system.settings
Store the system settings of the current session.
SELECT * FROM system.settings;
+---------------------------------------+--------------+--------------+---------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+--------+
| name | value | default | level | description | type |
+---------------------------------------+--------------+--------------+---------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+--------+
| collation | binary | binary | SESSION | Sets the character collation. Available values include "binary" and "utf8". | String |
| enable_bushy_join | 0 | 0 | SESSION | Enables generating a bushy join plan with the optimizer. | UInt64 |
| enable_cbo | 1 | 1 | SESSION | Enables cost-based optimization. | UInt64 |
| enable_distributed_eval_index | 1 | 1 | SESSION | Enables evaluated indexes to be created and maintained across multiple nodes. | UInt64 |
| enable_dphyp | 0 | 0 | SESSION | Enables dphyp join order algorithm. | UInt64 |
| enable_query_result_cache | 0 | 0 | SESSION | Enables caching query results to improve performance for identical queries. | UInt64 |
| enable_runtime_filter | 0 | 0 | SESSION | Enables runtime filter optimization for JOIN. | UInt64 |
| flight_client_timeout | 60 | 60 | SESSION | Sets the maximum time in seconds that a flight client request can be processed. | UInt64 |
| group_by_shuffle_mode | before_merge | before_merge | SESSION | Group by shuffle mode, 'before_partial' is more balanced, but more data needs to exchange. | String |
| group_by_two_level_threshold | 20000 | 20000 | SESSION | Sets the number of keys in a GROUP BY operation that will trigger a two-level aggregation. | UInt64 |
| hide_options_in_show_create_table | 1 | 1 | SESSION | Hides table-relevant information, such as SNAPSHOT_LOCATION and STORAGE_FORMAT, at the end of the result of SHOW TABLE CREATE. | UInt64 |
| input_read_buffer_size | 1048576 | 1048576 | SESSION | Sets the memory size in bytes allocated to the buffer used by the buffered reader to read data from storage. | UInt64 |
| lazy_topn_threshold | 0 | 0 | SESSION | Enable lazy materialization and set the limit threshold of Top-N queries. Set the value to 0 to disable this setting. | UInt64 |
| load_file_metadata_expire_hours | 168 | 168 | SESSION | Sets the hours that the metadata of files you load data from with COPY INTO will expire in. | UInt64 |
| max_block_size | 65536 | 65536 | SESSION | Sets the maximum byte size of a single data block that can be read. | UInt64 |
| max_execute_time | 0 | 0 | SESSION | Sets the maximum query execution time in seconds. Setting it to 0 means no limit. | UInt64 |
| max_inlist_to_or | 3 | 3 | SESSION | Sets the maximum number of values that can be included in an IN expression to be converted to an OR operator. | UInt64 |
| max_memory_usage | 79819535155 | 79819535155 | SESSION | Sets the maximum memory usage in bytes for processing a single query. | UInt64 |
| max_result_rows | 0 | 0 | SESSION | Sets the maximum number of rows that can be returned in a query result when no specific row count is specified. Setting it to 0 means no limit. | UInt64 |
| max_storage_io_requests | 48 | 48 | SESSION | Sets the maximum number of concurrent I/O requests. | UInt64 |
| max_threads | 40 | 40 | SESSION | Sets the maximum number of threads to execute a request. | UInt64 |
| parquet_fast_read_bytes | 0 | 0 | SESSION | Parquet file with smaller size will be read as a whole file, instead of column by column. | UInt64 |
| parquet_uncompressed_buffer_size | 2097152 | 2097152 | SESSION | Sets the byte size of the buffer used for reading Parquet files. | UInt64 |
| prefer_broadcast_join | 1 | 1 | SESSION | Enables broadcast join. | UInt64 |
| query_result_cache_allow_inconsistent | 0 | 0 | SESSION | Determines whether Databend will return cached query results that are inconsistent with the underlying data. | UInt64 |
| query_result_cache_max_bytes | 1048576 | 1048576 | SESSION | Sets the maximum byte size of cache for a single query result. | UInt64 |
| query_result_cache_ttl_secs | 300 | 300 | SESSION | Sets the time-to-live (TTL) in seconds for cached query results. Once the TTL for a cached result has expired, the result is considered stale and will not be used for new queries. | UInt64 |
| quoted_ident_case_sensitive | 1 | 1 | SESSION | Determines whether Databend treats quoted identifiers as case-sensitive. | UInt64 |
| retention_period | 12 | 12 | SESSION | Sets the retention period in hours. | UInt64 |
| sandbox_tenant | | | SESSION | Injects a custom 'sandbox_tenant' into this session. This is only for testing purposes and will take effect only when 'internal_enable_sandbox_tenant' is turned on. | String |
| spilling_bytes_threshold_per_proc | 0 | 0 | SESSION | Sets the maximum amount of memory in bytes that an aggregator can use before spilling data to storage during query execution. | UInt64 |
| sql_dialect | PostgreSQL | PostgreSQL | SESSION | Sets the SQL dialect. Available values include "PostgreSQL", "MySQL", and "Hive". | String |
| storage_fetch_part_num | 2 | 2 | SESSION | Sets the number of partitions that are fetched in parallel from storage during query execution. | UInt64 |
| storage_io_max_page_bytes_for_read | 524288 | 524288 | SESSION | Sets the maximum byte size of data pages that can be read from storage in a single I/O operation. | UInt64 |
| storage_io_min_bytes_for_seek | 48 | 48 | SESSION | Sets the minimum byte size of data that must be read from storage in a single I/O operation when seeking a new location in the data file. | UInt64 |
| storage_read_buffer_size | 1048576 | 1048576 | SESSION | Sets the byte size of the buffer used for reading data into memory. | UInt64 |
| timezone | UTC | UTC | SESSION | Sets the timezone. | String |
| unquoted_ident_case_sensitive | 0 | 0 | SESSION | Determines whether Databend treats unquoted identifiers as case-sensitive. | UInt64 |
+---------------------------------------+--------------+--------------+---------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+--------+