| # 2017-02-15 |
| # |
| # The author disclaims copyright to this source code. In place of |
| # a legal notice, here is a blessing: |
| # |
| # May you do good and not evil. |
| # May you find forgiveness for yourself and forgive others. |
| # May you share freely, never taking more than you give. |
| # |
| #*********************************************************************** |
| # |
| # Test cases to show that a join involving an empty table is very fast. |
| # |
| |
| set testdir [file dirname $argv0] |
| source $testdir/tester.tcl |
| |
| # Build some test data |
| # |
| do_execsql_test emptytable-100 { |
| CREATE TABLE t1(a); |
| WITH RECURSIVE c(x) AS (VALUES(1) UNION ALL SELECT x+1 FROM c WHERE x<100) |
| INSERT INTO t1(a) SELECT x FROM c; |
| CREATE TABLE empty(x); |
| SELECT count(*) FROM t1; |
| } {100} |
| |
| # Interrupt queries after 1M cycles to prevent burning excess CPU |
| proc stopDb {args} { |
| db interrupt |
| } |
| db progress 1000000 {stopDb} |
| |
| # Prior to the query planner optimization on 2017-02-15, this query would |
| # take a ridiculous amount of time. If that optimization stops working, |
| # the result here will be in interrupt for running too long. |
| # |
| do_catchsql_test emptytable-110 { |
| SELECT count(*) FROM t1, t1, t1, t1, t1, t1, empty; |
| } {0 0} |
| |
| do_catchsql_test emptytable-120 { |
| SELECT count(*) FROM t1, t1 LEFT JOIN empty; |
| } {0 10000} |
| do_catchsql_test emptytable-121 { |
| SELECT count(*) FROM t1, t1 LEFT JOIN t1, empty; |
| } {0 0} |
| |
| |
| finish_test |