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Coordinator DB
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Database settings ​

The server exposes effective database settings in system.settings. SET persists log_queries, log_queries_min_query_duration_ms, max_execution_time, max_memory_usage, max_result_rows, max_response_bytes and max_threads for the selected database. Other connected clients observe committed values before later requests.

Changes require a selected database, autocommit and no active transactions in that database. Resource values are sampled once per request; a SET in a multi-statement request changes defaults for later requests.

The foreign_keys, recursive_triggers, user_version and application_id rows use PRAGMA or catalog writes; SET does not accept these four names. A nonzero server XML request ceiling can only be tightened by database settings; 0 means no additional limit at that level.

Defaults ​

Setting Type Default Meaning
application_id Int32 0 Application-managed database file identifier.
foreign_keys Bool 0 Enforce foreign-key constraints in database sessions.
log_queries Bool 1 Record TCP and HTTP requests in the structured query journal.
log_queries_min_query_duration_ms UInt64 0 Minimum logged request duration in milliseconds.
max_execution_time Float64 0 Maximum SQL processing time in seconds; zero disables the limit.
max_memory_usage UInt64 0 Maximum live SQL heap bytes; zero disables the limit.
max_response_bytes UInt64 0 Maximum formatted native response bytes; zero disables this setting.
max_result_rows UInt64 0 Maximum cumulative returned rows per request; zero disables the limit.
max_threads UInt64 0 Maximum threads per query, from 0 through 64. Zero selects automatically; one keeps execution serial.
recursive_triggers Bool 0 Allow triggers to invoke themselves recursively.
user_version Int32 0 Application-managed database schema version.

Inspect effective values ​

sql
SELECT name,value,type,"default" FROM system.settings WHERE readonly=0 ORDER BY name FORMAT csv;
text
"application_id","0","Int32","0"
"foreign_keys","0","Bool","0"
"log_queries","1","Bool","1"
"log_queries_min_query_duration_ms","0","UInt64","0"
"max_execution_time","0","Float64","0"
"max_memory_usage","0","UInt64","0"
"max_response_bytes","0","UInt64","0"
"max_result_rows","0","UInt64","0"
"max_threads","0","UInt64","0"
"recursive_triggers","0","Bool","0"
"user_version","0","Int32","0"

The changed column compares an effective value with its built-in default. Server ceilings can make the effective value differ from the saved value in main.settings. Format options appear separately as read-only defaults; server-only XML options are not listed.