Metrics

OmniStateStore can connect to the Flink Metric framework to provide metrics for monitoring its internal status, such as memory usage and cache hit ratio, during task execution. These metrics serve as a reference for performance tuning and operational analysis in Flink scenarios.

You can add and view these metrics on the Metric page during task execution on the Flink WebUI to learn and analyze the running performance of OmniStateStore in real time.

Collecting metric data introduces additional performance overhead, which may affect task execution performance. It is recommended to enable the metric feature only during task testing or for performance-insensitive tasks.
The unit of all data volume metrics is byte, and the unit of all time metrics is second.

MemoryManager Module

**Table 1** Metric references
Metric	Description
ockdb_memory_used_fresh	Used memory of the FreshTable type.
ockdb_memory_used_slice	Used memory of the SliceTable type.
ockdb_memory_used_file	Used memory of the LSMStore type.
ockdb_memory_used_snapshot	Used memory of the Snapshot type.
ockdb_memory_used_borrow_heap	Used memory of the BorrowHeap type.
ockdb_memory_used_db	Managed memory used by a single TaskSlot.
ockdb_memory_max_fresh	Allocated memory of the FreshTable type.
ockdb_memory_max_slice	Allocated memory of the SliceTable type.
ockdb_memory_max_file	Allocated memory of the LSMStore type.
ockdb_memory_max_snapshot	Allocated memory of the Snapshot type.
ockdb_memory_max_borrow_heap	Allocated memory of the BorrowHeap type.
ockdb_memory_max_db	Managed memory allocated to a single TaskSlot.

FreshTable Module

**Table 2** Metric references
Metric	Description
ockdb_fresh_hit_count	Number of FreshTable hits.
ockdb_fresh_miss_count	Number of FreshTable misses.
ockdb_fresh_record_count	Total number of FreshTable accesses.
ockdb_fresh_flushing_record_count	Number of KV records that are being evicted by the FreshTable.
ockdb_fresh_flushing_segment_count	Number of segments that are being evicted by the FreshTable.
ockdb_fresh_flushed_record_count	Number of KV records that have been evicted by the FreshTable.
ockdb_fresh_flushed_segment_count	Number of segments that have been evicted by the FreshTable.
ockdb_fresh_segment_create_fail_count	Number of times that FreshTable fails to generate segments due to insufficient memory.
ockdb_fresh_flush_count	Total number of times that FreshTable evicts data to SliceTable.
ockdb_fresh_binary_key_size	Total size of all keys in the FreshTable.
ockdb_fresh_binary_value_size	Total size of all values in the FreshTable.
ockdb_fresh_binary_map_node_size	Total size of all MapNodes in the FreshTable.
ockdb_fresh_wasted_size	Total size of free segment space when segments in the FreshTable are evicted to the SliceTable.

SliceTable Module

**Table 3** Metric references
Metric	Description
ockdb_slice_hit_count	Number of SliceTable hits.
ockdb_slice_miss_count	Number of SliceTable misses.
ockdb_slice_read_count	Total number of SliceTable accesses.
ockdb_slice_read_avg_size	Average length of the slice chain traversed in the SliceTable during access.
ockdb_slice_evict_waiting_count	Number of slices to be evicted.
ockdb_slice_compaction_count	Completed compaction tasks in the SliceTable.
ockdb_slice_compaction_slice_count	Total number of slices for compaction in the SliceTable.
ockdb_slice_compaction_avg_slice_count	Average number of slices processed by each compaction task in the SliceTable.
ockdb_slice_chain_avg_size	Average SliceChain length.
ockdb_slice_avg_size	Average size of a single slice.

FileCache Module

**Table 4** Metric references
Metric	Description
ockdb_index_block_hit_count	Number of IndexBlock hits in the BlockCache.
ockdb_index_block_hit_size	Data volume of IndexBlock hits in the BlockCache.
ockdb_index_block_miss_count	Number of IndexBlock misses in the BlockCache.
ockdb_index_block_miss_size	Data volume of IndexBlock misses in the BlockCache.
ockdb_index_block_cache_count	Number of IndexBlocks cached in the BlockCache.
ockdb_index_block_cache_size	Size of the IndexBlock cache in the BlockCache.
ockdb_data_block_hit_count	Number of DataBlock hits in the BlockCache.
ockdb_data_block_hit_size	Data volume of DataBlock hits in the BlockCache.
ockdb_data_block_miss_count	Number of DataBlock misses in the BlockCache.
ockdb_data_block_miss_size	Data volume of DataBlock misses in the BlockCache.
ockdb_data_block_cache_count	Number of DataBlocks cached in the BlockCache.
ockdb_data_block_cache_size	Size of the DataBlock cache in the BlockCache.
ockdb_filter_hit_count	Number of FilterBlock hits in the BlockCache.
ockdb_filter_hit_size	Data volume of FilterBlock hits in the BlockCache.
ockdb_filter_miss_count	Number of FilterBlock misses in the BlockCache.
ockdb_filter_miss_size	Data volume of FilterBlock misses in the BlockCache.
ockdb_filter_cache_count	Number of FilterBlocks cached in the BlockCache.
ockdb_filter_cache_size	Size of the FilterBlock cache in the BlockCache.
ockdb_filter_success_count	Number of occurrences where the key is not present in the FilterBlock's filtered result.
ockdb_filter_exist_success_count	Number of occurrences where the key is present in the FilterBlock's filtered result and actually exists.
ockdb_filter_exist_fail_count	Number of occurrences where the key is present in the FilterBlock's filtered result but actually does not exist.

