Database

To create a database, new database name should be set to db control namespace. If no database exists, it will be created automatically.

Database can be created, opened or deleted before or after environment startup.

Database has following states: offline, online, recover, shutdown, malfunction. Database sets malfunction status if any unrecoverable error occurs.

name	type	description
db.name.name	string, ro	Get database name
db.name.id	int	Database's sequential id number. This number is used in the transaction log for the database identification.
db.name.status	string, ro	Get database status.
db.name.storage	string	Set storage mode: anti-cache, cache, in-memory.
db.name.format	string	Set database format: kv, document.
db.name.amqf	int	enable or disable AMQ Filter.
db.name.path	string	Set folder to store database data. If variable is not set, it will be automatically set as sophia.path/database_name.
db.name.path_fail_on_exists	int	Produce error if path already exists.
db.name.path_fail_on_drop	int	Produce error on attempt to open 'dropped' database directory.
db.name.cache_mode	int	Mark this database as a cache.
db.name.cache	string	Set name of a cache database to use.
db.name.mmap	int	Enable or disable mmap mode.
db.name.sync	int	Sync node file on the branch creation or compaction completion.
db.name.node_preload	int	Preload whole node into memory for compaction.
db.name.node_size	int	Set a node file size in bytes. Node file can grow up to two times the size before the old node file is being split.
db.name.page_size	int	Set size of a page to use.
db.name.page_checksum	int	Check checksum during compaction.
db.name.compression_key	int	Enable or disable prefix (multi-part) compression.
db.name.compression	string	Specify compression driver. Supported: lz4, zstd, none (default).
db.name.compression_branch	string	Specify compression driver for branches.
db.name.lru	int	Enable LRU mode.
db.name.lru_step	int	Set LRU accuracy.
db.name.branch	function	Force branch creation.
db.name.compact	function	Force compaction.
db.name.compact_index	function	Force two-level compaction.
db.name.index.memory_used	int, ro	Memory used by database for in-memory key indexes in bytes.
db.name.index.size	int, ro	Sum of nodes size in bytes (compressed). This is equal to the full database size.
db.name.index.size_uncompressed	int, ro	Full database size before the compression.
db.name.index.size_snapshot	int, ro	Snapshot file size.
db.name.index.size_amqf	int, ro	Total size used by AMQ Filter.
db.name.index.count	int, ro	Total number of keys stored in database. This includes transactional duplicates and not yet-merged duplicates.
db.name.index.count_dup	int, ro	Total number of transactional duplicates.
db.name.index.read_disk	int, ro	Number of disk reads since start.
db.name.index.read_cache	int, ro	Number of cache reads since start.
db.name.index.temperature_avg	int, ro	Average index temperature.
db.name.index.temperature_min	int, ro	Min index node temperature.
db.name.index.temperature_max	int, ro	Max index node temperature.
db.name.index.temperature_histogram	string, ro	Index temperature distribution histogram.
db.name.index.node_count	int, ro	Number of active nodes.
db.name.index.branch_count	int, ro	Total number of branches.
db.name.index.branch_avg	int, ro	Average number of branches per node.
db.name.index.branch_max	int, ro	Maximum number of branches per node.
db.name.index.branch_histogram	string, ro	Branch histogram distribution through all nodes.
db.name.index.page_count	int, ro	Total number of pages.
db.name.index.upsert	function	Set upsert callback function.
db.name.index.upsert_arg	function	Set upsert function argument.
db.name.index.key	string	Set index key type (string, u32, u64, u32_rev, u64_rev). See database section for details.