# 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 ```typescript 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 | | ------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------ | | `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. ```typescript 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).