsfirst[iClause];
int op_strategy;
Oid op_lefttype;
Oid op_righttype;
Oid sortfunc;
if (!IsA(qual, OpExpr)) {
ereport(ERROR,
(errcode(ERRCODE_UNRECOGNIZED_NODE_TYPE),
errmsg("mergejoin clause is not an OpExpr %d", nodeTag(qual))));
}
* Prepare the input expressions for execution.
*/
clause->lexpr = ExecInitExpr((Expr*)linitial(qual->args), parent);
clause->rexpr = ExecInitExpr((Expr*)lsecond(qual->args), parent);
clause->ssup.ssup_cxt = CurrentMemoryContext;
clause->ssup.ssup_collation = collation;
if (opstrategy == BTLessStrategyNumber)
clause->ssup.ssup_reverse = false;
else if (opstrategy == BTGreaterStrategyNumber)
clause->ssup.ssup_reverse = true;
else
ereport(ERROR, (errcode(ERRCODE_DATA_CORRUPTED), errmsg("unsupported mergejoin strategy %d", opstrategy)));
clause->ssup.ssup_nulls_first = nulls_first;
get_op_opfamily_properties(qual->opno, opfamily, false, &op_strategy, &op_lefttype, &op_righttype);
if (op_strategy != BTEqualStrategyNumber)
ereport(ERROR,
(errcode(ERRCODE_DATA_CORRUPTED),
errmsg("cannot merge using non-equality operator %u, strategy is %d", qual->opno, op_strategy)));
* sortsupport routine must know if abbreviation optimization is
* applicable in principle. It is never applicable for merge joins
* because there is no convenient opportunity to convert to alternative
* representation.
*/
clause->ssup.abbreviate = false;
sortfunc = get_opfamily_proc(opfamily, op_lefttype, op_righttype, BTSORTSUPPORT_PROC);
if (OidIsValid(sortfunc)) {
OidFunctionCall1(sortfunc, PointerGetDatum(&clause->ssup));
Assert(clause->ssup.comparator != NULL);
} else {
sortfunc = get_opfamily_proc(opfamily, op_lefttype, op_righttype, BTORDER_PROC);
if (!OidIsValid(sortfunc))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("missing support function %d(%u,%u) in opfamily %u",
BTORDER_PROC,
op_lefttype,
op_righttype,
opfamily)));
PrepareSortSupportComparisonShim(sortfunc, &clause->ssup);
}
iClause++;
}
return clauses;
}
* MJEvalOuterValues
*
* Compute the values of the mergejoined expressions for the current
* outer tuple. We also detect whether it's impossible for the current
* outer tuple to match anything --- this is true if it yields a NULL
* input, since we assume mergejoin operators are strict. If the NULL
* is in the first join column, and that column sorts nulls last, then
* we can further conclude that no following tuple can match anything
* either, since they must all have nulls in the first column. However,
* that case is only interesting if we're not in FillOuter mode, else
* we have to visit all the tuples anyway.
*
* For the convenience of callers, we also make this routine responsible
* for testing for end-of-input (null outer tuple), and returning
* MJEVAL_ENDOFJOIN when that's seen. This allows the same code to be used
* for both real end-of-input and the effective end-of-input represented by
* a first-column NULL.
*
* We evaluate the values in OuterEContext, which can be reset each
* time we move to a new tuple.
*/
static MJEvalResult MJEvalOuterValues(MergeJoinState* merge_state)
{
ExprContext* econtext = merge_state->mj_OuterEContext;
MJEvalResult result = MJEVAL_MATCHABLE;
int i;
MemoryContext old_context;
if (TupIsNull(merge_state->mj_OuterTupleSlot))
return MJEVAL_ENDOFJOIN;
ResetExprContext(econtext);
old_context = MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
econtext->ecxt_outertuple = merge_state->mj_OuterTupleSlot;
for (i = 0; i < merge_state->mj_NumClauses; i++) {
MergeJoinClause clause = &merge_state->mj_Clauses[i];
clause->ldatum = ExecEvalExpr(clause->lexpr, econtext, &clause->lisnull, NULL);
if (clause->lisnull && merge_state->js.nulleqqual == NIL) {
if (i == 0 && !clause->ssup.ssup_nulls_first && !merge_state->mj_FillOuter)
result = MJEVAL_ENDOFJOIN;
else if (result == MJEVAL_MATCHABLE)
result = MJEVAL_NONMATCHABLE;
}
}
MemoryContextSwitchTo(old_context);
return result;
}
* MJEvalInnerValues
*
* Same as above, but for the inner tuple. Here, we have to be prepared
* to load data from either the true current inner, or the marked inner,
* so caller must tell us which slot to load from.
*/
static MJEvalResult MJEvalInnerValues(MergeJoinState* merge_state, TupleTableSlot* inner_slot)
{
ExprContext* econtext = merge_state->mj_InnerEContext;
MJEvalResult result = MJEVAL_MATCHABLE;
int i;
MemoryContext old_context;
if (TupIsNull(inner_slot))
return MJEVAL_ENDOFJOIN;
ResetExprContext(econtext);
old_context = MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
econtext->ecxt_innertuple = inner_slot;
for (i = 0; i < merge_state->mj_NumClauses; i++) {
MergeJoinClause clause = &merge_state->mj_Clauses[i];
clause->rdatum = ExecEvalExpr(clause->rexpr, econtext, &clause->risnull, NULL);
if (clause->risnull && merge_state->js.nulleqqual == NIL) {
if (i == 0 && !clause->ssup.ssup_nulls_first && !merge_state->mj_FillInner)
result = MJEVAL_ENDOFJOIN;
else if (result == MJEVAL_MATCHABLE)
result = MJEVAL_NONMATCHABLE;
}
}
MemoryContextSwitchTo(old_context);
return result;
}
* MJCompare
*
* Compare the mergejoinable values of the current two input tuples
* and return 0 if they are equal (ie, the mergejoin equalities all
* succeed), >0 if outer > inner, <0 if outer < inner.
