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rocksdb/table/mock_table.cc

149 lines
4.7 KiB

// 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/mock_table.h"
#include "db/dbformat.h"
Introduce a new storage specific Env API (#5761) Summary: The current Env API encompasses both storage/file operations, as well as OS related operations. Most of the APIs return a Status, which does not have enough metadata about an error, such as whether its retry-able or not, scope (i.e fault domain) of the error etc., that may be required in order to properly handle a storage error. The file APIs also do not provide enough control over the IO SLA, such as timeout, prioritization, hinting about placement and redundancy etc. This PR separates out the file/storage APIs from Env into a new FileSystem class. The APIs are updated to return an IOStatus with metadata about the error, as well as to take an IOOptions structure as input in order to allow more control over the IO. The user can set both ```options.env``` and ```options.file_system``` to specify that RocksDB should use the former for OS related operations and the latter for storage operations. Internally, a ```CompositeEnvWrapper``` has been introduced that inherits from ```Env``` and redirects individual methods to either an ```Env``` implementation or the ```FileSystem``` as appropriate. When options are sanitized during ```DB::Open```, ```options.env``` is replaced with a newly allocated ```CompositeEnvWrapper``` instance if both env and file_system have been specified. This way, the rest of the RocksDB code can continue to function as before. This PR also ports PosixEnv to the new API by splitting it into two - PosixEnv and PosixFileSystem. PosixEnv is defined as a sub-class of CompositeEnvWrapper, and threading/time functions are overridden with Posix specific implementations in order to avoid an extra level of indirection. The ```CompositeEnvWrapper``` translates ```IOStatus``` return code to ```Status```, and sets the severity to ```kSoftError``` if the io_status is retryable. The error handling code in RocksDB can then recover the DB automatically. Pull Request resolved: https://github.com/facebook/rocksdb/pull/5761 Differential Revision: D18868376 Pulled By: anand1976 fbshipit-source-id: 39efe18a162ea746fabac6360ff529baba48486f
5 years ago
#include "env/composite_env_wrapper.h"
#include "file/random_access_file_reader.h"
#include "port/port.h"
#include "rocksdb/table_properties.h"
#include "table/get_context.h"
#include "util/coding.h"
namespace ROCKSDB_NAMESPACE {
namespace mock {
namespace {
const InternalKeyComparator icmp_(BytewiseComparator());
} // namespace
stl_wrappers::KVMap MakeMockFile(
std::initializer_list<std::pair<const std::string, std::string>> l) {
return stl_wrappers::KVMap(l, stl_wrappers::LessOfComparator(&icmp_));
}
InternalIterator* MockTableReader::NewIterator(
const ReadOptions&, const SliceTransform* /* prefix_extractor */,
Arena* /*arena*/, bool /*skip_filters*/, TableReaderCaller /*caller*/,
Properly report IO errors when IndexType::kBinarySearchWithFirstKey is used (#6621) Summary: Context: Index type `kBinarySearchWithFirstKey` added the ability for sst file iterator to sometimes report a key from index without reading the corresponding data block. This is useful when sst blocks are cut at some meaningful boundaries (e.g. one block per key prefix), and many seeks land between blocks (e.g. for each prefix, the ranges of keys in different sst files are nearly disjoint, so a typical seek needs to read a data block from only one file even if all files have the prefix). But this added a new error condition, which rocksdb code was really not equipped to deal with: `InternalIterator::value()` may fail with an IO error or Status::Incomplete, but it's just a method returning a Slice, with no way to report error instead. Before this PR, this type of error wasn't handled at all (an empty slice was returned), and kBinarySearchWithFirstKey implementation was considered a prototype. Now that we (LogDevice) have experimented with kBinarySearchWithFirstKey for a while and confirmed that it's really useful, this PR is adding the missing error handling. It's a pretty inconvenient situation implementation-wise. The error needs to be reported from InternalIterator when trying to access value. But there are ~700 call sites of `InternalIterator::value()`, most of which either can't hit the error condition (because the iterator is reading from memtable or from index or something) or wouldn't benefit from the deferred loading of the value (e.g. compaction iterator that reads all values anyway). Adding error handling to all these call sites would needlessly bloat the code. So instead I made the deferred value loading optional: only the call sites that may use deferred loading have to call the new method `PrepareValue()` before calling `value()`. The feature is enabled with a new bool argument `allow_unprepared_value` to a bunch of methods that create iterators (it wouldn't make sense to put it in ReadOptions because it's completely internal to iterators, with virtually no user-visible effect). Lmk if you have better ideas. Note that the deferred value loading only happens for *internal* iterators. The user-visible iterator (DBIter) always prepares the value before returning from Seek/Next/etc. We could go further and add an API to defer that value loading too, but that's most likely not useful for LogDevice, so it doesn't seem worth the complexity for now. Pull Request resolved: https://github.com/facebook/rocksdb/pull/6621 Test Plan: make -j5 check . Will also deploy to some logdevice test clusters and look at stats. Reviewed By: siying Differential Revision: D20786930 Pulled By: al13n321 fbshipit-source-id: 6da77d918bad3780522e918f17f4d5513d3e99ee
