44 lines
1.3 KiB
JavaScript
44 lines
1.3 KiB
JavaScript
// Check that a new plan will be selected if a recorded plan performs poorly.
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t = db.jstests_queryoptimizer4;
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function reset( matches, filler ) {
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t.drop();
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t.ensureIndex({a:1});
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t.ensureIndex({b:1});
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// {a:1} index best for query {a:1,b:1}
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t.save({a:1,b:1});
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t.save({a:2,b:1});
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// {b:1} index best for query {a:100,b:100}
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for( i = 0; i < matches; ++i ) {
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t.save({a:100,b:100});
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}
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for( i = 0; i < filler; ++i ) {
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t.save({a:100,b:5});
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}
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}
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function checkCursor( query, cursor ) {
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t.find(query).itcount();
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// Check that index on 'cursor' was chosen in the above query.
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var x = t.find(query).explain(true);
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assert.eq( 'BtreeCursor ' + cursor, x.oldPlan.cursor , tojson(x) );
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}
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// Check {b:1} takes over when {a:1} is much worse for query {a:100,b:100}.
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reset( 1, 50 );
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checkCursor( {a:1,b:1}, 'a_1' );
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checkCursor( {a:100,b:100}, 'b_1' );
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// Check smallest filler for which {b:1} will take over.
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reset( 2, 12 );
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checkCursor( {a:1,b:1}, 'a_1' );
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checkCursor( {a:100,b:100}, 'b_1' );
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// Check largest filler for which {b:1} will not take over - demonstrating that new plans run alongside the old plan.
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reset( 2, 11 );
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checkCursor( {a:1,b:1}, 'a_1' );
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checkCursor( {a:100,b:100}, 'a_1' );
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