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  1. 2 server with same configuration but huge difference in performance

    Sumeet Shukla <sumeet.k.shukla@gmail.com> — 2017-08-01T13:41:51Z

    Hi,

I have 2 PG servers with same h/w and configuration and they are not in
replication.

On server A it takes 20 minutes to execute the script.
On server B it takes more than 20 hours. (Seems to be stuck with create
index and and create foreign key steps)

Any guidance to troubleshoot this would be highly appreciated.

Thanks & Regards,
Sumeet Shukla

  2. Re: 2 server with same configuration but huge difference in performance

    Keith <keith@keithf4.com> — 2017-08-01T14:16:04Z

    On Tue, Aug 1, 2017 at 9:41 AM, Sumeet Shukla <sumeet.k.shukla@gmail.com>
wrote:

> Hi,
>
> I have 2 PG servers with same h/w and configuration and they are not in
> replication.
>
> On server A it takes 20 minutes to execute the script.
> On server B it takes more than 20 hours. (Seems to be stuck with create
> index and and create foreign key steps)
>
> Any guidance to troubleshoot this would be highly appreciated.
>
> Thanks & Regards,
> Sumeet Shukla
>
>
Check for long running queries on the server that is taking longer. If it's
things like CREATE INDEX or ALTER TABLE statements that are being blocked,
a transaction running on the table involved will cause those commands to be
held until those transactions complete.

If it's normal read/write queries to that are taking longer, ensure the
database statistics are up to date by running an analyze.

Keith

  3. Re: [PERFORM] 2 server with same configuration but huge difference in performance

    Anthony Sotolongo <asotolongo@gmail.com> — 2017-08-01T14:21:02Z

    Hi Sumeet Shukla

While script is running check the pg_stat_activity, this view can be util


Regards

Anthony


On 01/08/17 10:16, Keith wrote:
>
> On Tue, Aug 1, 2017 at 9:41 AM, Sumeet Shukla 
> <sumeet.k.shukla@gmail.com <mailto:sumeet.k.shukla@gmail.com>> wrote:
>
>     Hi,
>
>     I have 2 PG servers with same h/w and configuration and they are
>     not in replication.
>
>     On server A it takes 20 minutes to execute the script.
>     On server B it takes more than 20 hours. (Seems to be stuck with
>     create index and and create foreign key steps)
>
>     Any guidance to troubleshoot this would be highly appreciated.
>
>     Thanks & Regards,
>     Sumeet Shukla
>
>
> Check for long running queries on the server that is taking longer. If 
> it's things like CREATE INDEX or ALTER TABLE statements that are being 
> blocked, a transaction running on the table involved will cause those 
> commands to be held until those transactions complete.
>
> If it's normal read/write queries to that are taking longer, ensure 
> the database statistics are up to date by running an analyze.
>
> Keith

  4. Re: [PERFORM] 2 server with same configuration but huge difference in performance

    Scott Marlowe <scott.marlowe@gmail.com> — 2017-08-01T15:35:20Z

    On Tue, Aug 1, 2017 at 6:41 AM, Sumeet Shukla <sumeet.k.shukla@gmail.com> wrote:
> Hi,
>
> I have 2 PG servers with same h/w and configuration and they are not in
> replication.
>
> On server A it takes 20 minutes to execute the script.
> On server B it takes more than 20 hours. (Seems to be stuck with create
> index and and create foreign key steps)
>
> Any guidance to troubleshoot this would be highly appreciated.

There's lots of areas where you could be running into problems. I
suggest reading this wiki page on reporting performance problems.
It'll help you gather more evidence of where and what the problem is.

https://wiki.postgresql.org/wiki/Guide_to_reporting_problems

  5. Re: [PERFORM] 2 server with same configuration but huge difference in performance

    Sumeet Shukla <sumeet.k.shukla@gmail.com> — 2017-08-01T15:45:14Z

    It seems that it is happening because of the way the database is created.
On an old database it runs perfectly fine or if I use the old DB as
template to create the new one, it  runs fine. But if I create a new DB
with same settings and permissions it hangs. I'm now trying to find the
difference between these 2 databases.

