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Revision 7168d16103cb9e48bde9f435c21b0f02186f5d7f authored by Levi Tamasi on 20 December 2019, 02:03:24 UTC, committed by Levi Tamasi on 20 December 2019, 02:29:39 UTC 
BlobDB: only compare CF IDs when checking whether an API call is for the default CF (#6226)
 
Summary:
BlobDB currently only supports using the default column family. The earlier
code enforces this by comparing the `ColumnFamilyHandle` passed to the
`Get`/`Put`/etc. call with the handle returned by `DefaultColumnFamily`
(which, at the end of the day, comes from `DBImpl::default_cf_handle_`).
Since other `ColumnFamilyHandle`s can also point to the default column
family, this can reject legitimate requests as well. (As an example,
with the earlier code, the handle returned by `BlobDB::Open` cannot
actually be used in API calls.) The patch fixes this by comparing only
the IDs of the column family handles instead of the pointers themselves.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/6226

Test Plan: `make check`

Differential Revision: D19187461

Pulled By: ltamasi

fbshipit-source-id: 54ce2e12ebb1f07e6d1e70e3b1e0213dfa94bda2
1 parent d848059
Raw File
persistent_cache_helper.cc 
//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
//  This source code is licensed under both the GPLv2 (found in the
//  COPYING file in the root directory) and Apache 2.0 License
//  (found in the LICENSE.Apache file in the root directory).

#include "table/persistent_cache_helper.h"
#include "table/block_based/block_based_table_reader.h"
#include "table/format.h"

namespace rocksdb {

void PersistentCacheHelper::InsertRawPage(
    const PersistentCacheOptions& cache_options, const BlockHandle& handle,
    const char* data, const size_t size) {
  assert(cache_options.persistent_cache);
  assert(cache_options.persistent_cache->IsCompressed());

  // construct the page key
  char cache_key[BlockBasedTable::kMaxCacheKeyPrefixSize + kMaxVarint64Length];
  auto key = BlockBasedTable::GetCacheKey(cache_options.key_prefix.c_str(),
                                          cache_options.key_prefix.size(),
                                          handle, cache_key);
  // insert content to cache
  cache_options.persistent_cache->Insert(key, data, size);
}

void PersistentCacheHelper::InsertUncompressedPage(
    const PersistentCacheOptions& cache_options, const BlockHandle& handle,
    const BlockContents& contents) {
  assert(cache_options.persistent_cache);
  assert(!cache_options.persistent_cache->IsCompressed());
  // Precondition:
  // (1) content is cacheable
  // (2) content is not compressed

  // construct the page key
  char cache_key[BlockBasedTable::kMaxCacheKeyPrefixSize + kMaxVarint64Length];
  auto key = BlockBasedTable::GetCacheKey(cache_options.key_prefix.c_str(),
                                          cache_options.key_prefix.size(),
                                          handle, cache_key);
  // insert block contents to page cache
  cache_options.persistent_cache->Insert(key, contents.data.data(),
                                         contents.data.size());
}

Status PersistentCacheHelper::LookupRawPage(
    const PersistentCacheOptions& cache_options, const BlockHandle& handle,
    std::unique_ptr<char[]>* raw_data, const size_t raw_data_size) {
#ifdef NDEBUG
  (void)raw_data_size;
#endif
  assert(cache_options.persistent_cache);
  assert(cache_options.persistent_cache->IsCompressed());

  // construct the page key
  char cache_key[BlockBasedTable::kMaxCacheKeyPrefixSize + kMaxVarint64Length];
  auto key = BlockBasedTable::GetCacheKey(cache_options.key_prefix.c_str(),
                                          cache_options.key_prefix.size(),
                                          handle, cache_key);
  // Lookup page
  size_t size;
  Status s = cache_options.persistent_cache->Lookup(key, raw_data, &size);
  if (!s.ok()) {
    // cache miss
    RecordTick(cache_options.statistics, PERSISTENT_CACHE_MISS);
    return s;
  }

  // cache hit
  assert(raw_data_size == handle.size() + kBlockTrailerSize);
  assert(size == raw_data_size);
  RecordTick(cache_options.statistics, PERSISTENT_CACHE_HIT);
  return Status::OK();
}

Status PersistentCacheHelper::LookupUncompressedPage(
    const PersistentCacheOptions& cache_options, const BlockHandle& handle,
    BlockContents* contents) {
  assert(cache_options.persistent_cache);
  assert(!cache_options.persistent_cache->IsCompressed());
  if (!contents) {
    // We shouldn't lookup in the cache. Either
    // (1) Nowhere to store
    return Status::NotFound();
  }

  // construct the page key
  char cache_key[BlockBasedTable::kMaxCacheKeyPrefixSize + kMaxVarint64Length];
  auto key = BlockBasedTable::GetCacheKey(cache_options.key_prefix.c_str(),
                                          cache_options.key_prefix.size(),
                                          handle, cache_key);
  // Lookup page
  std::unique_ptr<char[]> data;
  size_t size;
  Status s = cache_options.persistent_cache->Lookup(key, &data, &size);
  if (!s.ok()) {
    // cache miss
    RecordTick(cache_options.statistics, PERSISTENT_CACHE_MISS);
    return s;
  }

  // please note we are potentially comparing compressed data size with
  // uncompressed data size
  assert(handle.size() <= size);

  // update stats
  RecordTick(cache_options.statistics, PERSISTENT_CACHE_HIT);
  // construct result and return
  *contents = BlockContents(std::move(data), size);
  return Status::OK();
}

}  // namespace rocksdb
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