Results of 1 - 10 of about 53 for Scan (0.002 sec.)
- Replacement Scans 14958
- The replacement scan API can be used to register a callback that is called when a table is read that does not exist in the catalog. For example, when a query such as SELECT * FROM my_table is executed and my_table does not exist, the replac
...ement scan callback will be called with my_table as parameter. The replacement scan can then insert a table function with a specific...parameter to replace the read of the table. API Reference Overview void duckdb_add_replacement_scan ( duckdb_database db , duckdb_replacement_callback_t replacement , void * extra_data , duckdb_delete_callback_t delete_cal...lback ); void duckdb_replacement_scan_set_function_name ( duckdb_replacement_scan_info info , const char * function_name ); void duckdb_replacement_scan_add_par... - https://man.mtool.work/duckdb/2.0/clients/c/replacement_scans.html
- Delta Extension 10850
- The delta extension adds support for the Delta Lake open-source storage format . It is built using the Delta Kernel . The extension reads Delta tables, local and remote, and writes them: it can create tables and append to them. For implemen
...he official extension repository. If you would like to install and load it manually, run: INSTALL AND LOAD delta; Usage To scan a local Delta table, run: SELECT * FROM delta_scan('file:///⟨path⟩'); Attaching Tables A Delta table can also be attached...to the same table: ATTACH 'file:///⟨path⟩' AS my_table (TYPE delta); SELECT * FROM my_table; Reading from an S3 Bucket To scan a Delta table in an S3 bucket , run: SELECT * FROM delta_scan('s3://⟨my_bucket⟩/⟨path⟩'); To authenticate, create a secret...: CREATE SECRET ( TYPE s3, PROVIDER credential_chain ); SELECT * FROM delta_scan('s3://⟨my_bucket⟩/⟨path⟩'); For a public bucket, you may need to set its region in a secret: CREATE SECRET ( TYPE s3, REGI... - https://man.mtool.work/duckdb/2.0/core_extensions/delta.html
- Iceberg Functions 9644
- The iceberg extension provides the following functions: Function Description iceberg_scan(source) Reads an Iceberg table from a path. iceberg_metadata(source) Returns the manifest entries of an Iceberg table. iceberg_snapshots(source) Retur
...hes and tags of an Iceberg table. iceberg_partition_specs(source) Returns the partition specs of an Iceberg table. iceberg_scan_plan(table) Returns the scan tasks (files to read) planned for an Iceberg table. iceberg_view_metadata(view) Returns the r...transform of a value. The examples on this page use the iceberg_data.zip file; download and unzip it to run them. iceberg_scan The iceberg_scan function reads an Iceberg table from a path, without requiring an attached catalog: SELECT count(*) FROM...iceberg_scan('data/iceberg/lineitem_iceberg', allow_moved_paths = true); count_star() 51793 The path can also point directly to a metad... - https://man.mtool.work/duckdb/2.0/core_extensions/iceberg/iceberg_functions.html
- Iceberg Extension 9644
- The iceberg extension implements support for the Apache Iceberg open table format . There are two ways to work with Iceberg in DuckDB: Individual tables are read directly from storage, by pointing at a table's metadata. This requires no cat
...g and schema evolution. Iceberg Functions documents the functions provided by the extension. Iceberg Options documents the scan parameters, ATTACH options, secret options and settings. Catalogs explains how to attach an Iceberg REST Catalog, with ins...at you have the latest version, update your extensions : UPDATE EXTENSIONS; Reading Iceberg Tables Individual Iceberg tables can be read directly from storage with the iceberg_scan function, without attaching to a catalog. To test the examples, downl...oad the iceberg_data.zip file and unzip it. Querying Individual Tables Use the iceberg_scan function to read an Iceberg table from a path: SELECT count(*) FROM iceberg_scan('data/iceberg/lineitem_iceberg', allow_mo... - https://man.mtool.work/duckdb/2.0/core_extensions/iceberg/overview.html
- EXPLAIN: Inspect Query Plans 8930
- 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
...in Type: INNER │ │ Conditions: sid = sid │ │ ~1 row │ ╰─────────────┬────────────╯ ├──────────────────────────────╮ ╭─ Seq Scan ──┴────────────╮ ╭─ Seq Scan ───┴──────────────╮ │ Table: memory.main.exams │ │ Table: memory.main.students │ │ Type: Sequ...ential Scan │ │ Type: Sequential Scan │ │ Projections: sid │ │ Projections: sid, name │ │ ~3 rows │ │ Filters: name >= 'Ma' │ ╰───────...~3 rows ), which is calculated by using the statistics of the base tables and applying heuristics for each operator. Table scan operators display the fully qualified table name including catalog and schema (e.g., memory.main.exams ). Additional Expla... - https://man.mtool.work/duckdb/2.0/guides/meta/explain.html
- EXPLAIN ANALYZE: Profile Queries 8930