FileStore Module

**Table 5** Metric references
Metric	Description
ockdb_lsm_flush_count	Total number of files flushed by the LSMStore module to drives.
ockdb_lsm_flush_size	Total data volume of files flushed by the LSMStore module to drives.
ockdb_lsm_compaction_count	Total number of compaction tasks completed in the LSMStore module.
ockdb_lsm_hit_count	Number of LSMStore hits.
ockdb_lsm_miss_count	Number of LSMStore misses.
ockdb_level0_hit_count	Number of LSMStore Level0 file hits.
ockdb_level0_miss_count	Number of LSMStore Level0 file misses.
ockdb_level1_hit_count	Number of LSMStore Level1 file hits.
ockdb_level1_miss_count	Number of LSMStore Level1 file misses.
ockdb_level2_hit_count	Number of LSMStore Level2 file hits.
ockdb_level2_miss_count	Number of LSMStore Level2 file misses.
ockdb_above_level2_hit_count	Number of LSMStore Level3 and above file hits.
ockdb_above_level2_miss_count	Number of LSMStore Level3 and above file misses.
ockdb_level0_file_size	Total data volume of LSMStore Level0 files.
ockdb_level1_file_size	Total data volume of LSMStore Level1 files.
ockdb_level2_file_size	Total data volume of LSMStore Level2 files.
ockdb_level3_file_size	Total data volume of LSMStore Level3 files.
ockdb_above_level3_file_size	Total data volume of LSMStore Level4 and above files.
ockdb_lsm_file_size	Total data volume of files at all LSMStore layers.
ockdb_lsm_compaction_read_size	Total size of files read during LSMStore compaction task execution.
ockdb_lsm_compaction_write_size	Total size of files written during LSMStore compaction task execution.
ockdb_level0_compaction_rate	Compression rate of LSMStore Level0 files.
ockdb_level1_compaction_rate	Compression rate of LSMStore Level1 files.
ockdb_level2_compaction_rate	Compression rate of LSMStore Level2 files.
ockdb_level3_compaction_rate	Compression rate of LSMStore Level3 files.
ockdb_lsm_compaction_rate	Compression rate of files at all LSMStore levels.
ockdb_lsm_file_count	Number of files at all LSMStore levels.

Snapshot Module

**Table 6** Metric reference
Metric	Description
ockdb_snapshot_total_time	Total execution duration of the latest snapshot task.
ockdb_snapshot_upload_time	Total upload duration of the latest snapshot task.
ockdb_snapshot_file_count	Number of files created in the latest snapshot task.
ockdb_snapshot_file_size	Size of files created in the latest snapshot task.
ockdb_snapshot_incremental_size	Size of incremental files created in the latest snapshot task.
ockdb_snapshot_slice_file_count	Number of SliceTable snapshot files created in the latest snapshot task.
ockdb_snapshot_slice_incremental_file_size	Size of incremental SliceTable files created in the latest snapshot task.
ockdb_snapshot_slice_file_size	Size of SliceTable snapshot files created in the latest snapshot task.
ockdb_snapshot_sst_file_count	Number of LSMStore snapshot files created in the latest snapshot task.
ockdb_snapshot_sst_incremental_file_size	Size of incremental LSMStore files created in the latest snapshot task.
ockdb_snapshot_sst_file_size	Size of LSMStore snapshot files created in the latest snapshot task.

Restore Module

**Table 7** Metric references
Metric	Description
ockdb_restore_total_time	Total duration of the latest snapshot restoration task.
ockdb_restore_download_time	Download duration of the latest snapshot restoration task.
ockdb_restore_lazy_download_time	Lazy loading duration of the latest snapshot restoration task.

Parent topic: References