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- Tuning Workloads 13267
- DuckDB aims to perform well out of the box, so most workloads do not require any tuning. When tuning is worthwhile, there is no single configuration or magic number that is optimal for every workload: the right settings depend on what you a
.... The preserve_insertion_order Option When importing or exporting datasets (from/to the Parquet or CSV formats), which are much larger than the available memory, an out of memory error may occur: Out of Memory Error: failed to allocate data of size ....olumns that are regularly used for filters: this increases the effectiveness of the filters in reducing IO. To inspect how much remote data is transferred for a query, EXPLAIN ANALYZE can be used to print out the total number of requests and total da...connections can parallelize some operations, although it is typically not necessary. DuckDB does attempt to parallelize as much as possible within each individual query, but it is not possible to parallelize in all cases. Making multiple connections... - https://man.mtool.work/duckdb/2.0/guides/performance/how_to_tune_workloads.html
- Julia Client 12188
- The DuckDB Julia package provides a high-performance front-end for DuckDB. Much like SQLite, DuckDB runs in-process within the Julia client, and provides a DBInterface front-end. The package also supports multi-threaded execution. It uses J
...con, "SELECT * FROM my_df") print(results) Appender API The DuckDB Julia package also supports the Appender API , which is much faster than using prepared statements or individual INSERT INTO statements. Appends are made in row-wise format. For every... - https://man.mtool.work/duckdb/2.0/clients/tertiary_clients/julia.html
- Python Function API 10029
- You can create a DuckDB user-defined function (UDF) from a Python function so it can be used in SQL queries. Similarly to regular functions , they need to have a name, a return type and parameter types. Creating Functions To register a Pyth
...pe = 'native' is assumed, but you can specify type = 'arrow' to use PyArrow Arrays. In general, using an Arrow UDF will be much more efficient than native because it will be able to operate in batches. null_handling (optional): By default, NULL value...d also expect an array of the same amount of rows to be returned from the function. In general, using an Arrow UDF will be much more efficient than native because it will be able to operate in batches. import duckdb import pyarrow as pa from duckdb.s... - https://man.mtool.work/duckdb/2.0/clients/python/function.html
- R-Tree Indexes 10029
- The spatial extension provides support for spatial indexing through the R-tree extension index type. Why Should I Use an R-Tree Index? When working with geospatial datasets, it is very common that you want to filter rows based on their spat
...re reached, only the specific rows whose geometries intersect the query region have to be fetched from disk, and the often much more expensive exact spatial predicate check (and any other filters) only have to be executed for these rows. What Are the...──────────┘ Performance Considerations Bulk Loading & Maintenance Creating R-trees on top of an already populated table is much faster than first creating the index and then inserting the data. This is because the R-tree will have to periodically reb... - https://man.mtool.work/duckdb/2.0/core_extensions/spatial/r-tree_indexes.html
- Comparisons 9498
- Comparison Operators The table below shows the standard comparison operators. Whenever either of the input arguments is NULL , the output of the comparison is NULL . Operator Description Example Result < less than 2 < 3 true > greater than
...[NOT] NULL Besides the standard comparison operators there are also the BETWEEN and IS (NOT) NULL operators. These behave much like operators, but have special syntax mandated by the SQL standard. They are shown in the table below. Note that BETWEEN... - https://man.mtool.work/duckdb/2.0/sql/expressions/comparison_operators.html
- QUALIFY Clause 9498
- The QUALIFY clause is used to filter the results of WINDOW functions . This filtering of results is similar to how a HAVING clause filters the results of aggregate functions applied based on the GROUP BY clause . The QUALIFY clause avoids t
...he need for a subquery or WITH clause to perform this filtering (much like HAVING avoids a subquery). An example using a WITH clause instead of QUALIFY is included below the QUALIFY examples.... - https://man.mtool.work/duckdb/2.0/sql/query_syntax/qualify.html
- Import Data 8418
- Overview The Go client offers two ways to load data into DuckDB in bulk: the high-performance Appender for inserting rows generated in Go, and reading directly from data files such as Parquet, CSV, and JSON. Both are described below. For in
...atement is fine; the options here are for volume. Appender The Appender is the fastest way to insert rows generated in Go, much faster than issuing INSERT statements. It operates on a raw DuckDB connection, so it is created from a Connector rather th... - https://man.mtool.work/duckdb/2.0/clients/go/data_import.html
- Securing Quack with a Reverse Proxy 8418
- By default, the Quack server binds to localhost and speaks plain HTTP. See Security for the rationale behind these configurations. For any deployment beyond local-only, the recommended pattern is the same as for any other HTTP-based databas
...eing buffered in Caddy. flush_interval -1 } # Equivalent of nginx `client_max_body_size`. PREPARE / APPEND bodies # can be much larger than the default request body cap. request_body { max_size 256MB } } Caddy handles certificate issuance and renewal... - https://man.mtool.work/duckdb/2.0/quack/setup/reverse_proxy.html
- Geometry Data Type 8418
- Name Description GEOMETRY Geospatial entity The GEOMETRY data type is used to store and manipulate geometric objects, such as points, lines, and polygons. The GEOMETRY type was part of the spatial extension but became a built-in data type i
...──┘ -- While the geometry column in `shredded_db` is decomposed into primitive DOUBLE segments, -- which can be compressed much more efficiently! SELECT DISTINCT(segment_type) FROM pragma_storage_info('shredded_db.points'); ---- ┌──────────────┐ │ se...etry functions provided by the extension, including functions for calculating areas, distances, intersections, unions, and much more.... - https://man.mtool.work/duckdb/2.0/sql/data_types/geometry.html
- Union Type 8418
- A UNION type (not to be confused with the SQL UNION operator ) is a nested type capable of holding one of multiple “alternative” values, much like the union in C. The main difference is that these UNION types are tagged unions and thus alwa
... - https://man.mtool.work/duckdb/2.0/sql/data_types/union.html
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