Triggering verify for gets also

Summary: Will use iterators to verify keys in the db for half of its keys and Gets for the other half.

Test Plan: ./db_stress --max_key=1000 --ops_per_thread=100

Reviewers: dhruba, haobo

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D13227

tools/db_stress.cc

@@ -698,8 +698,7 @@ class StressTest {
     }
 
     if (!FLAGS_test_batches_snapshots) {
-      thread->shared->GetStressTest()->VerifyDb(*(thread->shared),
-                                                 thread->tid);
+      thread->shared->GetStressTest()->VerifyDb(thread);
     }
 
     {
@@ -1064,15 +1063,18 @@ class StressTest {
     thread->stats.Stop();
   }
 
-  void VerifyDb(const SharedState &shared, long tid) const {
+  void VerifyDb(ThreadState* thread) const {
     ReadOptions options(FLAGS_verify_checksum, true);
-    long max_key = shared.GetMaxKey();
+    const SharedState& shared = *(thread->shared);
+    static const long max_key = shared.GetMaxKey();
     static const long keys_per_thread = max_key / shared.GetNumThreads();
-    long start = keys_per_thread * tid;
+    long start = keys_per_thread * thread->tid;
     long end = start + keys_per_thread;
-    if (tid == shared.GetNumThreads() - 1) {
+    if (thread->tid == shared.GetNumThreads() - 1) {
       end = max_key;
     }
+    if (!thread->rand.OneIn(2)) {
+      // Use iterator to verify this range
       unique_ptr<Iterator> iter(db_->NewIterator(options));
       iter->Seek(Key(start));
       for (long i = start; i < end; i++) {
@@ -1100,6 +1102,20 @@ class StressTest {
         }
       }
     }
+    else {
+      // Use Get to verify this range
+      for (long i = start; i < end; i++) {
+        std::string from_db;
+        std::string keystr = Key(i);
+        Slice k = keystr;
+        Status s = db_->Get(options, k, &from_db);
+        VerifyValue(i, options, shared, from_db, s, true);
+        if (from_db.length()) {
+          PrintKeyValue(i, from_db.data(), from_db.length());
+        }
+      }
+    }
+  }
 
   void VerificationAbort(std::string msg, long key) const {
     fprintf(stderr, "Verification failed for key %ld: %s\n",