summaryrefslogtreecommitdiff
path: root/contrib/tsm_system_rows/tsm_system_rows.c
AgeCommit message (Collapse)Author
2025-03-26Use PG_MODULE_MAGIC_EXT in our installable shared libraries.Tom Lane
It seems potentially useful to label our shared libraries with version information, now that a facility exists for retrieving that. This patch labels them with the PG_VERSION string. There was some discussion about using semantic versioning conventions, but that doesn't seem terribly helpful for modules with no SQL-level presence; and for those that do have SQL objects, we typically expect them to support multiple revisions of the SQL definitions, so it'd still not be very helpful. I did not label any of src/test/modules/. It seems unnecessary since we don't install those, and besides there ought to be someplace that still provides test coverage for the original PG_MODULE_MAGIC macro. Author: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/dd4d1b59-d0fe-49d5-b28f-1e463b68fa32@gmail.com
2025-01-01Update copyright for 2025Bruce Momjian
Backpatch-through: 13
2024-10-28Remove unused #include's from contrib, pl, test .c filesPeter Eisentraut
as determined by IWYU Similar to commit dbbca2cf299, but for contrib, pl, and src/test/. Reviewed-by: Alvaro Herrera <alvherre@alvh.no-ip.org> Discussion: https://www.postgresql.org/message-id/flat/0df1d5b1-8ca8-4f84-93be-121081bde049%40eisentraut.org
2024-01-03Update copyright for 2024Bruce Momjian
Reported-by: Michael Paquier Discussion: https://postgr.es/m/ZZKTDPxBBMt3C0J9@paquier.xyz Backpatch-through: 12
2023-01-02Update copyright for 2023Bruce Momjian
Backpatch-through: 11
2022-01-07Update copyright for 2022Bruce Momjian
Backpatch-through: 10
2021-11-28Replace random(), pg_erand48(), etc with a better PRNG API and algorithm.Tom Lane
Standardize on xoroshiro128** as our basic PRNG algorithm, eliminating a bunch of platform dependencies as well as fundamentally-obsolete PRNG code. In addition, this API replacement will ease replacing the algorithm again in future, should that become necessary. xoroshiro128** is a few percent slower than the drand48 family, but it can produce full-width 64-bit random values not only 48-bit, and it should be much more trustworthy. It's likely to be noticeably faster than the platform's random(), depending on which platform you are thinking about; and we can have non-global state vectors easily, unlike with random(). It is not cryptographically strong, but neither are the functions it replaces. Fabien Coelho, reviewed by Dean Rasheed, Aleksander Alekseev, and myself Discussion: https://postgr.es/m/alpine.DEB.2.22.394.2105241211230.165418@pseudo
2021-01-02Update copyright for 2021Bruce Momjian
Backpatch-through: 9.5
2020-01-01Update copyrights for 2020Bruce Momjian
Backpatch-through: update all files in master, backpatch legal files through 9.4
2019-05-22Phase 2 pgindent run for v12.Tom Lane
Switch to 2.1 version of pg_bsd_indent. This formats multiline function declarations "correctly", that is with additional lines of parameter declarations indented to match where the first line's left parenthesis is. Discussion: https://postgr.es/m/CAEepm=0P3FeTXRcU5B2W3jv3PgRVZ-kGUXLGfd42FFhUROO3ug@mail.gmail.com
2019-03-31tableam: sample scan.Andres Freund
This moves sample scan support to below tableam. It's not optional as there is, in contrast to e.g. bitmap heap scans, no alternative way to perform tablesample queries. If an AM can't deal with the block based API, it will have to throw an ERROR. The tableam callbacks for this are block based, but given the current TsmRoutine interface, that seems to be required. The new interface doesn't require TsmRoutines to perform visibility checks anymore - that requires the TsmRoutine to know details about the AM, which we want to avoid. To continue to allow taking the returned number of tuples account SampleScanState now has a donetuples field (which previously e.g. existed in SystemRowsSamplerData), which is only incremented after the visibility check succeeds. Author: Andres Freund Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de
2019-03-11tableam: Add and use scan APIs.Andres Freund
Too allow table accesses to be not directly dependent on heap, several new abstractions are needed. Specifically: 1) Heap scans need to be generalized into table scans. Do this by introducing TableScanDesc, which will be the "base class" for individual AMs. This contains the AM independent fields from HeapScanDesc. The previous heap_{beginscan,rescan,endscan} et al. have been replaced with a table_ version. There's no direct replacement for heap_getnext(), as that returned a HeapTuple, which is undesirable for a other AMs. Instead there's table_scan_getnextslot(). But note that heap_getnext() lives on, it's still used widely to access catalog tables. This is achieved by new scan_begin, scan_end, scan_rescan, scan_getnextslot callbacks. 2) The portion of parallel scans that's shared between backends need to be able to do so without the user doing per-AM work. To achieve that new parallelscan_{estimate, initialize, reinitialize} callbacks are introduced, which operate on a new ParallelTableScanDesc, which again can be subclassed by AMs. As it is likely that several AMs are going to be block oriented, block oriented callbacks that can be shared between such AMs are provided and used by heap. table_block_parallelscan_{estimate, intiialize, reinitialize} as callbacks, and table_block_parallelscan_{nextpage, init} for use in AMs. These operate on a ParallelBlockTableScanDesc. 