stats.md

Stats

Overview

rocksdb-js provides database-level RocksDB and transaction log stats using db.getStats() or db.getStat(statName) as well as per-store transaction log stats using log.getStats().

There are three types of stats:

• tickers - 64-bit unsigned integer counters that only ever increase (lifetime totals)
• gauges - point-in-time values (current sizes, counts, and ages) that can go up or down
• histograms - objects describing the distribution of a measurement across operations

Certain stats are only available when enableStats is true when the database was opened.

Database Stats

const db: RocksDatabase = RocksDatabase.open('path/to/db');

const basicStats: StatsDefault = db.getStats();
// or
const allStats: StatsAll = db.getStats(true);

// get a single stat
const keysWritten: number = db.getStat('rocksdb.number.keys.written');
const keysWrittenHistogram: StatsHistogramData = db.getStat('rocksdb.db.flush.micros');

Basic Stats

By default, db.getStats() returns properties only.

Name	Description	Type
commitPipeline.commitQueueDepth	Number of async commits queued on the database's commit lane but not yet started (in the default single-lane mode this covers the whole commit: log write + RocksDB commit).	gauge
commitPipeline.logQueueDepth	Number of async commits queued on the database's transaction-log lane but not yet started (always 0 in the default single-lane mode; see ROCKSDB_JS_COMMIT_THREAD=2).	gauge
rocksdb.block-cache-capacity	Capacity in bytes of the block cache.	gauge
rocksdb.block-cache-pinned-usage	Bytes occupied by pinned block cache entries.	gauge
rocksdb.block-cache-usage	Bytes currently used by block cache entries.	gauge
rocksdb.compaction-pending	1 if at least one compaction is pending, else 0.	gauge
rocksdb.cur-size-active-mem-table	Approximate size in bytes of the active memtable.	gauge
rocksdb.cur-size-all-mem-tables	Approximate size in bytes of the active and unflushed immutable memtables.	gauge
rocksdb.current-super-version-number	Current super-version number, incremented on each LSM change.	gauge
rocksdb.estimate-live-data-size	Estimated size in bytes of the live data.	gauge
rocksdb.estimate-num-keys	Estimated number of live keys.	gauge
rocksdb.estimate-pending-compaction-bytes	Estimated bytes compaction must rewrite to rebalance the LSM tree.	gauge
rocksdb.live-blob-file-size	Total size in bytes of blob files in the current version.	gauge
rocksdb.live-sst-files-size	Total size in bytes of SST files in the current version.	gauge
rocksdb.mem-table-flush-pending	1 if a memtable flush is pending, else 0.	gauge
rocksdb.num-blob-files	Number of blob files in the current version.	gauge
rocksdb.num-deletes-active-mem-table	Number of delete entries in the active memtable.	gauge
rocksdb.num-entries-active-mem-table	Number of entries in the active memtable.	gauge
rocksdb.num-immutable-mem-table	Number of immutable memtables not yet flushed.	gauge
rocksdb.num-immutable-mem-table-flushed	Number of immutable memtables already flushed.	gauge
rocksdb.num-live-versions	Number of live LSM versions (high values indicate versions held by iterators/snapshots).	gauge
rocksdb.num-running-compactions	Number of compactions currently running.	gauge
rocksdb.num-running-flushes	Number of flushes currently running.	gauge
rocksdb.oldest-snapshot-time	Unix timestamp of the oldest unreleased snapshot, or 0.	gauge
rocksdb.size-all-mem-tables	Approximate size in bytes of active, unflushed, and pinned memtables.	gauge
rocksdb.total-blob-file-size	Total size in bytes of all blob files across all versions.	gauge
rocksdb.total-sst-files-size	Total size in bytes of all SST files across all versions.	gauge
txnlog.activeMaps	Number of transaction log files currently memory-mapped, summed across all logs.	gauge
txnlog.bytesWritten	Cumulative bytes written to transaction logs (entry payload plus entry header, excluding file headers), summed across all logs.	ticker
txnlog.fileCount	Total number of transaction log files on disk, summed across all logs.	gauge
txnlog.logCount	Number of transaction log stores attached to the database.	gauge
txnlog.mappedBytes	Virtual address space in bytes reserved for memory-mapped log files, summed across all logs (on POSIX the active write file maps the full configured maxFileSize, so this is allocated address space, not resident memory).	gauge
txnlog.overlayBytes	File-backed overlay portion in bytes (POSIX only; 0 on Windows), summed across all logs — a closer proxy for real memory consumption than mappedBytes.	gauge
txnlog.pendingTransactions	Number of transactions bound to a log but not yet written via writeBatch(), summed across all logs.	gauge
txnlog.replayGapBytes	Bytes between the last flushed position and the write head (written but not yet flushed to the database), summed across all logs.	gauge
txnlog.totalSizeBytes	Total on-disk size in bytes of all transaction log files, summed across all logs.	gauge
txnlog.transactionsWritten	Cumulative number of transactions successfully written to the logs (lifetime total), summed across all logs.	ticker
txnlog.uncommittedTransactions	Number of transactions written to a log but not yet committed to RocksDB, summed across all logs.	gauge

