DpmFlushOldRequests < LCG

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---+ DPM Flushing Old Requests utility


---++ Introduction

This page describes how to flush old requests (put, get, copy and bring online requests) of the DPM DB. Tables affected are dpm_put_filereq, dpm_get_filereq, dpm_req and dpm_copy_filereq. For the moment, the tool works only for !MySQL DB. if you need it for Oracle, please send [[mailto:lana.abadie@cern.ch][me]] a mail.
This tool *must be used* as long as the flushing mechanism is not integrated in the DPM server. 

---++ Outline of the tool
The tool consists of a command line dpm-flush-req which takes the following input arguments:
   * *dpm_db_name* : the DPM DB name (yaim uses by default dpm_db). However there is no default value
   * *dpm_db_host* : the DPM !MySQL DB host name (need to be put even if you run the command locally, i.e. if localhost is passed as dpm_db_host, the db connection will fail
   * *dpm_db_pwd* : password of the DPM DB
   * *dpm_db_user* : login od the DPM DB(yaim by default uses dpmmgr)
   * *max_request_lifetime* :  maximum time to keep a request in the tables. Time to be given in seconds. If this argument is omitted, the default value is 2592000

---++ Installation
   * Download and extract the tar file. Type make and if needed edit the makefile to match your environment.
   * The executable and the log files will be located in the output directory.
   * you will need mysql-devel : yum install mysql-devel
   
---++ Example of usage
To delete old requests which have been performed two months (5270400 sec) before, type:
<pre>
./dpm-flush-oldreq --dpm_db_name dpm_db --dpm_db_pwd <pwd> --dpm_db_host lxn1177.cernc.h --dpm_db_user dpm_mgr --max_request_lifetime 5270400
</pre>

Then look at the log file produced dpm-flush-oldreq.log to see if the execution was successful.

---++ Remark
if the number of requests to be flushed is very big around millions of row, it might be a good idea to start this script before migrating to a new DPM version so that it doesn't impact the performance of the DPM. it takes roughly one hour to delete around a few millions of old requests. Of course the execution time will depend on the DPM load. 

---++ Any problems or questions?
   * if you get the following error in the log file: *the total number of locks exceeds the lock table size*, then you need to increase the *innodb_buffer_size* as follows:
      * edit your /etc/my.cnf (!MySQL configurable parameters) 
      * add in [mysqld] section : innodb_buffer_pool_size=256M (provided that this value does not exceed 80% of the physical memory of the machine).
      * restart mysql (service mysql/mysqld restart resp for SL3/SL4)
send [[mailto:lana.abadie@cern.ch][me]] a mail

-- Main.LanaAbadie - 15 Oct 2007

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I	Attachment	History	Action	Size	Date	Who	Comment
tar	dpm-flush.tar	r1	manage	230.0 K	2007-10-16 - 22:03	LanaAbadie

Topic revision: r5 - 2008-05-07 - LanaAbadie

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