Make the 'block read count' performance counters consistent (#5484)

Summary:
The patch brings the semantics of per-block-type read performance
context counters in sync with the generic block_read_count by only
incrementing the counter if the block was actually read from the file.
It also fixes index_block_read_count, which fell victim to the
refactoring in PR https://github.com/facebook/rocksdb/issues/5298.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5484

Test Plan: Extended the unit tests.

Differential Revision: D15887431

Pulled By: ltamasi

fbshipit-source-id: a3889759d0ac5759d56625d692cd828d1b9207a6

HISTORY.md

@@ -7,6 +7,7 @@
 * options.keep_log_file_num will be enforced strictly all the time. File names of all log files will be tracked, which may take significantly amount of memory if options.keep_log_file_num is large and either of options.max_log_file_size or options.log_file_time_to_roll is set.
 * Add initial support for Get/Put with user timestamps. Users can specify timestamps via ReadOptions and WriteOptions when calling DB::Get and DB::Put.
 * Accessing a partition of a partitioned filter or index through a pinned reference is no longer considered a cache hit.
+* The semantics of the per-block-type block read counts in the performance context now match those of the generic block_read_count.
 
 ### New Features
 * Add an option `snap_refresh_nanos` (default to 0.1s) to periodically refresh the snapshot list in compaction jobs. Assign to 0 to disable the feature.

table/block_based/block_based_table_reader.cc

@@ -80,14 +80,14 @@ Status ReadBlockFromFile(
     RandomAccessFileReader* file, FilePrefetchBuffer* prefetch_buffer,
     const Footer& footer, const ReadOptions& options, const BlockHandle& handle,
     std::unique_ptr<Block>* result, const ImmutableCFOptions& ioptions,
-    bool do_uncompress, bool maybe_compressed,
+    bool do_uncompress, bool maybe_compressed, BlockType block_type,
     const UncompressionDict& uncompression_dict,
     const PersistentCacheOptions& cache_options, SequenceNumber global_seqno,
     size_t read_amp_bytes_per_bit, MemoryAllocator* memory_allocator) {
   BlockContents contents;
   BlockFetcher block_fetcher(file, prefetch_buffer, footer, options, handle,
                              &contents, ioptions, do_uncompress,
-                             maybe_compressed, uncompression_dict,
+                             maybe_compressed, block_type, uncompression_dict,
                              cache_options, memory_allocator);
   Status s = block_fetcher.ReadBlockContents();
   if (s.ok()) {
@@ -603,8 +603,8 @@ class HashIndexReader : public BlockBasedTable::IndexReaderCommon {
     BlockFetcher prefixes_block_fetcher(
         file, prefetch_buffer, footer, ReadOptions(), prefixes_handle,
         &prefixes_contents, ioptions, true /*decompress*/,
-        true /*maybe_compressed*/, UncompressionDict::GetEmptyDict(),
-        cache_options, memory_allocator);
+        true /*maybe_compressed*/, BlockType::kHashIndexPrefixes,
+        UncompressionDict::GetEmptyDict(), cache_options, memory_allocator);
     s = prefixes_block_fetcher.ReadBlockContents();
     if (!s.ok()) {
       return s;
@@ -613,8 +613,8 @@ class HashIndexReader : public BlockBasedTable::IndexReaderCommon {
     BlockFetcher prefixes_meta_block_fetcher(
         file, prefetch_buffer, footer, ReadOptions(), prefixes_meta_handle,
         &prefixes_meta_contents, ioptions, true /*decompress*/,
-        true /*maybe_compressed*/, UncompressionDict::GetEmptyDict(),
-        cache_options, memory_allocator);
+        true /*maybe_compressed*/, BlockType::kHashIndexMetadata,
+        UncompressionDict::GetEmptyDict(), cache_options, memory_allocator);
     s = prefixes_meta_block_fetcher.ReadBlockContents();
     if (!s.ok()) {
       // TODO: log error
@@ -1373,7 +1373,8 @@ Status BlockBasedTable::ReadCompressionDictBlock(
         rep_->file.get(), prefetch_buffer, rep_->footer, read_options,
         rep_->compression_dict_handle, compression_dict_cont.get(),
         rep_->ioptions, false /* decompress */, false /*maybe_compressed*/,
-        UncompressionDict::GetEmptyDict(), cache_options);
+        BlockType::kCompressionDictionary, UncompressionDict::GetEmptyDict(),
+        cache_options);
     s = compression_block_fetcher.ReadBlockContents();
 
