Results of 1 - 10 of about 12 for speed up (0.002 sec.)
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- SAMPLE Clause 16311
- The SAMPLE clause allows you to run the query on a sample from the base table. This can significantly speed up processing of queries, at the expense of accuracy in the result. Samples can also be used to quickly see a snapshot of the data w
...e is written. Syntactically, the USING SAMPLE clause appears at the end of the SELECT statement body: after the WHERE , GROUP BY , HAVING , and QUALIFY clauses, and before ORDER BY and LIMIT . So it is written after grouping and filtering, but it i... - https://man.mtool.work/duckdb/2.0/sql/query_syntax/sample.html
- Schema 15979
- Types It is important to use the correct type for encoding columns (e.g., BIGINT , DATE , DATETIME ). While it is always possible to use string types ( VARCHAR , etc.) to encode more specific values, this is not recommended. Strings use mor
...required to complete a query. DuckDB's bitpacking compression means small values stored in larger data types will not take up larger sizes on disk, but they will take up more memory during processing – hence, using the most restrictive types possib...ns is necessary to reduce memory consumption. Microbenchmark: Using Timestamps We illustrate the difference in aggregation speed using the creationDate column of the LDBC Comment table on scale factor 300 . This table has approx. 554 million unordered...ences a separate dimension table . This is the same idea as a star schema, and it keeps the large fact table narrow, which speeds up grouping and joining. (For a fixed, known set of values, the ENUM type achieves a similar effect automatically.) First... - https://man.mtool.work/duckdb/2.0/guides/performance/schema.html
- Building DuckDB from Source 15516
- When Should You Build DuckDB? DuckDB binaries are available for stable and preview builds on the installation page . In most cases, it's recommended to use these binaries. When you are running on an experimental platform (e.g., Raspberry Pi
...NCHMARK=1 make # build with benchmarks debug builds use a lot of disk space – make sure you have at least 25 GB available. Speeding up Subsequent Builds You can speed up subsequent builds using ccache . On macOS, you can install and configure it as fo...llows: brew install ccache ccache -M 50G Platforms Platforms with Full Support DuckDB fully supports Linux, macOS and Windows. Both x86_64 (amd64) and AArch64 (ARM64) builds are available for these...platforms (except for macOS on x86_64, which only has partial support, see below), and almost all extensions are distributed for these platforms. Platform name Description Comment linux_am... - https://man.mtool.work/duckdb/2.0/dev/building/overview.html
- I/O 15441
- Warning DuckDB ships with safe defaults. The configuration options described on this page are advanced options, so proceed with caution when changing them. Asynchronous I/O New Asynchronous I/O was introduced in DuckDB 2.0. Starting with v2
....0, DuckDB supports asynchronous I/O. Instead of blocking a worker thread until requested data arrives, DuckDB issues reads in the backgr...d and keeps multiple requests in flight while worker threads process data that has already arrived. This can significantly speed up queries when synchronous I/O does not saturate the available bandwidth, e.g., when reading data from object storage suc...h as S3. For a detailed explanation of the design and benchmark results, see the “Asynchronous I/O in DuckDB” blog post . Supported Formats Asynchronous I/O is currently supported for the following formats: Parquet files uncompressed, seekable CSV... - https://man.mtool.work/duckdb/2.0/data/io.html
- Indexes 14965
- Index Types DuckDB has two built-in index types. Indexes can also be defined via extensions . Min-Max Index (Zonemap) A min-max index (also known as zonemap or block range index) is automatically created for columns of all general-purpose d
...ata types . Adaptive Radix Tree (ART) An Adaptive Radix Tree (ART) is mainly used to ensure primary key constraints and to speed up point and very highly selective (i.e., < 0.1%) queries. ART indexes can be created manually using the CREATE INDEX clau...void creating ART indexes if the index does not fit in memory during index creation. Indexes Defined by Extensions DuckDB supports R-trees for spatial indexing via the spatial extension. Persistence Both min-max indexes and ART indexes are persiste...at is also stored in secondary indexes. As expected, indexes have a strong effect on performance, slowing down loading and updates, but speeding up certain queries. Please consult the Performance Guide for details. Constraint Checking in UPDATE Sta... - https://man.mtool.work/duckdb/2.0/sql/indexes.html
- SELECT Statement 14965
