Weird issue with redis-cli BGREWRITEAOF in cron

[Julien Genestoux]

Heya,

So, we updagred both our servers and client libes to the last stable release :)

So far so good... but today, I noticed that our BGREWRITEAOF cron job wasn't working.

After a few minutes of investigation, I found out that the last version to date of the client was generating an error : "ERR wrong number of arguments for 'bgrewriteaof' command", which is odd because it used to work fine, and it still does work perfectly fine if I type this command direcly from the shell :/

The cronfile looks like this :

# crontab -l

*/3 * * * *  redis-cli BGREWRITEAOF

Anyone has a clue?

Cheers!

[Julien Genestoux]

Also, I actually found a way :

*/3 * * * * echo "BGREWRITEAOF" | redis-cli

But it's probably not as "clean" as the simple redis-cli BGREWRITEAOF!

[Salvatore Sanfilippo]

Hello Julien,

this is a problem specifically related to running redis cli inside the cron job.
Pieter hacked about this issue recently, so I'll lave the reply to him ;)

Thanks for reporting.

Cheers,
Salvatore

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[Julien Genestoux]

Cool :)

[Joran Greef]

Would it be possible to add a conf option to have Redis run
BGREWRITEAOF automatically at intervals?

[Salvatore Sanfilippo]

On Thu, Sep 9, 2010 at 11:42 AM, Joran Greef <joran...@gmail.com> wrote:
> Would it be possible to add a conf option to have Redis run
> BGREWRITEAOF automatically at intervals?

Yes, this makes sense and should be done indeed...

Cheers,
Salvatore

[Joran Greef]

Thanks Salvatore

On Sep 9, 12:16 pm, Salvatore Sanfilippo <anti...@gmail.com> wrote:

> On Thu, Sep 9, 2010 at 11:42 AM, Joran Greef <jorangr...@gmail.com> wrote:
> > Would it be possible to add a conf option to have Redis run
> > BGREWRITEAOF automatically at intervals?
>
> Yes, this makes sense and should be done indeed...
>
> Cheers,
> Salvatore
>
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> > To post to this group, send email to redi...@googlegroups.com.
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> Salvatore 'antirez' Sanfilippohttp://invece.org

[Julien]

So, it looks like after updating to the last version of the server,
even `echo "BGREWRITEAOF" | redis-cli` doesn't work anymore.. which is
very very very annoying.
Any suggestion on how to achieve this, while you guys are implementing
this timing feature in redis ?

Thanks.

[Julien]

What's the status of this?
We had a server dying once again because of this defect. it's very
very very annoying.

I underdtand you cannot release a fix right now, but what do you
suggest? What do people use to BGREWRITEAOF run regularly?


Thanks,

[Tim Haines]

I use a scheduled resque job to kick it off..

[Pieter Noordhuis]

Hi Julien,

There were numerous issues with redis-cli and reading from STDIN. The
initial idea to make it as unix-intuitive as possible (e.g. reading
from a pipe when there is a pipe). Unfortunately, this appeared to
have unexpected consequences when run from scripts (or cron for that
matter), where redis-cli would block waiting for data from a pipe,
when there was none. To circumvent this, we've (re-)added a flag to
redis-cli that tells it to read the last argument from STDIN. Now,
adding the -x option will read from STDIN instead of it being
automatically (thus sometimes falsely) detected.

Example:
2.0.0: "echo /proc/cpuinfo | redis-cli set cpuinfo" would detect the
pipe when run from a tty, but otherwise it would block.
2.0.1: "echo /proc/cpuinfo | redis-cli -x set cpuinfo" will never
block because you must supply the -x flag.

So, earlier, you had to "echo BGREWRITEAOF | redis-cli", because it
was trying to read from STDIN in the cron. Now, reading from STDIN
requires an extra flag, so you can simply issue "redis-cli
BGREWRITEAOF".

Cheers,
Pieter

[Salvatore Sanfilippo]

On Thu, Oct 21, 2010 at 9:44 AM, Pieter Noordhuis <pcnoo...@gmail.com> wrote:

> So, earlier, you had to "echo BGREWRITEAOF | redis-cli", because it
> was trying to read from STDIN in the cron. Now, reading from STDIN
> requires an extra flag, so you can simply issue "redis-cli
> BGREWRITEAOF".

Thank you Pieter.
This was my idea as well. Julien can you please confirm that you were
using not the latest version?

Cheers,
Salvatore

--
Salvatore 'antirez' Sanfilippo

[Julien Genestoux]

Hi, sorry for the late response... I didn't know about the -x option, but we do use redis-cli which comes with redis 2.0.2.

I'm deploying the code with it now. Let's see what happens.

Thanks,