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Diffstat (limited to 'test/emptytable.test')
-rw-r--r-- | test/emptytable.test | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/test/emptytable.test b/test/emptytable.test new file mode 100644 index 0000000..79cd16e --- /dev/null +++ b/test/emptytable.test @@ -0,0 +1,50 @@ +# 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 |