- The SELECT statement retrieves rows from the database. Examples Select all columns from the table tbl : SELECT * FROM tbl; Select the rows from tbl : SELECT j FROM tbl WHERE i = 3; Perform an aggregate grouped by the column i : SELECT i, su
...m(j) FROM tbl GROUP BY i; Select only the top 3 rows from the tbl : SELECT * FROM tbl ORDER BY i DESC LIMIT 3; Join two tables together using...ss common clauses being indented: SELECT ⟨select_list⟩ FROM ⟨tables⟩ USING SAMPLE ⟨sample_expression⟩ WHERE ⟨condition⟩ GROUP BY ⟨groups⟩ HAVING ⟨group_filter⟩ WINDOW ⟨window_expression⟩ QUALIFY ⟨qualify_filter⟩ ORDER BY ⟨order_expression⟩ LIMIT ⟨n...node. SAMPLE Clause The SAMPLE clause allows you to run the query on a sample from the base table. This can significantly speed up processing of queries, at the expense of accuracy in the result. Samples can also be used to quickly see a snapshot of... - https://man.mtool.work/duckdb/2.0/sql/statements/select.html
- Constraints 13617
- In SQL, constraints can be specified for tables. Constraints enforce certain properties over data that is inserted into a table. Constraints can be specified along with the schema of the table as part of the CREATE TABLE statement . In cert
...ain cases, constraints can also be added to a table using the ALTER TABLE statement , but this is not currently supported for all constraints. Warning Constraints have a strong impact on performance: they slow down loading and updates but...speed up certain queries. Please consult the Performance Guide for details. Syntax Check Constraint Check constraints allow you...e VARCHAR); INSERT INTO students VALUES (1, 'Student 1'); INSERT INTO students VALUES (1, 'Student 2'); Constraint Error: Duplicate key "id: 1" violates primary key constraint CREATE TABLE students (id INTEGER, name VARCHAR, PRIMARY KEY (id, name))... - https://man.mtool.work/duckdb/2.0/sql/constraints.html
- Migrating to DuckDB 2.0 13387
- DuckDB 2.0.0 is packed with new features and performance improvements, including query optimization and asynchronous I/O. It also ships a small set of breaking changes, most notably a new default storage format, which DuckDB versions before
...fore migrating to DuckDB 2.0.0, assess whether your workload is mission-critical. For such workloads, consider waiting for upcoming patch releases, which address issues that surface shortly after a major release. To help facilitate this, the DuckDB...development team extended support for DuckDB 1.5 until March 2027 . Note that DuckDB 1.4 LTS reaches its end of life on November 17, 2026. Bestpractice...fying CTEs and nested schemas Asynchronous I/O for faster reads from object storage Optimizer and engine improvements that speed up existing queries, including on Windows Self-hostable extension repositories for signing and distributing your own exten... - https://man.mtool.work/duckdb/2.0/operations_manual/migration.html
- File Formats 13067
- Handling Parquet Files DuckDB has advanced support for Parquet files, which includes directly querying Parquet files . When deciding on whether to query these files directly or to first load them to the database, you need to consider severa
...the Parquet files to DuckDB tables. The improved statistics likely help obtain a better join order. Repeated queries: If you plan to run multiple queries on the same dataset, it is worth loading the data into DuckDB. The queries will always be some...many queries on the same dataset, load the Parquet files into the database first. The compression algorithm and the row group sizes in the Parquet files have a large effect on performance: study these using the parquet_metadata function . The Effec...CSV sniffer on all files. For many small files, this may cause an unnecessarily high overhead. A potential optimization to speed this up is to turn the sniffer off. Assuming that all files have the same CSV dialect and column names/types, get the snif... - https://man.mtool.work/duckdb/2.0/guides/performance/file_formats.html
- Tuning Workloads 12534
- 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
...larger than memory Disabling preserve_insertion_order The preserve_insertion_order option Using all available cores Row group sizing and the threads setting Parallelism Processing data larger than memory Configuring the spill-to-disk directory Larg...rve row order and which do not, see the Order Preservation page . Parallelism (Multi-Core Processing) The Effect of Row Groups on Parallelism DuckDB parallelizes the workload based on row groups , i.e., groups of rows that are stored together at th...This can be more helpful if DuckDB is not CPU limited, but instead bottlenecked by another resource like network transfer speed. Persistent vs. In-Memory Tables DuckDB supports lightweight compression techniques . By default, compression is only appl... - https://man.mtool.work/duckdb/2.0/guides/performance/how_to_tune_workloads.html
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