*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/executor/nodeMergejoin.c,v 1.22 1999/02/22 19:40:10 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/backend/executor/nodeMergejoin.c,v 1.23 1999/02/23 07:35:09 thomas Exp $
*
*-------------------------------------------------------------------------
*/
*
* NOTES
* Essential operation of the merge join algorithm is as follows:
- * (** indicates the tuples satisify the merge clause).
+ * (** indicates the tuples satisfy the merge clause).
*
* Join { -
* get initial outer and inner tuples INITIALIZE
* Skip Outer SKIPOUTER
* } -
*
- * Currently, the merge join operation is coded in the fashion
+ * 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
*
- * Warning: This code is known to fail for inequality operations
- * and is being redesigned. Specifically, = and > work
- * but the logic is not correct for <. Since mergejoins
- * are no better then nestloops for inequalitys, the planner
- * should not plan them anyways. Alternatively, the
- * planner could just exchange the inner/outer relations
- * if it ever sees a <... -cim 7/1/90
- *
- * Update: The executor tuple table has long since alleviated the
- * problem described above -cim 4/23/91
- *
*/
#include "postgres.h"
#include "utils/lsyscache.h"
#include "utils/psort.h"
+
static bool MergeCompare(List *eqQual, List *compareQual, ExprContext *econtext);
#define MarkInnerTuple(innerTupleSlot, mergestate) \
true) \
)
+
/* ----------------------------------------------------------------
* MJFormOSortopI
*
* ----------------------------------------------------------------
*/
#ifdef EXEC_MERGEJOINDEBUG
+void
+ExecMergeTupleDumpInner(ExprContext *econtext);
+
void
ExecMergeTupleDumpInner(ExprContext *econtext)
{
if (TupIsNull(innerSlot))
printf("(nil)\n");
else
- debugtup(innerSlot->val,
- innerSlot->ttc_tupleDescriptor);
+ MJ_debugtup(innerSlot->val,
+ innerSlot->ttc_tupleDescriptor);
}
+void
+ExecMergeTupleDumpOuter(ExprContext *econtext);
+
void
ExecMergeTupleDumpOuter(ExprContext *econtext)
{
if (TupIsNull(outerSlot))
printf("(nil)\n");
else
- debugtup(outerSlot->val,
- outerSlot->ttc_tupleDescriptor);
+ MJ_debugtup(outerSlot->val,
+ outerSlot->ttc_tupleDescriptor);
}
+void
+ExecMergeTupleDumpMarked(ExprContext *econtext,
+ MergeJoinState *mergestate);
+
void
ExecMergeTupleDumpMarked(ExprContext *econtext,
MergeJoinState *mergestate)
if (TupIsNull(markedSlot))
printf("(nil)\n");
else
- debugtup(markedSlot->val,
- markedSlot->ttc_tupleDescriptor);
+ MJ_debugtup(markedSlot->val,
+ markedSlot->ttc_tupleDescriptor);
}
+void
+ExecMergeTupleDump(ExprContext *econtext, MergeJoinState *mergestate);
+
void
ExecMergeTupleDump(ExprContext *econtext, MergeJoinState *mergestate)
{
printf("******** \n");
}
-
#endif
/* ----------------------------------------------------------------
ExprContext *econtext;
+#ifdef ENABLE_OUTER_JOINS
+ /* These should be set from the expression context!
+ * - thomas 1999-02-20
+ */
+ static bool isLeftJoin = true;
+ static bool isRightJoin = false;
+#endif
+
/* ----------------
* get information from node
* ----------------
switch (mergestate->mj_JoinState)
{
- /* ---------------------------------------------------
- * EXEC_MJ_INITIALIZE
- * means that this is the first time ExecMergeJoin() has
- * been called and so we have to initialize the inner,
- * outer and marked tuples as well as various stuff in the
- * expression context.
- * ---------------------------------------------------
- */
+ /*********************************
+ * EXEC_MJ_INITIALIZE means that this is the first time
+ * ExecMergeJoin() has been called and so we have to initialize
+ * the inner, outer and marked tuples as well as various stuff
+ * in the expression context.
