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December 18th, 2012 16:00

Are there any negatives to setting SYMCLI_CTL_ACCESS to PARALLEL

We are starting to run more and more symcli scripts in our environment,

and are running into locks on the SYAMPI database.  We are looking at

changing the SYMCLI_CTL_ACCESS variable from the default of

"EXCLUSIVE" to "PARALLEL". 

Does anyone know of any reasons NOT to set the variable to "PARALLEL"?

We are assuming there must be some negatives since the default is

"EXCLUSIVE".

Thanks in advance.

Will

859 Posts

December 19th, 2012 01:00

Well if you set it to parallel then the commands that require "Read only" access to symapi database (to list some output) will work. If you set it to exclusive then only one cmd will be allowed to execute at a time.

I dont think setting it to parallel can have any negative effect as commands that need to modify the database would still have an exclusive lock on the database.

226 Posts

December 19th, 2012 05:00

Hi Will,

I have routinely enabled PARALLEL mode in SYMCLI scripts for years, and rarely (if ever) have run into a problem with it. I know there was an issue a while back with symrecover not working correctly in parallel mode -- I'm not sure offhand if this has been fixed, but symrecover is for SRDF/A recovery so it wouldn't apply to your environment anyway...

Thanks,

- Sean

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63 Posts

December 19th, 2012 07:00

First, thanks for the responses so far.  However, a followup questions....

Will setting this really help if we're doing writes to the SYAMPI database.  For example, if someone is expanding a striped meta (which can take a very long time), and a script needs to run snaps, will this setting help or not?  Will the script be able to run while the command to expand the meta is still running?

465 Posts

December 19th, 2012 15:00

With the environment variable set to PARALLEL, any updates will still take en exclusive lock. This difference is the exclusive lock is taken and released around the update, not for the entire duration of the script. How much benefit you get out of setting the parameter does indeed depend on how often the SYMAPI_DB.BIN is updated.

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