Results of 1 - 8 of about 8 for optimizers (0.002 sec.)
- Join Operations 11712
- How to Force a Join Order DuckDB has a cost-based query optimizer, which uses statistics in the base tables (stored in a DuckDB database or Parquet files) to estimate the cardinality of operations. Turn off the Join Order Optimizer To turn
...off the join order optimizer, set the following PRAGMA s : SET disabled_optimizers = 'join_order,build_side_probe_side'; This disables both the join order optimizer and left/right swapping for joins. This...is performed first JOIN ...; -- this join is performed second Once the query in question has been executed, turn back the optimizers with the following command: SET disabled_optimizers = ''; Create Temporary Tables To force a particular join order, you ca...rogramming algorithm. As the number of tables in a join grows, exact enumeration becomes expensive, so for large joins the optimizer switches to an approximate (greedy) algorithm. The approximate_join_order_threshold setting controls when this happens: joi... - https://man.mtool.work/duckdb/2.0/guides/performance/join_operations.html
- Pragmas 10917
- The PRAGMA statement is a SQL extension adopted by DuckDB from SQLite. PRAGMA statements can be issued in a similar manner to regular SQL statements. PRAGMA commands may alter the internal state of the database engine, and can influence the
...e query optimizer: PRAGMA disable_optimizer; To enable the query optimizer: PRAGMA enable_optimizer; Selectively Disabling Optimizers The disabled_optimizers option allows selectively disabling optimization steps. For example, to disable filter_pushdown an...d statistics_propagation , run: SET disabled_optimizers = 'filter_pushdown,statistics_propagation'; The available optimizations can be queried using the duckdb_optimizers() table...function . To re-enable the optimizers, run: SET disabled_optimizers = ''; Warning The disabled_optimizers option should only be used for debugging performance i... - https://man.mtool.work/duckdb/2.0/configuration/pragmas.html
- Metrics 10917
- DuckDB provides a set of metrics that can be used to monitor the performance and health of the database. Metrics are named ⟨group⟩.⟨metric⟩ , e.g., query.total_time or operator.timing . The set of collected metrics is controlled with the tr
...r the operator to scan operator.type string Type of the operator optimizer Metrics Metrics measuring the time spent in the optimizers . Name Type Unit Description optimizer.total_time double seconds Time spent in all optimizers combined Additionally, each...n seconds) spent in that optimizer. These metrics are only collected when the specific optimizer is enabled. The available optimizers can be queried using the duckdb_optimizers() table function : optimizer.expression_rewriter , optimizer.filter_pullup , op...l_time": 0.001491167 } } The second example collects all query and planner metrics, as well as the total time spent in the optimizers. SET tracked_metrics = ['query.*', 'planner.*', 'optimizer.total_time']; SELECT name FROM students JOIN exams USING (sid)... - https://man.mtool.work/duckdb/2.0/dev/metrics.html
- Overview of DuckDB Internals 8946
- Tip For a detailed explanation of DuckDB internals, see the Design and Implementation of DuckDB Internals ("DiDi") library entry. On this page is a brief description of the internals of the DuckDB engine. Parser The parser converts a query
...ase, the actual logical query tree is created. Optimizer After the logical planner has created the logical query tree, the optimizers are run over that query tree to create an optimized query plan. The following query optimizers are run: Expression Rewrite... - https://man.mtool.work/duckdb/2.0/internals/overview.html
- sqllogictest Introduction 8368
- For testing plain SQL, we use an extended version of the SQL logic test suite, adopted from SQLite . Every test is a single self-contained file located in the test/sql directory. To run tests located outside of the default test directory, s
...tra validation to ensure that the underlying code runs correctly. The most important part of that is that it verifies that optimizers do not cause bugs in the query. It does this by running both an unoptimized and optimized version of the query, and verify...g that the results of these queries are identical. Query verification is very useful because it not only discovers bugs in optimizers, but also finds bugs in e.g., join implementations. This is because the unoptimized version will typically run using cross... - https://man.mtool.work/duckdb/2.0/dev/sqllogictest/intro.html
- DuckDB Environment 7573
- DuckDB provides a number of functions and PRAGMA options to retrieve information on the running DuckDB instance and its environment. Version The version() function returns the version number of DuckDB. SELECT version() AS version; version v
...nctions() : functions duckdb_indexes() : secondary indexes duckdb_keywords() : DuckDB's keywords and reserved words duckdb_optimizers() : the available optimization rules in the DuckDB instance duckdb_schemas() : schemas duckdb_sequences() : sequences duck... - https://man.mtool.work/duckdb/2.0/guides/meta/duckdb_environment.html
- DuckDB_% Metadata Functions 7193
- DuckDB offers a collection of table functions that provide metadata about the current database. These functions reside in the main schema and their names are prefixed with duckdb_ . The resultset returned by a duckdb_ table function may be
...ory_usage_bytes The memory used (in bytes). BIGINT temporary_storage_bytes The disk storage used (in bytes). BIGINT duckdb_optimizers The duckdb_optimizers() function provides metadata about the optimization rules (e.g., expression_rewriter , filter_pushdo...wn ) available in the DuckDB instance. These can be selectively turned off using PRAGMA disabled_optimizers . Column Description Type name The name of the optimization rule. VARCHAR duckdb_prepared_statements The duckdb_prepared_s... - https://man.mtool.work/duckdb/2.0/sql/meta/duckdb_table_functions.html
- Configuration 6597
- 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 . They can be reset to their original values usi
...ting their access, e.g., LocalFileSystem. VARCHAR disabled_log_types Sets the list of disabled log types. VARCHAR disabled_optimizers Disable a specific, comma-separated set of optimizers. VARCHAR duckdb_api Specifies which client API/binding opened the da... - https://man.mtool.work/duckdb/2.0/configuration/overview.html
PREV
1
NEXT
DuckDB 2.0 Documentation / man.mtool.work