b4d7209428
Summary: The first key is used to defer reading the data block until this file gets to the top of merging iterator's heap. For short range scans, most files never make it to the top of the heap, so this change can reduce read amplification by a lot sometimes. Consider the following workload. There are a few data streams (we'll be calling them "logs"), each stream consisting of a sequence of blobs (we'll be calling them "records"). Each record is identified by log ID and a sequence number within the log. RocksDB key is concatenation of log ID and sequence number (big endian). Reads are mostly relatively short range scans, each within a single log. Writes are mostly sequential for each log, but writes to different logs are randomly interleaved. Compactions are disabled; instead, when we accumulate a few tens of sst files, we create a new column family and start writing to it. So, a typical sst file consists of a few ranges of blocks, each range corresponding to one log ID (we use FlushBlockPolicy to cut blocks at log boundaries). A typical read would go like this. First, iterator Seek() reads one block from each sst file. Then a series of Next()s move through one sst file (since writes to each log are mostly sequential) until the subiterator reaches the end of this log in this sst file; then Next() switches to the next sst file and reads sequentially from that, and so on. Often a range scan will only return records from a small number of blocks in small number of sst files; in this case, the cost of initial Seek() reading one block from each file may be bigger than the cost of reading the actually useful blocks. Neither iterate_upper_bound nor bloom filters can prevent reading one block from each file in Seek(). But this PR can: if the index contains first key from each block, we don't have to read the block until this block actually makes it to the top of merging iterator's heap, so for short range scans we won't read any blocks from most of the sst files. This PR does the deferred block loading inside value() call. This is not ideal: there's no good way to report an IO error from inside value(). As discussed with siying offline, it would probably be better to change InternalIterator's interface to explicitly fetch deferred value and get status. I'll do it in a separate PR. Pull Request resolved: https://github.com/facebook/rocksdb/pull/5289 Differential Revision: D15256423 Pulled By: al13n321 fbshipit-source-id: 750e4c39ce88e8d41662f701cf6275d9388ba46a
525 lines
20 KiB
C++
525 lines
20 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under both the GPLv2 (found in the
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// COPYING file in the root directory) and Apache 2.0 License
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// (found in the LICENSE.Apache file in the root directory).
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#include "table/meta_blocks.h"
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#include <map>
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#include <string>
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#include "block_fetcher.h"
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#include "db/table_properties_collector.h"
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#include "rocksdb/table.h"
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#include "rocksdb/table_properties.h"
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#include "table/block_based/block.h"
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#include "table/format.h"
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#include "table/internal_iterator.h"
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#include "table/persistent_cache_helper.h"
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#include "table/table_properties_internal.h"
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#include "test_util/sync_point.h"
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#include "util/coding.h"
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#include "util/file_reader_writer.h"
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namespace rocksdb {
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MetaIndexBuilder::MetaIndexBuilder()
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: meta_index_block_(new BlockBuilder(1 /* restart interval */)) {}
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void MetaIndexBuilder::Add(const std::string& key,
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const BlockHandle& handle) {
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std::string handle_encoding;
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handle.EncodeTo(&handle_encoding);
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meta_block_handles_.insert({key, handle_encoding});
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}
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Slice MetaIndexBuilder::Finish() {
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for (const auto& metablock : meta_block_handles_) {
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meta_index_block_->Add(metablock.first, metablock.second);
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}
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return meta_index_block_->Finish();
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}
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// Property block will be read sequentially and cached in a heap located
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// object, so there's no need for restart points. Thus we set the restart
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// interval to infinity to save space.