Basic + Curated Stats

If enableStats is true when the database was opened, then db.getStats() returns everything above plus the following curated list of stats:

Name	Description	Type
rocksdb.blobdb.value.size	Distribution of blob value sizes.	histogram
rocksdb.block.cache.data.hit	Block cache hits for data blocks.	ticker
rocksdb.block.cache.data.miss	Block cache misses for data blocks.	ticker
rocksdb.block.cache.filter.hit	Block cache hits for filter blocks.	ticker
rocksdb.block.cache.filter.miss	Block cache misses for filter blocks.	ticker
rocksdb.block.cache.hit	Total block cache hits across all block types.	ticker
rocksdb.block.cache.index.hit	Block cache hits for index blocks.	ticker
rocksdb.block.cache.index.miss	Block cache misses for index blocks.	ticker
rocksdb.block.cache.miss	Total block cache misses across all block types.	ticker
rocksdb.bloom.filter.full.positive	Times a full bloom filter reported a key as possibly present.	ticker
rocksdb.bloom.filter.full.true.positive	Times a full bloom filter positive turned out to be a true positive (the key actually existed).	ticker
rocksdb.bloom.filter.useful	Times the bloom filter avoided reading a data block for a non-existent key.	ticker
rocksdb.bytes.read	Total uncompressed bytes read by Get(), MultiGet(), and iterator operations.	ticker
rocksdb.bytes.written	Total uncompressed bytes written via WriteBatch payloads.	ticker
rocksdb.compact.read.bytes	Bytes read during compaction.	ticker
rocksdb.compact.write.bytes	Bytes written during compaction.	ticker
rocksdb.compaction.cancelled	Number of compactions cancelled (e.g. on shutdown or manual cancellation).	ticker
rocksdb.compaction.times.micros	Distribution of total compaction durations (microseconds).	histogram
rocksdb.db.flush.micros	Distribution of memtable flush durations (microseconds).	histogram
rocksdb.db.get.micros	Distribution of Get() latencies (microseconds).	histogram
rocksdb.db.iter.bytes.read	Total bytes (key plus value) read through iterators.	ticker
rocksdb.db.seek.micros	Distribution of iterator Seek() / SeekToFirst() / SeekToLast() latencies (microseconds).	histogram
rocksdb.db.write.micros	Distribution of Write() latencies (microseconds).	histogram
rocksdb.db.write.stall	Distribution of write stall durations (microseconds).	histogram
rocksdb.memtable.hit	Number of reads served from the memtable.	ticker
rocksdb.memtable.miss	Number of reads that missed the memtable and fell through to SST files.	ticker
rocksdb.no.file.errors	Number of errors encountered while reading from files.	ticker
rocksdb.number.keys.read	Total number of keys read via Get() and MultiGet().	ticker
rocksdb.number.keys.written	Total number of keys written.	ticker
rocksdb.number.reseeks.iteration	Number of internal reseeks performed during iteration (e.g. skipping past many tombstones or stale versions).	ticker
rocksdb.read.amp.estimate.useful.bytes	Estimated useful bytes read (read-amplification accounting; requires read_amp_bytes_per_bit).	ticker
rocksdb.read.amp.total.read.bytes	Total bytes read (read-amplification accounting).	ticker
rocksdb.sst.read.micros	Distribution of SST file read latencies (microseconds).	histogram
rocksdb.stall.micros	Total microseconds writes were stalled.	ticker
rocksdb.txn.overhead.mutex.old.commit.map	Number of times the old-commit-map mutex was acquired for pessimistic-transaction commit bookkeeping (overhead accounting).	ticker
rocksdb.txn.overhead.mutex.prepare	Number of times the prepare-heap mutex was acquired for pessimistic-transaction prepare bookkeeping (overhead accounting).	ticker
rocksdb.txn.overhead.mutex.snapshot	Number of times the snapshot-list mutex was acquired for pessimistic-transaction snapshot bookkeeping (overhead accounting).	ticker

All Stats

If enableStats is true, calling db.getStats(true) returns all stats, which includes all of the stats above plus the following:

