DiannaHohensee

Local           Remote

no metadata     no metadata
no metadata     metadata

metadata        metadata
metadata        more metadata
metadata        new epoch metadata
metadata        new epoch but mixed chunk old and new versions
metadata        no metadata

DiannaHohensee

Local						Remote

no metadata     no metadata
no metadata     metadata

metadata        metadata
metadata        more metadata
metadata        new epoch metadata
metadata        new epoch but mixed chunk old and new versions
metadata        no metadata

DiannaHohensee

Local           Remote

no metadata     no metadata
no metadata     metadata

metadata        metadata
metadata        more metadata
metadata        new epoch metadata
metadata        new epoch but mixed chunk old and new versions
metadata        no metadata

DiannaHohensee

        // Decide whether to handle the shard version that may have been sent along with the
        // command.
        bool useShardVersionProtocolAndFiltering = false;

        // We do not redo shard version handling if this command was issued via the direct client.
        if (!opCtx->getClient()->isInDirectClient()) {
            // Only primary handles shard version in fcv 3.4.
            if (serverGlobalParams.featureCompatibility.version.load() ==
                    ServerGlobalParams::FeatureCompatibility::Version::k34 &&
                iAmPrimary) {

DiannaHohensee

w/ changes and no pre-allocate

Benchmark                                                             Time           CPU Iterations
----------------------------------------------------------------------------------------------------
DConcurrencyTest/BM_StdMutex/threads:1                               21 ns         21 ns   29382112
DConcurrencyTest/BM_StdMutex/threads:2                               68 ns        126 ns    4815998
DConcurrencyTest/BM_StdMutex/threads:4                              146 ns        535 ns    1275356
DConcurrencyTest/BM_StdMutex/threads:8                              172 ns       1247 ns     499720
DConcurrencyTest/BM_StdMutex/threads:16                             208 ns       3132 ns     160000
DConcurrencyTest/BM_ResourceMutexShared/threads:1                   179 ns        180 ns    3674763

DiannaHohensee

diff --git a/src/mongo/db/session_test.cpp b/src/mongo/db/session_test.cpp
index 0b0f3c7..34d2e4c 100644
--- a/src/mongo/db/session_test.cpp
+++ b/src/mongo/db/session_test.cpp
@@ -591,6 +591,24 @@ TEST_F(SessionTest, StashAndUnstashResources) {
     opCtx()->getWriteUnitOfWork()->commit();
 }

+// Test that transactions will abort if locks cannot be taken immediately.
+TEST_F(SessionTest, TransactionAbortsIfLockIsUnavailable) {

DiannaHohensee

"available-snapshot-settings" : {
      "cache pressure percentage threshold" : <num>.
      "max available snapshots window size in seconds" : <num>,
      "target available snapshots window size in seconds" : <num>,
      "current available snapshots window size in seconds" : <num>,
      "latest majority snapshot timestamp available" : <num>,
      "oldest majority snapshot timestamp available" : <num>
}

DiannaHohensee

"available-snapshot-settings" : {
      "cache pressure percentage threshold" : <num>.
      "current cache pressure percentage" : <num>,
      "max available snapshots window size in seconds" : <num>,
      "target available snapshots window size in seconds" : <num>,
      "current available snapshots window size in seconds" : <num>,
      "latest majority snapshot timestamp available" : <num>,
      "oldest majority snapshot timestamp available" : <num>
}
// Just made up the strings, so they may change whenever I think of something more informative.

DiannaHohensee

[5/5 (100%) 0.521s]LINK build/ninja/mongo/db/snapshot_window_util_test
FAILED: build/ninja/mongo/db/snapshot_window_util_test
/usr/bin/icerun /opt/mongodbtoolchain/v2/bin/clang++ @build/ninja/mongo/db/snapshot_window_util_test.rsp
build/ninja/mongo/db/s/libsharding.so: error: undefined reference to 'mongo::ShardServerCatalogCacheLoader::ShardServerCatalogCacheLoader(std::unique_ptr<mongo::CatalogCacheLoader, std::default_delete<mongo::CatalogCacheLoader> >)'
build/ninja/mongo/db/s/libsharding.so: error: undefined reference to 'vtable for mongo::ReadOnlyCatalogCacheLoader'
/opt/mongodbtoolchain/v2/bin/ld.gold: the vtable symbol may be undefined because the class is missing its key function
build/ninja/mongo/db/s/libsharding.so: error: undefined reference to 'mongo::ChunkSplitter::setReplicaSetMode(bool)'
build/ninja/mongo/db/s/libsharding.so: error: undefined reference to 'mongo::ChunkSplitter::get(mongo::OperationContext*)'
clang-3.9: error: linker command failed with exit code 1 (use -v to see invocation)
ni

DiannaHohensee

Failing on jstests/core/txns/no_implicit_collection_creation_in_txn.js (https://github.com/mongodb/mongo/blob/fb9e6ec91f45036266e9678e4806ca5cbb318164/jstests/core/txns/no_implicit_collection_creation_in_txn.js#L91)

Code drops the collection, then proceeds to attempt to update a document taking an IX lock, which conflicts with asynchronous 2-phase drop that has the X lock.

{
    ....
    const sessionColl = sessionDb[collName];
    ....

    assert.commandWorked(testDB.runCommand({drop: collName, writeConcern: {w: "majority"}}));