- Prepending a query with EXPLAIN ANALYZE both pretty-prints the query plan, and executes it, providing run-time performance numbers and the actual cardinality (number of rows produced) for every operator. EXPLAIN ANALYZE SELECT * FROM tbl; N
...s │ ╰────────────────────────────┰┰───────────────────────────╯ ┃┠─────────────────────────────────────────────┰┒ ╭─ Table Scan ───────────────┚┖───────────────────────────╮ ╭─ Table Scan ─┚┖─────────────╮ │ Table: memory.main.exams │ │ Table: memory....main.students │ │ Type: Sequential Scan │ │ Type: Sequential Scan │ │ Projections: sid │ │ Projections: sid, name │ │ Dynamic Filters: │ │ Filters: name >= 'Ma' │...│ optional: (sid IN (1, 3)) AND optional: sid IN PRF(sid) │ │ Row Groups Scanned: 1 / 1 │ │ Row Groups Scanned: 1 / 1 │ │ 2 rows 0µs │ │ 2 rows 0µs │ ╰─────────────────────────────╯ ╰─────────────────... - https://man.mtool.work/duckdb/2.0/guides/meta/explain_analyze.html
- Indexing 8930
- DuckDB has two types of indexes: zonemaps and ART indexes. Zonemaps DuckDB automatically creates zonemaps (also known as min-max indexes) for the columns of all general-purpose data types . Operations like predicate pushdown into scan opera
...UUID for columns queried using selective filters. In a scenario where a table contains out-of-order UUID s, DuckDB has to scan many row groups to find a specific UUID value. An ordered INTEGER column allows skipping all row groups except those conta...sing the indexed column. An ART index does not affect the performance of join, aggregation, and sorting queries. ART Index Scans ART index scans probe a single-column ART index for the requested data instead of scanning a table sequentially. Probing...can improve the performance of some queries. DuckDB will try to use an index scan for equality and IN(...) conditions. It also pushes dynamic filters, e.g., from hash joins, into the scan, allowing dynami... - https://man.mtool.work/duckdb/2.0/guides/performance/indexing.html
- Write User Defined Functions 8826
- Overview The Go client can register user-defined functions written in Go: scalar functions that map input rows to a single output value, and table functions that produce a set of rows. It can also register a replacement scan that rewrites a
...e into a query. Scalar and table functions are registered on a connection checked out with db.Conn() , while a replacement scan is registered on a Connector ; in each case the function is then callable from SQL like any built-in. The sections below b...egisterScalarUDF(conn, "my_length", udf)) var length int32 row := db.QueryRow(`SELECT my_length('hello world')`) check(row.Scan(&length)) // 11 } Once registered, the function is called from SQL by the name passed to RegisterScalarUDF() : SELECT my_l...lumnInfos() declares the result columns, each a duckdb.ColumnInfo with a name and a TypeInfo . Init() runs once before the scan. FillRow() is called repeatedly, filling one duckdb.Row per call with duckdb.SetRowValue() and returning true while there... - https://man.mtool.work/duckdb/2.0/clients/go/functions.html
- Unity Catalog Extension 8826
- The unity_catalog extension attaches a Unity Catalog catalog, on Databricks or Unity Catalog OSS, as a DuckDB database. You can list, read, insert into and create its Delta Lake tables. It uses the delta extension to access the tables. For
...ks the server for the workspace's default namespace. READ_ONLY BOOLEAN false Attach the catalog in read-only mode. USE_IRC_SCAN_PLAN BOOLEAN false Plan scans on the server (Databricks only); see Server-Side Scan Planning . Reading Tables are named ⟨c...umns New Support for VARIANT columns was introduced in DuckDB 2.0. Unity Catalog's variant maps to VARIANT . VARIANT columns can be read whether their files are shredded or not. Inserts write shredded variants if the table sets delta.enableVariantShr...a.my_external_table (id INTEGER, name VARCHAR) WITH (location = 's3://⟨my_bucket⟩/⟨path⟩'); Both managed and external tables can be partitioned: CREATE TABLE my_catalog.my_schema.my_partitioned_table (id INTEGER, part VARCHAR) PARTITIONED BY (part);... - https://man.mtool.work/duckdb/2.0/core_extensions/unity_catalog.html
- Configuration 8498
- 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
...ng the RESET statement . The values of configuration options can be queried via the current_setting() scalar function or using the duckdb_settings() table function . For example: SELECT...sh the allocator after completing a task. VARCHAR 134217728B allow_asterisks_in_http_paths Allow '*' character in URLs users can query BOOLEAN false allow_community_extensions Allow loading extensions build by the community. BOOLEAN true allow_extens...e always cached. BOOLEAN false catalog_error_max_schemas The maximum number of schemas in the catalog that the system will scan to generate the "did you mean..." error message. UBIGINT 100 checkpoint_on_detach Override checkpoint behavior when detach... - https://man.mtool.work/duckdb/2.0/configuration/overview.html
DuckDB 2.0 Documentation / man.mtool.work