5 years ago
size_t /*compaction_readahead_size*/, bool /* allow_unprepared_value */) {
return new MockTableIterator(table_);
}
Status MockTableReader::Get(const ReadOptions&, const Slice& key,
GetContext* get_context,
const SliceTransform* /*prefix_extractor*/,
bool /*skip_filters*/) {
std::unique_ptr<MockTableIterator> iter(new MockTableIterator(table_));
for (iter->Seek(key); iter->Valid(); iter->Next()) {
ParsedInternalKey parsed_key;
if (!ParseInternalKey(iter->key(), &parsed_key)) {
return Status::Corruption(Slice());
}
bool dont_care __attribute__((__unused__));
if (!get_context->SaveValue(parsed_key, iter->value(), &dont_care)) {
break;
}
}
return Status::OK();
}
std::shared_ptr<const TableProperties> MockTableReader::GetTableProperties()
const {
return std::shared_ptr<const TableProperties>(new TableProperties());
}
MockTableFactory::MockTableFactory() : next_id_(1) {}
Status MockTableFactory::NewTableReader(
const TableReaderOptions& /*table_reader_options*/,
std::unique_ptr<RandomAccessFileReader>&& file, uint64_t /*file_size*/,
std::unique_ptr<TableReader>* table_reader,
bool /*prefetch_index_and_filter_in_cache*/) const {
uint32_t id = GetIDFromFile(file.get());
MutexLock lock_guard(&file_system_.mutex);
auto it = file_system_.files.find(id);
if (it == file_system_.files.end()) {
return Status::IOError("Mock file not found");
}
table_reader->reset(new MockTableReader(it->second));
return Status::OK();
}
TableBuilder* MockTableFactory::NewTableBuilder(
const TableBuilderOptions& /*table_builder_options*/,
uint32_t /*column_family_id*/, WritableFileWriter* file) const {
uint32_t id = GetAndWriteNextID(file);
return new MockTableBuilder(id, &file_system_);
}
Status MockTableFactory::CreateMockTable(Env* env, const std::string& fname,
stl_wrappers::KVMap file_contents) {
std::unique_ptr<WritableFile> file;
auto s = env->NewWritableFile(fname, &file, EnvOptions());
if (!s.ok()) {
return s;
}
Introduce a new storage specific Env API (#5761) Summary: The current Env API encompasses both storage/file operations, as well as OS related operations. Most of the APIs return a Status, which does not have enough metadata about an error, such as whether its retry-able or not, scope (i.e fault domain) of the error etc., that may be required in order to properly handle a storage error. The file APIs also do not provide enough control over the IO SLA, such as timeout, prioritization, hinting about placement and redundancy etc. This PR separates out the file/storage APIs from Env into a new FileSystem class. The APIs are updated to return an IOStatus with metadata about the error, as well as to take an IOOptions structure as input in order to allow more control over the IO. The user can set both ```options.env``` and ```options.file_system``` to specify that RocksDB should use the former for OS related operations and the latter for storage operations. Internally, a ```CompositeEnvWrapper``` has been introduced that inherits from ```Env``` and redirects individual methods to either an ```Env``` implementation or the ```FileSystem``` as appropriate. When options are sanitized during ```DB::Open```, ```options.env``` is replaced with a newly allocated ```CompositeEnvWrapper``` instance if both env and file_system have been specified. This way, the rest of the RocksDB code can continue to function as before. This PR also ports PosixEnv to the new API by splitting it into two - PosixEnv and PosixFileSystem. PosixEnv is defined as a sub-class of CompositeEnvWrapper, and threading/time functions are overridden with Posix specific implementations in order to avoid an extra level of indirection. The ```CompositeEnvWrapper``` translates ```IOStatus``` return code to ```Status```, and sets the severity to ```kSoftError``` if the io_status is retryable. The error handling code in RocksDB can then recover the DB automatically. Pull Request resolved: https://github.com/facebook/rocksdb/pull/5761 Differential Revision: D18868376 Pulled By: anand1976 fbshipit-source-id: 39efe18a162ea746fabac6360ff529baba48486f
5 years ago
WritableFileWriter file_writer(NewLegacyWritableFileWrapper(std::move(file)),
fname, EnvOptions());
uint32_t id = GetAndWriteNextID(&file_writer);
file_system_.files.insert({id, std::move(file_contents)});
return Status::OK();
}
uint32_t MockTableFactory::GetAndWriteNextID(WritableFileWriter* file) const {
uint32_t next_id = next_id_.fetch_add(1);
char buf[4];
EncodeFixed32(buf, next_id);
file->Append(Slice(buf, 4));
return next_id;
}
uint32_t MockTableFactory::GetIDFromFile(RandomAccessFileReader* file) const {
char buf[4];
Slice result;
file->Read(IOOptions(), 0, 4, &result, buf, nullptr);
assert(result.size() == 4);
return DecodeFixed32(buf);
}
void MockTableFactory::AssertSingleFile(
const stl_wrappers::KVMap& file_contents) {
ASSERT_EQ(file_system_.files.size(), 1U);
ASSERT_EQ(file_contents, file_system_.files.begin()->second);
}
void MockTableFactory::AssertLatestFile(
const stl_wrappers::KVMap& file_contents) {
ASSERT_GE(file_system_.files.size(), 1U);
auto latest = file_system_.files.end();
--latest;
if (file_contents != latest->second) {
std::cout << "Wrong content! Content of latest file:" << std::endl;
for (const auto& kv : latest->second) {
ParsedInternalKey ikey;
std::string key, value;
std::tie(key, value) = kv;
ParseInternalKey(Slice(key), &ikey);
std::cout << ikey.DebugString(false) << " -> " << value << std::endl;
}
FAIL();
}
}
} // namespace mock
} // namespace ROCKSDB_NAMESPACE