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rocksdb/table/block_based/partitioned_index_reader.cc

186 lines
6.7 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).
//
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#include "table/block_based/partitioned_index_reader.h"
#include "file/file_util.h"
De-template block based table iterator (#6531) Summary: Right now block based table iterator is used as both of iterating data for block based table, and for the index iterator for partitioend index. This was initially convenient for introducing a new iterator and block type for new index format, while reducing code change. However, these two usage doesn't go with each other very well. For example, Prev() is never called for partitioned index iterator, and some other complexity is maintained in block based iterators, which is not needed for index iterator but maintainers will always need to reason about it. Furthermore, the template usage is not following Google C++ Style which we are following, and makes a large chunk of code tangled together. This commit separate the two iterators. Right now, here is what it is done: 1. Copy the block based iterator code into partitioned index iterator, and de-template them. 2. Remove some code not needed for partitioned index. The upper bound check and tricks are removed. We never tested performance for those tricks when partitioned index is enabled in the first place. It's unlikelyl to generate performance regression, as creating new partitioned index block is much rarer than data blocks. 3. Separate out the prefetch logic to a helper class and both classes call them. This commit will enable future follow-ups. One direction is that we might separate index iterator interface for data blocks and index blocks, as they are quite different. Pull Request resolved: https://github.com/facebook/rocksdb/pull/6531 Test Plan: build using make and cmake. And build release Differential Revision: D20473108 fbshipit-source-id: e48011783b339a4257c204cc07507b171b834b0f
5 years ago
#include "table/block_based/partitioned_index_iterator.h"
namespace ROCKSDB_NAMESPACE {
Status PartitionIndexReader::Create(
const BlockBasedTable* table, const ReadOptions& ro,
FilePrefetchBuffer* prefetch_buffer, bool use_cache, bool prefetch,
bool pin, BlockCacheLookupContext* lookup_context,
std::unique_ptr<IndexReader>* index_reader) {
assert(table != nullptr);
assert(table->get_rep());
assert(!pin || prefetch);
assert(index_reader != nullptr);
CachableEntry<Block> index_block;
if (prefetch || !use_cache) {
const Status s =
ReadIndexBlock(table, prefetch_buffer, ro, use_cache,
/*get_context=*/nullptr, lookup_context, &index_block);
if (!s.ok()) {
return s;
}
if (use_cache && !pin) {
index_block.Reset();
}
}
index_reader->reset(new PartitionIndexReader(table, std::move(index_block)));
return Status::OK();
}
InternalIteratorBase<IndexValue>* PartitionIndexReader::NewIterator(
const ReadOptions& read_options, bool /* disable_prefix_seek */,
IndexBlockIter* iter, GetContext* get_context,
BlockCacheLookupContext* lookup_context) {
const bool no_io = (read_options.read_tier == kBlockCacheTier);
CachableEntry<Block> index_block;
const Status s =
GetOrReadIndexBlock(no_io, get_context, lookup_context, &index_block);
if (!s.ok()) {
if (iter != nullptr) {
iter->Invalidate(s);
return iter;
}
return NewErrorInternalIterator<IndexValue>(s);
}
const BlockBasedTable::Rep* rep = table()->rep_;
InternalIteratorBase<IndexValue>* it = nullptr;
Statistics* kNullStats = nullptr;
// Filters are already checked before seeking the index
if (!partition_map_.empty()) {
// We don't return pinned data from index blocks, so no need
// to set `block_contents_pinned`.