Name	Description	Type
rocksdb.async.prefetch.abort.micros	Distribution of time spent aborting outstanding async prefetch requests (microseconds).	histogram
rocksdb.async.read.bytes	Distribution of bytes read per asynchronous read request.	histogram
rocksdb.async.read.error.count	Number of errors returned by asynchronous read requests.	ticker
rocksdb.backup.read.bytes	Bytes read while creating backups.	ticker
rocksdb.backup.write.bytes	Bytes written while creating backups.	ticker
rocksdb.blobdb.blob.file.bytes.read	Bytes read from blob files.	ticker
rocksdb.blobdb.blob.file.bytes.written	Bytes written to blob files.	ticker
rocksdb.blobdb.blob.file.read.micros	Distribution of blob file read latencies (microseconds).	histogram
rocksdb.blobdb.blob.file.sync.micros	Distribution of blob file sync latencies (microseconds).	histogram
rocksdb.blobdb.blob.file.synced	Number of blob file syncs.	ticker
rocksdb.blobdb.blob.file.write.micros	Distribution of blob file write latencies (microseconds).	histogram
rocksdb.blobdb.blob.index.evicted.count	Number of blob index entries evicted from the base DB by garbage collection (legacy stacked BlobDB).	ticker
rocksdb.blobdb.blob.index.evicted.size	Size in bytes of blobs evicted by garbage collection (legacy stacked BlobDB).	ticker
rocksdb.blobdb.blob.index.expired.count	Number of blobs expired due to TTL (legacy stacked BlobDB).	ticker
rocksdb.blobdb.blob.index.expired.size	Size in bytes of blobs expired due to TTL (legacy stacked BlobDB).	ticker
rocksdb.blobdb.bytes.read	Total bytes read from blobs (legacy stacked BlobDB).	ticker
rocksdb.blobdb.bytes.written	Total bytes written to blobs (legacy stacked BlobDB).	ticker
rocksdb.blobdb.cache.add	Number of blobs added to the blob cache.	ticker
rocksdb.blobdb.cache.add.failures	Number of failures adding blobs to the blob cache.	ticker
rocksdb.blobdb.cache.bytes.read	Bytes read from the blob cache.	ticker
rocksdb.blobdb.cache.bytes.write	Bytes written to the blob cache.	ticker
rocksdb.blobdb.cache.hit	Blob cache hits.	ticker
rocksdb.blobdb.cache.miss	Blob cache misses.	ticker
rocksdb.blobdb.compression.micros	Distribution of blob compression latencies (microseconds).	histogram
rocksdb.blobdb.decompression.micros	Distribution of blob decompression latencies (microseconds).	histogram
rocksdb.blobdb.fifo.bytes.evicted	Bytes evicted by the FIFO eviction policy (legacy stacked BlobDB).	ticker
rocksdb.blobdb.fifo.num.files.evicted	Number of blob files evicted by the FIFO eviction policy (legacy stacked BlobDB).	ticker
rocksdb.blobdb.fifo.num.keys.evicted	Number of keys evicted by the FIFO eviction policy (legacy stacked BlobDB).	ticker
rocksdb.blobdb.gc.bytes.relocated	Bytes of valid blobs relocated during blob garbage collection.	ticker
rocksdb.blobdb.gc.failures	Number of blob garbage collection failures.	ticker
rocksdb.blobdb.gc.num.files	Number of blob files obsoleted by garbage collection (legacy stacked BlobDB).	ticker
rocksdb.blobdb.gc.num.keys.relocated	Number of valid blobs relocated during blob garbage collection.	ticker
rocksdb.blobdb.gc.num.new.files	Number of new blob files generated by garbage collection (legacy stacked BlobDB).	ticker
rocksdb.blobdb.get.micros	Distribution of Get() latencies (microseconds) (legacy stacked BlobDB).	histogram
rocksdb.blobdb.key.size	Distribution of key sizes for BlobDB operations.	histogram
rocksdb.blobdb.multiget.micros	Distribution of MultiGet() latencies (microseconds) (legacy stacked BlobDB).	histogram
rocksdb.blobdb.next.micros	Distribution of iterator Next() latencies (microseconds) (legacy stacked BlobDB).	histogram
rocksdb.blobdb.num.get	Number of Get() calls (legacy stacked BlobDB).	ticker
rocksdb.blobdb.num.keys.read	Number of keys read (legacy stacked BlobDB).	ticker
rocksdb.blobdb.num.keys.written	Number of keys written (legacy stacked BlobDB).	ticker
rocksdb.blobdb.num.multiget	Number of MultiGet() calls (legacy stacked BlobDB).	ticker
rocksdb.blobdb.num.next	Number of iterator Next() calls (legacy stacked BlobDB).	ticker
rocksdb.blobdb.num.prev	Number of iterator Prev() calls (legacy stacked BlobDB).	ticker
rocksdb.blobdb.num.put	Number of Put() calls (legacy stacked BlobDB).	ticker
rocksdb.blobdb.num.seek	Number of iterator Seek() calls (legacy stacked BlobDB).	ticker
rocksdb.blobdb.num.write	Number of Write() calls (legacy stacked BlobDB).	ticker
rocksdb.blobdb.prev.micros	Distribution of iterator Prev() latencies (microseconds) (legacy stacked BlobDB).	histogram
rocksdb.blobdb.seek.micros	Distribution of iterator Seek() latencies (microseconds) (legacy stacked BlobDB).	histogram
rocksdb.blobdb.write.blob	Number of (non-TTL) values written to blob files (legacy stacked BlobDB).	ticker
rocksdb.blobdb.write.blob.ttl	Number of TTL values written to blob files (legacy stacked BlobDB).	ticker
rocksdb.blobdb.write.inlined	Number of (non-TTL) values inlined in the base DB instead of a blob file (legacy stacked BlobDB).	ticker
rocksdb.blobdb.write.inlined.ttl	Number of TTL values inlined in the base DB instead of a blob file (legacy stacked BlobDB).	ticker