     if (!s.ok()) {
@@ -1583,7 +1584,7 @@ Status BlockBasedTable::ReadMetaBlock(FilePrefetchBuffer* prefetch_buffer,
   Status s = ReadBlockFromFile(
       rep_->file.get(), prefetch_buffer, rep_->footer, ReadOptions(),
       rep_->footer.metaindex_handle(), &meta, rep_->ioptions,
-      true /* decompress */, true /*maybe_compressed*/,
+      true /* decompress */, true /*maybe_compressed*/, BlockType::kMetaIndex,
       UncompressionDict::GetEmptyDict(), rep_->persistent_cache_options,
       kDisableGlobalSequenceNumber, 0 /* read_amp_bytes_per_bit */,
       GetMemoryAllocator(rep_->table_options));
@@ -1818,8 +1819,9 @@ FilterBlockReader* BlockBasedTable::ReadFilter(
   BlockFetcher block_fetcher(
       rep->file.get(), prefetch_buffer, rep->footer, ReadOptions(),
       filter_handle, &block, rep->ioptions, false /* decompress */,
-      false /*maybe_compressed*/, UncompressionDict::GetEmptyDict(),
-      rep->persistent_cache_options, GetMemoryAllocator(rep->table_options));
+      false /*maybe_compressed*/, BlockType::kFilter,
+      UncompressionDict::GetEmptyDict(), rep->persistent_cache_options,
+      GetMemoryAllocator(rep->table_options));
   Status s = block_fetcher.ReadBlockContents();
 
   if (!s.ok()) {
@@ -1940,7 +1942,6 @@ CachableEntry<FilterBlockReader> BlockBasedTable::GetFilter(
               ? Cache::Priority::HIGH
               : Cache::Priority::LOW);
       if (s.ok()) {
-        PERF_COUNTER_ADD(filter_block_read_count, 1);
         UpdateCacheInsertionMetrics(BlockType::kFilter, get_context, usage);
       } else {
         RecordTick(rep_->ioptions.statistics, BLOCK_CACHE_ADD_FAILURES);
@@ -2021,7 +2022,6 @@ CachableEntry<UncompressionDict> BlockBasedTable::GetUncompressionDict(
               : Cache::Priority::LOW);
 
       if (s.ok()) {
-        PERF_COUNTER_ADD(compression_dict_block_read_count, 1);
         UpdateCacheInsertionMetrics(BlockType::kCompressionDictionary,
                                     get_context, usage);
         dict = uncompression_dict.release();
@@ -2217,7 +2217,7 @@ Status BlockBasedTable::MaybeReadBlockAndLoadToCache(
             rep_->file.get(), prefetch_buffer, rep_->footer, ro, handle,
             &raw_block_contents, rep_->ioptions,
             do_decompress /* do uncompress */, rep_->blocks_maybe_compressed,
-            uncompression_dict, rep_->persistent_cache_options,
+            block_type, uncompression_dict, rep_->persistent_cache_options,
             GetMemoryAllocator(rep_->table_options),
             GetMemoryAllocatorForCompressedBlock(rep_->table_options));
         s = block_fetcher.ReadBlockContents();
@@ -2335,7 +2335,7 @@ Status BlockBasedTable::RetrieveBlock(
     s = ReadBlockFromFile(
         rep_->file.get(), prefetch_buffer, rep_->footer, ro, handle, &block,
         rep_->ioptions, rep_->blocks_maybe_compressed,
-        rep_->blocks_maybe_compressed, uncompression_dict,
+        rep_->blocks_maybe_compressed, block_type, uncompression_dict,
         rep_->persistent_cache_options, rep_->get_global_seqno(block_type),
         block_type == BlockType::kData
             ? rep_->table_options.read_amp_bytes_per_bit
@@ -3335,7 +3335,7 @@ Status BlockBasedTable::VerifyChecksumInBlocks(
     BlockFetcher block_fetcher(
         rep_->file.get(), nullptr /* prefetch buffer */, rep_->footer,
         ReadOptions(), handle, &contents, rep_->ioptions,
-        false /* decompress */, false /*maybe_compressed*/,
+        false /* decompress */, false /*maybe_compressed*/, BlockType::kData,
         UncompressionDict::GetEmptyDict(), rep_->persistent_cache_options);
     s = block_fetcher.ReadBlockContents();
     if (!s.ok()) {
@@ -3345,6 +3345,38 @@ Status BlockBasedTable::VerifyChecksumInBlocks(
   return s;
 }
 