Thanks & Regards,
Sumeet Shukla


On Tue, Aug 1, 2017 at 9:05 PM, Scott Marlowe <scott.marlowe@gmail.com>
wrote:

> On Tue, Aug 1, 2017 at 6:41 AM, Sumeet Shukla <sumeet.k.shukla@gmail.com>
> wrote:
> > Hi,
> >
> > I have 2 PG servers with same h/w and configuration and they are not in
> > replication.
> >
> > On server A it takes 20 minutes to execute the script.
> > On server B it takes more than 20 hours. (Seems to be stuck with create
> > index and and create foreign key steps)
> >
> > Any guidance to troubleshoot this would be highly appreciated.
>
> There's lots of areas where you could be running into problems. I
> suggest reading this wiki page on reporting performance problems.
> It'll help you gather more evidence of where and what the problem is.
>
> https://wiki.postgresql.org/wiki/Guide_to_reporting_problems
>

  6. Re: 2 server with same configuration but huge difference in performance

    Scott Marlowe <scott.marlowe@gmail.com> — 2017-08-01T16:13:47Z

    On Tue, Aug 1, 2017 at 8:45 AM, Sumeet Shukla <sumeet.k.shukla@gmail.com> wrote:
> It seems that it is happening because of the way the database is created. On
> an old database it runs perfectly fine or if I use the old DB as template to
> create the new one, it  runs fine. But if I create a new DB with same
> settings and permissions it hangs. I'm now trying to find the difference
> between these 2 databases.

Likely a difference in encoding or collation. What does \l show you
(that's a lower case L btw)

smarlowe=> \l
                                  List of databases
   Name    |  Owner   | Encoding |   Collate   |    Ctype    |
Access privileges
-----------+----------+----------+-------------+-------------+-----------------------
 postgres  | smarlowe | UTF8     | en_US.UTF-8 | en_US.UTF-8 |
 smarlowe  | smarlowe | UTF8     | en_US.UTF-8 | en_US.UTF-8 |

UTF8 and en_US are much more expensive than SQL_ASCII and C would be
for text and such. Basically indexes either don't work or work as well
under en_US if you're comparing or sorting text.

  7. Re: [PERFORM] 2 server with same configuration but huge difference in performance

    Naveen Kumar <naveenchowdaryon@gmail.com> — 2017-08-01T22:14:46Z

    Hello Sumeet,

Compare schema on both database to make sure there is no mismatches. And
verify LOCKs. if all looks good,
do analyze on newly created database before start execution. This will help
you. New database doesn't have any stats for generate execution plan.



Thanks & Regards,
Naveen Kumar .M,
Sr. PostgreSQL Database Administrator,
Mobile: 7755929449.
*My attitude will always be based on how you treat me. *


On Tue, Aug 1, 2017 at 9:43 PM, Scott Marlowe <scott.marlowe@gmail.com>
wrote:

> On Tue, Aug 1, 2017 at 8:45 AM, Sumeet Shukla <sumeet.k.shukla@gmail.com>
> wrote:
> > It seems that it is happening because of the way the database is
> created. On
> > an old database it runs perfectly fine or if I use the old DB as
> template to
> > create the new one, it  runs fine. But if I create a new DB with same
> > settings and permissions it hangs. I'm now trying to find the difference
> > between these 2 databases.
>
> Likely a difference in encoding or collation. What does \l show you
> (that's a lower case L btw)
>
> smarlowe=> \l
>                                   List of databases
>    Name    |  Owner   | Encoding |   Collate   |    Ctype    |
> Access privileges
> -----------+----------+----------+-------------+------------
> -+-----------------------
>  postgres  | smarlowe | UTF8     | en_US.UTF-8 | en_US.UTF-8 |
>  smarlowe  | smarlowe | UTF8     | en_US.UTF-8 | en_US.UTF-8 |
>
> UTF8 and en_US are much more expensive than SQL_ASCII and C would be
> for text and such. Basically indexes either don't work or work as well
> under en_US if you're comparing or sorting text.
>
>
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