3) Index scans need to be able to access tables to return a tuple, and there needs to be state across individual accesses to the heap to store state like buffers. That's now handled by introducing a sort-of-scan IndexFetchTable, which again is intended to be subclassed by individual AMs (for heap IndexFetchHeap). The relevant callbacks for an AM are index_fetch_{end, begin, reset} to create the necessary state, and index_fetch_tuple to retrieve an indexed tuple. Note that index_fetch_tuple implementations need to be smarter than just blindly fetching the tuples for AMs that have optimizations similar to heap's HOT - the currently alive tuple in the update chain needs to be fetched if appropriate. Similar to table_scan_getnextslot(), it's undesirable to continue to return HeapTuples. Thus index_fetch_heap (might want to rename that later) now accepts a slot as an argument. Core code doesn't have a lot of call sites performing index scans without going through the systable_* API (in contrast to loads of heap_getnext calls and working directly with HeapTuples). Index scans now store the result of a search in IndexScanDesc->xs_heaptid, rather than xs_ctup->t_self. As the target is not generally a HeapTuple anymore that seems cleaner. To be able to sensible adapt code to use the above, two further callbacks have been introduced: a) slot_callbacks returns a TupleTableSlotOps* suitable for creating slots capable of holding a tuple of the AMs type. table_slot_callbacks() and table_slot_create() are based upon that, but have additional logic to deal with views, foreign tables, etc. While this change could have been done separately, nearly all the call sites that needed to be adapted for the rest of this commit also would have been needed to be adapted for table_slot_callbacks(), making separation not worthwhile. b) tuple_satisfies_snapshot checks whether the tuple in a slot is currently visible according to a snapshot. That's required as a few places now don't have a buffer + HeapTuple around, but a slot (which in heap's case internally has that information). Additionally a few infrastructure changes were needed: I) SysScanDesc, as used by systable_{beginscan, getnext} et al. now internally uses a slot to keep track of tuples. While systable_getnext() still returns HeapTuples, and will so for the foreseeable future, the index API (see 1) above) now only deals with slots. The remainder, and largest part, of this commit is then adjusting all scans in postgres to use the new APIs. Author: Andres Freund, Haribabu Kommi, Alvaro Herrera Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de https://postgr.es/m/20160812231527.GA690404@alvherre.pgsql
2019-01-29Refactor planner's header files.Tom Lane
Create a new header optimizer/optimizer.h, which exposes just the planner functions that can be used "at arm's length", without need to access Paths or the other planner-internal data structures defined in nodes/relation.h. This is intended to provide the whole planner API seen by most of the rest of the system; although FDWs still need to use additional stuff, and more thought is also needed about just what selfuncs.c should rely on. The main point of doing this now is to limit the amount of new #include baggage that will be needed by "planner support functions", which I expect to introduce later, and which will be in relevant datatype modules rather than anywhere near the planner. This commit just moves relevant declarations into optimizer.h from other header files (a couple of which go away because everything got moved), and adjusts #include lists to match. There's further cleanup that could be done if we want to decide that some stuff being exposed by optimizer.h doesn't belong in the planner at all, but I'll leave that for another day. Discussion: https://postgr.es/m/11460.1548706639@sss.pgh.pa.us
2019-01-14Don't include heapam.h from others headers.Andres Freund
heapam.h previously was included in a number of widely used headers (e.g. execnodes.h, indirectly in executor.h, ...). That's problematic on its own, as heapam.h contains a lot of low-level details that don't need to be exposed that widely, but becomes more problematic with the upcoming introduction of pluggable table storage - it seems inappropriate for heapam.h to be included that widely afterwards. heapam.h was largely only included in other headers to get the HeapScanDesc typedef (which was defined in heapam.h, even though HeapScanDescData is defined in relscan.h). The better solution here seems to be to just use the underlying struct (forward declared where necessary). Similar for BulkInsertState. Another problem was that LockTupleMode was used in executor.h - parts of the file tried to cope without heapam.h, but due to the fact that it indirectly included it, several subsequent violations of that goal were not not noticed. We could just reuse the approach of declaring parameters as int, but it seems nicer to move LockTupleMode to lockoptions.h - that's not a perfect location, but also doesn't seem bad. As a number of files relied on implicitly included heapam.h, a significant number of files grew an explicit include. It's quite probably that a few external projects will need to do the same. Author: Andres Freund Reviewed-By: Alvaro Herrera Discussion: https://postgr.es/m/20190114000701.y4ttcb74jpskkcfb@alap3.anarazel.de
2019-01-02Update copyright for 2019Bruce Momjian
Backpatch-through: certain files through 9.4
2018-01-02Update copyright for 2018Bruce Momjian
Backpatch-through: certain files through 9.3
2017-01-03Update copyright via script for 2017Bruce Momjian
2016-01-02Update copyright for 2016Bruce Momjian
Backpatch certain files through 9.1
2015-07-25Redesign tablesample method API, and do extensive code review.Tom Lane
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.
2015-05-23pgindent run for 9.5Bruce Momjian
2015-05-15contrib/tsm_system_rowsSimon Riggs