+BlockType BlockBasedTable::GetBlockTypeForMetaBlockByName(
+    const Slice& meta_block_name) {
+  if (meta_block_name.starts_with(kFilterBlockPrefix) ||
+      meta_block_name.starts_with(kFullFilterBlockPrefix) ||
+      meta_block_name.starts_with(kPartitionedFilterBlockPrefix)) {
+    return BlockType::kFilter;
+  }
+
+  if (meta_block_name == kPropertiesBlock) {
+    return BlockType::kProperties;
+  }
+
+  if (meta_block_name == kCompressionDictBlock) {
+    return BlockType::kCompressionDictionary;
+  }
+
+  if (meta_block_name == kRangeDelBlock) {
+    return BlockType::kRangeDeletion;
+  }
+
+  if (meta_block_name == kHashIndexPrefixesBlock) {
+    return BlockType::kHashIndexPrefixes;
+  }
+
+  if (meta_block_name == kHashIndexPrefixesMetadataBlock) {
+    return BlockType::kHashIndexMetadata;
+  }
+
+  assert(false);
+  return BlockType::kInvalid;
+}
+
 Status BlockBasedTable::VerifyChecksumInMetaBlocks(
     InternalIteratorBase<Slice>* index_iter) {
   Status s;
@@ -3357,13 +3389,15 @@ Status BlockBasedTable::VerifyChecksumInMetaBlocks(
     Slice input = index_iter->value();
     s = handle.DecodeFrom(&input);
     BlockContents contents;
+    const Slice meta_block_name = index_iter->key();
     BlockFetcher block_fetcher(
         rep_->file.get(), nullptr /* prefetch buffer */, rep_->footer,
         ReadOptions(), handle, &contents, rep_->ioptions,
         false /* decompress */, false /*maybe_compressed*/,
+        GetBlockTypeForMetaBlockByName(meta_block_name),
         UncompressionDict::GetEmptyDict(), rep_->persistent_cache_options);
     s = block_fetcher.ReadBlockContents();
-    if (s.IsCorruption() && index_iter->key() == kPropertiesBlock) {
+    if (s.IsCorruption() && meta_block_name == kPropertiesBlock) {
       TableProperties* table_properties;
       s = TryReadPropertiesWithGlobalSeqno(nullptr /* prefetch_buffer */,
                                            index_iter->value(),
@@ -3662,7 +3696,7 @@ Status BlockBasedTable::DumpTable(WritableFile* out_file,
               rep_->file.get(), nullptr /* prefetch_buffer */, rep_->footer,
               ReadOptions(), handle, &block, rep_->ioptions,
               false /*decompress*/, false /*maybe_compressed*/,
-              UncompressionDict::GetEmptyDict(),
+              BlockType::kFilter, UncompressionDict::GetEmptyDict(),
               rep_->persistent_cache_options);
           s = block_fetcher.ReadBlockContents();
           if (!s.ok()) {

table/block_based/block_based_table_reader.h

@@ -407,6 +407,8 @@ class BlockBasedTable : public TableReader {
       const BlockBasedTableOptions& table_options, const int level,
       BlockCacheLookupContext* lookup_context);
 
