ceph/src/rocksdb/utilities/cassandra/cassandra_compaction_filter.h

   1 // Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
   2 //  This source code is licensed under both the GPLv2 (found in the
   3 //  COPYING file in the root directory) and Apache 2.0 License
   4 //  (found in the LICENSE.Apache file in the root directory).
   5
   6 #pragma once
   7 #include <string>
   8 #include "rocksdb/compaction_filter.h"
   9 #include "rocksdb/slice.h"
  10
  11 namespace ROCKSDB_NAMESPACE {
  12 namespace cassandra {
  13
  14 /**
  15  * Compaction filter for removing expired Cassandra data with ttl.
  16  * If option `purge_ttl_on_expiration` is set to true, expired data
  17  * will be directly purged. Otherwise expired data will be converted
  18  * tombstones first, then be eventally removed after gc grace period.
  19  * `purge_ttl_on_expiration` should only be on in the case all the
  20  * writes have same ttl setting, otherwise it could bring old data back.
  21  *
  22  * Compaction filter is also in charge of removing tombstone that has been
  23  * promoted to kValue type after serials of merging in compaction.
  24  */
  25 class CassandraCompactionFilter : public CompactionFilter {
  26 public:
  27  explicit CassandraCompactionFilter(bool purge_ttl_on_expiration,
  28                                     int32_t gc_grace_period_in_seconds)
  29      : purge_ttl_on_expiration_(purge_ttl_on_expiration),
  30        gc_grace_period_in_seconds_(gc_grace_period_in_seconds) {}
  31
  32  const char* Name() const override;
  33  virtual Decision FilterV2(int level, const Slice& key, ValueType value_type,
  34                            const Slice& existing_value, std::string* new_value,
  35                            std::string* skip_until) const override;
  36
  37 private:
  38   bool purge_ttl_on_expiration_;
  39   int32_t gc_grace_period_in_seconds_;
  40 };
  41 }  // namespace cassandra
  42 }  // namespace ROCKSDB_NAMESPACE