*
* MJEvalOuterValues and MJEvalInnerValues must already have been called
* for the current outer and inner tuples, respectively.
*/
static int MJCompare(MergeJoinState* merge_state)
{
int result = 0;
bool null_eq_null = false;
ExprContext* econtext = merge_state->js.ps.ps_ExprContext;
int i;
MemoryContext old_context;
* Call the comparison functions in short-lived context, in case they leak
* memory.
*/
ResetExprContext(econtext);
old_context = MemoryContextSwitchTo(econtext->ecxt_per_tuple_memory);
for (i = 0; i < merge_state->mj_NumClauses; i++) {
MergeJoinClause clause = &merge_state->mj_Clauses[i];
* Special case for NULL-vs-NULL, else use standard comparison.
*/
if (clause->lisnull && clause->risnull) {
null_eq_null = true;
continue;
}
result = ApplySortComparator(clause->ldatum, clause->lisnull, clause->rdatum, clause->risnull, &clause->ssup);
if (result != 0)
break;
}
* If we had any NULL-vs-NULL inputs, we do not want to report that the
* tuples are equal. Instead, if result is still 0, change it to +1. This
* will result in advancing the inner side of the join.
*
* Likewise, if there was a constant-false join_qual, do not report
* equality. We have to check this as part of the mergequals, else the
* rescan logic will do the wrong thing.
*/
if (result == 0 && ((null_eq_null && merge_state->js.nulleqqual == NIL) || merge_state->mj_ConstFalseJoin))
result = 1;
MemoryContextSwitchTo(old_context);
return result;
}
* Generate a fake join tuple with nulls for the inner tuple,
* and return it if it passes the non-join quals.
*/
static TupleTableSlot* MJFillOuter(MergeJoinState* node)
{
ExprContext* econtext = node->js.ps.ps_ExprContext;
List* other_qual = node->js.ps.qual;
ResetExprContext(econtext);
econtext->ecxt_outertuple = node->mj_OuterTupleSlot;
econtext->ecxt_innertuple = node->mj_NullInnerTupleSlot;
if (ExecQual(other_qual, econtext, false)) {
* qualification succeeded. now form the desired projection tuple and
* return the slot containing it.
*/
ExprDoneCond isDone;
MJ_printf("ExecMergeJoin: returning outer fill tuple\n");
TupleTableSlot* result = ExecProject(node->js.ps.ps_ProjInfo, &isDone);
if (isDone != ExprEndResult) {
node->js.ps.ps_vec_TupFromTlist = (isDone == ExprMultipleResult);
return result;
}
} else
InstrCountFiltered2(node, 1);
return NULL;
}
* Generate a fake join tuple with nulls for the outer tuple,
* and return it if it passes the non-join quals.
*/
static TupleTableSlot* MJFillInner(MergeJoinState* node)
{
ExprContext* econtext = node->js.ps.ps_ExprContext;
List* other_qual = node->js.ps.qual;
ResetExprContext(econtext);
econtext->ecxt_outertuple = node->mj_NullOuterTupleSlot;
econtext->ecxt_innertuple = node->mj_InnerTupleSlot;
if (ExecQual(other_qual, econtext, false)) {
* qualification succeeded. now form the desired projection tuple and
* return the slot containing it.
*/
ExprDoneCond isDone;
MJ_printf("ExecMergeJoin: returning inner fill tuple\n");
TupleTableSlot* result = ExecProject(node->js.ps.ps_ProjInfo, &isDone);
if (isDone != ExprEndResult) {
node->js.ps.ps_vec_TupFromTlist = (isDone == ExprMultipleResult);
return result;
}
} else
InstrCountFiltered2(node, 1);
return NULL;
}
* Check that a qual condition is constant true or constant false.
* If it is constant false (or null), set *is_const_false to TRUE.
*
* Constant true would normally be represented by a NIL list, but we allow an
* actual bool Const as well. We do expect that the planner will have thrown
* away any non-constant terms that have been ANDed with a constant false.
