crash_test to cover options.avoid_flush_during_recovery (#6712)

Summary:
Options.avoid_flush_during_recovery is uncovered in crash_test. Add the coverage with a chance of 1/8, as it is a less frequently used options.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6712

Test Plan: Run crash_test and see the option can be used or not used by chance.

Reviewed By: ltamasi

Differential Revision: D21056566

fbshipit-source-id: c3b1521517cfc204786e6ef8c6acd7fffda64793

db_stress_tool/db_stress_common.h

@@ -215,6 +215,7 @@ DECLARE_bool(use_full_merge_v1);
 DECLARE_int32(sync_wal_one_in);
 DECLARE_bool(avoid_unnecessary_blocking_io);
 DECLARE_bool(write_dbid_to_manifest);
+DECLARE_bool(avoid_flush_during_recovery);
 DECLARE_uint64(max_write_batch_group_size_bytes);
 DECLARE_bool(level_compaction_dynamic_level_bytes);
 DECLARE_int32(verify_checksum_one_in);

db_stress_tool/db_stress_gflags.cc

@@ -646,6 +646,10 @@ DEFINE_bool(write_dbid_to_manifest,
             ROCKSDB_NAMESPACE::Options().write_dbid_to_manifest,
             "Write DB_ID to manifest");
 
+DEFINE_bool(avoid_flush_during_recovery,
+            ROCKSDB_NAMESPACE::Options().avoid_flush_during_recovery,
+            "Avoid flush during recovery");
+
 DEFINE_uint64(max_write_batch_group_size_bytes,
               ROCKSDB_NAMESPACE::Options().max_write_batch_group_size_bytes,
               "Max write batch group size");

db_stress_tool/db_stress_test_base.cc

@@ -1826,6 +1826,7 @@ void StressTest::Open() {
     options_.avoid_unnecessary_blocking_io =
         FLAGS_avoid_unnecessary_blocking_io;
     options_.write_dbid_to_manifest = FLAGS_write_dbid_to_manifest;
+    options_.avoid_flush_during_recovery = FLAGS_avoid_flush_during_recovery;
     options_.max_write_batch_group_size_bytes =
         FLAGS_max_write_batch_group_size_bytes;
     options_.level_compaction_dynamic_level_bytes =

tools/db_crashtest.py

@@ -106,6 +106,8 @@ default_params = {
         [0, 0, 0, 1024 * 1024, 8 * 1024 * 1024, 128 * 1024 * 1024]),
     "avoid_unnecessary_blocking_io" : random.randint(0, 1),
     "write_dbid_to_manifest" : random.randint(0, 1),
+    "avoid_flush_during_recovery" : random.choice(
+        [1 if t == 0 else 0 for t in range(0, 8)]),
     "max_write_batch_group_size_bytes" : lambda: random.choice(
         [16, 64, 1024 * 1024, 16 * 1024 * 1024]),
     "level_compaction_dynamic_level_bytes" : True,