crash_test: cover concurrent memtable insert in default crash test

Summary: Default crash test uses prefix hash memtable, which is not compatible to concurrent memtable. Allow prefix test run with skip list and use skip list memtable when concurrent insert is used.

Test Plan: Run "python -u tools/db_crashtest.py whitebox" and watch sometimes skip list is used.

Reviewers: anthony, yhchiang, kradhakrishnan, andrewkr, IslamAbdelRahman

Reviewed By: IslamAbdelRahman

Subscribers: leveldb, dhruba

Differential Revision: https://reviews.facebook.net/D53907

tools/db_crashtest.py

@@ -134,6 +134,7 @@ def finalize_and_sanitize(src_params):
     # --allow_concurrent_memtable_write with --filter_deletes is not supported.
     if dest_params.get("allow_concurrent_memtable_write", 1) == 1:
         dest_params["filter_deletes"] = 0
+        dest_params["memtablerep"] = "skip_list"
     return dest_params
 
 

tools/db_stress.cc

@@ -2008,11 +2008,17 @@ class StressTest {
         FLAGS_allow_concurrent_memtable_write;
     options_.enable_write_thread_adaptive_yield =
         FLAGS_enable_write_thread_adaptive_yield;
-    if ((FLAGS_prefix_size == 0) == (FLAGS_rep_factory == kHashSkipList)) {
+
+    if (FLAGS_prefix_size == 0 && FLAGS_rep_factory == kHashSkipList) {
       fprintf(stderr,
-            "prefix_size should be non-zero iff memtablerep == prefix_hash\n");
+              "prefeix_size cannot be zero if memtablerep == prefix_hash\n");
       exit(1);
     }
+    if (FLAGS_prefix_size != 0 && FLAGS_rep_factory != kHashSkipList) {
+      fprintf(stderr,
+              "WARNING: prefix_size is non-zero but "
+              "memtablerep != prefix_hash\n");
+    }
     switch (FLAGS_rep_factory) {
       case kSkipList:
         // no need to do anything