Re: jsonb value retrieval performance

[Tom Smith <tomsmith1989sk@xxxxxxxxx>]

It can be any jsonb so I am asking a general question of the implementaion

for each jsonb storage (not about GIN or table wide indexing, but only within

a single jsonb item in a single row.

A sample would be like (no quotes)

{
a1: {b1:v1, b2:v2, b100:v100}

a3000: {c1:x1, c2: x2. c200: v200
}

you get the idea.  I wonder how postgresql does it when try

jsonb->a1->b1,

 does it read in the whole jsonb tree structure in memory

and get to v1  or it has some optimization so only get v1 instead

of reading in the whole structure.

On Tue, Sep 8, 2015 at 11:58 AM, Teodor Sigaev <teodor@xxxxxxxxx> wrote:

and I am trying to get value via  jsonb->parentKey->childKey
it seems it is very slow.
Would it be actually faster to use top level key only and parse it at client side?

Suppose, most time is spent for decompressing huge value, not for actual search inside jsonb. If so, we need to implement some search method which decompress some chunks of jsonb.


Could you send to me an example of that jsonb?



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Teodor Sigaev                                   E-mail: teodor@xxxxxxxxx
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