Horton

Re: [proposal] de-TOAST'ing using a iterator

Binguo Bao <djydewang@gmail.com>

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From: Binguo Bao <djydewang@gmail.com>
To: Thomas Munro <thomas.munro@gmail.com>
Cc: Andrey Borodin <x4mmm@yandex-team.ru>, Atri Sharma <atri.jiit@gmail.com>, Stephen Frost <sfrost@snowman.net>, Владимир Лесков <vladimirlesk@yandex-team.ru>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2019-07-10T16:39:05Z
Lists: pgsql-hackers

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Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Use single-byte Boyer-Moore-Horspool search even with multibyte encodings.

Attachments

This is the patch that fix warnings.

Best Regards,
Binguo Bao

Binguo Bao <djydewang@gmail.com> 于2019年7月10日周三 下午10:18写道：

> Hi Thomas,
> I've fixed the warnings.
>
> Thomas Munro <thomas.munro@gmail.com> 于2019年7月5日周五 下午12:21写道：
>
>> On Thu, Jun 20, 2019 at 1:51 AM Binguo Bao <djydewang@gmail.com> wrote:
>> > Hi hackers!
>> > This proposal aims to provide the ability to de-TOAST a fully TOAST'd
>> and compressed field using an iterator and then update the appropriate
>> parts of the code to use the iterator where possible instead of
>> de-TOAST'ing and de-compressing the entire value. Examples where this can
>> be helpful include using position() from the beginning of the value, or
>> doing a pattern or substring match.
>> >
>> > de-TOAST iterator overview:
>> > 1. The caller requests the slice of the attribute value from the
>> de-TOAST iterator.
>> > 2. The de-TOAST iterator checks if there is a slice available in the
>> output buffer, if there is, return the result directly,
>> >     otherwise goto the step3.
>> > 3. The de-TOAST iterator checks if there is the slice available in the
>> input buffer, if there is, goto step44. Otherwise,
>> >     call fetch_datum_iterator to fetch datums from disk to input buffer.
>> > 4. If the data in the input buffer is compressed, extract some data
>> from the input buffer to the output buffer until the caller's
>> >     needs are met.
>> >
>> > I've implemented the prototype and apply it to the position() function
>> to test performance.
>>
>> Hi Binguo,
>>
>> Interesting work, and nice performance improvements so far.  Just by
>> the way, the patch currently generates warnings:
>>
>> https://travis-ci.org/postgresql-cfbot/postgresql/builds/554345719
>>
>> --
>> Thomas Munro
>> https://enterprisedb.com
>>
>