// Check explain results when an in order plan is selected among mixed in order and out of order // plans. t = db.jstests_explaina; t.drop(); t.ensureIndex( { a:1 } ); t.ensureIndex( { b:1 } ); for( i = 0; i < 1000; ++i ) { t.save( { a:i, b:i%3 } ); } // Query with an initial set of documents. explain1 = t.find( { a:{ $gte:0 }, b:2 } ).sort( { a:1 } ).explain( true ); for( i = 1000; i < 2000; ++i ) { t.save( { a:i, b:i%3 } ); } // Query with some additional documents. explain2 = t.find( { a:{ $gte:0 }, b:2 } ).sort( { a:1 } ).explain( true ); function plan( explain, cursor ) { for( i in explain.allPlans ) { e = explain.allPlans[ i ]; if ( e.cursor == cursor ) { return e; } } assert( false ); } // Check query totals. assert.eq( 333, explain1.n ); assert.eq( 666, explain2.n ); // Check totals for the selected in order a:1 plan. assert.eq( 333, plan( explain1, "BtreeCursor a_1" ).n ); assert.eq( 1000, plan( explain1, "BtreeCursor a_1" ).nscanned ); assert.eq( 666, plan( explain2, "BtreeCursor a_1" ).n ); assert.eq( 2000, plan( explain2, "BtreeCursor a_1" ).nscanned ); // Check that results only examined after the a:1 plan is selected will not affect plan explain // output for other plans. assert.eq( plan( explain1, "BtreeCursor b_1" ), plan( explain2, "BtreeCursor b_1" ) ); assert.eq( plan( explain1, "BasicCursor" ), plan( explain2, "BasicCursor" ) );