rocksdb.blobdb.write.micros	Distribution of Write() latencies (microseconds) (legacy stacked BlobDB).	histogram
rocksdb.block.cache.add	Number of blocks added to the block cache.	ticker
rocksdb.block.cache.add.failures	Number of failures adding blocks to the block cache.	ticker
rocksdb.block.cache.add.redundant	Number of redundant block cache insertions (a block added concurrently by another thread).	ticker
rocksdb.block.cache.bytes.read	Bytes read from the block cache.	ticker
rocksdb.block.cache.bytes.write	Bytes inserted into the block cache.	ticker
rocksdb.block.cache.compression.dict.add	Number of compression-dictionary blocks added to the block cache.	ticker
rocksdb.block.cache.compression.dict.add.redundant	Number of redundant compression-dictionary block insertions.	ticker
rocksdb.block.cache.compression.dict.bytes.insert	Bytes of compression-dictionary blocks inserted into the block cache.	ticker
rocksdb.block.cache.compression.dict.hit	Block cache hits for compression-dictionary blocks.	ticker
rocksdb.block.cache.compression.dict.miss	Block cache misses for compression-dictionary blocks.	ticker
rocksdb.block.cache.data.add	Number of data blocks added to the block cache.	ticker
rocksdb.block.cache.data.add.redundant	Number of redundant data block insertions.	ticker
rocksdb.block.cache.data.bytes.insert	Bytes of data blocks inserted into the block cache.	ticker
rocksdb.block.cache.filter.add	Number of filter blocks added to the block cache.	ticker
rocksdb.block.cache.filter.add.redundant	Number of redundant filter block insertions.	ticker
rocksdb.block.cache.filter.bytes.insert	Bytes of filter blocks inserted into the block cache.	ticker
rocksdb.block.cache.index.add	Number of index blocks added to the block cache.	ticker
rocksdb.block.cache.index.add.redundant	Number of redundant index block insertions.	ticker
rocksdb.block.cache.index.bytes.insert	Bytes of index blocks inserted into the block cache.	ticker
rocksdb.block.checksum.compute.count	Number of block checksums computed while reading blocks.	ticker
rocksdb.block.checksum.mismatch.count	Number of block checksum mismatches detected (corruption).	ticker
rocksdb.block.key.distribution.cv	Distribution of the coefficient of variation of key sizes within data blocks.	histogram
rocksdb.bloom.filter.prefix.checked	Number of times the prefix bloom filter was checked.	ticker
rocksdb.bloom.filter.prefix.true.positive	Number of prefix bloom filter positives that were true positives.	ticker
rocksdb.bloom.filter.prefix.useful	Number of times the prefix bloom filter avoided a read.	ticker
rocksdb.bytes.compressed.from	Uncompressed input bytes fed into block compression.	ticker
rocksdb.bytes.compressed.to	Compressed output bytes produced by block compression.	ticker
rocksdb.bytes.compression_bypassed	Uncompressed bytes for blocks that bypassed compression (e.g. below the size threshold).	ticker
rocksdb.bytes.compression.rejected	Uncompressed bytes for blocks where compression was rejected for an insufficient ratio.	ticker
rocksdb.bytes.decompressed.from	Compressed input bytes fed into block decompression.	ticker
rocksdb.bytes.decompressed.to	Uncompressed output bytes produced by block decompression.	ticker
rocksdb.bytes.per.multiget	Distribution of total bytes read per MultiGet() call.	histogram
rocksdb.bytes.per.read	Distribution of bytes read per Get() call.	histogram
rocksdb.bytes.per.write	Distribution of bytes written per Write() call.	histogram
rocksdb.cold.file.read.bytes	Bytes read from files with the cold temperature.	ticker
rocksdb.cold.file.read.count	Number of reads from files with the cold temperature.	ticker
rocksdb.compact.read.marked.bytes	Bytes read while compacting files marked for compaction.	ticker
rocksdb.compact.read.periodic.bytes	Bytes read during periodic compaction.	ticker
rocksdb.compact.read.ttl.bytes	Bytes read during TTL-triggered compaction.	ticker
rocksdb.compact.write.marked.bytes	Bytes written while compacting files marked for compaction.	ticker
rocksdb.compact.write.periodic.bytes	Bytes written during periodic compaction.	ticker
rocksdb.compact.write.ttl.bytes	Bytes written during TTL-triggered compaction.	ticker
rocksdb.compaction.aborted	Number of compactions aborted.	ticker
rocksdb.compaction.key.drop.new	Keys dropped during compaction because a newer version of the key exists.	ticker
rocksdb.compaction.key.drop.obsolete	Keys dropped during compaction because they are obsolete (deleted or expired).	ticker
rocksdb.compaction.key.drop.range_del	Keys dropped during compaction by range deletions.	ticker
rocksdb.compaction.key.drop.user	Keys dropped during compaction by the user-defined compaction filter.	ticker
rocksdb.compaction.optimized.del.drop.obsolete	Obsolete keys dropped via the optimized deletion path during compaction.	ticker
rocksdb.compaction.outfile.sync.micros	Distribution of compaction output-file sync latencies (microseconds).	histogram
rocksdb.compaction.prefetch.bytes	Distribution of bytes prefetched during compaction reads.	histogram
rocksdb.compaction.range_del.drop.obsolete	Range-deletion tombstones dropped as obsolete during compaction.	ticker