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PropertyBlockBuilder::PropertyBlockBuilder()
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: properties_block_(
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new BlockBuilder(port::kMaxInt32 /* restart interval */)) {}
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void PropertyBlockBuilder::Add(const std::string& name,
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const std::string& val) {
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props_.insert({name, val});
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}
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void PropertyBlockBuilder::Add(const std::string& name, uint64_t val) {
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assert(props_.find(name) == props_.end());
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std::string dst;
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PutVarint64(&dst, val);
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Add(name, dst);
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}
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void PropertyBlockBuilder::Add(
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const UserCollectedProperties& user_collected_properties) {
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for (const auto& prop : user_collected_properties) {
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Add(prop.first, prop.second);
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}
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}
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void PropertyBlockBuilder::AddTableProperty(const TableProperties& props) {
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TEST_SYNC_POINT_CALLBACK("PropertyBlockBuilder::AddTableProperty:Start",
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const_cast<TableProperties*>(&props));
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Add(TablePropertiesNames::kRawKeySize, props.raw_key_size);
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Add(TablePropertiesNames::kRawValueSize, props.raw_value_size);
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Add(TablePropertiesNames::kDataSize, props.data_size);
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Add(TablePropertiesNames::kIndexSize, props.index_size);
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if (props.index_partitions != 0) {
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Add(TablePropertiesNames::kIndexPartitions, props.index_partitions);
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Add(TablePropertiesNames::kTopLevelIndexSize, props.top_level_index_size);
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}
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Add(TablePropertiesNames::kIndexKeyIsUserKey, props.index_key_is_user_key);
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Add(TablePropertiesNames::kIndexValueIsDeltaEncoded,
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props.index_value_is_delta_encoded);
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Add(TablePropertiesNames::kNumEntries, props.num_entries);
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Add(TablePropertiesNames::kDeletedKeys, props.num_deletions);
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Add(TablePropertiesNames::kMergeOperands, props.num_merge_operands);
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Add(TablePropertiesNames::kNumRangeDeletions, props.num_range_deletions);
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Add(TablePropertiesNames::kNumDataBlocks, props.num_data_blocks);
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Add(TablePropertiesNames::kFilterSize, props.filter_size);
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Add(TablePropertiesNames::kFormatVersion, props.format_version);
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Add(TablePropertiesNames::kFixedKeyLen, props.fixed_key_len);
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Add(TablePropertiesNames::kColumnFamilyId, props.column_family_id);
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Add(TablePropertiesNames::kCreationTime, props.creation_time);
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Add(TablePropertiesNames::kOldestKeyTime, props.oldest_key_time);
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if (props.file_creation_time > 0) {
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Add(TablePropertiesNames::kFileCreationTime, props.file_creation_time);
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}
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if (!props.filter_policy_name.empty()) {
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Add(TablePropertiesNames::kFilterPolicy, props.filter_policy_name);
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}
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if (!props.comparator_name.empty()) {
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Add(TablePropertiesNames::kComparator, props.comparator_name);
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}
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if (!props.merge_operator_name.empty()) {
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Add(TablePropertiesNames::kMergeOperator, props.merge_operator_name);
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}
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if (!props.prefix_extractor_name.empty()) {
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Add(TablePropertiesNames::kPrefixExtractorName,
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props.prefix_extractor_name);
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}
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if (!props.property_collectors_names.empty()) {
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Add(TablePropertiesNames::kPropertyCollectors,
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props.property_collectors_names);
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}
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if (!props.column_family_name.empty()) {
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Add(TablePropertiesNames::kColumnFamilyName, props.column_family_name);
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}
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if (!props.compression_name.empty()) {
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Add(TablePropertiesNames::kCompression, props.compression_name);
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}
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if (!props.compression_options.empty()) {
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Add(TablePropertiesNames::kCompressionOptions, props.compression_options);
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}
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}
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Slice PropertyBlockBuilder::Finish() {
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for (const auto& prop : props_) {
