Critical - P2 Problem
Observed a 10% drop in throughput for the mongo-perf test Commands.v1.DistinctWithoutIndex. Appears to beyond normal observed variance. This is 2.6.7 vs RC9/10 MMAPV1
2.6.7 1555.64 Stddev 33.33
RC9 1418.79 Stddev 6.21
RC10 1425.96 Stddev 6.46
This appears to happen at client threads counts higher than the number of cores available to MongoDB. In the attached results, MongoDB was pinned to 8 cores, the drop appears to start after 12 client threads.
Testcase
tests.push( genDistinctTest( "Commands.v1.DistinctWithoutIndex", false, false ) ); function genDistinctTest( name, index, query ) { var doc = { name : name, tags: ['distinct','command','sanity','daily','weekly','monthly'] }; if ( index ) { doc.pre = function( collection ) { collection.drop(); for ( var i = 0; i < 4800; i++ ) { collection.insert( { x : 1 } ); collection.insert( { x : 2 } ); collection.insert( { x : 3 } ); } collection.ensureIndex( { x : 1 } ); }; } else { doc.pre = function( collection ) { collection.drop(); for ( var i = 0; i < 4800; i++ ) { collection.insert( { x : 1 } ); collection.insert( { x : 2 } ); collection.insert( { x : 3 } ); } collection.getDB().getLastError(); }; } var op = { op: "command", tags: ['distinct','command','sanity','daily','weekly','monthly'], ns : "#B_DB", command : { distinct : "#B_COLL", key : "x" } }; if ( query ) op.command.query = { x : 1 }; doc.ops = [ op ]; return doc; }
