better db_bench options for transactions

Summary:
Pessimistic Transaction expiration time checking currently causes a performace regression,  Lets disable it in db_bench by default.

Also, in order to be able to better tune how much contention we're simulating, added new optinos to set lock timeout and snapshot.

Test Plan: run db_bench randomtranansaction

Reviewers: sdong, igor, yhchiang, MarkCallaghan

Reviewed By: MarkCallaghan

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D45831

db/db_bench.cc

@@ -487,10 +487,18 @@ DEFINE_uint64(transaction_sets, 2,
               "Number of keys each transaction will "
               "modify (use in RandomTransaction only).  Max: 9999");
 
+DEFINE_bool(transaction_set_snapshot, false,
+            "Setting to true will have each transaction call SetSnapshot()"
+            " upon creation.");
+
 DEFINE_int32(transaction_sleep, 0,
              "Max microseconds to sleep in between "
              "reading and writing a value (used in RandomTransaction only). ");
 
+DEFINE_uint64(transaction_lock_timeout, 100,
+              "If using a transaction_db, specifies the lock wait timeout in"
+              " milliseconds before failing a transaction waiting on a lock");
+
 DEFINE_bool(compaction_measure_io_stats, false,
             "Measure times spents on I/Os while in compactions. ");
 
@@ -3645,13 +3653,20 @@ class Benchmark {
         assert(txn);
       } else if (FLAGS_transaction_db) {
         TransactionDB* txn_db = reinterpret_cast<TransactionDB*>(db_.db);
+
         TransactionOptions txn_options;
-        txn_options.expiration = 10000000;
+        txn_options.lock_timeout = FLAGS_transaction_lock_timeout;
+
         txn = txn_db->BeginTransaction(write_options_, txn_options);
+        assert(txn);
       } else {
         batch = new WriteBatch();
       }
 
+      if (txn && FLAGS_transaction_set_snapshot) {
+        txn->SetSnapshot();
+      }
+
       // pick a random number to use to increment a key in each set
       uint64_t incr = (thread->rand.Next() % 100) + 1;
 
@@ -3686,9 +3701,13 @@ class Benchmark {
           }
         } else if (s.IsNotFound()) {
           int_value = 0;
-        } else {
+        } else if (!(s.IsBusy() || s.IsTimedOut() || s.IsTryAgain())) {
-          fprintf(stderr, "Get returned an error: %s\n", s.ToString().c_str());
+          fprintf(stderr, "Get returned an unexpected error: %s\n",
+                  s.ToString().c_str());
           abort();
+        } else {
+          failed = true;
+          break;
         }
 
         if (FLAGS_transaction_sleep > 0) {
@@ -3700,8 +3719,10 @@ class Benchmark {
         if (txn) {
           s = txn->Put(key, sum);
           if (!s.ok()) {
-            failed = true;
+            // Since we did a GetForUpdate, Put should not fail.
-            break;
+            fprintf(stderr, "Put returned an unexpected error: %s\n",
+                    s.ToString().c_str());
+            abort();
           }
         } else {
           batch->Put(key, sum);
@@ -3710,7 +3731,9 @@ class Benchmark {
 
       if (txn) {
         if (failed) {
+          transactions_aborted++;
           txn->Rollback();
+          s = Status::OK();
         } else {
           s = txn->Commit();
         }
@@ -3719,10 +3742,15 @@ class Benchmark {
       }
 
       if (!s.ok()) {
+        failed = true;
+
         // Ideally, we'd want to run this stress test with enough concurrency
         // on a small enough set of keys that we get some failed transactions
         // due to conflicts.
-        if (txn && s.IsBusy()) {
+        if (FLAGS_optimistic_transaction_db &&
+            (s.IsBusy() || s.IsTimedOut() || s.IsTryAgain())) {
+          transactions_aborted++;
+        } else if (FLAGS_transaction_db && s.IsExpired()) {
           transactions_aborted++;
         } else {
           fprintf(stderr, "Unexpected write error: %s\n", s.ToString().c_str());
@@ -3737,6 +3765,10 @@ class Benchmark {
         delete batch;
       }
 
+      if (!failed) {
+        thread->stats.FinishedOps(nullptr, db, 1);
+      }
+
       transactions_done++;
     }
 
@@ -3807,8 +3839,7 @@ class Benchmark {
       prev_total = total;
     }
 
-    fprintf(stdout, "RandomTransactionVerify Success! Total:%" PRIu64 "\n",
+    fprintf(stdout, "RandomTransactionVerify Success!\n");
-            prev_total);
   }
 
   void Compact(ThreadState* thread) {