Fix executor to work correctly with mergejoins where left and
right sides have different data types.
This commit is contained in:
Tom Lane
parent
98f739454c
commit
dc77be0432
@ -7,7 +7,7 @@
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*
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*
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* IDENTIFICATION
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* $Header: /cvsroot/pgsql/src/backend/executor/nodeMergejoin.c,v 1.24 1999/02/24 10:20:07 momjian Exp $
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* $Header: /cvsroot/pgsql/src/backend/executor/nodeMergejoin.c,v 1.25 1999/02/28 00:36:05 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -67,6 +67,7 @@
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#include "postgres.h"
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#include "access/heapam.h"
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#include "catalog/pg_operator.h"
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#include "executor/executor.h"
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#include "executor/execdefs.h"
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#include "executor/nodeMergejoin.h"
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@ -87,28 +88,31 @@ static bool MergeCompare(List *eqQual, List *compareQual, ExprContext *econtext)
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/* ----------------------------------------------------------------
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* MJFormOSortopI
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* MJFormSkipQual
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*
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* This takes the mergeclause which is a qualification of the
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* form ((= expr expr) (= expr expr) ...) and forms a new
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* qualification like ((> expr expr) (> expr expr) ...) which
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* is used by ExecMergeJoin() in order to determine if we should
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* skip tuples.
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*
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* old comments
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* The 'qual' must be of the form:
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* {(= outerkey1 innerkey1)(= outerkey2 innerkey2) ...}
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* The "sortOp outerkey innerkey" is formed by substituting the "="
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* by "sortOp".
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* skip tuples. The replacement operators are named either ">"
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* or "<" according to the replaceopname parameter, and have the
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* same operand data types as the "=" operators they replace.
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* (We expect there to be such operators because the "=" operators
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* were marked mergejoinable; however, there might be a different
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* one needed in each qual clause.)
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* ----------------------------------------------------------------
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*/
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static List *
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MJFormOSortopI(List *qualList, Oid sortOp)
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MJFormSkipQual(List *qualList, char * replaceopname)
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{
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List *qualCopy;
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List *qualcdr;
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Expr *qual;
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Oper *op;
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HeapTuple optup;
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Form_pg_operator opform;
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Oid oprleft,
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oprright;
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/* ----------------
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* qualList is a list: ((op .. ..) ...)
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@ -132,75 +136,52 @@ MJFormOSortopI(List *qualList, Oid sortOp)
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*/
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op = (Oper *) qual->oper;
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if (!IsA(op, Oper))
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{
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elog(DEBUG, "MJFormOSortopI: op not an Oper!");
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return NIL;
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}
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elog(ERROR, "MJFormSkipQual: op not an Oper!");
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/* ----------------
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* change it's opid and since Op nodes now carry around a
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* cached pointer to the associated op function, we have
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* to make sure we invalidate this. Otherwise you get bizarre
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* behavior when someone runs a mergejoin with _exec_repeat_ > 1
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* -cim 4/23/91
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* Get the declared left and right operand types of the operator.
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* Note we do *not* use the actual operand types, since those might
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* be different in scenarios with binary-compatible data types.
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* There should be "<" and ">" operators matching a mergejoinable
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* "=" operator's declared operand types, but we might not find them
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* if we search with the actual operand types.
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* ----------------
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*/
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op->opid = sortOp;
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optup = get_operator_tuple(op->opno);
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if (!HeapTupleIsValid(optup)) /* shouldn't happen */
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elog(ERROR, "MJFormSkipQual: operator %d not found", op->opno);
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opform = (Form_pg_operator) GETSTRUCT(optup);
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oprleft = opform->oprleft;
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oprright = opform->oprright;
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/* ----------------
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* Now look up the matching "<" or ">" operator. If there isn't one,
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* whoever marked the "=" operator mergejoinable was a loser.
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* ----------------
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*/
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optup = SearchSysCacheTuple(OPRNAME,
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PointerGetDatum(replaceopname),
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ObjectIdGetDatum(oprleft),
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ObjectIdGetDatum(oprright),
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CharGetDatum('b'));
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if (!HeapTupleIsValid(optup))
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elog(ERROR,
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"MJFormSkipQual: mergejoin operator %d has no matching %s op",
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op->opno, replaceopname);
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opform = (Form_pg_operator) GETSTRUCT(optup);
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/* ----------------
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* And replace the data in the copied operator node.
