Volodymyr Vysotskyi created CALCITE-2329: --------------------------------------------
Summary: Enhance SubQueryRemoveRule to rewrite IN operator with the constant from the left side more optimally Key: CALCITE-2329 URL: https://issues.apache.org/jira/browse/CALCITE-2329 Project: Calcite Issue Type: Improvement Reporter: Volodymyr Vysotskyi Assignee: Julian Hyde Currently, for queries like this: {code:sql} select sal from emp where 2 IN (select deptno from dept) {code} SubQueryRemoveRule rules expand query plan in such a way: {noformat} LogicalProject(SAL=[$5]) LogicalProject(EMPNO=[$0], ENAME=[$1], JOB=[$2], MGR=[$3], HIREDATE=[$4], SAL=[$5], COMM=[$6], DEPTNO=[$7], SLACKER=[$8]) LogicalJoin(condition=[=(2, $9)], joinType=[inner]) LogicalTableScan(table=[[CATALOG, SALES, EMP]]) LogicalProject(DEPTNO=[$0]) LogicalTableScan(table=[[CATALOG, SALES, DEPT]]) {noformat} Since join condition is actually a filter condition, it will be pushed into the filter during further planning stages and join with the true condition is left. But these types of the queries may be rewritten in the same way as EXISTS queries: {code:sql} select sal from emp where EXISTS (select deptno from dept where deptno=2) {code} with the more optimal plan: {noformat} LogicalProject(SAL=[$5]) LogicalProject(EMPNO=[$0], ENAME=[$1], JOB=[$2], MGR=[$3], HIREDATE=[$4], SAL=[$5], COMM=[$6], DEPTNO=[$7], SLACKER=[$8]) LogicalJoin(condition=[true], joinType=[inner]) LogicalTableScan(table=[[CATALOG, SALES, EMP]]) LogicalAggregate(group=[{0}]) LogicalProject(i=[true]) LogicalFilter(condition=[=($0, 2)]) LogicalTableScan(table=[[CATALOG, SALES, DEPT]]) {noformat} -- This message was sent by Atlassian JIRA (v7.6.3#76005)