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 . |
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cache_max_wait_ms | the maximum number of milliseconds an application thread will wait for space to be available in cache before giving up. Default will wait forever. | an integer greater than or equal to 0; default 0 . |
cache_overflow = ( | cache overflow configuration options. | a set of related configuration options defined below. |
file_max | The maximum number of bytes that WiredTiger is allowed to use for its cache overflow mechanism. If the cache overflow file exceeds this size, a panic will be triggered. The default value means that the cache overflow file is unbounded and may use as much space as the filesystem will accommodate. The minimum non-zero setting is 100MB. | an integer greater than or equal to 0; default 0 . |
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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 . |
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compatibility = ( | set compatibility version of database. Changing the compatibility version requires that there are no active operations for the duration of the call. | a set of related configuration options defined below. |
release | compatibility release version string. | a string; default empty. |
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debug_mode = ( | control the settings of various extended debugging features. | a set of related configuration options defined below. |
checkpoint_retention | adjust log archiving to retain the log records of this number of checkpoints. Zero or one means perform normal archiving. | an integer between 0 and 1024; default 0 . |
eviction | if true, modify internal algorithms to change skew to force lookaside eviction to happen more aggressively. This includes but is not limited to not skewing newest, not favoring leaf pages, and modifying the eviction score mechanism. | a boolean flag; default false . |
rollback_error | return a WT_ROLLBACK error from a transaction operation about every Nth operation to simulate a collision. | an integer between 0 and 10M; default 0 . |
table_logging | if true, write transaction related information to the log for all operations, even operations for tables with logging turned off. This setting introduces a log format change that may break older versions of WiredTiger. These operations are informational and skipped in recovery. | a boolean flag; default false . |
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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 . |
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eviction_checkpoint_target | perform eviction at the beginning of checkpoints to bring the dirty content in cache to this level. It is a percentage of the cache size if the value is within the range of 0 to 100 or an absolute size when greater than 100. The value is not allowed to exceed the cache_size . Ignored if set to zero or in_memory is true . | an integer between 0 and 10TB; default 1 . |
eviction_dirty_target | perform eviction in worker threads when the cache contains at least this much dirty content. It is a percentage of the cache size if the value is within the range of 1 to 100 or an absolute size when greater than 100. The value is not allowed to exceed the cache_size . | an integer between 1 and 10TB; default 5 . |
eviction_dirty_trigger | trigger application threads to perform eviction when the cache contains at least this much dirty content. It is a percentage of the cache size if the value is within the range of 1 to 100 or an absolute size when greater than 100. The value is not allowed to exceed the cache_size . This setting only alters behavior if it is lower than eviction_trigger. | an integer between 1 and 10TB; default 20 . |
eviction_target | perform eviction in worker threads when the cache contains at least this much content. It is a percentage of the cache size if the value is within the range of 10 to 100 or an absolute size when greater than 100. The value is not allowed to exceed the cache_size . | an integer between 10 and 10TB; default 80 . |
eviction_trigger | trigger application threads to perform eviction when the cache contains at least this much content. It is a percentage of the cache size if the value is within the range of 10 to 100 or an absolute size when greater than 100. The value is not allowed to exceed the cache_size . | an integer between 10 and 10TB; 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 . |
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io_capacity = ( | control how many bytes per second are written and read. Exceeding the capacity results in throttling. | a set of related configuration options defined below. |
total | number of bytes per second available to all subsystems in total. When set, decisions about what subsystems are throttled, and in what proportion, are made internally. The minimum non-zero setting is 1MB. | an integer between 0 and 1TB; default 0 . |
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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 . |
os_cache_dirty_pct | maximum dirty system buffer cache usage, as a percentage of the log's file_max . If non-zero, schedule writes for dirty blocks belonging to the log in the system buffer cache after that percentage of the log has been written into the buffer cache without an intervening file sync. | an integer between 0 and 100; default 0 . |
prealloc | pre-allocate log files. | a boolean flag; default true . |
zero_fill | manually write zeroes into log files. | a boolean flag; default false . |
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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 . |
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operation_tracking = ( | enable tracking of performance-critical functions. See Track function calls for more information. | a set of related configuration options defined below. |
enabled | enable operation tracking subsystem. | a boolean flag; default false . |
path | the name of a directory into which operation tracking files are written. The directory must already exist. If the value is not an absolute path, the path is relative to the database home (see Absolute paths for more information). | a string; default "." . |
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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 shared cache can not have absolute values configured for cache eviction settings. | 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 . |
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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 . |
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verbose | enable messages for various events. Options are given as a list, such as "verbose=[evictserver,read]" . | a list, with values chosen from the following options: "api" , "block" , "checkpoint" , "checkpoint_progress" , "compact" , "compact_progress" , "error_returns" , "evict" , "evict_stuck" , "evictserver" , "fileops" , "handleops" , "log" , "lookaside" , "lookaside_activity" , "lsm" , "lsm_manager" , "metadata" , "mutex" , "overflow" , "read" , "rebalance" , "reconcile" , "recovery" , "recovery_progress" , "salvage" , "shared_cache" , "split" , "temporary" , "thread_group" , "timestamp" , "transaction" , "verify" , "version" , "write" ; default empty. |