Re: jsonb_delete with arrays - Mailing list pgsql-hackers

From Dmitry Dolgov
Subject Re: jsonb_delete with arrays
Date
Msg-id CA+q6zcXd_TaYD3kUz8TfSrTp_sOn-cMZV+SC0MuUvkoujotbSw@mail.gmail.com
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In response to jsonb_delete with arrays  (Magnus Hagander <magnus@hagander.net>)
Responses Re: jsonb_delete with arrays
List pgsql-hackers
> On 15 November 2016 at 22:53, Magnus Hagander <magnus@hagander.net> wrote:
> Attached is an implantation of jsonb_delete that instead of taking a single key to remove accepts an array of keys (it still does just keys, so it's using the - operator, it's not like the path delete function that also takes an array, but uses a different operator).
> In some simple testing of working through a real world usecases where we needed to delete 7 keys from jsonb data, it shows approximately a 9x speedup over calling the - operator multiple times. I'm guessing since we copy a lot less and don't have to re-traverse the structure.

I wonder, is it worth it to create some sort of helper function to handle both
deleting one key and deleting an array of keys (like `setPath` for `jsonb_set`,
`jsonb_insert` and `jsonb_delete_path`)? At first glance it looks like
`jsonb_delete` and `jsonb_delete_array` can reuse some code.

Speaking about the performance I believe it's the same problem as here [1],
since for each key the full jsonb will be decompressed. Looks like we need a
new set of functions to read/update/delete an array of elements at once.

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