Disable recycle_log_file_num when it is incompatible with recovery mode (#6351)

Summary:
Non-zero recycle_log_file_num is incompatible with kPointInTimeRecovery and kAbsoluteConsistency recovery modes. Currently SanitizeOptions changes the recovery mode to kTolerateCorruptedTailRecords, while to resolve this option conflict it makes more sense to compromise recycle_log_file_num, which is a performance feature, instead of wal_recovery_mode, which is a safety feature.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6351

Differential Revision: D19648931

Pulled By: maysamyabandeh

fbshipit-source-id: dd0bf78349edc007518a00c4d63931fd69294ad7

HISTORY.md

@@ -7,6 +7,7 @@
 
 ### Public API Change
 * The BlobDB garbage collector now emits the statistics `BLOB_DB_GC_NUM_FILES` (number of blob files obsoleted during GC), `BLOB_DB_GC_NUM_NEW_FILES` (number of new blob files generated during GC), `BLOB_DB_GC_FAILURES` (number of failed GC passes), `BLOB_DB_GC_NUM_KEYS_RELOCATED` (number of blobs relocated during GC), and `BLOB_DB_GC_BYTES_RELOCATED` (total size of blobs relocated during GC). On the other hand, the following statistics, which are not relevant for the new GC implementation, are now deprecated: `BLOB_DB_GC_NUM_KEYS_OVERWRITTEN`, `BLOB_DB_GC_NUM_KEYS_EXPIRED`, `BLOB_DB_GC_BYTES_OVERWRITTEN`, `BLOB_DB_GC_BYTES_EXPIRED`, and `BLOB_DB_GC_MICROS`.
+* Disable recycle_log_file_num when an inconsistent recovery modes are requested: kPointInTimeRecovery and kAbsoluteConsistency
 
 ## 6.7.0 (01/21/2020)
 ### Public API Change

db/db_impl/db_impl_open.cc

@@ -100,12 +100,11 @@ DBOptions SanitizeOptions(const std::string& dbname, const DBOptions& src) {
   if (result.recycle_log_file_num &&
       (result.wal_recovery_mode == WALRecoveryMode::kPointInTimeRecovery ||
        result.wal_recovery_mode == WALRecoveryMode::kAbsoluteConsistency)) {
-    // kPointInTimeRecovery is indistinguishable from
-    // kTolerateCorruptedTailRecords in recycle mode since we define
-    // the "end" of the log as the first corrupt record we encounter.
+    // kPointInTimeRecovery is inconsistent with recycle log file feature since
+    // we define the "end" of the log as the first corrupt record we encounter.
     // kAbsoluteConsistency doesn't make sense because even a clean
     // shutdown leaves old junk at the end of the log file.
-    result.wal_recovery_mode = WALRecoveryMode::kTolerateCorruptedTailRecords;
+    result.recycle_log_file_num = 0;
   }
 
   if (result.wal_dir.empty()) {