*/
bool check_constant_qual(List* qual, bool* is_const_false)
{
ListCell* lc = NULL;
foreach (lc, qual) {
Const* con = (Const*)lfirst(lc);
if (con == NULL || !IsA(con, Const))
return false;
if (con->constisnull || !DatumGetBool(con->constvalue))
*is_const_false = true;
}
return true;
}
* ExecMergeTupleDump
*
* This function is called through the MJ_dump() macro
* when EXEC_MERGEJOINDEBUG is defined
* ----------------------------------------------------------------
*/
#ifdef EXEC_MERGEJOINDEBUG
static void ExecMergeTupleDumpOuter(MergeJoinState* merge_state)
{
TupleTableSlot* outerSlot = merge_state->mj_OuterTupleSlot;
printf("==== outer tuple ====\n");
if (TupIsNull(outerSlot))
printf("(nil)\n");
else
MJ_debugtup(outerSlot);
}
static void ExecMergeTupleDumpInner(MergeJoinState* merge_state)
{
TupleTableSlot* innerSlot = merge_state->mj_InnerTupleSlot;
printf("==== inner tuple ====\n");
if (TupIsNull(innerSlot))
printf("(nil)\n");
else
MJ_debugtup(innerSlot);
}
static void ExecMergeTupleDumpMarked(MergeJoinState* merge_state)
{
TupleTableSlot* marked_slot = merge_state->mj_MarkedTupleSlot;
printf("==== marked tuple ====\n");
if (TupIsNull(marked_slot))
printf("(nil)\n");
else
MJ_debugtup(marked_slot);
}
static void ExecMergeTupleDump(MergeJoinState* merge_state)
{
printf("******** ExecMergeTupleDump ********\n");
ExecMergeTupleDumpOuter(merge_state);
ExecMergeTupleDumpInner(merge_state);
ExecMergeTupleDumpMarked(merge_state);
printf("******** \n");
}
#endif
* ExecMergeJoin
* ----------------------------------------------------------------
*/
static TupleTableSlot* ExecMergeJoin(PlanState* state)
{
MergeJoinState* node = castNode(MergeJoinState, state);
bool qual_result = false;
int compare_result;
TupleTableSlot* inner_tuple_slot = NULL;
TupleTableSlot* outer_tuple_slot = NULL;
ExprDoneCond isDone;
CHECK_FOR_INTERRUPTS();
* get information from node
*/
PlanState* inner_plan = innerPlanState(node);
PlanState* outer_plan = outerPlanState(node);
ExprContext* econtext = node->js.ps.ps_ExprContext;
List* join_qual = node->js.joinqual;
List* other_qual = node->js.ps.qual;
bool do_fill_outer = node->mj_FillOuter;
bool do_fill_inner = node->mj_FillInner;
* 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_vec_TupFromTlist) {
TupleTableSlot* result = NULL;
result = ExecProject(node->js.ps.ps_ProjInfo, &isDone);
if (isDone == ExprMultipleResult)
return result;
node->js.ps.ps_vec_TupFromTlist = false;
}
* 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.. let's go to work
*/
for (;;) {
MJ_dump(node);
* get the current state of the join and do things accordingly.
*/
switch (node->mj_JoinState) {
* EXEC_MJ_INITIALIZE_OUTER means that this is the first time
* ExecMergeJoin() has been called and so we have to fetch the
* first matchable tuple for both outer and inner subplans. We
* do the outer side in INITIALIZE_OUTER state, then advance
* to INITIALIZE_INNER state for the inner subplan.
*/
case EXEC_MJ_INITIALIZE_OUTER:
MJ_printf("ExecMergeJoin: EXEC_MJ_INITIALIZE_OUTER\n");
outer_tuple_slot = ExecProcNode(outer_plan);
node->mj_OuterTupleSlot = outer_tuple_slot;
switch (MJEvalOuterValues(node)) {
case MJEVAL_MATCHABLE:
node->mj_JoinState = EXEC_MJ_INITIALIZE_INNER;
break;
case MJEVAL_NONMATCHABLE:
if (do_fill_outer) {
* Generate a fake join tuple with nulls for the
* inner tuple, and return it if it passes the
* non-join quals.
*/
TupleTableSlot* result = NULL;
result = MJFillOuter(node);
if (result != NULL)
return result;
}
break;
case MJEVAL_ENDOFJOIN:
MJ_printf("ExecMergeJoin: nothing in outer subplan\n");
if (do_fill_inner) {
* Need to emit right-join tuples for remaining
* inner tuples. We set MatchedInner = true to
* force the ENDOUTER state to advance inner.
*/
node->mj_JoinState = EXEC_MJ_ENDOUTER;
node->mj_MatchedInner = true;
break;
}
* If one side of MergeJoin returns 0 tuple and no need to
* generate a fake join tuple with nulls, we should deinit
* the consumer under MergeJoin earlier.
* It should be noticed that we can not do early deinit
* within predpush.
*/
if (((PlanState*)node) != NULL && !CheckParamWalker((PlanState*)node)) {
ExecEarlyDeinitConsumer((PlanState*)node);
}
goto done;
default:
break;
}
break;
case EXEC_MJ_INITIALIZE_INNER:
MJ_printf("ExecMergeJoin: EXEC_MJ_INITIALIZE_INNER\n");
inner_tuple_slot = ExecProcNode(inner_plan);
node->mj_InnerTupleSlot = inner_tuple_slot;
switch (MJEvalInnerValues(node, inner_tuple_slot)) {
case MJEVAL_MATCHABLE:
* OK, we have the initial tuples. Begin by skipping
* non-matching tuples.
*/
node->mj_JoinState = EXEC_MJ_SKIP_TEST;
break;
case MJEVAL_NONMATCHABLE:
if (node->mj_ExtraMarks)
ExecMarkPos(inner_plan);
if (do_fill_inner) {
* Generate a fake join tuple with nulls for the
* outer tuple, and return it if it passes the
* non-join quals.
*/
TupleTableSlot* result = NULL;
result = MJFillInner(node);
if (result != NULL)
return result;
}
break;
case MJEVAL_ENDOFJOIN:
MJ_printf("ExecMergeJoin: nothing in inner subplan\n");
if (do_fill_outer) {
* Need to emit left-join tuples for all outer
* tuples, including the one we just fetched. We
* set MatchedOuter = false to force the ENDINNER
* state to emit first tuple before advancing
* outer.
*/
node->mj_JoinState = EXEC_MJ_ENDINNER;
node->mj_MatchedOuter = false;
break;
}
* If one side of MergeJoin returns 0 tuple and no need to
* generate a fake join tuple with nulls, we should deinit
* the consumer under MergeJoin earlier.