+ *********************************/
case EXEC_MJ_INITIALIZE:
MJ_printf("ExecMergeJoin: EXEC_MJ_INITIALIZE\n");
/* ----------------
mergestate->mj_JoinState = EXEC_MJ_SKIPINNER;
break;
- /* ---------------------------------------------------
- * EXEC_MJ_JOINMARK
- * means we have just found a new outer tuple and a possible
- * matching inner tuple. This is the case after the
- * INITIALIZE, SKIPOUTER or SKIPINNER states.
- * ----------------------------------------------------
- */
+ /*********************************
+ * EXEC_MJ_JOINMARK means we have just found a new outer tuple
+ * and a possible matching inner tuple. This is the case after
+ * the INITIALIZE, SKIPOUTER or SKIPINNER states.
+ *********************************/
case EXEC_MJ_JOINMARK:
MJ_printf("ExecMergeJoin: EXEC_MJ_JOINMARK\n");
ExecMarkPos(innerPlan);
mergestate->mj_JoinState = EXEC_MJ_JOINTEST;
break;
- /* ----------------------------------------------------
- * EXEC_MJ_JOINTEST
- * means we have two tuples which might satisify the merge
- * clause, so we test them.
+ /*********************************
+ * EXEC_MJ_JOINTEST means we have two tuples which might
+ * satisfy the merge clause, so we test them.
*
- * If they do satisify, then we join them and move on to the
+ * If they do satisfy, then we join them and move on to the
* next inner tuple (EXEC_MJ_JOINTUPLES).
*
- * If they do not satisify then advance to next outer tuple.
- * ------------------------------------------------------
- */
+ * If they do not satisfy then advance to next outer tuple.
+ *********************************/
case EXEC_MJ_JOINTEST:
MJ_printf("ExecMergeJoin: EXEC_MJ_JOINTEST\n");
mergestate->mj_JoinState = EXEC_MJ_NEXTOUTER;
break;
- /* ----------------------------------------------------
- * EXEC_MJ_JOINTUPLES
- * means we have two tuples which satisified the merge
- * clause so we join them and then proceed to get the next
- * inner tuple (EXEC_NEXT_INNER).
- * ----------------------------------------------------
- */
+ /*********************************
+ * EXEC_MJ_JOINTUPLES means we have two tuples which
+ * satisified the merge clause so we join them and then
+ * proceed to get the next inner tuple (EXEC_NEXT_INNER).
+ *********************************/
case EXEC_MJ_JOINTUPLES:
MJ_printf("ExecMergeJoin: EXEC_MJ_JOINTUPLES\n");
mergestate->mj_JoinState = EXEC_MJ_NEXTINNER;
}
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.
- * ----------------------------------------------------
- */
+ /*********************************
+ * 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.
+ *********************************/
case EXEC_MJ_NEXTINNER:
MJ_printf("ExecMergeJoin: EXEC_MJ_NEXTINNER\n");
mergestate->mj_JoinState = EXEC_MJ_JOINTEST;
break;
- /* --------------------------------------------------
- * EXEC_MJ_NEXTOUTER
- * means
- * outer inner
- * outer tuple - 5 5 - marked tuple
- * 5 5
- * 6 6 - inner tuple
- * 7 7
+ /*********************************
+ * 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 so get a new outer tuple and then
+ * we know we just bumped into the
+ * first inner tuple > current outer tuple
+ * so get a new outer tuple and then
* proceed to test it against the marked tuple
* (EXEC_MJ_TESTOUTER)
- * -------------------------------------------------
- */
+ *********************************/
case EXEC_MJ_NEXTOUTER:
MJ_printf("ExecMergeJoin: EXEC_MJ_NEXTOUTER\n");
mergestate->mj_JoinState = EXEC_MJ_TESTOUTER;
break;
- /* ---------------------------------------------------
- * EXEC_MJ_TESTOUTER
- * If the new outer tuple and the marked tuple satisify 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 tuples
- * with the inner tuples (EXEC_MJ_JOINTEST)
+ /*********************************
+ * 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 tuples with the inner tuples (EXEC_MJ_JOINTEST)
*
* This is the case when
* outer inner
* 7 12
*
*
- * new outer tuple > marked tuple
+ * new outer tuple > marked tuple
*
- * -----------------------------------------------------------
- */
+ *********************************/
case EXEC_MJ_TESTOUTER:
MJ_printf("ExecMergeJoin: EXEC_MJ_TESTOUTER\n");
* tuple didn't match the marked outer tuple then
* we may have the case:
*
- * outer inner
- * 4 4 - marked tuple
- * new outer - 5 4
- * 6 nil - inner tuple
- * 7
+ * outer inner
+ * 4 4 - marked tuple
+ * new outer - 5 4
+ * 6 nil - inner tuple
+ * 7
*
* which means that all subsequent outer tuples will be
* larger than our inner tuples.