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* ----------------
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*/
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op->opno = optup->t_data->t_oid;
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op->opid = opform->oprcode;
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op->op_fcache = NULL;
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}
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return qualCopy;
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}
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/* ----------------------------------------------------------------
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* MJFormISortopO
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*
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* This does the same thing as MJFormOSortopI() except that
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* it also reverses the expressions in the qualifications.
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* For example: ((= expr1 expr2)) produces ((> expr2 expr1))
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*
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* old comments
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* The 'qual' must be of the form:
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* {(= outerkey1 innerkey1) (= outerkey2 innerkey2) ...}
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* The 'sortOp innerkey1 outerkey" is formed by substituting the "="
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* by "sortOp" and reversing the positions of the keys.
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* ----------------------------------------------------------------
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*/
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static List *
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MJFormISortopO(List *qualList, Oid sortOp)
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{
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List *ISortopO;
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List *qualcdr;
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/* ----------------
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* first generate OSortopI, a list of the form
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* ((op outer inner) (op outer inner) ... )
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* ----------------
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*/
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ISortopO = MJFormOSortopI(qualList, sortOp);
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/* ----------------
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* now swap the cadr and caddr of each qual to form ISortopO,
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* ((op inner outer) (op inner outer) ... )
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* ----------------
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*/
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foreach(qualcdr, ISortopO)
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{
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Expr *qual;
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List *inner;
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List *outer;
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qual = lfirst(qualcdr);
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inner = lfirst(qual->args);
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outer = lfirst(lnext(qual->args));
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lfirst(qual->args) = outer;
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lfirst(lnext(qual->args)) = inner;
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}
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return ISortopO;
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}
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/* ----------------------------------------------------------------
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* MergeCompare
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*
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@ -215,6 +196,7 @@ MJFormISortopO(List *qualList, Oid sortOp)
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* the first keys being most significant. Therefore, the clauses
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* are evaluated in order and the 'compareQual' is satisfied
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* if (key1i > key2i) is true and (key1j = key2j) for 0 < j < i.
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* We use the original mergeclause items to detect equality.
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* ----------------------------------------------------------------
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*/
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static bool
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@ -386,12 +368,16 @@ ExecMergeTupleDump(ExprContext *econtext, MergeJoinState *mergestate)
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*
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* Therefore, when initializing the merge-join node, the executor
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* creates the "greater/smaller" clause by substituting the "="
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* operator in the join clauses with the sort operator used to
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* sort the outer and inner relation forming (outerKey sortOp innerKey).
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* The sort operator is "<" if the relations are in ascending order
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* otherwise, it is ">" if the relations are in descending order.
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* The opposite "smaller/greater" clause is formed by reversing the
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* outer and inner keys forming (innerKey sortOp outerKey).
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* operator in the join clauses with the corresponding ">" operator.
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* The opposite "smaller/greater" clause is formed by substituting "<".
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*
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* Note: prior to v6.5, the relational clauses were formed using the
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* sort op used to sort the inner relation, which of course would fail
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* if the outer and inner keys were of different data types.
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* In the current code, we instead assume that operators named "<" and ">"
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* will do the right thing. This should be true since the mergejoin "="
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* operator's pg_operator entry will have told the planner to sort by
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* "<" for each of the left and right sides.
