rocksdb/table/sst_file_reader.cc
Levi Tamasi 61932cdf1d Add blob support to DBIter (#7731)
Summary:
The patch adds iterator support to the integrated BlobDB implementation.
Whenever a blob reference is encountered during iteration, the corresponding
blob is retrieved by calling `Version::GetBlob`, assuming the `expose_blob_index`
(formerly `allow_blob`) flag is *not* set. (Note: the flag is set by the old stacked
BlobDB implementation, which has its own blob file handling/blob retrieval logic.)

In addition, `DBIter` now uniformly returns `Status::NotSupported` with the error
message `"BlobDB does not support merge operator."` when encountering a
blob reference while performing a merge (instead of potentially returning a
message that implies the database should be opened using the stacked BlobDB's
`Open`.)

TODO: We can implement support for lazily retrieving the blob value (or in other
words, bypassing the retrieval of blob values based on key) by extending the `Iterator`
API with a new `PrepareValue` method (similarly to `InternalIterator`, which already
supports lazy values).

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7731

Test Plan: `make check`

Reviewed By: riversand963

Differential Revision: D25256293

Pulled By: ltamasi

fbshipit-source-id: c39cd782011495a526cdff99c16f5fca400c4811
2020-12-04 21:29:38 -08:00

99 lines
3.3 KiB
C++

// 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).
#ifndef ROCKSDB_LITE
#include "rocksdb/sst_file_reader.h"
#include "db/arena_wrapped_db_iter.h"
#include "db/db_iter.h"
#include "db/dbformat.h"
#include "env/composite_env_wrapper.h"
#include "file/random_access_file_reader.h"
#include "options/cf_options.h"
#include "table/get_context.h"
#include "table/table_builder.h"
#include "table/table_reader.h"
namespace ROCKSDB_NAMESPACE {
struct SstFileReader::Rep {
Options options;
EnvOptions soptions;
ImmutableCFOptions ioptions;
MutableCFOptions moptions;
std::unique_ptr<TableReader> table_reader;
Rep(const Options& opts)
: options(opts),
soptions(options),
ioptions(options),
moptions(ColumnFamilyOptions(options)) {}
};
SstFileReader::SstFileReader(const Options& options) : rep_(new Rep(options)) {}
SstFileReader::~SstFileReader() {}
Status SstFileReader::Open(const std::string& file_path) {
auto r = rep_.get();
Status s;
uint64_t file_size = 0;
std::unique_ptr<RandomAccessFile> file;
std::unique_ptr<RandomAccessFileReader> file_reader;
s = r->options.env->GetFileSize(file_path, &file_size);
if (s.ok()) {
s = r->options.env->NewRandomAccessFile(file_path, &file, r->soptions);
}
if (s.ok()) {
file_reader.reset(new RandomAccessFileReader(
NewLegacyRandomAccessFileWrapper(file), file_path));
}
if (s.ok()) {
TableReaderOptions t_opt(r->ioptions, r->moptions.prefix_extractor.get(),
r->soptions, r->ioptions.internal_comparator);
// Allow open file with global sequence number for backward compatibility.
t_opt.largest_seqno = kMaxSequenceNumber;
s = r->options.table_factory->NewTableReader(t_opt, std::move(file_reader),
file_size, &r->table_reader);
}
return s;
}
Iterator* SstFileReader::NewIterator(const ReadOptions& roptions) {
auto r = rep_.get();
auto sequence = roptions.snapshot != nullptr
? roptions.snapshot->GetSequenceNumber()
: kMaxSequenceNumber;
ArenaWrappedDBIter* res = new ArenaWrappedDBIter();
res->Init(r->options.env, roptions, r->ioptions, r->moptions,
nullptr /* version */, sequence,
r->moptions.max_sequential_skip_in_iterations,
0 /* version_number */, nullptr /* read_callback */,
nullptr /* db_impl */, nullptr /* cfd */,
true /* expose_blob_index */, false /* allow_refresh */);
auto internal_iter = r->table_reader->NewIterator(
res->GetReadOptions(), r->moptions.prefix_extractor.get(),
res->GetArena(), false /* skip_filters */,
TableReaderCaller::kSSTFileReader);
res->SetIterUnderDBIter(internal_iter);
return res;
}
std::shared_ptr<const TableProperties> SstFileReader::GetTableProperties()
const {
return rep_->table_reader->GetTableProperties();
}
Status SstFileReader::VerifyChecksum(const ReadOptions& read_options) {
return rep_->table_reader->VerifyChecksum(read_options,
TableReaderCaller::kSSTFileReader);
}
} // namespace ROCKSDB_NAMESPACE
#endif // !ROCKSDB_LITE