rocksdb.compaction.times.cpu_micros	Distribution of compaction CPU times (microseconds).	histogram
rocksdb.compaction.total.time.cpu_micros	Total CPU time spent in compaction (microseconds).	ticker
rocksdb.compressed.secondary.cache.dummy.hits	Dummy (placeholder) hits in the compressed secondary cache.	ticker
rocksdb.compressed.secondary.cache.hits	Hits in the compressed secondary cache.	ticker
rocksdb.compressed.secondary.cache.promotion.skips	Entries not promoted from the compressed secondary cache to the primary cache.	ticker
rocksdb.compressed.secondary.cache.promotions	Entries promoted from the compressed secondary cache to the primary cache.	ticker
rocksdb.compression.times.nanos	Distribution of block compression times (nanoseconds).	histogram
rocksdb.cool.file.read.bytes	Bytes read from files with the cool temperature.	ticker
rocksdb.cool.file.read.count	Number of reads from files with the cool temperature.	ticker
rocksdb.db.multiget.micros	Distribution of MultiGet() latencies (microseconds).	histogram
rocksdb.db.mutex.wait.micros	Total time threads spent waiting on the DB mutex (microseconds).	ticker
rocksdb.decompression.times.nanos	Distribution of block decompression times (nanoseconds).	histogram
rocksdb.error.handler.autoresume.count	Number of automatic recovery attempts after a background error.	ticker
rocksdb.error.handler.autoresume.retry.count	Distribution of retries per automatic recovery attempt.	histogram
rocksdb.error.handler.autoresume.retry.total.count	Total automatic recovery retries across all attempts.	ticker
rocksdb.error.handler.autoresume.success.count	Number of successful automatic recoveries.	ticker
rocksdb.error.handler.bg.error.count	Number of background errors flagged by the error handler.	ticker
rocksdb.error.handler.bg.io.error.count	Number of background I/O errors flagged by the error handler.	ticker
rocksdb.error.handler.bg.retryable.io.error.count	Number of retryable background I/O errors flagged by the error handler.	ticker
rocksdb.fifo.change_temperature.compactions	Number of FIFO compactions triggered to change file temperature.	ticker
rocksdb.fifo.max.size.compactions	Number of FIFO compactions triggered by exceeding the maximum size.	ticker
rocksdb.fifo.ttl.compactions	Number of FIFO compactions triggered by TTL.	ticker
rocksdb.file.read.compaction.micros	Distribution of file read latencies during compaction (microseconds).	histogram
rocksdb.file.read.corruption.retry.count	Number of file read retries triggered by corruption.	ticker
rocksdb.file.read.corruption.retry.success.count	Number of file read corruption retries that succeeded.	ticker
rocksdb.file.read.db.iterator.micros	Distribution of file read latencies during iteration (microseconds).	histogram
rocksdb.file.read.db.open.micros	Distribution of file read latencies during DB open (microseconds).	histogram
rocksdb.file.read.flush.micros	Distribution of file read latencies during flush (microseconds).	histogram
rocksdb.file.read.get.micros	Distribution of file read latencies during Get() (microseconds).	histogram
rocksdb.file.read.multiget.micros	Distribution of file read latencies during MultiGet() (microseconds).	histogram
rocksdb.file.read.verify.db.checksum.micros	Distribution of file read latencies during full-DB checksum verification (microseconds).	histogram
rocksdb.file.read.verify.file.checksums.micros	Distribution of file read latencies during per-file checksum verification (microseconds).	histogram
rocksdb.file.write.compaction.micros	Distribution of file write latencies during compaction (microseconds).	histogram
rocksdb.file.write.db.open.micros	Distribution of file write latencies during DB open (microseconds).	histogram
rocksdb.file.write.flush.micros	Distribution of file write latencies during flush (microseconds).	histogram
rocksdb.files.deleted.immediately	Number of files deleted immediately rather than via rate-limited (trash) deletion.	ticker
rocksdb.files.marked.trash	Number of files marked as trash for rate-limited deletion.	ticker
rocksdb.files.marked.trash.deleted	Number of trash-marked files that were subsequently deleted.	ticker
rocksdb.filter.operation.time.nanos	Total time spent in filter operations (nanoseconds).	ticker
rocksdb.flush.write.bytes	Bytes written by memtable flushes.	ticker
rocksdb.footer.corruption.count	Number of SST footer corruptions detected.	ticker
rocksdb.getupdatessince.calls	Number of GetUpdatesSince() calls (WAL reads, e.g. for replication).	ticker
rocksdb.hot.file.read.bytes	Bytes read from files with the hot temperature.	ticker
rocksdb.hot.file.read.count	Number of reads from files with the hot temperature.	ticker
rocksdb.ice.file.read.bytes	Bytes read from files with the ice temperature.	ticker
rocksdb.ice.file.read.count	Number of reads from files with the ice temperature.	ticker
rocksdb.l0.hit	Number of Get() reads satisfied at level 0.	ticker
rocksdb.l1.hit	Number of Get() reads satisfied at level 1.	ticker
rocksdb.l2andup.hit	Number of Get() reads satisfied at level 2 or higher.	ticker
rocksdb.last.level.read.bytes	Bytes read from the last (bottommost) level.	ticker