* It should be noticed that we can not do early deinit
* within predpush.
*/
if (((PlanState*)node) != NULL && !CheckParamWalker((PlanState*)node)) {
ExecEarlyDeinitConsumer((PlanState*)node);
}
goto done;
default:
break;
}
break;
* EXEC_MJ_JOINTUPLES means we have two tuples which satisfied
* the merge clause so we join them and then proceed to get
* the next inner tuple (EXEC_MJ_NEXTINNER).
*/
case EXEC_MJ_JOINTUPLES:
MJ_printf("ExecMergeJoin: EXEC_MJ_JOINTUPLES\n");
* Set the next state machine state. The right things will
* happen whether we return this join tuple or just fall
* through to continue the state machine execution.
*/
node->mj_JoinState = EXEC_MJ_NEXTINNER;
* Check the extra qual conditions to see if we actually want
* to return this join tuple. If not, can proceed with merge.
* We must distinguish the additional joinquals (which must
* pass to consider the tuples "matched" for outer-join logic)
* from the otherquals (which must pass before we actually
* return the tuple).
*
* We don't bother with a ResetExprContext here, on the
* assumption that we just did one while checking the merge
* qual. One per tuple should be sufficient. We do have to
* set up the econtext links to the tuples for ExecQual to
* use.
*/
outer_tuple_slot = node->mj_OuterTupleSlot;
econtext->ecxt_outertuple = outer_tuple_slot;
inner_tuple_slot = node->mj_InnerTupleSlot;
econtext->ecxt_innertuple = inner_tuple_slot;
qual_result = (join_qual == NIL || ExecQual(join_qual, econtext));
MJ_DEBUG_QUAL(join_qual, qual_result);
if (qual_result) {
node->mj_MatchedOuter = true;
node->mj_MatchedInner = true;
* JOIN_RIGHT_ANTI_FULL can not create mergejoin plain,
* so we do not consider it here. */
if (node->js.jointype == JOIN_ANTI || node->js.jointype == JOIN_LEFT_ANTI_FULL) {
node->mj_JoinState = EXEC_MJ_NEXTOUTER;
break;
}
if (node->js.single_match) {
node->mj_JoinState = EXEC_MJ_NEXTOUTER;
}
qual_result = (other_qual == NIL || ExecQual(other_qual, econtext));
MJ_DEBUG_QUAL(other_qual, qual_result);
if (qual_result) {
* qualification succeeded. now form the desired
* projection tuple and return the slot containing it.
*/
ExprDoneCond isDone;
MJ_printf("ExecMergeJoin: returning tuple\n");
TupleTableSlot* result = ExecProject(node->js.ps.ps_ProjInfo, &isDone);
if (isDone != ExprEndResult) {
node->js.ps.ps_vec_TupFromTlist = (isDone == ExprMultipleResult);
return result;
}
} else
InstrCountFiltered2(node, 1);
} else
InstrCountFiltered1(node, 1);
break;
* EXEC_MJ_NEXTINNER means advance the inner scan to the next
* tuple. If the tuple is not nil, we then proceed to test it
* against the join qualification.
*
* Before advancing, we check to see if we must emit an
* outer-join fill tuple for this inner tuple.
*/
case EXEC_MJ_NEXTINNER:
MJ_printf("ExecMergeJoin: EXEC_MJ_NEXTINNER\n");
if (do_fill_inner && !node->mj_MatchedInner) {
* Generate a fake join tuple with nulls for the outer
* tuple, and return it if it passes the non-join quals.
*/
node->mj_MatchedInner = true;
TupleTableSlot* result = MJFillInner(node);
if (result != NULL)
return result;
}
* now we get the next inner tuple, if any. If there's none,
* advance to next outer tuple (which may be able to join to
* previously marked tuples).
*
* NB: must NOT do "extraMarks" here, since we may need to
* return to previously marked tuples.
*/
inner_tuple_slot = ExecProcNode(inner_plan);
node->mj_InnerTupleSlot = inner_tuple_slot;
MJ_DEBUG_PROC_NODE(inner_tuple_slot);
node->mj_MatchedInner = false;
switch (MJEvalInnerValues(node, inner_tuple_slot)) {
case MJEVAL_MATCHABLE:
* Test the new inner tuple to see if it matches
* outer.
*
* If they do match, then we join them and move on to
* the next inner tuple (EXEC_MJ_JOINTUPLES).
*
* If they do not match then advance to next outer
* tuple.
*/
compare_result = MJCompare(node);
MJ_DEBUG_COMPARE(compare_result);
if (compare_result == 0)
node->mj_JoinState = EXEC_MJ_JOINTUPLES;
else {
Assert(compare_result < 0);
node->mj_JoinState = EXEC_MJ_NEXTOUTER;
}
break;
case MJEVAL_NONMATCHABLE:
* It contains a NULL and hence can't match any outer
* tuple, so we can skip the comparison and assume the
* new tuple is greater than current outer.
*/
node->mj_JoinState = EXEC_MJ_NEXTOUTER;
break;
case MJEVAL_ENDOFJOIN:
* No more inner tuples. However, this might be only
* effective and not physical end of inner plan, so
* force mj_InnerTupleSlot to null to make sure we
* don't fetch more inner tuples. (We need this hack
* because we are not transiting to a state where the
* inner plan is assumed to be exhausted.)
