*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/executor/nodeMergejoin.c,v 1.24 1999/02/24 10:20:07 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/backend/executor/nodeMergejoin.c,v 1.25 1999/02/28 00:36:05 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/heapam.h"
+#include "catalog/pg_operator.h"
#include "executor/executor.h"
#include "executor/execdefs.h"
#include "executor/nodeMergejoin.h"
/* ----------------------------------------------------------------
- * MJFormOSortopI
+ * MJFormSkipQual
*
* This takes the mergeclause which is a qualification of the
* form ((= expr expr) (= expr expr) ...) and forms a new
* qualification like ((> expr expr) (> expr expr) ...) which
* is used by ExecMergeJoin() in order to determine if we should
- * skip tuples.
- *
- * old comments
- * The 'qual' must be of the form:
- * {(= outerkey1 innerkey1)(= outerkey2 innerkey2) ...}
- * The "sortOp outerkey innerkey" is formed by substituting the "="
- * by "sortOp".
+ * skip tuples. The replacement operators are named either ">"
+ * or "<" according to the replaceopname parameter, and have the
+ * same operand data types as the "=" operators they replace.
+ * (We expect there to be such operators because the "=" operators
+ * were marked mergejoinable; however, there might be a different
+ * one needed in each qual clause.)
* ----------------------------------------------------------------
*/
static List *
-MJFormOSortopI(List *qualList, Oid sortOp)
+MJFormSkipQual(List *qualList, char * replaceopname)
{
List *qualCopy;
List *qualcdr;
Expr *qual;
Oper *op;
+ HeapTuple optup;
+ Form_pg_operator opform;
+ Oid oprleft,
+ oprright;
/* ----------------
* qualList is a list: ((op .. ..) ...)
*/
op = (Oper *) qual->oper;
if (!IsA(op, Oper))
- {
- elog(DEBUG, "MJFormOSortopI: op not an Oper!");
- return NIL;
- }
+ elog(ERROR, "MJFormSkipQual: op not an Oper!");
/* ----------------
- * change it's opid and since Op nodes now carry around a
- * cached pointer to the associated op function, we have
- * to make sure we invalidate this. Otherwise you get bizarre
- * behavior when someone runs a mergejoin with _exec_repeat_ > 1
- * -cim 4/23/91
+ * Get the declared left and right operand types of the operator.
+ * Note we do *not* use the actual operand types, since those might
+ * be different in scenarios with binary-compatible data types.
+ * There should be "<" and ">" operators matching a mergejoinable
+ * "=" operator's declared operand types, but we might not find them
+ * if we search with the actual operand types.
* ----------------
*/
- op->opid = sortOp;
- op->op_fcache = NULL;
- }
-
- return qualCopy;
-}
-
-/* ----------------------------------------------------------------
- * MJFormISortopO
- *
- * This does the same thing as MJFormOSortopI() except that
- * it also reverses the expressions in the qualifications.
- * For example: ((= expr1 expr2)) produces ((> expr2 expr1))
- *
- * old comments
- * The 'qual' must be of the form:
- * {(= outerkey1 innerkey1) (= outerkey2 innerkey2) ...}
- * The 'sortOp innerkey1 outerkey" is formed by substituting the "="
- * by "sortOp" and reversing the positions of the keys.
- * ----------------------------------------------------------------
- */
-static List *
-MJFormISortopO(List *qualList, Oid sortOp)
-{
- List *ISortopO;
- List *qualcdr;
-
- /* ----------------
- * first generate OSortopI, a list of the form
- * ((op outer inner) (op outer inner) ... )
- * ----------------
- */
- ISortopO = MJFormOSortopI(qualList, sortOp);
-
- /* ----------------
- * now swap the cadr and caddr of each qual to form ISortopO,
- * ((op inner outer) (op inner outer) ... )
- * ----------------
- */
- foreach(qualcdr, ISortopO)
- {
- Expr *qual;
- List *inner;
- List *outer;
+ optup = get_operator_tuple(op->opno);
+ if (!HeapTupleIsValid(optup)) /* shouldn't happen */
+ elog(ERROR, "MJFormSkipQual: operator %d not found", op->opno);
+ opform = (Form_pg_operator) GETSTRUCT(optup);
+ oprleft = opform->oprleft;
+ oprright = opform->oprright;
- qual = lfirst(qualcdr);
+ /* ----------------
+ * Now look up the matching "<" or ">" operator. If there isn't one,
+ * whoever marked the "=" operator mergejoinable was a loser.
+ * ----------------
+ */
+ optup = SearchSysCacheTuple(OPRNAME,
+ PointerGetDatum(replaceopname),
+ ObjectIdGetDatum(oprleft),
+ ObjectIdGetDatum(oprright),
+ CharGetDatum('b'));
+ if (!HeapTupleIsValid(optup))
+ elog(ERROR,
+ "MJFormSkipQual: mergejoin operator %d has no matching %s op",
+ op->opno, replaceopname);
+ opform = (Form_pg_operator) GETSTRUCT(optup);
- inner = lfirst(qual->args);
- outer = lfirst(lnext(qual->args));
- lfirst(qual->args) = outer;
- lfirst(lnext(qual->args)) = inner;
+ /* ----------------
+ * And replace the data in the copied operator node.
