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path: root/src/backend/access/tablesample/tablesample.c
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* Update copyright for 2025Bruce Momjian2025-01-01
| | | | Backpatch-through: 13
* Update copyright for 2024Bruce Momjian2024-01-03
| | | | | | | | Reported-by: Michael Paquier Discussion: https://postgr.es/m/ZZKTDPxBBMt3C0J9@paquier.xyz Backpatch-through: 12
* Update copyright for 2023Bruce Momjian2023-01-02
| | | | Backpatch-through: 11
* Update copyright for 2022Bruce Momjian2022-01-07
| | | | Backpatch-through: 10
* Update copyright for 2021Bruce Momjian2021-01-02
| | | | Backpatch-through: 9.5
* Update copyrights for 2020Bruce Momjian2020-01-01
| | | | Backpatch-through: update all files in master, backpatch legal files through 9.4
* Update copyright for 2019Bruce Momjian2019-01-02
| | | | Backpatch-through: certain files through 9.4
* Update copyright for 2018Bruce Momjian2018-01-02
| | | | Backpatch-through: certain files through 9.3
* Update copyright via script for 2017Bruce Momjian2017-01-03
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* Update copyright for 2016Bruce Momjian2016-01-02
| | | | Backpatch certain files through 9.1
* Redesign tablesample method API, and do extensive code review.Tom Lane2015-07-25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | The original implementation of TABLESAMPLE modeled the tablesample method API on index access methods, which wasn't a good choice because, without specialized DDL commands, there's no way to build an extension that can implement a TSM. (Raw inserts into system catalogs are not an acceptable thing to do, because we can't undo them during DROP EXTENSION, nor will pg_upgrade behave sanely.) Instead adopt an API more like procedural language handlers or foreign data wrappers, wherein the only SQL-level support object needed is a single handler function identified by having a special return type. This lets us get rid of the supporting catalog altogether, so that no custom DDL support is needed for the feature. Adjust the API so that it can support non-constant tablesample arguments (the original coding assumed we could evaluate the argument expressions at ExecInitSampleScan time, which is undesirable even if it weren't outright unsafe), and discourage sampling methods from looking at invisible tuples. Make sure that the BERNOULLI and SYSTEM methods are genuinely repeatable within and across queries, as required by the SQL standard, and deal more honestly with methods that can't support that requirement. Make a full code-review pass over the tablesample additions, and fix assorted bugs, omissions, infelicities, and cosmetic issues (such as failure to put the added code stanzas in a consistent ordering). Improve EXPLAIN's output of tablesample plans, too. Back-patch to 9.5 so that we don't have to support the original API in production.
* Remove useless check for NULL subexpression.Tom Lane2015-06-30
| | | | | | | Coverity rightly gripes that it's silly to have a test here when the adjacent ExecEvalExpr() would choke on a NULL expression pointer. Petr Jelinek
* Manual cleanup of pgindent results.Tom Lane2015-05-24
| | | | | | Fix some places where pgindent did silly stuff, often because project style wasn't followed to begin with. (I've not touched the atomics headers, though.)
* pgindent run for 9.5Bruce Momjian2015-05-23
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* TABLESAMPLE, SQL Standard and extensibleSimon Riggs2015-05-15
Add a TABLESAMPLE clause to SELECT statements that allows user to specify random BERNOULLI sampling or block level SYSTEM sampling. Implementation allows for extensible sampling functions to be written, using a standard API. Basic version follows SQLStandard exactly. Usable concrete use cases for the sampling API follow in later commits. Petr Jelinek Reviewed by Michael Paquier and Simon Riggs
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