SERVER-15570 Avoid querying system.indexes in ttl.cpp.

Changed so that the TTL indexes are processed in multiple phases:
  - Acquire an IS-mode lock on the database and find all of the
    TTL indexes

  For each TTL index,
  - Acquire an IX-mode lock on the collection and delete all of the
    expired documents

Also avoid checking `userFlags` of collection stats in TTL index
tests since it is not set by some storage engines.

2 files changed, 5 insertions, 15 deletions

diff --git a/jstests/noPassthroughWithMongod/ttl1.js b/jstests/noPassthroughWithMongod/ttl1.js
index 3ce494bc2ef..a2d923fc9f5 100644
--- a/jstests/noPassthroughWithMongod/ttl1.js
+++ b/jstests/noPassthroughWithMongod/ttl1.js
@@ -51,9 +51,7 @@ var msg = RegExp("ttl indexes require the expireAfterSeconds" +
 assertEntryMatches(log, msg);
 
 // Part 2
-assert.eq( 0, t.stats().userFlags );
 t.ensureIndex( { x : 1 } , { expireAfterSeconds : 20000 } );
-assert.eq( 1, t.stats().userFlags );
 
 assert.soon(
     function() {
diff --git a/jstests/noPassthroughWithMongod/ttl_repl.js b/jstests/noPassthroughWithMongod/ttl_repl.js
index 5646ce22a39..8311e8db85d 100644
--- a/jstests/noPassthroughWithMongod/ttl_repl.js
+++ b/jstests/noPassthroughWithMongod/ttl_repl.js
@@ -1,8 +1,7 @@
 /** Test TTL collections with replication
- *  Part 1: Initiate replica set. Insert some docs and create a TTL index. Check that both primary
- *          and secondary get userFlags=1 (indicating that usePowerOf2Sizes is on),
- *          and check that the correct # of docs age out.
- *  Part 2: Add a new member to the set.  Check it also gets userFlags=1 and correct # of docs.
+ *  Part 1: Initiate replica set. Insert some docs and create a TTL index.
+ *          Check that the correct # of docs age out.
+ *  Part 2: Add a new member to the set. Check that it also gets the correct # of docs.
  *  Part 3: Change the TTL expireAfterSeconds field and check successful propogation to secondary.
  */
 
@@ -38,18 +37,14 @@ rt.awaitReplication();
 assert.eq( 24 , mastercol.count() , "docs not inserted on primary" );
 assert.eq( 24 , slave1col.count() , "docs not inserted on secondary" );
 
-// before TTL index created, check that userFlags are 0
 print("Initial Stats:")
 print("Master:");
 printjson( mastercol.stats() );
 print("Slave1:");
 printjson( slave1col.stats() );
 
-assert.eq( 0 , mastercol.stats().userFlags , "userFlags not 0 on primary");
-assert.eq( 0 , slave1col.stats().userFlags , "userFlags not 0 on secondary");
-
 // create TTL index, wait for TTL monitor to kick in, then check that
-// userFlags get set to 1, and correct number of docs age out
+// the correct number of docs age out
 assert.commandWorked(mastercol.ensureIndex({ x: 1 }, { expireAfterSeconds: 20000 }));
 rt.awaitReplication();
 
@@ -61,8 +56,6 @@ printjson( mastercol.stats() );
 print("Slave1:");
 printjson( slave1col.stats() );
 
-assert.eq( 1 , mastercol.stats().userFlags , "userFlags not 1 on primary" );
-assert.eq( 1 , slave1col.stats().userFlags , "userFlags not 1 on secondary" );
 assert.eq( 6 , mastercol.count() , "docs not deleted on primary" );
 assert.eq( 6 , slave1col.count() , "docs not deleted on secondary" );
 
@@ -76,11 +69,10 @@ rt.awaitSecondaryNodes();
 
 var slave2col = slave.getDB( 'd' )[ 'c' ];
 
-// check that its userFlags are also 1, and it has right number of docs
+// check that the new secondary has the correct number of docs
 print("New Slave stats:");
 printjson( slave2col.stats() );
 
-assert.eq( 1 , slave2col.stats().userFlags , "userFlags not 1 on new secondary");
 assert.eq( 6 , slave2col.count() , "wrong number of docs on new secondary");