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properties_block_->Add(prop.first, prop.second);
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}
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return properties_block_->Finish();
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}
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void LogPropertiesCollectionError(
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Logger* info_log, const std::string& method, const std::string& name) {
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assert(method == "Add" || method == "Finish");
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std::string msg =
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"Encountered error when calling TablePropertiesCollector::" +
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method + "() with collector name: " + name;
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ROCKS_LOG_ERROR(info_log, "%s", msg.c_str());
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}
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bool NotifyCollectTableCollectorsOnAdd(
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const Slice& key, const Slice& value, uint64_t file_size,
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const std::vector<std::unique_ptr<IntTblPropCollector>>& collectors,
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Logger* info_log) {
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bool all_succeeded = true;
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for (auto& collector : collectors) {
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Status s = collector->InternalAdd(key, value, file_size);
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all_succeeded = all_succeeded && s.ok();
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if (!s.ok()) {
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LogPropertiesCollectionError(info_log, "Add" /* method */,
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collector->Name());
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}
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}
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return all_succeeded;
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}
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void NotifyCollectTableCollectorsOnBlockAdd(
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const std::vector<std::unique_ptr<IntTblPropCollector>>& collectors,
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const uint64_t blockRawBytes, const uint64_t blockCompressedBytesFast,
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const uint64_t blockCompressedBytesSlow) {
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for (auto& collector : collectors) {
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collector->BlockAdd(blockRawBytes, blockCompressedBytesFast,
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blockCompressedBytesSlow);
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}
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}
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bool NotifyCollectTableCollectorsOnFinish(
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const std::vector<std::unique_ptr<IntTblPropCollector>>& collectors,
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Logger* info_log, PropertyBlockBuilder* builder) {
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bool all_succeeded = true;
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for (auto& collector : collectors) {
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UserCollectedProperties user_collected_properties;
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Status s = collector->Finish(&user_collected_properties);
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all_succeeded = all_succeeded && s.ok();
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if (!s.ok()) {
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LogPropertiesCollectionError(info_log, "Finish" /* method */,
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collector->Name());
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} else {
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builder->Add(user_collected_properties);
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}
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}
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return all_succeeded;
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}
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Status ReadProperties(const Slice& handle_value, RandomAccessFileReader* file,
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FilePrefetchBuffer* prefetch_buffer, const Footer& footer,
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const ImmutableCFOptions& ioptions,
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TableProperties** table_properties, bool verify_checksum,
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BlockHandle* ret_block_handle,
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CacheAllocationPtr* verification_buf,
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bool /*compression_type_missing*/,
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MemoryAllocator* memory_allocator) {
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assert(table_properties);
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Slice v = handle_value;
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BlockHandle handle;
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if (!handle.DecodeFrom(&v).ok()) {
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return Status::InvalidArgument("Failed to decode properties block handle");
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}
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BlockContents block_contents;
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ReadOptions read_options;
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read_options.verify_checksums = verify_checksum;
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Status s;
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PersistentCacheOptions cache_options;
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BlockFetcher block_fetcher(
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file, prefetch_buffer, footer, read_options, handle, &block_contents,
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ioptions, false /* decompress */, false /*maybe_compressed*/,
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BlockType::kProperties, UncompressionDict::GetEmptyDict(), cache_options,
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memory_allocator);
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s = block_fetcher.ReadBlockContents();
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// property block is never compressed. Need to add uncompress logic if we are
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// to compress it..