rocksdb.last.level.read.count	Number of reads from the last (bottommost) level.	ticker
rocksdb.last.level.seek.data	Number of seeks that accessed data in the last level.	ticker
rocksdb.last.level.seek.data.useful.filter.match	Last-level seeks that returned useful data following a filter match.	ticker
rocksdb.last.level.seek.data.useful.no.filter	Last-level seeks that returned useful data with no filter present.	ticker
rocksdb.last.level.seek.filter.match	Last-level seeks where the bloom filter matched.	ticker
rocksdb.last.level.seek.filtered	Last-level seeks filtered out by the bloom filter.	ticker
rocksdb.manifest.file.sync.micros	Distribution of MANIFEST file sync latencies (microseconds).	histogram
rocksdb.memtable.garbage.bytes.at.flush	Bytes of garbage (overwritten or deleted entries) in the memtable at flush time.	ticker
rocksdb.memtable.payload.bytes.at.flush	Bytes of live payload in the memtable at flush time.	ticker
rocksdb.merge.operation.time.nanos	Total time spent in merge operator operations (nanoseconds).	ticker
rocksdb.multiget.coroutine.count	Number of MultiGet operations using the coroutine-based async path.	ticker
rocksdb.multiget.io.batch.size	Distribution of I/O batch sizes for MultiGet.	histogram
rocksdb.multiscan.blocks.from.cache	Number of blocks served from cache during multi-scan operations.	ticker
rocksdb.multiscan.blocks.per.prepare	Distribution of blocks accessed per multi-scan prepare.	histogram
rocksdb.multiscan.blocks.prefetched	Number of blocks prefetched for multi-scan operations.	ticker
rocksdb.multiscan.io.coalesced.nonadjacent	Number of non-adjacent I/O requests coalesced during multi-scan.	ticker
rocksdb.multiscan.io.requests	Number of I/O requests issued for multi-scan operations.	ticker
rocksdb.multiscan.op.prepare.iterators.micros	Distribution of time spent preparing iterators for multi-scan (microseconds).	histogram
rocksdb.multiscan.prefetch.blocks.wasted	Number of prefetched multi-scan blocks that went unused.	ticker
rocksdb.multiscan.prefetch.bytes	Bytes prefetched for multi-scan operations.	ticker
rocksdb.multiscan.prepare.calls	Number of multi-scan prepare calls.	ticker
rocksdb.multiscan.prepare.errors	Number of errors encountered during multi-scan prepare.	ticker
rocksdb.multiscan.prepare.micros	Distribution of multi-scan prepare latencies (microseconds).	histogram
rocksdb.multiscan.seek.errors	Number of seek errors during multi-scan.	ticker
rocksdb.no.file.opens	Number of successful SST file opens.	ticker
rocksdb.non.last.level.read.bytes	Bytes read from non-last (non-bottommost) levels.	ticker
rocksdb.non.last.level.read.count	Number of reads from non-last (non-bottommost) levels.	ticker
rocksdb.non.last.level.seek.data	Number of seeks that accessed data in non-last levels.	ticker
rocksdb.non.last.level.seek.data.useful.filter.match	Non-last-level seeks that returned useful data following a filter match.	ticker
rocksdb.non.last.level.seek.data.useful.no.filter	Non-last-level seeks that returned useful data with no filter present.	ticker
rocksdb.non.last.level.seek.filter.match	Non-last-level seeks where the bloom filter matched.	ticker
rocksdb.non.last.level.seek.filtered	Non-last-level seeks filtered out by the bloom filter.	ticker
rocksdb.num.index.and.filter.blocks.read.per.level	Distribution of index and filter blocks read per level per operation.	histogram
rocksdb.num.iterator.created	Number of iterators created.	ticker
rocksdb.num.iterator.deleted	Number of iterators destroyed.	ticker
rocksdb.num.level.read.per.multiget	Distribution of levels read per MultiGet call.	histogram
rocksdb.num.op.per.transaction	Distribution of operations per transaction.	histogram
rocksdb.num.sst.read.per.level	Distribution of SST files read per level per operation.	histogram
rocksdb.num.subcompactions.scheduled	Distribution of subcompactions scheduled per compaction.	histogram
rocksdb.number.block_compression_bypassed	Number of blocks that bypassed compression.	ticker
rocksdb.number.block_compression_rejected	Number of blocks where compression was rejected.	ticker
rocksdb.number.block.compressed	Number of blocks compressed.	ticker
rocksdb.number.block.decompressed	Number of blocks decompressed.	ticker
rocksdb.number.db.next	Number of iterator Next() calls.	ticker
rocksdb.number.db.next.found	Number of iterator Next() calls that returned a key.	ticker
rocksdb.number.db.prev	Number of iterator Prev() calls.	ticker
rocksdb.number.db.prev.found	Number of iterator Prev() calls that returned a key.	ticker
rocksdb.number.db.seek	Number of iterator Seek() calls.	ticker
rocksdb.number.db.seek.found	Number of iterator Seek() calls that landed on a key.	ticker
rocksdb.number.direct.load.table.properties	Number of times table properties were loaded directly, bypassing the cache.	ticker
rocksdb.number.iter.skip	Number of internal entries skipped during iteration (e.g. tombstones, stale versions).	ticker
rocksdb.number.keys.updated	Number of keys updated in place.	ticker
rocksdb.number.merge.failures	Number of merge operator failures.	ticker
rocksdb.number.multiget.bytes.read	Total bytes read by MultiGet() calls.	ticker
rocksdb.number.multiget.get	Number of MultiGet() calls.	ticker