+  static BlockType GetBlockTypeForMetaBlockByName(const Slice& meta_block_name);
+
   Status VerifyChecksumInMetaBlocks(InternalIteratorBase<Slice>* index_iter);
   Status VerifyChecksumInBlocks(InternalIteratorBase<BlockHandle>* index_iter);
 

table/block_based/block_type.h

@@ -5,6 +5,8 @@
 
 #pragma once
 
+#include <cstdint>
+
 namespace rocksdb {
 
 // Represents the types of blocks used in the block based table format.
@@ -17,8 +19,12 @@ enum class BlockType : uint8_t {
   kProperties,
   kCompressionDictionary,
   kRangeDeletion,
+  kHashIndexPrefixes,
+  kHashIndexMetadata,
   kMetaIndex,
   kIndex,
+  // Note: keep kInvalid the last value when adding new enum values.
+  kInvalid
 };
 
 }  // namespace rocksdb

table/block_fetcher.cc

@@ -220,6 +220,26 @@ Status BlockFetcher::ReadBlockContents() {
                             &slice_, used_buf_);
     }
     PERF_COUNTER_ADD(block_read_count, 1);
+
+    // TODO: introduce dedicated perf counter for range tombstones
+    switch (block_type_) {
+      case BlockType::kFilter:
+        PERF_COUNTER_ADD(filter_block_read_count, 1);
+        break;
+
+      case BlockType::kCompressionDictionary:
+        PERF_COUNTER_ADD(compression_dict_block_read_count, 1);
+        break;
+
+      case BlockType::kIndex:
+        PERF_COUNTER_ADD(index_block_read_count, 1);
+        break;
+
+      // Nothing to do here as we don't have counters for the other types.
+      default:
+        break;
+    }
+
     PERF_COUNTER_ADD(block_read_byte, block_size_ + kBlockTrailerSize);
     if (!status_.ok()) {
       return status_;

table/block_fetcher.h

@@ -10,6 +10,7 @@
 #pragma once
 #include "memory/memory_allocator.h"
 #include "table/block_based/block.h"
+#include "table/block_based/block_type.h"
 #include "table/format.h"
 
 namespace rocksdb {
@@ -39,7 +40,7 @@ class BlockFetcher {
                FilePrefetchBuffer* prefetch_buffer, const Footer& footer,
                const ReadOptions& read_options, const BlockHandle& handle,
                BlockContents* contents, const ImmutableCFOptions& ioptions,
-               bool do_uncompress, bool maybe_compressed,
+               bool do_uncompress, bool maybe_compressed, BlockType block_type,
                const UncompressionDict& uncompression_dict,
                const PersistentCacheOptions& cache_options,
                MemoryAllocator* memory_allocator = nullptr,
@@ -53,6 +54,7 @@ class BlockFetcher {
         ioptions_(ioptions),
         do_uncompress_(do_uncompress),
         maybe_compressed_(maybe_compressed),
+        block_type_(block_type),
         uncompression_dict_(uncompression_dict),
         cache_options_(cache_options),
         memory_allocator_(memory_allocator),
@@ -72,6 +74,7 @@ class BlockFetcher {
   const ImmutableCFOptions& ioptions_;
   bool do_uncompress_;
   bool maybe_compressed_;
+  BlockType block_type_;
   const UncompressionDict& uncompression_dict_;
   const PersistentCacheOptions& cache_options_;
   MemoryAllocator* memory_allocator_;

