Results of 1 - 7 of about 7 for Projections (0.001 sec.)
- EXPLAIN: Inspect Query Plans 11832
- 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
...ature', 3); EXPLAIN SELECT name FROM students JOIN exams USING (sid) WHERE name LIKE 'Ma%'; ╭─ Projection ─────────────╮ │ Projections: name │ │ ~1 row │ ╰─────────────┬────────────╯ ╭─ Hash Join ─┴────────────╮ │ Join Type: INNER │ │ Conditions: sid = sid...──────╮ │ Table: memory.main.exams │ │ Table: memory.main.students │ │ Type: Sequential Scan │ │ Type: Sequential Scan │ │ Projections: sid │ │ Projections: sid, name │ │ ~3 rows │ │ Filters: name >= 'Ma' │ ╰──────────────────────────╯ │ ~1 row │ ╰─────────... - https://man.mtool.work/duckdb/2.0/guides/meta/explain.html
- EXPLAIN ANALYZE: Profile Queries 11832
- 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
...───────────╮ │ Total Time: 0.0015s │ ╰─────────────────────╯ ╭─ Projection ────────────────────────────────────────────╮ │ Projections: name │ │ 2 rows 0µs │ ╰────────────────────────────┒┎───────────────────────────╯ ╭─ Hash Join ────────────────┚┖────────...──────╮ │ 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:... - https://man.mtool.work/duckdb/2.0/guides/meta/explain_analyze.html
- Troubleshooting 9106
- Troubleshooting Running EXPLAIN Renders Newlines In Python, the output of the EXPLAIN statement contains hard line breaks ( \n ): In [1]: import duckdb ...: duckdb.sql("EXPLAIN SELECT 42 AS x") Out[1]: ┌───────────────┬─────────────────────
...─────────────────────────────────────────────────────────────────────────────────┤ │ physical_plan │ ╭─ Projection ───╮\n│ Projections: x │\n│ ~1 row │\n╰────────┬───────╯\n╭─ Dummy Scan ───╮\n │ │ │ ╰────────────────╯\n │ └───────────────┴─────────────────...t the output of the explain() function: In [2]: print(duckdb.sql("SELECT 42 AS x").explain()) Out[2]: ╭─ Projection ───╮ │ Projections: x │ │ ~1 row │ ╰────────┬───────╯ ╭─ Dummy Scan ───╮ ╰────────────────╯ In a Jupyter notebook, explain() displays the pla... - https://man.mtool.work/duckdb/2.0/clients/python/known_issues.html
- Reading and Writing Parquet Files 8088
- Examples Read a single Parquet file: SELECT * FROM 'test.parquet'; Figure out which columns/types are in a Parquet file: DESCRIBE SELECT * FROM 'test.parquet'; Create a table from a Parquet file: CREATE TABLE test AS SELECT * FROM 'test.par
...ides support for both reading and writing Parquet files in an efficient manner, as well as support for pushing filters and projections into the Parquet file scans. Parquet datasets differ based on the number of files, the size of individual files, the compr...ing is disabled with the disable_parquet_prefetching setting). With auto , DuckDB picks a strategy at runtime based on the projections and filters of the query. With whole_group , the entire row group is always prefetched. Added in DuckDB 2.0. VARCHAR auto... - https://man.mtool.work/duckdb/2.0/data/parquet/overview.html
- Troubleshoot 7906
- Overview This page collects common issues encountered when using DuckDB-Wasm, together with their workarounds. If you run into a problem that is not covered here, search the duckdb-wasm issue tracker on GitHub. Network Error When Querying R
...lizing them all at once with query() . Read only the columns and rows you need. Because DuckDB reads Parquet files lazily, projections, filters, and LIMIT clauses let entire row groups be skipped rather than loaded into memory. See Limitations for the other... - https://man.mtool.work/duckdb/2.0/clients/wasm/troubleshoot.html
- R-Tree Indexes 7397
- 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
...┘ ┌─────────────┴─────────────┐ │ RTREE_INDEX_SCAN │ │ ──────────────────── │ │ t1 (RTREE INDEX SCAN : │ │ my_idx) │ │ │ │ Projections: geom │ │ │ │ ~10000 Rows │ └───────────────────────────┘ Performance Considerations Bulk Loading & Maintenance Creating R... - https://man.mtool.work/duckdb/2.0/core_extensions/spatial/r-tree_indexes.html
- Metrics 7397
- 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
..._rows": 0, "intermediate_size_bytes": 0, "timing": 5.458e-06, "type": "RESULT_COLLECTOR", "children": [ { "extra_info": { "Projections": "name", "Estimated Cardinality": "1" }, "intermediate_rows": 2, "intermediate_size_bytes": 40, "timing": 8.3e-08, "type"... - https://man.mtool.work/duckdb/2.0/dev/metrics.html
PREV
1
NEXT
DuckDB 2.0 Documentation / man.mtool.work