*/
node->mj_InnerTupleSlot = NULL;
node->mj_JoinState = EXEC_MJ_NEXTOUTER;
break;
default:
break;
}
break;
* EXEC_MJ_NEXTOUTER means
*
* outer inner
* outer tuple - 5 5 - marked tuple
* 5 5
* 6 6 - inner tuple
* 7 7
*
* we know we just bumped into the
* first inner tuple > current outer tuple (or possibly
* the end of the inner stream)
* so get a new outer tuple and then
* proceed to test it against the marked tuple
* (EXEC_MJ_TESTOUTER)
*
* Before advancing, we check to see if we must emit an
* outer-join fill tuple for this outer tuple.
* ------------------------------------------------
*/
case EXEC_MJ_NEXTOUTER:
MJ_printf("ExecMergeJoin: EXEC_MJ_NEXTOUTER\n");
if (do_fill_outer && !node->mj_MatchedOuter) {
* Generate a fake join tuple with nulls for the inner
* tuple, and return it if it passes the non-join quals.
*/
node->mj_MatchedOuter = true;
TupleTableSlot* result = MJFillOuter(node);
if (result != NULL)
return result;
}
* now we get the next outer tuple, if any
*/
outer_tuple_slot = ExecProcNode(outer_plan);
node->mj_OuterTupleSlot = outer_tuple_slot;
MJ_DEBUG_PROC_NODE(outer_tuple_slot);
node->mj_MatchedOuter = false;
switch (MJEvalOuterValues(node)) {
case MJEVAL_MATCHABLE:
node->mj_JoinState = EXEC_MJ_TESTOUTER;
break;
case MJEVAL_NONMATCHABLE:
node->mj_JoinState = EXEC_MJ_NEXTOUTER;
break;
case MJEVAL_ENDOFJOIN:
MJ_printf("ExecMergeJoin: end of outer subplan\n");
inner_tuple_slot = node->mj_InnerTupleSlot;
if (do_fill_inner && !TupIsNull(inner_tuple_slot)) {
* Need to emit right-join tuples for remaining
* inner tuples.
*/
node->mj_JoinState = EXEC_MJ_ENDOUTER;
break;
}
goto done;
default:
break;
}
break;
* EXEC_MJ_TESTOUTER If the new outer tuple and the marked
* tuple satisfy the merge clause then we know we have
* duplicates in the outer scan so we have to restore the
* inner scan to the marked tuple and proceed to join the
* new outer tuple with the inner tuples.
*
* This is the case when
* outer inner
* 4 5 - marked tuple
* outer tuple - 5 5
* new outer tuple - 5 5
* 6 8 - inner tuple
* 7 12
*
* new outer tuple == marked tuple
*
* If the outer tuple fails the test, then we are done
* with the marked tuples, and we have to look for a
* match to the current inner tuple. So we will
* proceed to skip outer tuples until outer >= inner
* (EXEC_MJ_SKIP_TEST).
*
* This is the case when
*
* outer inner
* 5 5 - marked tuple
* outer tuple - 5 5
* new outer tuple - 6 8 - inner tuple
* 7 12
*
* new outer tuple > marked tuple
*
* ---------------------------------------------------------
*/
case EXEC_MJ_TESTOUTER:
MJ_printf("ExecMergeJoin: EXEC_MJ_TESTOUTER\n");
* Here we must compare the outer tuple with the marked inner
* tuple. (We can ignore the result of MJEvalInnerValues,
* since the marked inner tuple is certainly matchable.)
*/
inner_tuple_slot = node->mj_MarkedTupleSlot;
(void)MJEvalInnerValues(node, inner_tuple_slot);
compare_result = MJCompare(node);
MJ_DEBUG_COMPARE(compare_result);
if (compare_result == 0) {
* the merge clause matched so now we restore the inner
* scan position to the first mark, and go join that tuple
* (and any following ones) to the new outer.
*
* NOTE: we do not need to worry about the MatchedInner
* state for the rescanned inner tuples. We know all of
* them will match this new outer tuple and therefore
* won't be emitted as fill tuples. This works *only*
* because we require the extra joinquals to be constant
* when doing a right or full join --- otherwise some of
* the rescanned tuples might fail the extra joinquals.
* This obviously won't happen for a constant-true extra
* join_qual, while the constant-false case is handled by
* forcing the merge clause to never match, so we never
* get here.
*/
if (!node->mj_SkipMarkRestore) {
ExecRestrPos(inner_plan);
node->mj_InnerTupleSlot = inner_tuple_slot;
}
node->mj_JoinState = EXEC_MJ_JOINTUPLES;
} else {
* if the new outer tuple didn't match the marked inner
* tuple then we have a case like:
*
* outer inner
* 4 4 - marked tuple
* new outer - 5 4
* 6 5 - inner tuple
* 7
*
* which means that all subsequent outer tuples will be
* larger than our marked inner tuples. So we need not
* revisit any of the marked tuples but can proceed to
* look for a match to the current inner. If there's
* no more inners, no more matches are possible.
* ----------------
*/
Assert(compare_result > 0);
inner_tuple_slot = node->mj_InnerTupleSlot;
switch (MJEvalInnerValues(node, inner_tuple_slot)) {
case MJEVAL_MATCHABLE:
node->mj_JoinState = EXEC_MJ_SKIP_TEST;
break;
case MJEVAL_NONMATCHABLE:
* current inner can't possibly match any outer;
* better to advance the inner scan than the
* outer.
*/
node->mj_JoinState = EXEC_MJ_SKIPINNER_ADVANCE;
break;
case MJEVAL_ENDOFJOIN:
if (do_fill_outer) {
* Need to emit left-join tuples for remaining
* outer tuples.