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if (!s.ok()) {
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return s;
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}
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Block properties_block(std::move(block_contents),
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kDisableGlobalSequenceNumber);
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DataBlockIter iter;
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properties_block.NewDataIterator(BytewiseComparator(), BytewiseComparator(),
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&iter);
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auto new_table_properties = new TableProperties();
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// All pre-defined properties of type uint64_t
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std::unordered_map<std::string, uint64_t*> predefined_uint64_properties = {
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{TablePropertiesNames::kDataSize, &new_table_properties->data_size},
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{TablePropertiesNames::kIndexSize, &new_table_properties->index_size},
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{TablePropertiesNames::kIndexPartitions,
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&new_table_properties->index_partitions},
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{TablePropertiesNames::kTopLevelIndexSize,
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&new_table_properties->top_level_index_size},
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{TablePropertiesNames::kIndexKeyIsUserKey,
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&new_table_properties->index_key_is_user_key},
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{TablePropertiesNames::kIndexValueIsDeltaEncoded,
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&new_table_properties->index_value_is_delta_encoded},
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{TablePropertiesNames::kFilterSize, &new_table_properties->filter_size},
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{TablePropertiesNames::kRawKeySize, &new_table_properties->raw_key_size},
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{TablePropertiesNames::kRawValueSize,
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&new_table_properties->raw_value_size},
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{TablePropertiesNames::kNumDataBlocks,
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&new_table_properties->num_data_blocks},
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{TablePropertiesNames::kNumEntries, &new_table_properties->num_entries},
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{TablePropertiesNames::kDeletedKeys,
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&new_table_properties->num_deletions},
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{TablePropertiesNames::kMergeOperands,
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&new_table_properties->num_merge_operands},
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{TablePropertiesNames::kNumRangeDeletions,
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&new_table_properties->num_range_deletions},
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{TablePropertiesNames::kFormatVersion,
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&new_table_properties->format_version},
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{TablePropertiesNames::kFixedKeyLen,
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&new_table_properties->fixed_key_len},
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{TablePropertiesNames::kColumnFamilyId,
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&new_table_properties->column_family_id},
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{TablePropertiesNames::kCreationTime,
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&new_table_properties->creation_time},
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{TablePropertiesNames::kOldestKeyTime,
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&new_table_properties->oldest_key_time},
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{TablePropertiesNames::kFileCreationTime,
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&new_table_properties->file_creation_time},
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};
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std::string last_key;
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for (iter.SeekToFirstOrReport(); iter.Valid(); iter.NextOrReport()) {
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s = iter.status();
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if (!s.ok()) {
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break;
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}
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auto key = iter.key().ToString();
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// properties block should be strictly sorted with no duplicate key.
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if (!last_key.empty() &&
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BytewiseComparator()->Compare(key, last_key) <= 0) {
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s = Status::Corruption("properties unsorted");
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break;
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}
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last_key = key;
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auto raw_val = iter.value();
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auto pos = predefined_uint64_properties.find(key);
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new_table_properties->properties_offsets.insert(
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{key, handle.offset() + iter.ValueOffset()});
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if (pos != predefined_uint64_properties.end()) {
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if (key == TablePropertiesNames::kDeletedKeys ||
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key == TablePropertiesNames::kMergeOperands) {
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// Insert in user-collected properties for API backwards compatibility
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new_table_properties->user_collected_properties.insert(
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{key, raw_val.ToString()});
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}
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// handle predefined rocksdb properties
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uint64_t val;
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if (!GetVarint64(&raw_val, &val)) {
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// skip malformed value
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auto error_msg =
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"Detect malformed value in properties meta-block:"
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"\tkey: " + key + "\tval: " + raw_val.ToString();
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ROCKS_LOG_ERROR(ioptions.info_log, "%s", error_msg.c_str());
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continue;
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}
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*(pos->second) = val;
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} else if (key == TablePropertiesNames::kFilterPolicy) {
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new_table_properties->filter_policy_name = raw_val.ToString();
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} else if (key == TablePropertiesNames::kColumnFamilyName) {
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new_table_properties->column_family_name = raw_val.ToString();
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} else if (key == TablePropertiesNames::kComparator) {
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new_table_properties->comparator_name = raw_val.ToString();
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} else if (key == TablePropertiesNames::kMergeOperator) {
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new_table_properties->merge_operator_name = raw_val.ToString();
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} else if (key == TablePropertiesNames::kPrefixExtractorName) {
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new_table_properties->prefix_extractor_name = raw_val.ToString();
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} else if (key == TablePropertiesNames::kPropertyCollectors) {
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new_table_properties->property_collectors_names = raw_val.ToString();
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} else if (key == TablePropertiesNames::kCompression) {
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new_table_properties->compression_name = raw_val.ToString();
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} else if (key == TablePropertiesNames::kCompressionOptions) {