table/meta_blocks.cc

@@ -216,7 +216,8 @@ Status ReadProperties(const Slice& handle_value, RandomAccessFileReader* file,
   BlockFetcher block_fetcher(
       file, prefetch_buffer, footer, read_options, handle, &block_contents,
       ioptions, false /* decompress */, false /*maybe_compressed*/,
-      UncompressionDict::GetEmptyDict(), cache_options, memory_allocator);
+      BlockType::kProperties, UncompressionDict::GetEmptyDict(), cache_options,
+      memory_allocator);
   s = block_fetcher.ReadBlockContents();
   // property block is never compressed. Need to add uncompress logic if we are
   // to compress it..
@@ -375,8 +376,8 @@ Status ReadTableProperties(RandomAccessFileReader* file, uint64_t file_size,
   BlockFetcher block_fetcher(
       file, nullptr /* prefetch_buffer */, footer, read_options,
       metaindex_handle, &metaindex_contents, ioptions, false /* decompress */,
-      false /*maybe_compressed*/, UncompressionDict::GetEmptyDict(),
-      cache_options, memory_allocator);
+      false /*maybe_compressed*/, BlockType::kMetaIndex,
+      UncompressionDict::GetEmptyDict(), cache_options, memory_allocator);
   s = block_fetcher.ReadBlockContents();
   if (!s.ok()) {
     return s;
@@ -446,7 +447,8 @@ Status FindMetaBlock(RandomAccessFileReader* file, uint64_t file_size,
       file, nullptr /* prefetch_buffer */, footer, read_options,
       metaindex_handle, &metaindex_contents, ioptions,
       false /* do decompression */, false /*maybe_compressed*/,
-      UncompressionDict::GetEmptyDict(), cache_options, memory_allocator);
+      BlockType::kMetaIndex, UncompressionDict::GetEmptyDict(), cache_options,
+      memory_allocator);
   s = block_fetcher.ReadBlockContents();
   if (!s.ok()) {
     return s;
@@ -467,7 +469,7 @@ 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,
+                     const std::string& meta_block_name, BlockType block_type,
                      BlockContents* contents, bool /*compression_type_missing*/,
                      MemoryAllocator* memory_allocator) {
   Status status;
@@ -488,6 +490,7 @@ Status ReadMetaBlock(RandomAccessFileReader* file,
   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();
@@ -515,7 +518,7 @@ Status ReadMetaBlock(RandomAccessFileReader* file,
   // Reading metablock
   BlockFetcher block_fetcher2(
       file, prefetch_buffer, footer, read_options, block_handle, contents,
-      ioptions, false /* decompress */, false /*maybe_compressed*/,
+      ioptions, false /* decompress */, false /*maybe_compressed*/, block_type,
       UncompressionDict::GetEmptyDict(), cache_options, memory_allocator);
   return block_fetcher2.ReadBlockContents();
 }

table/meta_blocks.h

@@ -16,6 +16,7 @@
 #include "rocksdb/options.h"
 #include "rocksdb/slice.h"
 #include "table/block_based/block_builder.h"
+#include "table/block_based/block_type.h"
 #include "table/format.h"
 #include "util/kv_map.h"
 
@@ -143,7 +144,7 @@ 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,
+                     const std::string& meta_block_name, BlockType block_type,
                      BlockContents* contents,
                      bool compression_type_missing = false,
                      MemoryAllocator* memory_allocator = nullptr);

table/plain/plain_table_reader.cc

@@ -299,7 +299,7 @@ Status PlainTableReader::PopulateIndex(TableProperties* props,
   Status s = ReadMetaBlock(file_info_.file.get(), nullptr /* prefetch_buffer */,
                            file_size_, kPlainTableMagicNumber, ioptions_,
                            PlainTableIndexBuilder::kPlainTableIndexBlock,
-                           &index_block_contents,
+                           BlockType::kIndex, &index_block_contents,
                            true /* compression_type_missing */);
 
   bool index_in_file = s.ok();
@@ -310,7 +310,8 @@ Status PlainTableReader::PopulateIndex(TableProperties* props,
   if (index_in_file) {
     s = ReadMetaBlock(file_info_.file.get(), nullptr /* prefetch_buffer */,
                       file_size_, kPlainTableMagicNumber, ioptions_,
-                      BloomBlockBuilder::kBloomBlock, &bloom_block_contents,
+                      BloomBlockBuilder::kBloomBlock, BlockType::kFilter,
+                      &bloom_block_contents,
                       true /* compression_type_missing */);
     bloom_in_file = s.ok() && bloom_block_contents.data.size() > 0;
   }

