Re: How to make sure that the target file to read is not under writing by others?
| From: | Kyle Smith | Date: | Wed, 19 Aug 2009 12:13:56 +0000 |
| Subject: | Re: How to make sure that the target file to read is not under writing by others? | ||
| References: | 1 2 3 4 5 6 | Groups: | php.general |
| Request: | Send a blank email to php-general+get-296962@lists.php.net to get a copy of this message | ||
Nitebirdz wrote:
On Wed, Aug 19, 2009 at 11:59:39AM +0100, Ashley Sheridan wrote:No, what you're saying is 'use a log file in order to know when to look at another log file'. What would happen if you tried to access the control log file whilst it was in the process of being written to? Admittedly, you reduce your chances of failure because there is less data being written to the control log than the actual log, but the chance of reading incomplete data is still there!WARNING: total newbie here. If I understood Arno correctly, he was recommending to implement something like the old "/var/run/*pid" files in UNIX. That way, you can control whether or not the previous run is already done with the file before you move on. That is definitely the correct approach. Have the script which copies the log file touch a file called 'log_file.write' or some such. When it's done, remove the file. Your PHP script should exit if that file exists. Of course, given the 30 minute cron cycle, it would then have to wait until the next cycle. Maybe run it more often.