it = NewTwoLevelIterator(
new BlockBasedTable::PartitionedIndexIteratorState(table(),
&partition_map_),
index_block.GetValue()->NewIndexIterator(
Separate internal and user key comparators in `BlockIter` (#6944) Summary: Replace `BlockIter::comparator_` and `IndexBlockIter::user_comparator_wrapper_` with a concrete `UserComparatorWrapper` and `InternalKeyComparator`. The motivation for this change was the inconvenience of not knowing the concrete type of `BlockIter::comparator_`, which prevented calling specialized internal key comparison functions to optimize comparison of keys with global seqno applied. Pull Request resolved: https://github.com/facebook/rocksdb/pull/6944 Test Plan: benchmark setup -- single file DBs, in-memory, no compression. "normal_db" created by regular flush; "ingestion_db" created by ingesting a file. Both DBs have same contents. ``` $ TEST_TMPDIR=/dev/shm/normal_db/ ./db_bench -benchmarks=fillrandom,compact -write_buffer_size=10485760000 -disable_auto_compactions=true -compression_type=none -num=1000000 $ ./ldb write_extern_sst ./tmp.sst --db=/dev/shm/ingestion_db/dbbench/ --compression_type=no --hex --create_if_missing < <(./sst_dump --command=scan --output_hex --file=/dev/shm/normal_db/dbbench/000007.sst | awk 'began {print "0x" substr($1, 2, length($1) - 2), "==>", "0x" $5} ; /^Sst file format: block-based/ {began=1}') $ ./ldb ingest_extern_sst ./tmp.sst --db=/dev/shm/ingestion_db/dbbench/ ``` benchmark run command: ``` $ TEST_TMPDIR=/dev/shm/$DB/ ./db_bench -benchmarks=seekrandom -seek_nexts=$SEEK_NEXT -use_existing_db=true -cache_index_and_filter_blocks=false -num=1000000 -cache_size=0 -threads=1 -reads=200000000 -mmap_read=1 -verify_checksum=false ``` results: perf improved marginally for ingestion_db and did not change significantly for normal_db: SEEK_NEXT | DB | code | ops/sec | % change -- | -- | -- | -- | -- 0 | normal_db | master | 350880 |   0 | normal_db | PR6944 | 351040 | 0.0 0 | ingestion_db | master | 343255 |   0 | ingestion_db | PR6944 | 349424 | 1.8 10 | normal_db | master | 218711 |   10 | normal_db | PR6944 | 217892 | -0.4 10 | ingestion_db | master | 220334 |   10 | ingestion_db | PR6944 | 226437 | 2.8 Reviewed By: pdillinger Differential Revision: D21924676 Pulled By: ajkr fbshipit-source-id: ea4288a2eefa8112eb6c651a671c1de18c12e538
4 years ago
internal_comparator()->user_comparator(),
rep->get_global_seqno(BlockType::kIndex), nullptr, kNullStats, true,
index_has_first_key(), index_key_includes_seq(),
index_value_is_full()));
} else {
ReadOptions ro;
ro.fill_cache = read_options.fill_cache;
ro.deadline = read_options.deadline;
// We don't return pinned data from index blocks, so no need
// to set `block_contents_pinned`.
De-template block based table iterator (#6531) Summary: Right now block based table iterator is used as both of iterating data for block based table, and for the index iterator for partitioend index. This was initially convenient for introducing a new iterator and block type for new index format, while reducing code change. However, these two usage doesn't go with each other very well. For example, Prev() is never called for partitioned index iterator, and some other complexity is maintained in block based iterators, which is not needed for index iterator but maintainers will always need to reason about it. Furthermore, the template usage is not following Google C++ Style which we are following, and makes a large chunk of code tangled together. This commit separate the two iterators. Right now, here is what it is done: 1. Copy the block based iterator code into partitioned index iterator, and de-template them. 2. Remove some code not needed for partitioned index. The upper bound check and tricks are removed. We never tested performance for those tricks when partitioned index is enabled in the first place. It's unlikelyl to generate performance regression, as creating new partitioned index block is much rarer than data blocks. 3. Separate out the prefetch logic to a helper class and both classes call them. This commit will enable future follow-ups. One direction is that we might separate index iterator interface for data blocks and index blocks, as they are quite different. Pull Request resolved: https://github.com/facebook/rocksdb/pull/6531 Test Plan: build using make and cmake. And build release Differential Revision: D20473108 fbshipit-source-id: e48011783b339a4257c204cc07507b171b834b0f
5 years ago
std::unique_ptr<InternalIteratorBase<IndexValue>> index_iter(
index_block.GetValue()->NewIndexIterator(
