Re: Why is writing JSONB faster than just JSON?
От | Dmitry Dolgov |
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Тема | Re: Why is writing JSONB faster than just JSON? |
Дата | |
Msg-id | 20210502125047.vzsksguxxzv34vio@localhost обсуждение исходный текст |
Ответ на | Re: Why is writing JSONB faster than just JSON? (Mitar <mmitar@gmail.com>) |
Список | pgsql-general |
> On Fri, Apr 23, 2021 at 01:56:57AM -0700, Mitar wrote: > Hi! > > On Thu, Apr 15, 2021 at 12:11 PM Dmitry Dolgov <9erthalion6@gmail.com> wrote: > > > My point was that for JSON, after validating that the input is > > > syntactically correct, we just store it as-received. So in particular > > > the amount of whitespace in the value would depend on how the client > > > had chosen to format the JSON. This'd affect the stored size of > > > course, and I think it would have an effect on compression time too. > > > > Yes, I got it and just wanted to confirm you were right - this was the > > reason I've observed slowdown trying to reproduce the report. > > Thank you for trying to reproduce the report. I did a bit more digging > myself and I am still confused. > > ... > > So I do not know what is happening and why you cannot reproduce it. Could you maybe get a profile with perf for both cases? Since they're executed within a single backend, you can profile only a single pid. Having a reasonable profiling frequency, --call-graph dwarf and probably limit events to only user space with precise tagging (cycles:uppp) should give an impression what's going on.
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