Results of 1 - 10 of about 16 for optimizer (0.002 sec.)
- Metrics 14330
- 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
...kdb_available_metrics(); All Metrics The metrics are organized into the following groups: query system io storage operator optimizer parser planner physical_planner query Metrics Metrics measured over the entire query. Name Type Unit Description query.cpu...uint64 row_groups Total number of row groups available for 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 second...s Time spent in all optimizers combined Additionally, each optimizer has a corresponding metric that follows the template optimizer.⟨optimizer_name⟩ and... - https://man.mtool.work/duckdb/2.0/dev/metrics.html
- Join Operations 11090
- 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 or...der optimizer and left/right swapping for joins. This way, DuckDB builds a left-deep join tree following the order of JOIN clauses. SELE...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 c... - https://man.mtool.work/duckdb/2.0/guides/performance/join_operations.html
- Crashes 9582
- DuckDB is thoroughly tested via an extensive test suite. However, bugs can still occur and these can sometimes lead to crashes. This page contains practical information on how to troubleshoot DuckDB crashes. Types of Crashes There are a few
...ially related issues. DuckDB has a large community and there may be some suggestions for a workaround. Disabling the Query Optimizer Some crashes are caused by DuckDB's query optimizer component. To identify whether the optimizer is causing the crash, try...to turn it off and re-run the query: PRAGMA disable_optimizer; If the query finishes successfully, then the crash was caused by one or more optimizer rules. To pinpoint the specific ru...les that caused the crash, you can try to selectively disable optimizer rules . This way, your query can still benefit from the rest of the optimizer rules. Try to Isolate the Issue Some issues... - https://man.mtool.work/duckdb/2.0/guides/troubleshooting/crashes.html
- Pragmas 8958
- 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
...iling_coverage = 'ALL'; Profiling Format The format of enable_profiling can be specified as query_tree , json , query_tree_optimizer , or no_output . Each format prints its output to the configured output, except no_output . The default format is query_tr...eloped by the Database Systems Research Group at the University of Tübingen . To return the physical query plan, including optimizer and planner metrics: SET enable_profiling = 'query_tree_optimizer'; Database drivers and other applications can also acces...rics. Note This only affects the metrics when enable_profiling is set to json or no_output . The query_tree and query_tree_optimizer always use a default set of metrics. Metric names are grouped by stage and written in group.metric form, for example query... - https://man.mtool.work/duckdb/2.0/configuration/pragmas.html
- Profiling 8958
- Profiling is essential to help understand why certain queries exhibit specific performance characteristics. DuckDB contains several built-in features to enable query profiling, which this page covers. For a high-level example of using EXPLA
...Description Default Options enable_profiling , enable_profile Turn on profiling query_tree query_tree , json , query_tree_optimizer , no_output profiling_coverage Set the operators to profile SELECT SELECT , ALL profiling_output Set a profiling output fi...all tracked_metrics Select which metrics to collect ['*'] (all metrics) A list of metric glob patterns, e.g. ['query.*', 'optimizer.*'] . ( List of all available metrics ) disable_profiling , disable_profile Turn off profiling Table Functions These table...utput coverage VARCHAR Query coverage: 'select' or 'all' format VARCHAR Output format: 'query_tree' , 'json' , 'query_tree_optimizer' , 'no_output' All parameters are optional and named. You can also pass metrics as an unnamed parameter: CALL enable_profi... - https://man.mtool.work/duckdb/2.0/dev/profiling.html
- Overview of DuckDB Internals 8213
- 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
...planner creates LogicalOperator nodes from the bound statements. In this phase, 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 opt...imized query plan. The following query optimizers are run: Expression Rewriter : Simplifies expressions, performs constant folding Filter Pushdown : Pushes filters down in...s. Also prunes subtrees that are guaranteed to be empty (because of filters that statically evaluate to false). Join Order Optimizer : Reorders joins using dynamic programming. Specifically, the DPhyp algorithm from the paper Dynamic Programming Strikes B... - https://man.mtool.work/duckdb/2.0/internals/overview.html
- Configuration 7953
- 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 d...o disk before committing. Disable this to keep bulk appends in memory, e.g., for in-memory benchmarks. BOOLEAN true enable_optimizer Whether the query optimizer is enabled. BOOLEAN true enable_server_cert_verification Enable server side certificate verifi...VARCHAR NULL enable_profiling Enables profiling and sets the output format, which can be JSON , QUERY_TREE , or QUERY_TREE_OPTIMIZER . VARCHAR NULL enable_progress_bar_print Controls the printing of the progress bar and requires 'enable_progress_bar' to b... - https://man.mtool.work/duckdb/2.0/configuration/overview.html
- CONNECT and DISCONNECT Statements 7919
- New Support for the CONNECT and DISCONNECT statements was introduced in DuckDB 2.0. The CONNECT statement routes the current session to a remote database, so that subsequent queries execute on that remote and their results stream back. DISC
..., including: DuckDB servers reached over the Quack protocol . PostgreSQL and MySQL servers. For these, the remote pushdown optimizer ships SQL directly to the server instead of pulling tables over the wire. In-process local databases, such as the default... - https://man.mtool.work/duckdb/2.0/sql/statements/connect.html
- EXPLAIN: Inspect Query Plans 7884
- EXPLAIN SELECT * FROM tbl; The EXPLAIN statement displays the physical plan, i.e., the query plan that will get executed, and is enabled by prepending the query with EXPLAIN . The physical plan is a tree of operators that are executed in a
...specific order to produce the result of the query. To generate an efficient physical plan, the query optimizer transforms the existing physical plan into a better physical plan. To demonstrate, see the below example: CREATE TABLE stu... - https://man.mtool.work/duckdb/2.0/guides/meta/explain.html
- What's New in the Docs for 2.0 7745
- This page tracks the documentation for the features introduced in DuckDB 2.0, organized around the themes of the DuckDB 2.0.0 release announcement . Each section links to the relevant documentation. DuckDB as a Server: Quack and CONNECT Sin
...ew Thread pools and read-ahead Asynchronous I/O configuration settings Faster Queries Across the Board DuckDB 2.0 included optimizer and engine improvements, including faster recursive CTEs and better row-group pruning. Recursive CTEs and the blog post on... - https://man.mtool.work/duckdb/2.0/whats_new_in_the_docs.html
DuckDB 2.0 Documentation / man.mtool.work