Separate internal and user key comparators in `BlockIter` (#6944) Summary: Replace `BlockIter::comparator_` and `IndexBlockIter::user_comparator_wrapper_` with a concrete `UserComparatorWrapper` and `InternalKeyComparator`. The motivation for this change was the inconvenience of not knowing the concrete type of `BlockIter::comparator_`, which prevented calling specialized internal key comparison functions to optimize comparison of keys with global seqno applied. Pull Request resolved: https://github.com/facebook/rocksdb/pull/6944 Test Plan: benchmark setup -- single file DBs, in-memory, no compression. "normal_db" created by regular flush; "ingestion_db" created by ingesting a file. Both DBs have same contents. ``` $ TEST_TMPDIR=/dev/shm/normal_db/ ./db_bench -benchmarks=fillrandom,compact -write_buffer_size=10485760000 -disable_auto_compactions=true -compression_type=none -num=1000000 $ ./ldb write_extern_sst ./tmp.sst --db=/dev/shm/ingestion_db/dbbench/ --compression_type=no --hex --create_if_missing < <(./sst_dump --command=scan --output_hex --file=/dev/shm/normal_db/dbbench/000007.sst | awk 'began {print "0x" substr($1, 2, length($1) - 2), "==>", "0x" $5} ; /^Sst file format: block-based/ {began=1}') $ ./ldb ingest_extern_sst ./tmp.sst --db=/dev/shm/ingestion_db/dbbench/ ``` benchmark run command: ``` $ TEST_TMPDIR=/dev/shm/$DB/ ./db_bench -benchmarks=seekrandom -seek_nexts=$SEEK_NEXT -use_existing_db=true -cache_index_and_filter_blocks=false -num=1000000 -cache_size=0 -threads=1 -reads=200000000 -mmap_read=1 -verify_checksum=false ``` results: perf improved marginally for ingestion_db and did not change significantly for normal_db: SEEK_NEXT | DB | code | ops/sec | % change -- | -- | -- | -- | -- 0 | normal_db | master | 350880 |   0 | normal_db | PR6944 | 351040 | 0.0 0 | ingestion_db | master | 343255 |   0 | ingestion_db | PR6944 | 349424 | 1.8 10 | normal_db | master | 218711 |   10 | normal_db | PR6944 | 217892 | -0.4 10 | ingestion_db | master | 220334 |   10 | ingestion_db | PR6944 | 226437 | 2.8 Reviewed By: pdillinger Differential Revision: D21924676 Pulled By: ajkr fbshipit-source-id: ea4288a2eefa8112eb6c651a671c1de18c12e538
4 years ago
internal_comparator()->user_comparator(),
rep->get_global_seqno(BlockType::kIndex), nullptr, kNullStats, true,
index_has_first_key(), index_key_includes_seq(),
De-template block based table iterator (#6531) Summary: Right now block based table iterator is used as both of iterating data for block based table, and for the index iterator for partitioend index. This was initially convenient for introducing a new iterator and block type for new index format, while reducing code change. However, these two usage doesn't go with each other very well. For example, Prev() is never called for partitioned index iterator, and some other complexity is maintained in block based iterators, which is not needed for index iterator but maintainers will always need to reason about it. Furthermore, the template usage is not following Google C++ Style which we are following, and makes a large chunk of code tangled together. This commit separate the two iterators. Right now, here is what it is done: 1. Copy the block based iterator code into partitioned index iterator, and de-template them. 2. Remove some code not needed for partitioned index. The upper bound check and tricks are removed. We never tested performance for those tricks when partitioned index is enabled in the first place. It's unlikelyl to generate performance regression, as creating new partitioned index block is much rarer than data blocks. 3. Separate out the prefetch logic to a helper class and both classes call them. This commit will enable future follow-ups. One direction is that we might separate index iterator interface for data blocks and index blocks, as they are quite different. Pull Request resolved: https://github.com/facebook/rocksdb/pull/6531 Test Plan: build using make and cmake. And build release Differential Revision: D20473108 fbshipit-source-id: e48011783b339a4257c204cc07507b171b834b0f
5 years ago
index_value_is_full()));
it = new ParititionedIndexIterator(
table(), ro, *internal_comparator(), std::move(index_iter),
lookup_context ? lookup_context->caller
: TableReaderCaller::kUncategorized);
}
assert(it != nullptr);
index_block.TransferTo(it);
return it;
// TODO(myabandeh): Update TwoLevelIterator to be able to make use of
// on-stack BlockIter while the state is on heap. Currentlly it assumes
// the first level iter is always on heap and will attempt to delete it
// in its destructor.
}
void PartitionIndexReader::CacheDependencies(const ReadOptions& ro, bool pin) {
// Before read partitions, prefetch them to avoid lots of IOs
BlockCacheLookupContext lookup_context{TableReaderCaller::kPrefetch};
const BlockBasedTable::Rep* rep = table()->rep_;
IndexBlockIter biter;
BlockHandle handle;
Statistics* kNullStats = nullptr;
CachableEntry<Block> index_block;
Status s = GetOrReadIndexBlock(false /* no_io */, nullptr /* get_context */,
&lookup_context, &index_block);
if (!s.ok()) {
ROCKS_LOG_WARN(rep->ioptions.info_log,
"Error retrieving top-level index block while trying to "
"cache index partitions: %s",
s.ToString().c_str());
IGNORE_STATUS_IF_ERROR(s);
return;
}
// We don't return pinned data from index blocks, so no need
// to set `block_contents_pinned`.