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new_table_properties->compression_options = raw_val.ToString();
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} else {
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// handle user-collected properties
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new_table_properties->user_collected_properties.insert(
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{key, raw_val.ToString()});
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}
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}
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if (s.ok()) {
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*table_properties = new_table_properties;
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if (ret_block_handle != nullptr) {
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*ret_block_handle = handle;
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}
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if (verification_buf != nullptr) {
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size_t len = static_cast<size_t>(handle.size() + kBlockTrailerSize);
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*verification_buf = rocksdb::AllocateBlock(len, memory_allocator);
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if (verification_buf->get() != nullptr) {
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memcpy(verification_buf->get(), block_contents.data.data(), len);
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}
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}
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} else {
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delete new_table_properties;
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}
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return s;
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}
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Status ReadTableProperties(RandomAccessFileReader* file, uint64_t file_size,
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uint64_t table_magic_number,
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const ImmutableCFOptions& ioptions,
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TableProperties** properties,
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bool compression_type_missing,
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MemoryAllocator* memory_allocator) {
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// -- Read metaindex block
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Footer footer;
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auto s = ReadFooterFromFile(file, nullptr /* prefetch_buffer */, file_size,
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&footer, table_magic_number);
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if (!s.ok()) {
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return s;
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}
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auto metaindex_handle = footer.metaindex_handle();
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BlockContents metaindex_contents;
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ReadOptions read_options;
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read_options.verify_checksums = false;
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PersistentCacheOptions cache_options;
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BlockFetcher block_fetcher(
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file, nullptr /* prefetch_buffer */, footer, read_options,
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metaindex_handle, &metaindex_contents, ioptions, false /* decompress */,
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false /*maybe_compressed*/, BlockType::kMetaIndex,
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UncompressionDict::GetEmptyDict(), cache_options, memory_allocator);
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s = block_fetcher.ReadBlockContents();
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if (!s.ok()) {
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return s;
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}
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// property blocks are never compressed. Need to add uncompress logic if we
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// are to compress it.
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Block metaindex_block(std::move(metaindex_contents),
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kDisableGlobalSequenceNumber);
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std::unique_ptr<InternalIterator> meta_iter(metaindex_block.NewDataIterator(
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BytewiseComparator(), BytewiseComparator()));
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// -- Read property block
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bool found_properties_block = true;
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s = SeekToPropertiesBlock(meta_iter.get(), &found_properties_block);
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if (!s.ok()) {
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return s;
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}
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TableProperties table_properties;
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if (found_properties_block == true) {
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s = ReadProperties(
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meta_iter->value(), file, nullptr /* prefetch_buffer */, footer,
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ioptions, properties, false /* verify_checksum */,
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nullptr /* ret_block_hanel */, nullptr /* ret_block_contents */,
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compression_type_missing, memory_allocator);
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} else {
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s = Status::NotFound();
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}
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return s;
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}
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Status FindMetaBlock(InternalIterator* meta_index_iter,
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const std::string& meta_block_name,
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BlockHandle* block_handle) {
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meta_index_iter->Seek(meta_block_name);
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if (meta_index_iter->status().ok() && meta_index_iter->Valid() &&
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meta_index_iter->key() == meta_block_name) {
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Slice v = meta_index_iter->value();
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return block_handle->DecodeFrom(&v);
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} else {
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return Status::Corruption("Cannot find the meta block", meta_block_name);
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}
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}
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Status FindMetaBlock(RandomAccessFileReader* file, uint64_t file_size,
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uint64_t table_magic_number,
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const ImmutableCFOptions& ioptions,
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const std::string& meta_block_name,
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BlockHandle* block_handle,
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bool /*compression_type_missing*/,
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MemoryAllocator* memory_allocator) {
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Footer footer;
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auto s = ReadFooterFromFile(file, nullptr /* prefetch_buffer */, file_size,
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&footer, table_magic_number);
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if (!s.ok()) {
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return s;
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}
|
|
|
|
auto metaindex_handle = footer.metaindex_handle();
|
|
BlockContents metaindex_contents;
|
|
ReadOptions read_options;
|
|
read_options.verify_checksums = false;
|
|
PersistentCacheOptions cache_options;
|
|
BlockFetcher block_fetcher(
|
|
file, nullptr /* prefetch_buffer */, footer, read_options,
|
|
metaindex_handle, &metaindex_contents, ioptions,
|
|
false /* do decompression */, false /*maybe_compressed*/,
|
|
BlockType::kMetaIndex, UncompressionDict::GetEmptyDict(), cache_options,
|
|
memory_allocator);
|
|
s = block_fetcher.ReadBlockContents();
|
|
if (!s.ok()) {
|
|
return s;
|
|
}
|
|
// meta blocks are never compressed. Need to add uncompress logic if we are to
|
|
// compress it.