table/table_test.cc

@@ -2268,6 +2268,8 @@ TEST_P(BlockBasedTableTest, BlockReadCountTest) {
       if (index_and_filter_in_cache) {
         // data, index and filter block
         ASSERT_EQ(get_perf_context()->block_read_count, 3);
+        ASSERT_EQ(get_perf_context()->index_block_read_count, 1);
+        ASSERT_EQ(get_perf_context()->filter_block_read_count, 1);
       } else {
         // just the data block
         ASSERT_EQ(get_perf_context()->block_read_count, 1);
@@ -2293,9 +2295,12 @@ TEST_P(BlockBasedTableTest, BlockReadCountTest) {
         if (bloom_filter_type == 0) {
           // with block-based, we read index and then the filter
           ASSERT_EQ(get_perf_context()->block_read_count, 2);
+          ASSERT_EQ(get_perf_context()->index_block_read_count, 1);
+          ASSERT_EQ(get_perf_context()->filter_block_read_count, 1);
         } else {
           // with full-filter, we read filter first and then we stop
           ASSERT_EQ(get_perf_context()->block_read_count, 1);
+          ASSERT_EQ(get_perf_context()->filter_block_read_count, 1);
         }
       } else {
         // filter is already in memory and it figures out that the key doesn't
@@ -3565,7 +3570,7 @@ TEST_P(BlockBasedTableTest, PropertiesBlockRestartPointTest) {
     ASSERT_OK(ReadFooterFromFile(file, nullptr /* prefetch_buffer */, file_size,
                                  &footer, kBlockBasedTableMagicNumber));
 
-    auto BlockFetchHelper = [&](const BlockHandle& handle,
+    auto BlockFetchHelper = [&](const BlockHandle& handle, BlockType block_type,
                                 BlockContents* contents) {
       ReadOptions read_options;
       read_options.verify_checksums = false;
@@ -3574,8 +3579,8 @@ TEST_P(BlockBasedTableTest, PropertiesBlockRestartPointTest) {
       BlockFetcher block_fetcher(
           file, nullptr /* prefetch_buffer */, footer, read_options, handle,
           contents, ioptions, false /* decompress */,
-          false /*maybe_compressed*/, UncompressionDict::GetEmptyDict(),
-          cache_options);
+          false /*maybe_compressed*/, block_type,
+          UncompressionDict::GetEmptyDict(), cache_options);
 
       ASSERT_OK(block_fetcher.ReadBlockContents());
     };
@@ -3584,7 +3589,8 @@ TEST_P(BlockBasedTableTest, PropertiesBlockRestartPointTest) {
     auto metaindex_handle = footer.metaindex_handle();
     BlockContents metaindex_contents;
 
-    BlockFetchHelper(metaindex_handle, &metaindex_contents);
+    BlockFetchHelper(metaindex_handle, BlockType::kMetaIndex,
+        &metaindex_contents);
     Block metaindex_block(std::move(metaindex_contents),
                           kDisableGlobalSequenceNumber);
 
@@ -3601,7 +3607,8 @@ TEST_P(BlockBasedTableTest, PropertiesBlockRestartPointTest) {
     ASSERT_OK(properties_handle.DecodeFrom(&v));
     BlockContents properties_contents;
 
-    BlockFetchHelper(properties_handle, &properties_contents);
+    BlockFetchHelper(properties_handle, BlockType::kProperties,
+        &properties_contents);
     Block properties_block(std::move(properties_contents),
                            kDisableGlobalSequenceNumber);
 
@@ -3660,8 +3667,9 @@ TEST_P(BlockBasedTableTest, PropertiesMetaBlockLast) {
   BlockFetcher block_fetcher(
       table_reader.get(), nullptr /* prefetch_buffer */, footer, ReadOptions(),
       metaindex_handle, &metaindex_contents, ioptions, false /* decompress */,
-      false /*maybe_compressed*/, UncompressionDict::GetEmptyDict(),
-      pcache_opts, nullptr /*memory_allocator*/);
+      false /*maybe_compressed*/, BlockType::kMetaIndex,
+      UncompressionDict::GetEmptyDict(), pcache_opts,
+      nullptr /*memory_allocator*/);
   ASSERT_OK(block_fetcher.ReadBlockContents());
   Block metaindex_block(std::move(metaindex_contents),
                         kDisableGlobalSequenceNumber);