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*
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* (2) repositioning inner "cursor"
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*
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@ -452,13 +438,13 @@ ExecMergeJoin(MergeJoin *node)
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if (ScanDirectionIsForward(direction))
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{
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outerSkipQual = mergestate->mj_OSortopI;
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innerSkipQual = mergestate->mj_ISortopO;
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outerSkipQual = mergestate->mj_OuterSkipQual;
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innerSkipQual = mergestate->mj_InnerSkipQual;
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}
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else
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{
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outerSkipQual = mergestate->mj_ISortopO;
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innerSkipQual = mergestate->mj_OSortopI;
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outerSkipQual = mergestate->mj_InnerSkipQual;
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innerSkipQual = mergestate->mj_OuterSkipQual;
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}
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/* ----------------
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@ -1130,14 +1116,8 @@ ExecInitMergeJoin(MergeJoin *node, EState *estate, Plan *parent)
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{
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MergeJoinState *mergestate;
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List *joinclauses;
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RegProcedure rightsortop;
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RegProcedure leftsortop;
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RegProcedure sortop;
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TupleTableSlot *mjSlot;
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List *OSortopI;
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List *ISortopO;
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MJ1_printf("ExecInitMergeJoin: %s\n",
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"initializing node");
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@ -1153,14 +1133,14 @@ ExecInitMergeJoin(MergeJoin *node, EState *estate, Plan *parent)
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* ----------------
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*/
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mergestate = makeNode(MergeJoinState);
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mergestate->mj_OSortopI = NIL;
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mergestate->mj_ISortopO = NIL;
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mergestate->mj_OuterSkipQual = NIL;
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mergestate->mj_InnerSkipQual = NIL;
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mergestate->mj_JoinState = 0;
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mergestate->mj_MarkedTupleSlot = NULL;
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node->mergestate = mergestate;
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/* ----------------
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* Miscellanious initialization
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* Miscellaneous initialization
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*
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* + assign node's base_id
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* + assign debugging hooks and
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@ -1185,40 +1165,17 @@ ExecInitMergeJoin(MergeJoin *node, EState *estate, Plan *parent)
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mergestate->mj_MarkedTupleSlot = mjSlot;
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/* ----------------
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* get merge sort operators.
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*
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* XXX for now we assume all quals in the joinclauses were
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* sorted with the same operator in both the inner and
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* outer relations. -cim 11/2/89
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* form merge skip qualifications
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* ----------------
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*/
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joinclauses = node->mergeclauses;
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mergestate->mj_OuterSkipQual = MJFormSkipQual(joinclauses, "<");
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mergestate->mj_InnerSkipQual = MJFormSkipQual(joinclauses, ">");
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rightsortop = get_opcode(node->mergerightorder[0]);
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leftsortop = get_opcode(node->mergeleftorder[0]);
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if (leftsortop != rightsortop)
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elog(NOTICE, "ExecInitMergeJoin: %s",
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"left and right sortop's are unequal!");
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sortop = rightsortop;
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/* ----------------
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* form merge skip qualifications
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*
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* XXX MJform routines need to be extended
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* to take a list of sortops.. -cim 11/2/89
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* ----------------
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*/
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OSortopI = MJFormOSortopI(joinclauses, sortop);
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ISortopO = MJFormISortopO(joinclauses, sortop);
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mergestate->mj_OSortopI = OSortopI;
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mergestate->mj_ISortopO = ISortopO;
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MJ_printf("\nExecInitMergeJoin: OSortopI is ");
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MJ_nodeDisplay(OSortopI);
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MJ_printf("\nExecInitMergeJoin: ISortopO is ");
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MJ_nodeDisplay(ISortopO);
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MJ_printf("\nExecInitMergeJoin: OuterSkipQual is ");
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MJ_nodeDisplay(mergestate->mj_OuterSkipQual);
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MJ_printf("\nExecInitMergeJoin: InnerSkipQual is ");
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MJ_nodeDisplay(mergestate->mj_InnerSkipQual);
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MJ_printf("\n");
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/* ----------------
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@ -6,7 +6,7 @@
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*
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* Copyright (c) 1994, Regents of the University of California
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*
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* $Id: execnodes.h,v 1.25 1999/02/23 07:55:23 thomas Exp $
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* $Id: execnodes.h,v 1.26 1999/02/28 00:36:04 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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@ -463,8 +463,8 @@ typedef struct NestLoopState
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/* ----------------
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* MergeJoinState information
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*
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* OSortopI outerKey1 sortOp innerKey1 ...
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* ISortopO innerkey1 sortOp outerkey1 ...
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* OuterSkipQual outerKey1 < innerKey1 ...
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* InnerSkipQual outerKey1 > innerKey1 ...
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* JoinState current "state" of join. see executor.h
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* MarkedTupleSlot pointer to slot in tuple table for marked tuple
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*
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@ -483,8 +483,8 @@ typedef struct NestLoopState
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typedef struct MergeJoinState
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{
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JoinState jstate; /* its first field is NodeTag */
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List *mj_OSortopI;
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List *mj_ISortopO;
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List *mj_OuterSkipQual;
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List *mj_InnerSkipQual;
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int mj_JoinState;
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TupleTableSlot *mj_MarkedTupleSlot;
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} MergeJoinState;
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