rocksdb.number.multiget.keys.found	Number of keys found by MultiGet() calls.	ticker
rocksdb.number.multiget.keys.read	Number of keys requested across MultiGet() calls.	ticker
rocksdb.number.rate_limiter.drains	Number of times the rate limiter was fully drained.	ticker
rocksdb.number.superversion_acquires	Number of superversion acquisitions.	ticker
rocksdb.number.superversion_cleanups	Number of superversion cleanups.	ticker
rocksdb.number.superversion_releases	Number of superversion releases.	ticker
rocksdb.number.wbwi.ingest	Number of WriteBatchWithIndex entries ingested into the DB.	ticker
rocksdb.numfiles.in.singlecompaction	Distribution of the number of files in a single compaction.	histogram
rocksdb.persistent.cache.hit	Persistent cache hits.	ticker
rocksdb.persistent.cache.miss	Persistent cache misses.	ticker
rocksdb.poll.wait.micros	Distribution of time spent polling for async read completion (microseconds).	histogram
rocksdb.prefetch.bytes	Bytes prefetched.	ticker
rocksdb.prefetch.bytes.useful	Prefetched bytes that were actually used.	ticker
rocksdb.prefetch.hits	Number of reads satisfied from prefetched data.	ticker
rocksdb.prefetch.memory.bytes.granted	Bytes of prefetch buffer memory granted.	ticker
rocksdb.prefetch.memory.bytes.released	Bytes of prefetch buffer memory released.	ticker
rocksdb.prefetch.memory.requests.blocked	Number of prefetch memory requests blocked by the memory limit.	ticker
rocksdb.prefetched.bytes.discarded	Distribution of prefetched bytes that were discarded unused.	histogram
rocksdb.read.async.micros	Total time spent in asynchronous reads (microseconds).	ticker
rocksdb.read.block.compaction.micros	Distribution of block read latencies during compaction (microseconds).	histogram
rocksdb.read.block.get.micros	Distribution of block read latencies during Get() (microseconds).	histogram
rocksdb.read.num.merge_operands	Distribution of the number of merge operands read per query.	histogram
rocksdb.readahead.trimmed	Number of times the readahead size was trimmed.	ticker
rocksdb.remote.compact.read.bytes	Bytes read by remote (offloaded) compactions.	ticker
rocksdb.remote.compact.resumed.bytes	Bytes processed by resumed remote compactions.	ticker
rocksdb.remote.compact.write.bytes	Bytes written by remote (offloaded) compactions.	ticker
rocksdb.row.cache.hit	Row cache hits.	ticker
rocksdb.row.cache.miss	Row cache misses.	ticker
rocksdb.secondary.cache.data.hits	Secondary cache hits for data blocks.	ticker
rocksdb.secondary.cache.filter.hits	Secondary cache hits for filter blocks.	ticker
rocksdb.secondary.cache.hits	Total secondary cache hits.	ticker
rocksdb.secondary.cache.index.hits	Secondary cache hits for index blocks.	ticker
rocksdb.sim.block.cache.hit	Simulated block cache hits (from the cache simulator).	ticker
rocksdb.sim.block.cache.miss	Simulated block cache misses (from the cache simulator).	ticker
rocksdb.sst.batch.size	Distribution of SST write batch sizes.	histogram
rocksdb.sst.user.defined.index.load.fail.count	Number of failures loading user-defined SST indexes.	ticker
rocksdb.sst.write.micros	Distribution of SST file write latencies (microseconds).	histogram
rocksdb.subcompaction.setup.times.micros	Distribution of subcompaction setup times (microseconds).	histogram
rocksdb.table.open.io.micros	Distribution of SST table open I/O latencies (microseconds).	histogram
rocksdb.table.open.prefetch.tail.hit	Number of table opens that hit the prefetched file tail.	ticker
rocksdb.table.open.prefetch.tail.miss	Number of table opens that missed the prefetched file tail.	ticker
rocksdb.table.open.prefetch.tail.read.bytes	Distribution of bytes read while prefetching the SST file tail on open.	histogram
rocksdb.table.sync.micros	Distribution of new SST table file sync latencies (microseconds).	histogram
rocksdb.timestamp.filter.table.checked	Number of SST tables checked against the timestamp filter.	ticker
rocksdb.timestamp.filter.table.filtered	Number of SST tables filtered out by the timestamp filter.	ticker
rocksdb.txn.get.tryagain	Number of transaction Get() calls that returned TryAgain due to a snapshot conflict.	ticker
rocksdb.txn.overhead.duplicate.key	Transaction overhead incurred by duplicate-key checks.	ticker
rocksdb.verify_checksum.read.bytes	Bytes read during explicit checksum verification.	ticker
rocksdb.wal.bytes	Bytes written to the write-ahead log (WAL).	ticker
rocksdb.wal.file.sync.micros	Distribution of WAL file sync latencies (microseconds).	histogram
rocksdb.wal.synced	Number of WAL syncs.	ticker
rocksdb.warm.file.read.bytes	Bytes read from files with the warm temperature.	ticker
rocksdb.warm.file.read.count	Number of reads from files with the warm temperature.	ticker
rocksdb.write.other	Number of writes processed on behalf of another thread's write group (as a follower).	ticker
rocksdb.write.raw.block.micros	Distribution of raw block write latencies (microseconds).	histogram
rocksdb.write.self	Number of writes processed by the calling thread itself (as the write group leader).	ticker
rocksdb.write.wal	Number of writes that were written to the WAL.	ticker

