| From: | Jim Nasby <Jim(dot)Nasby(at)BlueTreble(dot)com> |
|---|---|
| To: | hari(dot)prasath <hari(dot)prasath(at)zohocorp(dot)com>, pgsql-general <pgsql-general(at)postgresql(dot)org> |
| Subject: | Re: Jsonb extraction very slow |
| Date: | 2016-08-11 13:08:00 |
| Message-ID: | ac044d8a-bddf-dd20-e96f-6b2ce8b250e8@BlueTreble.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-general |
Please CC the list.
On 8/11/16 2:19 AM, hari.prasath wrote:
>>Actually I've done some testing with this and there is a *significant*
>>overhead in getting multiple keys from a large document. There's a
>>significant extra cost for the first key, but there's also a non-trivial
>>cost for every key after that.
>
> Why is it take some extra cost for the first key and less for keys after
> that.?
> Is there any specific reason for this.? if so please explain..
I never dug into why. As Tom posited, decompression might explain the
time to get a single key out. Getting 10 keys instead of just 1 wasn't
10x more expensive, but it was significantly more expensive than just
getting a single key.
--
Jim Nasby, Data Architect, Blue Treble Consulting, Austin TX
Experts in Analytics, Data Architecture and PostgreSQL
Data in Trouble? Get it in Treble! http://BlueTreble.com
855-TREBLE2 (855-873-2532) mobile: 512-569-9461
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Tom Lane | 2016-08-11 13:45:52 | Re: Jsonb extraction very slow |
| Previous Message | Kevin Grittner | 2016-08-11 12:34:37 | Re: Serializable read and blocking |