| From: | Melanie Plageman <melanieplageman(at)gmail(dot)com> |
|---|---|
| To: | Tomas Vondra <tomas(at)vondra(dot)me> |
| Cc: | Nazir Bilal Yavuz <byavuz81(at)gmail(dot)com>, Dilip Kumar <dilipbalaut(at)gmail(dot)com>, Heikki Linnakangas <hlinnaka(at)iki(dot)fi>, Thomas Munro <thomas(dot)munro(at)gmail(dot)com>, Andres Freund <andres(at)anarazel(dot)de>, Pg Hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: BitmapHeapScan streaming read user and prelim refactoring |
| Date: | 2025-02-10 22:31:19 |
| Message-ID: | CAAKRu_a374oAKZdMG-WeOBV4jRXzT+PW2HZQwXM=VUvf2U0v3w@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Mon, Feb 10, 2025 at 4:22 PM Melanie Plageman
<melanieplageman(at)gmail(dot)com> wrote:
>
> I don't really know what to do about this. The behavior of master
> parallel bitmap heap scan can be emulated with the patch by increasing
> effective_io_concurrency. But, IIRC we didn't want to do that for some
> reason?
> Not only does effective_io_concurrency == 1 negatively affect read
> ahead, but it also prevents read combining regardless of the
> io_combine_limit.
Would a sensible default be something like 4?
I did some self-review on the patches and cleaned up the commit
messages etc. Attached is v29.
- Melanie
| Attachment | Content-Type | Size |
|---|---|---|
| v29-0002-Separate-TBM-Shared-Private-Iterator-and-TBMIter.patch | text/x-patch | 19.7 KB |
| v29-0001-Hard-code-TBMIterateResult-offsets-array-size.patch | text/x-patch | 5.4 KB |
| v29-0004-Remove-table-AM-callback-scan_bitmap_next_block.patch | text/x-patch | 22.0 KB |
| v29-0003-BitmapHeapScan-uses-read-stream-API.patch | text/x-patch | 30.9 KB |
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