*/
node->mj_JoinState = EXEC_MJ_ENDINNER;
break;
}
goto done;
default:
break;
}
}
break;
* EXEC_MJ_SKIP means compare tuples and if they do not
* match, skip whichever is lesser.
*
* For example:
*
* outer inner
* 5 5
* 5 5
* outer tuple - 6 8 - inner tuple
* 7 12
* 8 14
*
* we have to advance the outer scan
* until we find the outer 8.
*
* On the other hand:
*
* outer inner
* 5 5
* 5 5
* outer tuple - 12 8 - inner tuple
* 14 10
* 17 12
*
* we have to advance the inner scan
* until we find the inner 12.
* ----------------------------------------------------------
*/
case EXEC_MJ_SKIP_TEST:
MJ_printf("ExecMergeJoin: EXEC_MJ_SKIP_TEST\n");
* before we advance, make sure the current tuples do not
* satisfy the merge_clauses. If they do, then we update the
* marked tuple position and go join them.
*/
compare_result = MJCompare(node);
MJ_DEBUG_COMPARE(compare_result);
if (compare_result == 0) {
if (!node->mj_SkipMarkRestore) {
ExecMarkPos(inner_plan);
}
if (node->mj_InnerTupleSlot == NULL) {
ereport(ERROR,
(errcode(ERRCODE_UNEXPECTED_NULL_VALUE),
errmsg("mj_InnerTupleSlot cannot be NULL")));
}
MarkInnerTuple(node->mj_InnerTupleSlot, node);
node->mj_JoinState = EXEC_MJ_JOINTUPLES;
} else if (compare_result < 0)
node->mj_JoinState = EXEC_MJ_SKIPOUTER_ADVANCE;
else
node->mj_JoinState = EXEC_MJ_SKIPINNER_ADVANCE;
break;
* SKIPOUTER_ADVANCE: advance over an outer tuple that is
* known not to join to any inner tuple.
*
* Before advancing, we check to see if we must emit an
* outer-join fill tuple for this outer tuple.
*/
case EXEC_MJ_SKIPOUTER_ADVANCE:
MJ_printf("ExecMergeJoin: EXEC_MJ_SKIPOUTER_ADVANCE\n");
if (do_fill_outer && !node->mj_MatchedOuter) {
* Generate a fake join tuple with nulls for the inner
* tuple, and return it if it passes the non-join quals.
*/
node->mj_MatchedOuter = true;
TupleTableSlot* result = MJFillOuter(node);
if (result != NULL)
return result;
}
* now we get the next outer tuple, if any
*/
outer_tuple_slot = ExecProcNode(outer_plan);
node->mj_OuterTupleSlot = outer_tuple_slot;
MJ_DEBUG_PROC_NODE(outer_tuple_slot);
node->mj_MatchedOuter = false;
switch (MJEvalOuterValues(node)) {
case MJEVAL_MATCHABLE:
node->mj_JoinState = EXEC_MJ_SKIP_TEST;
break;
case MJEVAL_NONMATCHABLE:
node->mj_JoinState = EXEC_MJ_SKIPOUTER_ADVANCE;
break;
case MJEVAL_ENDOFJOIN:
MJ_printf("ExecMergeJoin: end of outer subplan\n");
inner_tuple_slot = node->mj_InnerTupleSlot;
if (do_fill_inner && !TupIsNull(inner_tuple_slot)) {
* Need to emit right-join tuples for remaining
* inner tuples.
*/
node->mj_JoinState = EXEC_MJ_ENDOUTER;
break;
}
goto done;
default:
break;
}
break;
* SKIPINNER_ADVANCE: advance over an inner tuple that is
* known not to join to any outer tuple.
*
* Before advancing, we check to see if we must emit an
* outer-join fill tuple for this inner tuple.
*/
case EXEC_MJ_SKIPINNER_ADVANCE:
MJ_printf("ExecMergeJoin: EXEC_MJ_SKIPINNER_ADVANCE\n");
if (do_fill_inner && !node->mj_MatchedInner) {
* Generate a fake join tuple with nulls for the outer
* tuple, and return it if it passes the non-join quals.
*/
node->mj_MatchedInner = true;
TupleTableSlot* result = MJFillInner(node);
if (result != NULL)
return result;
}
if (node->mj_ExtraMarks)
ExecMarkPos(inner_plan);
* now we get the next inner tuple, if any
*/
inner_tuple_slot = ExecProcNode(inner_plan);
node->mj_InnerTupleSlot = inner_tuple_slot;
MJ_DEBUG_PROC_NODE(inner_tuple_slot);
node->mj_MatchedInner = false;
switch (MJEvalInnerValues(node, inner_tuple_slot)) {
case MJEVAL_MATCHABLE:
node->mj_JoinState = EXEC_MJ_SKIP_TEST;
break;
case MJEVAL_NONMATCHABLE:
* current inner can't possibly match any outer;
* better to advance the inner scan than the outer.
*/
node->mj_JoinState = EXEC_MJ_SKIPINNER_ADVANCE;
break;
case MJEVAL_ENDOFJOIN:
MJ_printf("ExecMergeJoin: end of inner subplan\n");
outer_tuple_slot = node->mj_OuterTupleSlot;
if (do_fill_outer && !TupIsNull(outer_tuple_slot)) {
* Need to emit left-join tuples for remaining
* outer tuples.
*/
node->mj_JoinState = EXEC_MJ_ENDINNER;
break;
}
goto done;
default:
break;
}
break;
* EXEC_MJ_ENDOUTER means we have run out of outer tuples, but
* are doing a right/full join and therefore must null-fill
* any remaining unmatched inner tuples.
