ceph/src/rocksdb/table/persistent_cache_helper.cc

   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 #include "table/persistent_cache_helper.h"
   7
   8 #include "table/block_based/block_based_table_reader.h"
   9 #include "table/format.h"
  10
  11 namespace ROCKSDB_NAMESPACE {
  12
  13 const PersistentCacheOptions PersistentCacheOptions::kEmpty;
  14
  15 void PersistentCacheHelper::InsertSerialized(
  16     const PersistentCacheOptions& cache_options, const BlockHandle& handle,
  17     const char* data, const size_t size) {
  18   assert(cache_options.persistent_cache);
  19   assert(cache_options.persistent_cache->IsCompressed());
  20
  21   CacheKey key =
  22       BlockBasedTable::GetCacheKey(cache_options.base_cache_key, handle);
  23
  24   cache_options.persistent_cache->Insert(key.AsSlice(), data, size)
  25       .PermitUncheckedError();
  26 }
  27
  28 void PersistentCacheHelper::InsertUncompressed(
  29     const PersistentCacheOptions& cache_options, const BlockHandle& handle,
  30     const BlockContents& contents) {
  31   assert(cache_options.persistent_cache);
  32   assert(!cache_options.persistent_cache->IsCompressed());
  33   // Precondition:
  34   // (1) content is cacheable
  35   // (2) content is not compressed
  36
  37   CacheKey key =
  38       BlockBasedTable::GetCacheKey(cache_options.base_cache_key, handle);
  39
  40   cache_options.persistent_cache
  41       ->Insert(key.AsSlice(), contents.data.data(), contents.data.size())
  42       .PermitUncheckedError();
  43   ;
  44 }
  45
  46 Status PersistentCacheHelper::LookupSerialized(
  47     const PersistentCacheOptions& cache_options, const BlockHandle& handle,
  48     std::unique_ptr<char[]>* out_data, const size_t expected_data_size) {
  49 #ifdef NDEBUG
  50   (void)expected_data_size;
  51 #endif
  52   assert(cache_options.persistent_cache);
  53   assert(cache_options.persistent_cache->IsCompressed());
  54
  55   CacheKey key =
  56       BlockBasedTable::GetCacheKey(cache_options.base_cache_key, handle);
  57
  58   size_t size;
  59   Status s =
  60       cache_options.persistent_cache->Lookup(key.AsSlice(), out_data, &size);
  61   if (!s.ok()) {
  62     // cache miss
  63     RecordTick(cache_options.statistics, PERSISTENT_CACHE_MISS);
  64     return s;
  65   }
  66
  67   // cache hit
  68   // Block-based table is assumed
  69   assert(expected_data_size ==
  70          handle.size() + BlockBasedTable::kBlockTrailerSize);
  71   assert(size == expected_data_size);
  72   RecordTick(cache_options.statistics, PERSISTENT_CACHE_HIT);
  73   return Status::OK();
  74 }
  75
  76 Status PersistentCacheHelper::LookupUncompressed(
  77     const PersistentCacheOptions& cache_options, const BlockHandle& handle,
  78     BlockContents* contents) {
  79   assert(cache_options.persistent_cache);
  80   assert(!cache_options.persistent_cache->IsCompressed());
  81   if (!contents) {
  82     // We shouldn't lookup in the cache. Either
  83     // (1) Nowhere to store
  84     return Status::NotFound();
  85   }
  86
  87   CacheKey key =
  88       BlockBasedTable::GetCacheKey(cache_options.base_cache_key, handle);
  89
  90   std::unique_ptr<char[]> data;
  91   size_t size;
  92   Status s =
  93       cache_options.persistent_cache->Lookup(key.AsSlice(), &data, &size);
  94   if (!s.ok()) {
  95     // cache miss
  96     RecordTick(cache_options.statistics, PERSISTENT_CACHE_MISS);
  97     return s;
  98   }
  99
 100   // please note we are potentially comparing compressed data size with
 101   // uncompressed data size
 102   assert(handle.size() <= size);
 103
 104   // update stats
 105   RecordTick(cache_options.statistics, PERSISTENT_CACHE_HIT);
 106   // construct result and return
 107   *contents = BlockContents(std::move(data), size);
 108   return Status::OK();
 109 }
 110
 111 }  // namespace ROCKSDB_NAMESPACE