Transaction Log Stats

log.getStats() returns a detailed snapshot for a single transaction log store. All sizes are in bytes and all timestamps are milliseconds since the Unix epoch.

const db: RocksDatabase = RocksDatabase.open('path/to/db');
const log: TransactionLog = db.useLog('my-log');
const stats: TransactionLogStats = log.getStats();

log.getStats() returns an object with the following shape:

• name: string The name of the transaction log store.
• path: string Filesystem path to the log store's directory.
• fileCount: number Number of sequence log files on disk for this log.
• currentSequenceNumber: number Sequence number of the active write file.
• oldestSequenceNumber: number Sequence number of the oldest file still on disk.
• totalSizeBytes: number Total on-disk size of all of this log's files.
• currentFileSize: number Size of the active write file.
• pendingTransactions: number Transactions bound to this log but not yet written via writeBatch().
• uncommittedTransactions: number Transactions written to this log but not yet committed to RocksDB.
• replayGapBytes: number Bytes between the last flushed position and the write head (written but not yet flushed to the database).
• memory: object
  • mappedBytes: number Virtual address space reserved for memory-mapped files (the active write file maps the full configured maxFileSize on POSIX), not resident memory.
  • overlayBytes: number File-backed overlay portion (POSIX only; 0 on Windows) — a closer proxy for real memory consumption than mappedBytes.
  • activeMaps: number Number of log files currently memory-mapped.
• nextLogPosition: object Position where the next log entry will be written.
  • sequence: number The log file sequence number.
  • offset: number The byte offset within that file.
• lastFlushedPosition: object Position up to which data has been flushed to the database.
  • sequence: number The log file sequence number.
  • offset: number The byte offset within that file.
• lastCommittedPosition: object | null Position of the last transaction committed to RocksDB, or null if nothing has been committed yet.
  • sequence: number The log file sequence number.
  • offset: number The byte offset within that file.
• purge: object
  • oldestFileAgeMs: number Age in milliseconds of the oldest file on disk.
  • purgeableFiles: number Number of files eligible for purge under the retention policy.
  • retainedUnflushedFiles: number Number of files past the retention threshold but retained because they are unflushed.
  • lastPurgeMs: number Timestamp of the last purge scan.
• totals: object Lifetime counters since the log store was created.
  • transactionsWritten: number Cumulative number of transactions written to this log.
  • entriesWritten: number Cumulative number of entries written to this log.
  • bytesWritten: number Cumulative bytes written to this log (entry payload plus entry header, excluding file headers).
  • rotations: number Number of times the log rotated to a new file.
  • filesPurged: number Number of files purged by the retention policy.
  • bytesPurged: number Bytes reclaimed by purging files.
  • purgeRuns: number Number of purge scans run.
  • databaseFlushes: number Number of database flush events observed by this log.
  • writeFailures: number Number of write failures encountered by this log.
• config: object The store's configured limits.
  • maxFileSize: number Configured maximum size of a single log file.
  • retentionMs: number Configured retention period in milliseconds.
  • maxAgeThreshold: number Configured age threshold (a float between 0 and 1) at which files become purge-eligible.

A summarized subset of these stats is also rolled up into db.getStats() under the txnlog.* keys documented above (summed across all of a database's logs).