DB transactions when browser freezes

Started by dafNi zafover 12 years ago8 messagesgeneral
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#1dafNi zaf
dzaf88@gmail.com

Hello to everybody,

I started to upload (via phpPgAdmin) to a local server a huge file (20GB) in
order to fill up a database.
The uploding completed and the transactions started. But unfortunately, my
browser crashed/freezed in the middle of the transactions.

I wanted to know, given that the uploading of the file was completed, will
the
transactions keep executing on server??

Before the browser crashed there was a process that consumed 23.6% of the
CPU for the transactions and now, I see the same process with approximately
the same percentage.

Should I assume that the transactions keep running?

I am trying to avoid uploading the file all over again because it has
already been
running for 5 hours.

Thank you in advance!!
dafNi

#2Adrian Klaver
adrian.klaver@aklaver.com
In reply to: dafNi zaf (#1)
Re: DB transactions when browser freezes

On 08/08/2013 07:33 AM, dafNi zaf wrote:

Hello to everybody,

I started to upload (via phpPgAdmin) to a local server a huge file (20GB) in
order to fill up a database.
The uploding completed and the transactions started. But unfortunately, my
browser crashed/freezed in the middle of the transactions.

I wanted to know, given that the uploading of the file was completed,
will the
transactions keep executing on server??

Before the browser crashed there was a process that consumed 23.6% of the
CPU for the transactions and now, I see the same process with approximately
the same percentage.

Should I assume that the transactions keep running?

I am trying to avoid uploading the file all over again because it has
already been
running for 5 hours.

tail the server log and verify.

Thank you in advance!!
dafNi

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Adrian Klaver
adrian.klaver@gmail.com

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#3Alban Hertroys
haramrae@gmail.com
In reply to: dafNi zaf (#1)
Re: DB transactions when browser freezes

On 8 August 2013 16:33, dafNi zaf <dzaf88@gmail.com> wrote:

Hello to everybody,

I started to upload (via phpPgAdmin) to a local server a huge file (20GB)
in
order to fill up a database.
The uploding completed and the transactions started. But unfortunately, my
browser crashed/freezed in the middle of the transactions.

I wanted to know, given that the uploading of the file was completed, will
the
transactions keep executing on server??

Before the browser crashed there was a process that consumed 23.6% of the
CPU for the transactions and now, I see the same process with approximately
the same percentage.

Should I assume that the transactions keep running?

I am trying to avoid uploading the file all over again because it has
already been
running for 5 hours.

There is a chance that the database server is just still processing your
request and that it will only figure out that there's a client error once
it reaches the end of that 20GB file, after which the client returns an
error and the database rolls back the transaction.

Depending on how phpPgAdmin/PHP were implemented, that's not necessarily
what'll happen though, so you might just get lucky and the transaction
commits.

Hard to tell, I know nothing about the internals of phpPgAdmin.

What kind of file is it anyway? A database dump perhaps?

--
If you can't see the forest for the trees,
Cut the trees and you'll see there is no forest.

#4David G. Johnston
david.g.johnston@gmail.com
In reply to: dafNi zaf (#1)
Re: DB transactions when browser freezes

dafNi wrote

Should I assume that the transactions keep running?

Never assume...or at least try and verify those assumptions when possible.

To verify this assumption:

Connect to the DB directly as a super-user and run this (or something
similar):

SELECT procpid, current_query, client_addr, xact_start, query_start
FROM pg_stat_activity
ORDER BY xact_start ASC, client_addr;

to what activity is currently in-progress.

David J.

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#5Ian Lawrence Barwick
barwick@gmail.com
In reply to: dafNi zaf (#1)
Re: DB transactions when browser freezes

2013/8/8 dafNi zaf <dzaf88@gmail.com>:

Hello to everybody,

I started to upload (via phpPgAdmin) to a local server a huge file (20GB) in
order to fill up a database.

20GB is a lot to be uploading from a browser, even in this day and age.

Is the web server configured to accept uploads of that size?

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#6dafNi zaf
dzaf88@gmail.com
In reply to: David G. Johnston (#4)
Re: DB transactions when browser freezes

i execute it periodically and sometimes there is a transaction and other
times it's idle:

INSERT INTO traces VALUES (.....)
or
<IDLE> in transaction

So it's still running.. even thought there is some idle time.

Thank you very much!

On Thu, Aug 8, 2013 at 5:46 PM, David Johnston <polobo@yahoo.com> wrote:

Show quoted text

dafNi wrote

Should I assume that the transactions keep running?

Never assume...or at least try and verify those assumptions when possible.

To verify this assumption:

Connect to the DB directly as a super-user and run this (or something
similar):

SELECT procpid, current_query, client_addr, xact_start, query_start
FROM pg_stat_activity
ORDER BY xact_start ASC, client_addr;

to what activity is currently in-progress.

David J.

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http://postgresql.1045698.n5.nabble.com/DB-transactions-when-browser-freezes-tp5766824p5766829.html
Sent from the PostgreSQL - general mailing list archive at Nabble.com.

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#7dafNi zaf
dzaf88@gmail.com
In reply to: Alban Hertroys (#3)
Re: DB transactions when browser freezes

its a huge file with such queries:

BEGIN;
INSERT INTO traces VALUES (.....);
.
.
.
COMMIT;

Anyway, I managed to see that the transactions still occure like David
Johnston sugested. And luckily the browser is alive now after one hour that
it had been freezed...

thank you very much for the reply!

On Thu, Aug 8, 2013 at 5:46 PM, Alban Hertroys <haramrae@gmail.com> wrote:

Show quoted text

On 8 August 2013 16:33, dafNi zaf <dzaf88@gmail.com> wrote:

Hello to everybody,

I started to upload (via phpPgAdmin) to a local server a huge file (20GB)
in
order to fill up a database.
The uploding completed and the transactions started. But unfortunately, my
browser crashed/freezed in the middle of the transactions.

I wanted to know, given that the uploading of the file was completed,
will the
transactions keep executing on server??

Before the browser crashed there was a process that consumed 23.6% of the
CPU for the transactions and now, I see the same process with
approximately
the same percentage.

Should I assume that the transactions keep running?

I am trying to avoid uploading the file all over again because it has
already been
running for 5 hours.

There is a chance that the database server is just still processing your
request and that it will only figure out that there's a client error once
it reaches the end of that 20GB file, after which the client returns an
error and the database rolls back the transaction.

Depending on how phpPgAdmin/PHP were implemented, that's not necessarily
what'll happen though, so you might just get lucky and the transaction
commits.

Hard to tell, I know nothing about the internals of phpPgAdmin.

What kind of file is it anyway? A database dump perhaps?

--
If you can't see the forest for the trees,
Cut the trees and you'll see there is no forest.

#8dafNi zaf
dzaf88@gmail.com
In reply to: Ian Lawrence Barwick (#5)
Re: DB transactions when browser freezes

yes, I altered the php.ini file in /etc/php5/apache2/ directory in order to
accept huge files.

The uploading has been completed and the transactions started.

I can now see the transactions using either: ps aux | grep postgres (via
command line)
or the solution David Johnston sugested.

Thank you for the reply!
dafNi

On Thu, Aug 8, 2013 at 5:57 PM, Ian Lawrence Barwick <barwick@gmail.com>wrote:

2013/8/8 dafNi zaf <dzaf88@gmail.com>:

Hello to everybody,

I started to upload (via phpPgAdmin) to a local server a huge file

(20GB) in

order to fill up a database.

20GB is a lot to be uploading from a browser, even in this day and age.

Is the web server configured to accept uploads of that size?

Y