Name | Effect | Values |
async = ( | asynchronous operations configuration options. | a set of related configuration options defined below. |
enabled | enable asynchronous operation. | a boolean flag; default false . |
ops_max | maximum number of expected simultaneous asynchronous operations. | an integer between 1 and 4096; default 1024 . |
threads | the number of worker threads to service asynchronous requests. Each worker thread uses a session from the configured session_max. | an integer between 1 and 20; default 2 . |
) | | |
cache_overhead | assume the heap allocator overhead is the specified percentage, and adjust the cache usage by that amount (for example, if there is 10GB of data in cache, a percentage of 10 means WiredTiger treats this as 11GB). This value is configurable because different heap allocators have different overhead and different workloads will have different heap allocation sizes and patterns, therefore applications may need to adjust this value based on allocator choice and behavior in measured workloads. | an integer between 0 and 30; default 8 . |
cache_size | maximum heap memory to allocate for the cache. A database should configure either cache_size or shared_cache but not both. | an integer between 1MB and 10TB; default 100MB . |
checkpoint = ( | periodically checkpoint the database. Enabling the checkpoint server uses a session from the configured session_max. | a set of related configuration options defined below. |
log_size | wait for this amount of log record bytes to be written to the log between each checkpoint. If non-zero, this value will use a minimum of the log file size. A database can configure both log_size and wait to set an upper bound for checkpoints; setting this value above 0 configures periodic checkpoints. | an integer between 0 and 2GB; default 0 . |
wait | seconds to wait between each checkpoint; setting this value above 0 configures periodic checkpoints. | an integer between 0 and 100000; default 0 . |
) | | |
error_prefix | prefix string for error messages. | a string; default empty. |
eviction = ( | eviction configuration options. | a set of related configuration options defined below. |
threads_max | maximum number of threads WiredTiger will start to help evict pages from cache. The number of threads started will vary depending on the current eviction load. Each eviction worker thread uses a session from the configured session_max. | an integer between 1 and 20; default 8 . |
threads_min | minimum number of threads WiredTiger will start to help evict pages from cache. The number of threads currently running will vary depending on the current eviction load. | an integer between 1 and 20; default 1 . |
) | | |
eviction_checkpoint_target | perform eviction at the beginning of checkpoints to bring the dirty content in cache to this level, expressed as a percentage of the total cache size. Ignored if set to zero or in_memory is true . | an integer between 0 and 99; default 5 . |
eviction_dirty_target | perform eviction in worker threads when the cache contains at least this much dirty content, expressed as a percentage of the total cache size. | an integer between 1 and 99; default 5 . |
eviction_dirty_trigger | trigger application threads to perform eviction when the cache contains at least this much dirty content, expressed as a percentage of the total cache size. This setting only alters behavior if it is lower than eviction_trigger. | an integer between 1 and 99; default 20 . |
eviction_target | perform eviction in worker threads when the cache contains at least this much content, expressed as a percentage of the total cache size. Must be less than eviction_trigger . | an integer between 10 and 99; default 80 . |
eviction_trigger | trigger application threads to perform eviction when the cache contains at least this much content, expressed as a percentage of the total cache size. | an integer between 10 and 99; default 95 . |
file_manager = ( | control how file handles are managed. | a set of related configuration options defined below. |
close_handle_minimum | number of handles open before the file manager will look for handles to close. | an integer greater than or equal to 0; default 250 . |
close_idle_time | amount of time in seconds a file handle needs to be idle before attempting to close it. A setting of 0 means that idle handles are not closed. | an integer between 0 and 100000; default 30 . |
close_scan_interval | interval in seconds at which to check for files that are inactive and close them. | an integer between 1 and 100000; default 10 . |
) | | |
log = ( | enable logging. Enabling logging uses three sessions from the configured session_max. | a set of related configuration options defined below. |
archive | automatically archive unneeded log files. | a boolean flag; default true . |
prealloc | pre-allocate log files. | a boolean flag; default true . |
zero_fill | manually write zeroes into log files. | a boolean flag; default false . |
) | | |
lsm_manager = ( | configure database wide options for LSM tree management. The LSM manager is started automatically the first time an LSM tree is opened. The LSM manager uses a session from the configured session_max. | a set of related configuration options defined below. |
merge | merge LSM chunks where possible. | a boolean flag; default true . |
worker_thread_max | Configure a set of threads to manage merging LSM trees in the database. Each worker thread uses a session handle from the configured session_max. | an integer between 3 and 20; default 4 . |
) | | |
shared_cache = ( | shared cache configuration options. A database should configure either a cache_size or a shared_cache not both. Enabling a shared cache uses a session from the configured session_max. | a set of related configuration options defined below. |
chunk | the granularity that a shared cache is redistributed. | an integer between 1MB and 10TB; default 10MB . |
name | the name of a cache that is shared between databases or "none" when no shared cache is configured. | a string; default none . |
quota | maximum size of cache this database can be allocated from the shared cache. Defaults to the entire shared cache size. | an integer; default 0 . |
reserve | amount of cache this database is guaranteed to have available from the shared cache. This setting is per database. Defaults to the chunk size. | an integer; default 0 . |
size | maximum memory to allocate for the shared cache. Setting this will update the value if one is already set. | an integer between 1MB and 10TB; default 500MB . |
) | | |
statistics | Maintain database statistics, which may impact performance. Choosing "all" maintains all statistics regardless of cost, "fast" maintains a subset of statistics that are relatively inexpensive, "none" turns off all statistics. The "clear" configuration resets statistics after they are gathered, where appropriate (for example, a cache size statistic is not cleared, while the count of cursor insert operations will be cleared). When "clear" is configured for the database, gathered statistics are reset each time a statistics cursor is used to gather statistics, as well as each time statistics are logged using the statistics_log configuration. See Statistics for more information. | a list, with values chosen from the following options: "all" , "cache_walk" , "fast" , "none" , "clear" , "tree_walk" ; default none . |
statistics_log = ( | log any statistics the database is configured to maintain, to a file. See Statistics for more information. Enabling the statistics log server uses a session from the configured session_max. | a set of related configuration options defined below. |
json | encode statistics in JSON format. | a boolean flag; default false . |
on_close | log statistics on database close. | a boolean flag; default false . |
sources | if non-empty, include statistics for the list of data source URIs, if they are open at the time of the statistics logging. The list may include URIs matching a single data source ("table:mytable"), or a URI matching all data sources of a particular type ("table:"). | a list of strings; default empty. |
timestamp | a timestamp prepended to each log record, may contain strftime conversion specifications, when json is configured, defaults to "%FT%Y.000Z" . | a string; default "%b %d %H:%M:%S" . |
wait | seconds to wait between each write of the log records; setting this value above 0 configures statistics logging. | an integer between 0 and 100000; default 0 . |
) | | |
verbose | enable messages for various events. Only available if WiredTiger is configured with –enable-verbose. Options are given as a list, such as "verbose=[evictserver,read]" . | a list, with values chosen from the following options: "api" , "block" , "checkpoint" , "compact" , "evict" , "evict_stuck" , "evictserver" , "fileops" , "handleops" , "log" , "lsm" , "lsm_manager" , "metadata" , "mutex" , "overflow" , "read" , "rebalance" , "reconcile" , "recovery" , "recovery_progress" , "salvage" , "shared_cache" , "split" , "temporary" , "thread_group" , "transaction" , "verify" , "version" , "write" ; default empty. |