*/
if (TupIsNull(innerTupleSlot))
{
- MJ_printf("ExecMergeJoin: **** wierd case 1 ****\n");
+#ifdef ENABLE_OUTER_JOINS
+ if (isLeftJoin)
+ {
+ /* continue on to null fill outer tuples */
+ mergestate->mj_JoinState = EXEC_MJ_FILLOUTER;
+ break;
+ }
+#endif
+ MJ_printf("ExecMergeJoin: **** weird case 1 ****\n");
return NULL;
}
}
break;
- /* --------------------------------------------------
- * EXEC_MJ_SKIPOUTER
- * means skip over tuples in the outer plan until we find
- * an outer tuple > current inner tuple.
+ /*********************************
+ * EXEC_MJ_SKIPOUTER means skip over tuples in the outer plan
+ * until we find an outer tuple > current inner tuple.
*
* For example:
*
- * outer inner
- * 5 5
- * 5 5
- * outer tuple - 6 8 - inner tuple
- * 7 12
- * 8 14
+ * 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.
- * ------------------------------------------------
- */
+ * we have to advance the outer scan
+ * until we find the outer 8.
+ *********************************/
case EXEC_MJ_SKIPOUTER:
MJ_printf("ExecMergeJoin: EXEC_MJ_SKIPOUTER\n");
/* ----------------
* before we advance, make sure the current tuples
- * do not satisify the mergeclauses. If they do, then
+ * do not satisfy the mergeclauses. If they do, then
* we update the marked tuple and go join them.
* ----------------
*/
*/
if (compareResult)
{
+#ifdef ENABLE_OUTER_JOINS
+ /* ----------------
+ * if this is a left or full outer join, then fill
+ * ----------------
+ */
+ if (isLeftJoin)
+ {
+ mergestate->mj_JoinState = EXEC_MJ_FILLOUTER;
+ break;
+ }
+#endif
outerTupleSlot = ExecProcNode(outerPlan, (Plan *) node);
MJ_DEBUG_PROC_NODE(outerTupleSlot);
mergestate->mj_JoinState = EXEC_MJ_JOINMARK;
break;
- /* ------------------------------------------------
- * EXEC_MJ_SKIPINNER
- * means skip over tuples in the inner plan until we find
- * an inner tuple > current outer tuple.
+ /*********************************
+ * EXEC_MJ_SKIPINNER means skip over tuples in the inner plan
+ * until we find an inner tuple > current outer tuple.
*
* For example:
- * 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.
- * ---------------------------------------------------
- */
+ * 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_SKIPINNER:
MJ_printf("ExecMergeJoin: EXEC_MJ_SKIPINNER\n");
/* ----------------
* before we advance, make sure the current tuples
- * do not satisify the mergeclauses. If they do, then
+ * do not satisfy the mergeclauses. If they do, then
* we update the marked tuple and go join them.
* ----------------
*/
*/
if (compareResult)
{
+#ifdef ENABLE_OUTER_JOINS
+ /* ----------------
+ * if this is a right or full outer join, then fill
+ * ----------------
+ */
+ if (isRightJoin)
+ {
+ mergestate->mj_JoinState = EXEC_MJ_FILLINNER;
+ break;
+ }
+#endif
+
/* ----------------
* now try and get a new inner tuple
* ----------------
* This means the join should end.