+ * ----------------
+ */
+ op->opno = optup->t_data->t_oid;
+ op->opid = opform->oprcode;
+ op->op_fcache = NULL;
}
- return ISortopO;
+ return qualCopy;
}
/* ----------------------------------------------------------------
* the first keys being most significant. Therefore, the clauses
* are evaluated in order and the 'compareQual' is satisfied
* if (key1i > key2i) is true and (key1j = key2j) for 0 < j < i.
+ * We use the original mergeclause items to detect equality.
* ----------------------------------------------------------------
*/
static bool
*
* Therefore, when initializing the merge-join node, the executor
* creates the "greater/smaller" clause by substituting the "="
- * operator in the join clauses with the sort operator used to
- * sort the outer and inner relation forming (outerKey sortOp innerKey).
- * The sort operator is "<" if the relations are in ascending order
- * otherwise, it is ">" if the relations are in descending order.
- * The opposite "smaller/greater" clause is formed by reversing the
- * outer and inner keys forming (innerKey sortOp outerKey).
+ * operator in the join clauses with the corresponding ">" operator.
+ * The opposite "smaller/greater" clause is formed by substituting "<".
+ *
+ * Note: prior to v6.5, the relational clauses were formed using the
+ * sort op used to sort the inner relation, which of course would fail
+ * if the outer and inner keys were of different data types.
+ * In the current code, we instead assume that operators named "<" and ">"
+ * will do the right thing. This should be true since the mergejoin "="
+ * operator's pg_operator entry will have told the planner to sort by
+ * "<" for each of the left and right sides.
*
* (2) repositioning inner "cursor"
*
if (ScanDirectionIsForward(direction))
{
- outerSkipQual = mergestate->mj_OSortopI;
- innerSkipQual = mergestate->mj_ISortopO;
+ outerSkipQual = mergestate->mj_OuterSkipQual;
+ innerSkipQual = mergestate->mj_InnerSkipQual;
}
else
{
- outerSkipQual = mergestate->mj_ISortopO;
- innerSkipQual = mergestate->mj_OSortopI;
+ outerSkipQual = mergestate->mj_InnerSkipQual;
+ innerSkipQual = mergestate->mj_OuterSkipQual;
}
/* ----------------
{
MergeJoinState *mergestate;
List *joinclauses;
- RegProcedure rightsortop;
- RegProcedure leftsortop;
- RegProcedure sortop;
TupleTableSlot *mjSlot;
- List *OSortopI;
- List *ISortopO;
-
MJ1_printf("ExecInitMergeJoin: %s\n",
"initializing node");
* ----------------
*/
mergestate = makeNode(MergeJoinState);
- mergestate->mj_OSortopI = NIL;
- mergestate->mj_ISortopO = NIL;
+ mergestate->mj_OuterSkipQual = NIL;
+ mergestate->mj_InnerSkipQual = NIL;
mergestate->mj_JoinState = 0;
mergestate->mj_MarkedTupleSlot = NULL;
node->mergestate = mergestate;
/* ----------------
- * Miscellanious initialization
+ * Miscellaneous initialization
*
* + assign node's base_id
* + assign debugging hooks and
mergestate->mj_MarkedTupleSlot = mjSlot;
/* ----------------
- * get merge sort operators.
- *
- * XXX for now we assume all quals in the joinclauses were
- * sorted with the same operator in both the inner and
- * outer relations. -cim 11/2/89
+ * form merge skip qualifications
* ----------------
*/
joinclauses = node->mergeclauses;
+ mergestate->mj_OuterSkipQual = MJFormSkipQual(joinclauses, "<");
+ mergestate->mj_InnerSkipQual = MJFormSkipQual(joinclauses, ">");
- rightsortop = get_opcode(node->mergerightorder[0]);
- leftsortop = get_opcode(node->mergeleftorder[0]);
-
- if (leftsortop != rightsortop)
- elog(NOTICE, "ExecInitMergeJoin: %s",
- "left and right sortop's are unequal!");
-
- sortop = rightsortop;
-
- /* ----------------
- * form merge skip qualifications
- *
- * XXX MJform routines need to be extended
- * to take a list of sortops.. -cim 11/2/89
- * ----------------
- */
- OSortopI = MJFormOSortopI(joinclauses, sortop);
- ISortopO = MJFormISortopO(joinclauses, sortop);
- mergestate->mj_OSortopI = OSortopI;
- mergestate->mj_ISortopO = ISortopO;
-
- MJ_printf("\nExecInitMergeJoin: OSortopI is ");
- MJ_nodeDisplay(OSortopI);
- MJ_printf("\nExecInitMergeJoin: ISortopO is ");
- MJ_nodeDisplay(ISortopO);
+ MJ_printf("\nExecInitMergeJoin: OuterSkipQual is ");
+ MJ_nodeDisplay(mergestate->mj_OuterSkipQual);
+ MJ_printf("\nExecInitMergeJoin: InnerSkipQual is ");
+ MJ_nodeDisplay(mergestate->mj_InnerSkipQual);
MJ_printf("\n");
/* ----------------
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