index_block.GetValue()->NewIndexIterator(
Separate internal and user key comparators in `BlockIter` (#6944) Summary: Replace `BlockIter::comparator_` and `IndexBlockIter::user_comparator_wrapper_` with a concrete `UserComparatorWrapper` and `InternalKeyComparator`. The motivation for this change was the inconvenience of not knowing the concrete type of `BlockIter::comparator_`, which prevented calling specialized internal key comparison functions to optimize comparison of keys with global seqno applied. Pull Request resolved: https://github.com/facebook/rocksdb/pull/6944 Test Plan: benchmark setup -- single file DBs, in-memory, no compression. "normal_db" created by regular flush; "ingestion_db" created by ingesting a file. Both DBs have same contents. ``` $ TEST_TMPDIR=/dev/shm/normal_db/ ./db_bench -benchmarks=fillrandom,compact -write_buffer_size=10485760000 -disable_auto_compactions=true -compression_type=none -num=1000000 $ ./ldb write_extern_sst ./tmp.sst --db=/dev/shm/ingestion_db/dbbench/ --compression_type=no --hex --create_if_missing < <(./sst_dump --command=scan --output_hex --file=/dev/shm/normal_db/dbbench/000007.sst | awk 'began {print "0x" substr($1, 2, length($1) - 2), "==>", "0x" $5} ; /^Sst file format: block-based/ {began=1}') $ ./ldb ingest_extern_sst ./tmp.sst --db=/dev/shm/ingestion_db/dbbench/ ``` benchmark run command: ``` $ TEST_TMPDIR=/dev/shm/$DB/ ./db_bench -benchmarks=seekrandom -seek_nexts=$SEEK_NEXT -use_existing_db=true -cache_index_and_filter_blocks=false -num=1000000 -cache_size=0 -threads=1 -reads=200000000 -mmap_read=1 -verify_checksum=false ``` results: perf improved marginally for ingestion_db and did not change significantly for normal_db: SEEK_NEXT | DB | code | ops/sec | % change -- | -- | -- | -- | -- 0 | normal_db | master | 350880 |   0 | normal_db | PR6944 | 351040 | 0.0 0 | ingestion_db | master | 343255 |   0 | ingestion_db | PR6944 | 349424 | 1.8 10 | normal_db | master | 218711 |   10 | normal_db | PR6944 | 217892 | -0.4 10 | ingestion_db | master | 220334 |   10 | ingestion_db | PR6944 | 226437 | 2.8 Reviewed By: pdillinger Differential Revision: D21924676 Pulled By: ajkr fbshipit-source-id: ea4288a2eefa8112eb6c651a671c1de18c12e538
4 years ago
internal_comparator()->user_comparator(),
rep->get_global_seqno(BlockType::kIndex), &biter, kNullStats, true,
index_has_first_key(), index_key_includes_seq(), index_value_is_full());
// Index partitions are assumed to be consecuitive. Prefetch them all.
// Read the first block offset
biter.SeekToFirst();
if (!biter.Valid()) {
// Empty index.
return;
}
handle = biter.value().handle;
uint64_t prefetch_off = handle.offset();
// Read the last block's offset
biter.SeekToLast();
if (!biter.Valid()) {
// Empty index.
return;
}
handle = biter.value().handle;
uint64_t last_off = handle.offset() + block_size(handle);
uint64_t prefetch_len = last_off - prefetch_off;
std::unique_ptr<FilePrefetchBuffer> prefetch_buffer;
rep->CreateFilePrefetchBuffer(0, 0, &prefetch_buffer);
IOOptions opts;
s = PrepareIOFromReadOptions(ro, rep->file->env(), opts);
if (s.ok()) {
s = prefetch_buffer->Prefetch(opts, rep->file.get(), prefetch_off,
static_cast<size_t>(prefetch_len));
}
// After prefetch, read the partitions one by one
biter.SeekToFirst();
for (; biter.Valid(); biter.Next()) {
handle = biter.value().handle;
CachableEntry<Block> block;
// TODO: Support counter batch update for partitioned index and
// filter blocks
s = table()->MaybeReadBlockAndLoadToCache(
prefetch_buffer.get(), ro, handle, UncompressionDict::GetEmptyDict(),
&block, BlockType::kIndex, /*get_context=*/nullptr, &lookup_context,
/*contents=*/nullptr);
IGNORE_STATUS_IF_ERROR(s);
assert(s.ok() || block.GetValue() == nullptr);
if (s.ok() && block.GetValue() != nullptr) {
if (block.IsCached()) {
if (pin) {
partition_map_[handle.offset()] = std::move(block);
}
}
}
}
}
} // namespace ROCKSDB_NAMESPACE