*/
case EXEC_MJ_ENDOUTER:
MJ_printf("ExecMergeJoin: EXEC_MJ_ENDOUTER\n");
Assert(do_fill_inner);
if (!node->mj_MatchedInner) {
* Generate a fake join tuple with nulls for the outer
* tuple, and return it if it passes the non-join quals.
*/
node->mj_MatchedInner = true;
TupleTableSlot* result = MJFillInner(node);
if (result != NULL)
return result;
}
if (node->mj_ExtraMarks)
ExecMarkPos(inner_plan);
* now we get the next inner tuple, if any
*/
inner_tuple_slot = ExecProcNode(inner_plan);
node->mj_InnerTupleSlot = inner_tuple_slot;
MJ_DEBUG_PROC_NODE(inner_tuple_slot);
node->mj_MatchedInner = false;
if (TupIsNull(inner_tuple_slot)) {
MJ_printf("ExecMergeJoin: end of inner subplan\n");
goto done;
}
break;
* EXEC_MJ_ENDINNER means we have run out of inner tuples, but
* are doing a left/full join and therefore must null- fill
* any remaining unmatched outer tuples.
*/
case EXEC_MJ_ENDINNER:
MJ_printf("ExecMergeJoin: EXEC_MJ_ENDINNER\n");
Assert(do_fill_outer);
if (!node->mj_MatchedOuter) {
* Generate a fake join tuple with nulls for the inner
* tuple, and return it if it passes the non-join quals.
*/
node->mj_MatchedOuter = true;
TupleTableSlot* result = MJFillOuter(node);
if (result != NULL)
return result;
}
* now we get the next outer tuple, if any
*/
outer_tuple_slot = ExecProcNode(outer_plan);
node->mj_OuterTupleSlot = outer_tuple_slot;
MJ_DEBUG_PROC_NODE(outer_tuple_slot);
node->mj_MatchedOuter = false;
if (TupIsNull(outer_tuple_slot)) {
MJ_printf("ExecMergeJoin: end of outer subplan\n");
goto done;
}
break;
* broken state value?
*/
default:
ereport(ERROR,
(errcode(ERRCODE_UNRECOGNIZED_NODE_TYPE),
errmsg("unrecognized mergejoin state: %d", (int)node->mj_JoinState)));
}
}
done:
ExecEarlyFree(innerPlanState(node));
ExecEarlyFree(outerPlanState(node));
EARLY_FREE_LOG(elog(LOG,
"Early Free: MergeJoin is done "
"at node %d, memory used %d MB.",
(node->js.ps.plan)->plan_node_id,
getSessionMemoryUsageMB()));
return NULL;
}
* ExecInitMergeJoin
* ----------------------------------------------------------------
*/
MergeJoinState* ExecInitMergeJoin(MergeJoin* node, EState* estate, int eflags)
{
Assert(!(eflags & (EXEC_FLAG_BACKWARD | EXEC_FLAG_MARK)));
MJ1_printf("ExecInitMergeJoin: %s\n", "initializing node");
* create state structure
*/
MergeJoinState* merge_state = makeNode(MergeJoinState);
merge_state->js.ps.plan = (Plan*)node;
merge_state->js.ps.state = estate;
merge_state->js.ps.ExecProcNode = ExecMergeJoin;
* Miscellaneous initialization
*
* create expression context for node
*/
ExecAssignExprContext(estate, &merge_state->js.ps);
* we need two additional econtexts in which we can compute the join
* expressions from the left and right input tuples. The node's regular
* econtext won't do because it gets reset too often.
*/
merge_state->mj_OuterEContext = CreateExprContext(estate);
merge_state->mj_InnerEContext = CreateExprContext(estate);
* initialize child expressions
*/
if (estate->es_is_flt_frame) {
merge_state->js.ps.qual = (List*)ExecInitQualByFlatten(node->join.plan.qual, (PlanState*)merge_state);
merge_state->js.jointype = node->join.jointype;
merge_state->js.joinqual = (List*)ExecInitQualByFlatten(node->join.joinqual, (PlanState*)merge_state);
merge_state->js.nulleqqual = (List*)ExecInitQualByFlatten(node->join.nulleqqual, (PlanState*)merge_state);
merge_state->mj_ConstFalseJoin = false;
} else {
merge_state->js.ps.targetlist =
(List*)ExecInitExprByRecursion((Expr*)node->join.plan.targetlist, (PlanState*)merge_state);
merge_state->js.ps.qual = (List*)ExecInitExprByRecursion((Expr*)node->join.plan.qual, (PlanState*)merge_state);
merge_state->js.jointype = node->join.jointype;
merge_state->js.joinqual = (List*)ExecInitExprByRecursion((Expr*)node->join.joinqual, (PlanState*)merge_state);
merge_state->js.nulleqqual = (List*)ExecInitExprByRecursion((Expr*)node->join.nulleqqual, (PlanState*)merge_state);
}
merge_state->mj_ConstFalseJoin = false;
Assert(node->join.joinqual == NIL || !node->skip_mark_restore);
merge_state->mj_SkipMarkRestore = node->skip_mark_restore;
outerPlanState(merge_state) = ExecInitNode(outerPlan(node), estate, eflags);
innerPlanState(merge_state) =
ExecInitNode(innerPlan(node), estate, merge_state->mj_SkipMarkRestore ? eflags : (eflags | EXEC_FLAG_MARK));
if (IsA(innerPlan(node), Material) && (eflags & EXEC_FLAG_REWIND) == 0 && !merge_state->mj_SkipMarkRestore) {
merge_state->mj_ExtraMarks = true;
} else {
merge_state->mj_ExtraMarks = false;
}
* tuple table initialization
*/
ExecInitResultTupleSlot(estate, &merge_state->js.ps);
merge_state->mj_MarkedTupleSlot = ExecInitExtraTupleSlot(estate);
ExecSetSlotDescriptor(merge_state->mj_MarkedTupleSlot, ExecGetResultType(innerPlanState(merge_state)));
merge_state->js.single_match = (node->join.inner_unique || node->join.jointype == JOIN_SEMI);
switch (node->join.jointype) {
case JOIN_INNER:
case JOIN_SEMI:
merge_state->mj_FillOuter = false;
merge_state->mj_FillInner = false;
break;
case JOIN_LEFT:
case JOIN_ANTI:
case JOIN_LEFT_ANTI_FULL:
merge_state->mj_FillOuter = true;
merge_state->mj_FillInner = false;
merge_state->mj_NullInnerTupleSlot =
ExecInitNullTupleSlot(estate, ExecGetResultType(innerPlanState(merge_state)));
break;
case JOIN_RIGHT:
merge_state->mj_FillOuter = false;
merge_state->mj_FillInner = true;
merge_state->mj_NullOuterTupleSlot =
ExecInitNullTupleSlot(estate, ExecGetResultType(outerPlanState(merge_state)));
* Can't handle right or full join with non-constant extra
* joinclauses. This should have been caught by planner.
