DuckDB has a number of configuration options that can be used to change the behavior of the system. The configuration options can be set using either the SET statement or the PRAGMA statement.
Examples
-- set the memory limit of the system to 10GB
SET memory_limit='10GB';
-- configure the system to use 1 thread
SET threads TO 1;
-- enable printing of a progress bar during long-running queries
SET enable_progress_bar=true;
-- set the default null order to NULLS LAST
PRAGMA default_null_order='nulls_last';
-- show a list of all available settings
SELECT * FROM duckdb_settings();
-- return the current value of a specific setting
-- this example returns 'automatic'
SELECT current_setting('access_mode');
Configuration Reference
Below is a list of all available settings.
| name | description | input_type | default_value |
|---|---|---|---|
| access_mode | Access mode of the database (AUTOMATIC, READ_ONLY or READ_WRITE) | VARCHAR | AUTOMATIC |
| checkpoint_threshold, wal_autocheckpoint | The WAL size threshold at which to automatically trigger a checkpoint (e.g. 1GB) | VARCHAR | 16.7MB |
| default_collation | The collation setting used when none is specified | VARCHAR | |
| default_null_order, null_order | Null ordering used when none is specified (NULLS_FIRST or NULLS_LAST) | VARCHAR | NULLS_FIRST |
| default_order | The order type used when none is specified (ASC or DESC) | VARCHAR | ASC |
| enable_external_access | Allow the database to access external state (through e.g. loading/installing modules, COPY TO/FROM, CSV readers, pandas replacement scans, etc) | BOOLEAN | TRUE |
| enable_object_cache | Whether or not object cache is used to cache e.g. Parquet metadata | BOOLEAN | FALSE |
| enable_profiling | Enables profiling, and sets the output format (JSON, QUERY_TREE, QUERY_TREE_OPTIMIZER) | VARCHAR | NONE |
| enable_progress_bar | Enables the progress bar, printing progress to the terminal for long queries | BOOLEAN | FALSE |
| explain_output | Output of EXPLAIN statements (ALL, OPTIMIZED_ONLY, PHYSICAL_ONLY) | VARCHAR | PHYSICAL_ONLY |
| log_query_path | Specifies the path to which queries should be logged (default: empty string, queries are not logged) | VARCHAR | NULL |
| max_memory, memory_limit | The maximum memory of the system (e.g. 1GB) | VARCHAR | 75% of RAM |
| perfect_ht_threshold | Threshold in bytes for when to use a perfect hash table (default: 12) | BIGINT | 12 |
| profile_output, profiling_output | The file to which profile output should be saved, or empty to print to the terminal | VARCHAR | |
| profiler_history_size | Sets the profiler history size | BIGINT | NULL |
| profiling_mode | The profiling mode (STANDARD or DETAILED) | VARCHAR | STANDARD |
| progress_bar_time | Sets the time (in milliseconds) how long a query needs to take before we start printing a progress bar | BIGINT | 2000 |
| s3_access_key_id | S3 Access Key ID | VARCHAR | |
| s3_endpoint | S3 Endpoint (default s3.amazonaws.com) | VARCHAR | |
| s3_region | S3 Region | VARCHAR | |
| s3_secret_access_key | S3 Access Key | VARCHAR | |
| s3_session_token | S3 Session Token | VARCHAR | |
| schema | Sets the default search schema. Equivalent to setting search_path to a single value. | VARCHAR | |
| search_path | Sets the default search search path as a comma-separated list of values | VARCHAR | |
| temp_directory | Set the directory to which to write temp files | VARCHAR | |
| threads, worker_threads | The number of total threads used by the system. | BIGINT | # Cores |