Results of 1 - 10 of about 14 for Insertion (0.002 sec.)
- Order Preservation 14441
- For many operations, DuckDB preserves the order of rows, similarly to data frame libraries such as Pandas. Example Take the following table for example: CREATE TABLE tbl AS SELECT * FROM (VALUES (1, 'a'), (2, 'b'), (3, 'c')) t(x, y); SELECT
...re that row in this table too. Clauses The following clauses guarantee that the original row order is preserved: COPY (see Insertion Order ) FROM with a single table LIMIT OFFSET SELECT UNION ALL WHERE Window functions with an empty OVER clause Common tab...r in- nor output order are guaranteed) ORDER BY (specifically, ORDER BY may not use a stable algorithm ) Scalar subqueries Insertion Order By default, the following components preserve insertion order: CSV reader ( read_csv function) JSON reader ( read_js...on function) Parquet reader ( read_parquet function) The preserve_insertion_order setting governs whether this order is maintained as rows flow into a sink . A sink is any operation that consumes a... - https://man.mtool.work/duckdb/2.0/sql/dialect/order_preservation.html
- Out-of-Memory Issues 10415
- Configuration Options If you are experiencing out-of-memory issues with DuckDB, try tweaking the following configuration options: Reduce the number of threads using the SET threads = ... command. Setting the memory limit lower than the defa
...atement. If your query reads a large amount of data from a file or writes a large amount of data, try setting the preserve_insertion_order option to false : SET preserve_insertion_order = false . In short, try the settings: SET threads = ⟨lower_than_the_n...umber_of_available_threads⟩; SET memory_limit = ⟨lower_than_80%_of_system_memory⟩; SET preserve_insertion_order = false; Schema and Indexes If you run in a memory-constrained environment, using smaller data types (e.g., TINYINT... - https://man.mtool.work/duckdb/2.0/guides/performance/oom.html
- Tuning Workloads 9697
- 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
...asure its effect. If your priority is… Consider Covered in Loading or exporting data larger than memory Disabling preserve_insertion_order The preserve_insertion_order option Using all available cores Row group sizing and the threads setting Parallelism P...overs each of these areas in detail. See the configuration reference for the full list of available settings. The preserve_insertion_order Option When importing or exporting datasets (from/to the Parquet or CSV formats), which are much larger than the ava...cur: Out of Memory Error: failed to allocate data of size ... (.../... used) In these cases, consider setting the preserve_insertion_order configuration option to false : SET preserve_insertion_order = false; This allows the system to re-order any results... - https://man.mtool.work/duckdb/2.0/guides/performance/how_to_tune_workloads.html
- INSERT Statements 8454
- INSERT statements are the standard way of loading data into a relational database. When using INSERT statements, the values are supplied row-by-row. While simple, there is significant overhead involved in parsing and processing individual I
...NSERT statements. This makes lots of individual row-by-row insertions very inefficient for bulk insertion. Bestpractice As a rule-of-thumb, avoid using lots of individual row-by-row INSERT st... - https://man.mtool.work/duckdb/2.0/data/insert.html
- CSV Import 8174
- Examples The following examples use the flights.csv file. Read a CSV file from disk, auto-infer options: SELECT * FROM 'flights.csv'; Use the read_csv function with custom options: SELECT * FROM read_csv('flights.csv', delim = '|', header =
...us CSV files. For details, see the Reading Faulty CSV Files page . Order Preservation The CSV reader respects the preserve_insertion_order configuration option to preserve insertion order . When true (the default), the order of the rows in the result set... - https://man.mtool.work/duckdb/2.0/data/csv/overview.html
- Write User Defined Functions 8087
- Overview The JDBC driver can register user-defined functions (UDFs) written in Java, including scalar functions and table functions. This page covers building and registering both, from the simple functional-interface overloads to the vecto
...hreads, set the thread count with info.setMaxThreads() in the init callback. Parallel output may also require the preserve_insertion_order option set to false , in the connection string or the connection properties. Projection Pushdown By default a table...hat the Java table function API mirrors. Run Queries — calling registered functions from SQL. Configuration — the preserve_insertion_order option that parallel table functions may require.... - https://man.mtool.work/duckdb/2.0/clients/java/functions.html
- Connect 7999
- Overview Every DuckDB feature reachable from Rust starts with a Connection . Opening in-memory and file-backed databases, configuring a database instance with Config , opening read-only, pooling connections across threads, the crate's threa
...pplied by name with with() : let config = Config::default() .with("temp_directory", "/path/to/temp/dir/")? .with("preserve_insertion_order", "false")?; The full list of settings is on the Configuration page . Many of them can also be changed after connect... - https://man.mtool.work/duckdb/2.0/clients/rust/connecting.html
- sqllogictest Introduction 7999
- 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
...verification statement ok PRAGMA enable_verification # create table statement ok CREATE TABLE a (i INTEGER, j INTEGER); # insertion: 1 affected row statement ok INSERT INTO a VALUES (42, 84); query II SELECT * FROM a; ---- 42 84 In this example, three st... - https://man.mtool.work/duckdb/2.0/dev/sqllogictest/intro.html
- COPY Statement 7999
- Examples Read a CSV file into the lineitem table, using auto-detected CSV options: COPY lineitem FROM 'lineitem.csv'; Read a CSV file into the lineitem table, using manually specified CSV options: COPY lineitem FROM 'lineitem.csv' (DELIMITE
...t (empty) PRESERVE_ORDER Whether or not to preserve order during the copy operation. Defaults to the value of the preserve_insertion_order configuration option . BOOL (*) RETURN_FILES Whether or not to include the created filepath(s) (as a files VARCHAR[]...e string, e.g., 2MB , or an integer, i.e., the number of bytes. This option is only used when you have issued SET preserve_insertion_order = false; , otherwise, it is ignored. BIGINT row_group_size * 1024 ROW_GROUP_SIZE The target size, i.e., number of ro... - https://man.mtool.work/duckdb/2.0/sql/statements/copy.html
- Appender 7912
- Use an appender to insert rows that your Python code produces. It collects rows and writes them together in one SQL statement; this is called flushing. The with block below flushes on successful exit: import duckdb con = duckdb.connect() co
...and deletes the rows that match. A NULL key matches nothing. A plain insert writes the rows in append order while preserve_insertion_order is on, which is the default. An upsert does not keep append order. When a flush contains duplicate keys, an upsert k... - https://man.mtool.work/duckdb/2.0/clients/python/appender.html
DuckDB 2.0 Documentation / man.mtool.work