*/
if (!check_constant_qual(node->join.joinqual, &merge_state->mj_ConstFalseJoin))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("RIGHT JOIN is only supported with merge-joinable join conditions."),
errhint("Try other join methods like nestloop or hashjoin.")));
break;
case JOIN_FULL:
merge_state->mj_FillOuter = true;
merge_state->mj_FillInner = true;
merge_state->mj_NullOuterTupleSlot =
ExecInitNullTupleSlot(estate, ExecGetResultType(outerPlanState(merge_state)));
merge_state->mj_NullInnerTupleSlot =
ExecInitNullTupleSlot(estate, ExecGetResultType(innerPlanState(merge_state)));
* Can't handle right or full join with non-constant extra
* joinclauses. This should have been caught by planner.
*/
if (!check_constant_qual(node->join.joinqual, &merge_state->mj_ConstFalseJoin))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("FULL JOIN is only supported with merge-joinable join conditions."),
errhint("Try other join methods like nestloop or hashjoin.")));
break;
#ifdef USE_SPQ
case JOIN_LASJ_NOTIN:
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("LASJ NOTIN JOIN is not supported with merge-joinable join conditions.")));
break;
#endif
default:
ereport(ERROR,
(errcode(ERRCODE_UNRECOGNIZED_NODE_TYPE),
errmsg("unrecognized join type: %d for mergejoin.", (int)node->join.jointype)));
}
* initialize tuple type and projection info
* result table tuple slot for merge join contains virtual tuple, so the
* default tableAm type is set to HEAP.
*/
ExecAssignResultTypeFromTL(&merge_state->js.ps, TableAmHeap);
ExecAssignProjectionInfo(&merge_state->js.ps, NULL);
* preprocess the merge clauses
*/
merge_state->mj_NumClauses = list_length(node->mergeclauses);
merge_state->mj_Clauses = MJExamineQuals(node->mergeclauses,
node->mergeFamilies,
node->mergeCollations,
node->mergeStrategies,
node->mergeNullsFirst,
(PlanState*)merge_state);
* initialize join state
*/
merge_state->mj_JoinState = EXEC_MJ_INITIALIZE_OUTER;
merge_state->js.ps.ps_vec_TupFromTlist = false;
merge_state->mj_MatchedOuter = false;
merge_state->mj_MatchedInner = false;
merge_state->mj_OuterTupleSlot = NULL;
merge_state->mj_InnerTupleSlot = NULL;
* initialization successful
*/
MJ1_printf("ExecInitMergeJoin: %s\n", "node initialized");
return merge_state;
}
* ExecEndMergeJoin
*
* old comments
* frees storage allocated through C routines.
* ----------------------------------------------------------------
*/
void ExecEndMergeJoin(MergeJoinState* node)
{
MJ1_printf("ExecEndMergeJoin: %s\n", "ending node processing");
* Free the exprcontext
*/
ExecFreeExprContext(&node->js.ps);
* clean out the tuple table
*/
(void)ExecClearTuple(node->js.ps.ps_ResultTupleSlot);
(void)ExecClearTuple(node->mj_MarkedTupleSlot);
* shut down the subplans
*/
ExecEndNode(innerPlanState(node));
ExecEndNode(outerPlanState(node));
MJ1_printf("ExecEndMergeJoin: %s\n", "node processing ended");
}
void ExecReScanMergeJoin(MergeJoinState* node)
{
(void)ExecClearTuple(node->mj_MarkedTupleSlot);
node->mj_JoinState = EXEC_MJ_INITIALIZE_OUTER;
node->js.ps.ps_vec_TupFromTlist = false;
node->mj_MatchedOuter = false;
node->mj_MatchedInner = false;
node->mj_OuterTupleSlot = NULL;
node->mj_InnerTupleSlot = NULL;
* if chgParam of subnodes is not null then plans will be re-scanned by
* first ExecProcNode.
*/
if (node->js.ps.lefttree->chgParam == NULL)
ExecReScan(node->js.ps.lefttree);
if (node->js.ps.righttree->chgParam == NULL)
ExecReScan(node->js.ps.righttree);
}