Search Postgresql Archives

Re: Poor performance after restoring database from snapshot on AWS RDS

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Fri, Jun 7, 2024 at 4:36 AM Sam Kidman <sam@xxxxxxxxxx> wrote:
> This is due to the way that RDS restores snapshots.

Thanks, I never would have guessed. Would vacuum analyze be sufficient
to defeat the lazy loading or would we need to do something more
specific to our application? (for example. select(*) on some commonly
used tables)

https://www.postgresql.org/docs/14/pgprewarm.html

pg_prewarm is probably what you want.  Don't know if RDS Postgresql supports it or not, though.
 

I think vacuum full would certainly defeat the lazy loading since it
would copy all of the table data, but that may take a very long time
to run. I think vacuum analyze only scans a subset of rows but I might
be wrong about that.

Best, Sam

On Wed, Jun 5, 2024 at 10:09 PM Jeremy Smith <jeremy@xxxxxxxxxxxxxx> wrote:
>
> On Wed, Jun 5, 2024 at 4:23 AM Sam Kidman <sam@xxxxxxxxxx> wrote:
>
> > We get very poor performance in the staging environment after this
> > restore takes place - after some usage it seems to get better perhaps
> > because of caching.
> >
>
> This is due to the way that RDS restores snapshots.
>
> From the docs (https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/USER_RestoreFromSnapshot.html):
>
> You can use the restored DB instance as soon as its status is
> available. The DB instance continues to load data in the background.
> This is known as lazy loading.
>
> If you access data that hasn't been loaded yet, the DB instance
> immediately downloads the requested data from Amazon S3, and then
> continues loading the rest of the data in the background.
>
>
>
>   -Jeremy



[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Index of Archives]     [Postgresql Jobs]     [Postgresql Admin]     [Postgresql Performance]     [Linux Clusters]     [PHP Home]     [PHP on Windows]     [Kernel Newbies]     [PHP Classes]     [PHP Databases]     [Postgresql & PHP]     [Yosemite]

  Powered by Linux