Hi all, I am trying to put a MariaDB MyRocks database into production and right now I am facing problems regarding the memory usage of MyRocks. I haven't been able to identify one specific problem but the following links contained some useful information: https://github.com/facebook/rocksdb/issues/3216 https://github.com/facebook/rocksdb/wiki/Memory-usage-in-RocksDB The current behavior of the mysqld process is that when putting the database into production (an OLTPish process) on a machine with 64G RAM and a block cache configured with 16G it starts to slowly accumulate more and more memory until swap is used. This is obviously not suitable for production. Currently I am wondering about a particular statistic, the number of open and closed files. *Particularly I am wondering why Rocksdb_no_file_closes is staying a zero at all time while Rocksdb_no_file_opens slowly increases over time.* Does anybody know why that is? Could it be responsible for the steady memory increase? I experimented with the parameter rocksdb_max_open_files, it was set to -1, I tried setting it to 1536, 512 and 128. The lower the value the faster Rocksdb_no_file_opens increases (which seems right). However, at no setting do I see any change in Rocksdb_no_file_closes. Running MariaDB 10.2.18. Here are the settings regarding rocksdb in my.cnf: # MyRocks plugin-load-add = ha_rocksdb.so default-storage-engine = rocksdb default-tmp-storage-engine = MyISAM transaction-isolation = READ-COMMITTED rocksdb_unsafe_for_binlog = 1 # enables statement based replication rocksdb_datadir = /var/local/mysql/rocksdb rocksdb_wal_dir = /var/mysql_logs/rocksdb rocksdb_tmpdir = /var/mysql_logs/rocksdb rocksdb_flush_log_at_trx_commit = 0 rocksdb_use_direct_io_for_flush_and_compaction = 0 rocksdb_use_direct_reads = 0 rocksdb_max_open_files = 512 rocksdb_max_background_jobs = 8 rocksdb_max_total_wal_size = 4G rocksdb_block_size = 64K rocksdb_block_cache_size = 4G rocksdb_table_cache_numshardbits = 6 rocksdb_new_table_reader_for_compaction_inputs = 1 rocksdb_compaction_readahead_size = 4M #rocksdb_db_write_buffer_size = 0 # max write buffer across all column families, zero = disabled # rate limiter rocksdb_bytes_per_sync = 4M rocksdb_wal_bytes_per_sync = 4M rocksdb_rate_limiter_bytes_per_sec = 80M # MB/s. Increase if you're running on higher spec machines # triggering compaction if there are many sequential deletes rocksdb_compaction_sequential_deletes_count_sd = 1 rocksdb_compaction_sequential_deletes = 199999 rocksdb_compaction_sequential_deletes_window = 200000 # read free replication #rocksdb_rpl_lookup_rows=0 rocksdb_default_cf_options=write_buffer_size=128m;max_write_buffer_number=4;target_file_size_base=256m;max_bytes_for_level_base=2560m;target_file_size_multiplier=2;level0_file_num_compaction_trigger=4;level0_slowdown_writes_trigger=10;level0_stop_writes_trigger=15;compression=kSnappyCompression;bottommost_compression=kZlibCompression;compression_opts=-14:1:0;block_based_table_factory={cache_index_and_filter_blocks=1;filter_policy=bloomfilter:10:false;whole_key_filtering=1};level_compaction_dynamic_level_bytes=true;optimize_filters_for_hits=true;compaction_pri=kMinOverlappingRatio