Add data block hash index to crash test, fix MultiGet issue (facebook…

…#10220)

Summary:
There was a bug in the MultiGet enhancement in facebook#9899 with data
block hash index, which was not caught because data block hash index was
never added to stress tests. This change fixes both issues.

Fixes facebook#10186

I intend to pick this into the 7.4.0 release candidate

Pull Request resolved: facebook#10220

Test Plan:
Failure quickly reproduces in crash test with
kDataBlockBinaryAndHash, and does not seem to with the fix. Reproducing
the failure with a unit test I believe would be too tricky and fragile
to be worthwhile.

Reviewed By: anand1976

Differential Revision: D37315647

Pulled By: pdillinger

fbshipit-source-id: 9f648265bba867275edc752f7a56611a59401cba

HISTORY.md

@@ -13,6 +13,7 @@
 * Avoid a crash if the IDENTITY file is accidentally truncated to empty. A new DB ID will be written and generated on Open.
 * Fixed a possible corruption for users of `manual_wal_flush` and/or `FlushWAL(true /* sync */)`, together with `track_and_verify_wals_in_manifest == true`. For those users, losing unsynced data (e.g., due to power loss) could make future DB opens fail with a `Status::Corruption` complaining about missing WAL data.
 * Fixed a bug in `WriteBatchInternal::Append()` where WAL termination point in write batch was not considered and the function appends an incorrect number of checksums.
+* Fixed a crash bug introduced in 7.3.0 affecting users of MultiGet with `kDataBlockBinaryAndHash`.
 
 ### Public API changes
 * Add new API GetUnixTime in Snapshot class which returns the unix time at which Snapshot is taken.

db_stress_tool/db_stress_common.h

@@ -157,6 +157,7 @@ DECLARE_bool(partition_filters);
 DECLARE_bool(optimize_filters_for_memory);
 DECLARE_bool(detect_filter_construct_corruption);
 DECLARE_int32(index_type);
+DECLARE_int32(data_block_index_type);
 DECLARE_string(db);
 DECLARE_string(secondaries_base);
 DECLARE_bool(test_secondary);

db_stress_tool/db_stress_gflags.cc

@@ -493,9 +493,15 @@ DEFINE_bool(
 DEFINE_int32(
     index_type,
     static_cast<int32_t>(
-        ROCKSDB_NAMESPACE::BlockBasedTableOptions::kBinarySearch),
+        ROCKSDB_NAMESPACE::BlockBasedTableOptions().index_type),
     "Type of block-based table index (see `enum IndexType` in table.h)");
 
+DEFINE_int32(
+    data_block_index_type,
+    static_cast<int32_t>(
+        ROCKSDB_NAMESPACE::BlockBasedTableOptions().data_block_index_type),
+    "Index type for data blocks (see `enum DataBlockIndexType` in table.h)");
+
 DEFINE_string(db, "", "Use the db with the following name.");
 
 DEFINE_string(secondaries_base, "",

db_stress_tool/db_stress_test_base.cc

@@ -2775,6 +2775,9 @@ void InitializeOptionsFromFlags(
       FLAGS_detect_filter_construct_corruption;
   block_based_options.index_type =
       static_cast<BlockBasedTableOptions::IndexType>(FLAGS_index_type);
+  block_based_options.data_block_index_type =
+      static_cast<BlockBasedTableOptions::DataBlockIndexType>(
+          FLAGS_data_block_index_type);
   block_based_options.prepopulate_block_cache =
       static_cast<BlockBasedTableOptions::PrepopulateBlockCache>(
           FLAGS_prepopulate_block_cache);

table/block_based/block_based_table_reader_sync_and_async.h

@@ -610,15 +610,6 @@ DEFINE_SYNC_AND_ASYNC(void, BlockBasedTable::MultiGet)
           break;
         }
 
-        bool may_exist = biter->SeekForGet(key);
-        if (!may_exist) {
-          // HashSeek cannot find the key this block and the the iter is not
-          // the end of the block, i.e. cannot be in the following blocks
-          // either. In this case, the seek_key cannot be found, so we break
-          // from the top level for-loop.
-          break;
-        }
-
         // Reusing blocks complicates pinning/Cleanable, because the cache
         // entry referenced by biter can only be released once all returned
         // pinned values are released. This code previously did an extra
@@ -661,6 +652,15 @@ DEFINE_SYNC_AND_ASYNC(void, BlockBasedTable::MultiGet)
           value_pinner = nullptr;
         }
 
+        bool may_exist = biter->SeekForGet(key);
+        if (!may_exist) {
+          // HashSeek cannot find the key this block and the the iter is not
+          // the end of the block, i.e. cannot be in the following blocks
+          // either. In this case, the seek_key cannot be found, so we break
+          // from the top level for-loop.
+          break;
+        }
+
         // Call the *saver function on each entry/block until it returns false
         for (; biter->Valid(); biter->Next()) {
           ParsedInternalKey parsed_key;

tools/db_crashtest.py

@@ -63,6 +63,7 @@
     "clear_column_family_one_in": 0,
     "compact_files_one_in": 1000000,
     "compact_range_one_in": 1000000,
+    "data_block_index_type": lambda: random.choice([0, 1]),
     "delpercent": 4,
     "delrangepercent": 1,
     "destroy_db_initially": 0,