* ----------------
*/
- MJ_printf("ExecMergeJoin: **** wierd case 2 ****\n");
+ MJ_printf("ExecMergeJoin: **** weird case 2 ****\n");
return NULL;
}
break;
- /*
- * If we get here it means our code is messed up and so we
- * just end the join prematurely.
+#ifdef ENABLE_OUTER_JOINS
+ /*********************************
+ * EXEC_MJ_FILLINNER means we have an unmatched inner tuple
+ * which must be null-expanded into the projection tuple.
+ * get the next inner tuple and reset markers (EXEC_MJ_JOINMARK).
+ *********************************/
+ case EXEC_MJ_FILLINNER:
+ MJ_printf("ExecMergeJoin: EXEC_MJ_FILLINNER\n");
+ mergestate->mj_JoinState = EXEC_MJ_JOINMARK;
+
+ /* ----------------
+ * project the inner tuple into the result
+ * ----------------
*/
+ MJ_printf("ExecMergeJoin: project inner tuple into the result (not yet implemented)\n");
+
+ /* ----------------
+ * now skip this inner tuple
+ * ----------------
+ */
+ innerTupleSlot = ExecProcNode(innerPlan, (Plan *) node);
+ MJ_DEBUG_PROC_NODE(innerTupleSlot);
+ econtext->ecxt_innertuple = innerTupleSlot;
+
+ /* ----------------
+ * if the inner tuple is null then we know
+ * we have to restore the inner scan
+ * and advance to the next outer tuple
+ * ----------------
+ */
+ if (TupIsNull(innerTupleSlot))
+ {
+ if (isLeftJoin && !TupIsNull(outerTupleSlot))
+ {
+ mergestate->mj_JoinState = EXEC_MJ_FILLOUTER;
+ MJ_printf("ExecMergeJoin: try to complete outer fill\n");
+ break;
+ }
+
+ MJ_printf("ExecMergeJoin: **** weird case 2 ****\n");
+ return NULL;
+ }
+
+ /* ----------------
+ * otherwise test the new tuple against the skip qual.
+ * (we move to the EXEC_MJ_JOINMARK state)
+ * ----------------
+ */
+ break;
+
+ /*********************************
+ * EXEC_MJ_FILLOUTER means we have an unmatched outer tuple
+ * which must be null-expanded into the projection tuple.
+ * get the next outer tuple and reset markers (EXEC_MJ_JOINMARK).
+ *********************************/
+ case EXEC_MJ_FILLOUTER:
+ MJ_printf("ExecMergeJoin: EXEC_MJ_FILLOUTER\n");
+ mergestate->mj_JoinState = EXEC_MJ_JOINMARK;
+
+ /* ----------------
+ * project the outer tuple into the result
+ * ----------------
+ */
+ MJ_printf("ExecMergeJoin: project outer tuple into the result (not yet implemented)\n");
+
+ /* ----------------
+ * now skip this outer tuple
+ * ----------------
+ */
+ outerTupleSlot = ExecProcNode(outerPlan, (Plan *) node);
+ MJ_DEBUG_PROC_NODE(outerTupleSlot);
+ econtext->ecxt_outertuple = outerTupleSlot;
+
+ /* ----------------
+ * if the outer tuple is null then we know
+ * we are done with the left half of the join
+ * ----------------
+ */
+ if (TupIsNull(outerTupleSlot))
+ {
+ if (isRightJoin && !TupIsNull(innerTupleSlot))
+ {
+ mergestate->mj_JoinState = EXEC_MJ_FILLINNER;
+ MJ_printf("ExecMergeJoin: try to complete inner fill\n");
+ break;
+ }
+
+ MJ_printf("ExecMergeJoin: **** outerTuple is nil ****\n");
+ return NULL;
+ }
+
+ /* ----------------
+ * otherwise test the new tuple against the skip qual.
+ * (we move to the EXEC_MJ_JOINMARK state)
+ * ----------------
+ */
+ break;
+#endif
+
+ /*********************************
+ * if we get here it means our code is fouled up
+ * and so we just end the join prematurely.
+ *********************************/
default:
elog(NOTICE, "ExecMergeJoin: invalid join state. aborting");
return NULL;
projects / thirdparty / postgresql.git / commitdiff
