Re: Sudden insert performance degradation

[Sebastian Dressler <sebastian@xxxxxxxxxxx>]

Hi Henrique,

On 13. Jul 2020, at 18:42, Henrique Montenegro <typoon@xxxxxxxxx> wrote:

On Mon, Jul 13, 2020 at 11:20 AM Sebastian Dressler <sebastian@xxxxxxxxxxx> wrote:

Running the above loop worked fine for about 12 hours. Each file was taking
about 30 seconds to be processed. About 4 seconds to create the `users` table
and have the CSV data loaded into it and anything between 20 and 30 seconds to
insert the data from `users` into `users_no_dups`.

Do you see anything suspicious in the logs, i.e. something in the realms of running out of transaction IDs?

I set the log to debug1. I haven't seen anything that called my attention, but I am not really sure what to look for, so perhaps I missed it. Any suggestions on what to look for or any specific log configuration to do?

Not necessarily, if you'd run out of tx IDs you would notice that cleary, I guess. I also think that this is not the issue.

 

[...]

Recreating the table now isn't really providing any improvements. I tried
recreating it with a `fillfactor` of `10`, but it was taking too long and too
much space (the table had 300GB with the fillfactor set to 30; with it set to
10 it went up to almost 1TB).

To me it sounds like the UK/PK is getting too much to write. A possible solution could be to start partitioning the table.

I thought about partitioning it, but I can't figure out on what. The `user_id` column is a number that is somewhat random so I don't know what kinds of range I would use for it. I will try to look at the values again and see if there is something that I could perhaps use as a range. Any other suggestions?

Depending on granularity, maybe partition on `created_ts`? 

Cheers,

Sebastian

--

Sebastian Dressler, Solution Architect 
+49 30 994 0496 72 | sebastian@xxxxxxxxxxx 

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