Properties

GetProperty takes the property names of RocksDB, with the rocksdb. prefix, and returns a decimal integer as a string. It returns null for a name that it does not support. The values match those of RocksDB for the same writes, flushes, and compactions, except for the memory figures noted below.

string? value = db.GetProperty("rocksdb.num-files-at-level0", family);

Properties of a column family

These take a column family. When you pass none, they use the default column family.

Property	Value
rocksdb.num-entries-active-mem-table	The entries of the active memtable. Every put, delete, and range delete counts.
rocksdb.num-immutable-mem-table	The memtables that wait for a flush or are in a flush.
rocksdb.mem-table-flush-pending	1 when a memtable waits for a flush that has not started, else 0.
rocksdb.cur-size-all-mem-tables	The bytes of the active memtable and of the memtables not yet flushed.
rocksdb.estimate-table-readers-mem	The bytes that the open SSTables keep in memory: index, filter, and range tombstones. With CacheIndexAndFilterBlocks, the range tombstones only.
rocksdb.live-sst-files-size	The bytes of the SSTables of the current version.
rocksdb.num-files-at-level0 to rocksdb.num-files-at-level6	The SSTables in each level.
rocksdb.base-level	The level that level 0 compacts into.
rocksdb.block-cache-capacity	The capacity of the BlockCache of the column family.
rocksdb.block-cache-usage	The bytes in that cache, for everything that shares it, pinned entries included.
rocksdb.block-cache-pinned-usage	The bytes of that cache that cannot be evicted.
rocksdb.compaction-pending	1 when a level needs a compaction, else 0. That is, level 0 holds Level0FileNumCompactionTrigger files, or a sorted level above the bottom holds more than its target. The files that a compaction reads do not count.

Properties of the database

These are the same for every column family.

Property	Value
rocksdb.num-running-flushes	0 or 1. There is one flush thread.
rocksdb.num-running-compactions	The compactions that run now, from 0 to MaxBackgroundCompactions.
rocksdb.is-write-stopped	1 while writes are stopped, else 0.
rocksdb.actual-delayed-write-rate	The rate in bytes per second while writes are delayed, else 0.

Properties that return null

Property	Why
rocksdb.block-cache-capacity, rocksdb.block-cache-usage, rocksdb.block-cache-pinned-usage	For a column family without a BlockCache. RocksDB with no block cache also returns null.
Any other name	Not supported.

Memory figures

The memory figures count what the data needs, not what was allocated:

• cur-size-all-mem-tables counts the keys and values of each memtable, plus 32 bytes for each entry, and the fragments of its range tombstones. An empty memtable is 0. RocksDB counts the arena blocks that it allocated, 2 KB for an empty memtable.
• estimate-table-readers-mem counts the index keys and handles, the filter bits, and the range tombstones and their fragments of each open table. With CacheIndexAndFilterBlocks, it counts the range tombstones and their fragments only, as RocksDB leaves out the cached blocks.