Results of 1 - 10 of about 26 for Space (0.002 sec.)
- CHECKPOINT Statement 11604
- The CHECKPOINT statement synchronizes data in the write-ahead log (WAL) to the database data file. Examples Synchronize data in the default database: CHECKPOINT; Synchronize data in the specified database: CHECKPOINT file_db; Synchronize da
...':memory:' AS memory_compressed (COMPRESS); USE memory_compressed; Checkpointing triggers vacuuming deleted rows, allowing space to be reclaimed after deletes/truncation. Syntax Checkpoint operations happen automatically based on the WAL size (see Con...ead aborted any in-progress transactions. Also see the related PRAGMA option for further behavior modification. Reclaiming Space When performing a checkpoint (automatic or otherwise), the space occupied by deleted rows is partially reclaimed. Note tha...applies to in-memory databases (see Checkpointing In-Memory Tables ), where it likewise vacuums deleted rows and reclaims space. Warning The VACUUM statement does not trigger vacuuming deletes and hence does not reclaim space.... - https://man.mtool.work/duckdb/2.0/sql/statements/checkpoint.html
- Caveats 11423
- Equality Comparison Warning Currently, equality comparison of JSON files can differ based on the context. In some cases, it is based on raw text comparison, while in other cases, it uses logical content comparison. The following query retur
...ns true for all fields: SELECT a != b, -- Space is part of physical JSON content. Despite equal logical content, values are treated as not equal. c != d, -- Same. c[0] =...d[0], -- Equality because space was removed from physical content of fields: a = c[0], -- Indeed, field is equal to empty list without space... b != c[0],...-- ... but different from empty list with space. FROM ( SELECT '[]'::JSON AS a, '[ ]'::JSON AS b, '[[]]'::JSON AS c, '[[ ]]'::JSON AS d ); (a != b) (c != d) (c[0] = d[0])... - https://man.mtool.work/duckdb/2.0/data/json/caveats.html
- DELETE Statement 11075
- The DELETE statement removes rows from the table identified by the table-name. If the WHERE clause is not present, all records in the table are deleted. If a WHERE clause is supplied, then only those rows for which the WHERE clause results
...table, acting as an alias for DELETE FROM without a WHERE clause: TRUNCATE tbl; Limitations on Reclaiming Memory and Disk Space Running DELETE does not mean space is reclaimed. In general, rows are only marked as deleted. DuckDB reclaims space upon p...erforming a CHECKPOINT . VACUUM currently does not reclaim space.... - https://man.mtool.work/duckdb/2.0/sql/statements/delete.html
- DROP Statement 10894
- The DROP statement removes a catalog entry added previously with the CREATE command. Examples Delete the table with the name tbl : DROP TABLE tbl; Drop the view with the name view1 ; do not throw an error if the view does not exist: DROP VI
...his returns the following error message: Catalog Error: Table with name tbl does not exist! Limitations on Reclaiming Disk Space Running DROP TABLE should free the memory used by the table, but not always disk space. Even if disk space does not decrea...e following PRAGMA and check the number of free_blocks in the output: PRAGMA database_size; For instructions on reclaiming space after dropping a table, refer to the “Reclaiming space” page .... - https://man.mtool.work/duckdb/2.0/sql/statements/drop.html
- Reclaiming Space 10629
- DuckDB uses a single-file format, which has some inherent limitations w.r.t. reclaiming disk space. CHECKPOINT To reclaim space after deleting rows, use the CHECKPOINT statement . VACUUM The VACUUM statement does not trigger vacuuming delet
...es and hence does not reclaim space. Compacting a Database by Copying To compact the database, you can create a fresh copy of the database using the COPY FROM... - https://man.mtool.work/duckdb/2.0/operations_manual/footprint_of_duckdb/reclaimi...
- VACUUM Statement 10546
- The VACUUM statement only has basic support in DuckDB and is mostly provided for PostgreSQL-compatibility. Some variants of it, such as when calling for a given column, recompute the distinct statistics (the number of distinct entities) if
...disables the fallback). It can only be set before the database is started or per database as an ATTACH option. Reclaiming Space The VACUUM statement does not reclaim space. For instructions on reclaiming space, refer to the “Reclaiming space” page .... - https://man.mtool.work/duckdb/2.0/sql/statements/vacuum.html
- Struct Data Type 9389
- Conceptually, a STRUCT column contains an ordered list of columns called “entries”. The entries are referenced by name using strings. This document refers to those entry names as keys. Each row in the STRUCT column must have the same keys.
...ruct column a , which we then query with a.x . SELECT a.x FROM (SELECT {'x': 1, 'y': 2, 'z': 3} AS a); If a key contains a space, simply wrap it in double quotes ( " ). SELECT a."x space" FROM (SELECT {'x space': 1, 'y': 2, 'z': 3} AS a); Bracket nota...o specify a certain string key and only constant expressions may be used inside the brackets (no expressions): SELECT a['x space'] FROM (SELECT {'x space': 1, 'y': 2, 'z': 3} AS a); The struct_extract function is also equivalent. This returns 1: SELEC...T struct_extract({'x space': 1, 'y': 2, 'z': 3}, 'x space'); unnest / STRUCT.* Rather than retrieving a single key from a struct, the unnest special... - https://man.mtool.work/duckdb/2.0/sql/data_types/struct.html
- Limits 9125
- This page contains DuckDB's built-in limit values. To check the value of a setting on your system, use the current_setting function. Limit Values Limit Default value Configuration option Comment Array size 100000 - BLOB size 4 GB - Expressi
...mit Note: This limit only applies to the buffer manager. String size 4 GB - Temporary directory size 90% of available disk space max_temp_directory_size Size of Database Files DuckDB doesn't have a practical limit for the size of a single DuckDB datab...ase file. We have database files using 15 TB+ of disk space and they work fine. However, connecting to such a huge database may take a few seconds and checkpointing can be slower.... - https://man.mtool.work/duckdb/2.0/operations_manual/limits.html
- File Formats 8166
- 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
...n Parquet files. Storage considerations: Loading the data from Parquet files will require approximately the same amount of space for the DuckDB database file. Therefore, if the available disk space is constrained, it is worth running the queries direc...nchmark run approximately 1.1-5.0× slower on Parquet files than on a DuckDB database. Bestpractice If you have the storage space available, and have a join-heavy workload and/or plan to run many queries on the same dataset, load the Parquet files into... - https://man.mtool.work/duckdb/2.0/guides/performance/file_formats.html
- Text Functions 7802
- Text Functions and Operators This section describes functions and operators for examining and manipulating STRING values . Function Description string[index] Extracts a single character using a (1-based) index . string[begin:end] Extracts a
...[, characters]) Removes any occurrences of any of the characters from the left side of the string . characters defaults to space . md5(string) Returns the MD5 hash of the string as a VARCHAR . md5_number(string) Returns the MD5 hash of the string as a..., characters]) Removes any occurrences of any of the characters from the right side of the string . characters defaults to space . sha1(value) Returns a VARCHAR with the SHA-1 hash of the value . sha256(value) Returns a VARCHAR with the SHA-256 hash o...ng[, characters]) Removes any occurrences of any of the characters from either side of the string . characters defaults to space . ucase(string) Alias for upper . unbin(value) Converts a value from binary representation to a blob. unhex(value) Convert... - https://man.mtool.work/duckdb/2.0/sql/functions/text.html
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