|
|
Block metaindex_block(std::move(metaindex_contents),
|
|
kDisableGlobalSequenceNumber);
|
|
|
|
std::unique_ptr<InternalIterator> meta_iter;
|
|
meta_iter.reset(metaindex_block.NewDataIterator(BytewiseComparator(),
|
|
BytewiseComparator()));
|
|
|
|
return FindMetaBlock(meta_iter.get(), meta_block_name, block_handle);
|
|
}
|
|
|
|
Status ReadMetaBlock(RandomAccessFileReader* file,
|
|
FilePrefetchBuffer* prefetch_buffer, uint64_t file_size,
|
|
uint64_t table_magic_number,
|
|
const ImmutableCFOptions& ioptions,
|
|
const std::string& meta_block_name, BlockType block_type,
|
|
BlockContents* contents, bool /*compression_type_missing*/,
|
|
MemoryAllocator* memory_allocator) {
|
|
Status status;
|
|
Footer footer;
|
|
status = ReadFooterFromFile(file, prefetch_buffer, file_size, &footer,
|
|
table_magic_number);
|
|
if (!status.ok()) {
|
|
return status;
|
|
}
|
|
|
|
// Reading metaindex block
|
|
auto metaindex_handle = footer.metaindex_handle();
|
|
BlockContents metaindex_contents;
|
|
ReadOptions read_options;
|
|
read_options.verify_checksums = false;
|
|
PersistentCacheOptions cache_options;
|
|
|
|
BlockFetcher block_fetcher(
|
|
file, prefetch_buffer, footer, read_options, metaindex_handle,
|
|
&metaindex_contents, ioptions, false /* decompress */,
|
|
false /*maybe_compressed*/, BlockType::kMetaIndex,
|
|
UncompressionDict::GetEmptyDict(), cache_options, memory_allocator);
|
|
status = block_fetcher.ReadBlockContents();
|
|
if (!status.ok()) {
|
|
return status;
|
|
}
|
|
// meta block is never compressed. Need to add uncompress logic if we are to
|
|
// compress it.
|
|
|
|
// Finding metablock
|
|
Block metaindex_block(std::move(metaindex_contents),
|
|
kDisableGlobalSequenceNumber);
|
|
|
|
std::unique_ptr<InternalIterator> meta_iter;
|
|
meta_iter.reset(metaindex_block.NewDataIterator(BytewiseComparator(),
|
|
BytewiseComparator()));
|
|
|
|
BlockHandle block_handle;
|
|
status = FindMetaBlock(meta_iter.get(), meta_block_name, &block_handle);
|
|
|
|
if (!status.ok()) {
|
|
return status;
|
|
}
|
|
|
|
// Reading metablock
|
|
BlockFetcher block_fetcher2(
|
|
file, prefetch_buffer, footer, read_options, block_handle, contents,
|
|
ioptions, false /* decompress */, false /*maybe_compressed*/, block_type,
|
|
UncompressionDict::GetEmptyDict(), cache_options, memory_allocator);
|
|
return block_fetcher2.ReadBlockContents();
|
|
}
|
|
|
|
} // namespace rocksdb
|