Experimental Physics and
Industrial Control System

Michael Davidsaver <[email protected]> · Thu, 3 Nov 2016 17:40:34 -0400

On 11/03/2016 05:23 PM, Keith Thorne wrote:
> Dear Andrew (and others)
> 
> 	At LIGO, we appreciate the changes for faster loading of databases.
> 
> Question: do any of these changes (and the use of dbPvdTableSize shown below) relevant to EPICS gateways?
> We have some very busy gateways (> 100,000 PVs) at present.

No. this change is specific to the process database, specifically the
.db file parser.

https://code.launchpad.net/~epics-core/epics-base/bigdb-3.15/+merge/307834

> 	Thanks
> 		Keith Thorne
> 
>> On Nov 3, 2016, at 10:27 AM, Andrew Johnson <[email protected]> wrote:
>>
>> Hi Murali,
>>
>> On 11/02/2016 06:21 PM, Shankar, Murali wrote:
>>>>> The 3.15 branch does contain a major performance improvement to the IOC
>>>>> when loading large numbers of database records.
>>>
>>> Awesome, I can load 100K PV's into a softIOC in a couple of seconds!
>>> Thank you so much!
>>
>> If you are loading large numbers of records also make sure that you are
>> setting the size of the IOC's hash-table before dbLoadDatabase() or
>> dbLoadRecords() in your startup script. The size argument must be a
>> power of 2 up to 64K:
>>    dbPvdTableSize(65536)
>> The default size is 512, although we should probably increase that
>> nowadays. More hash buckets means more efficient name searches both at
>> load-time and by the CA name resolution task.
>>
>> - Andrew
>>
>> -- 
>> Arguing for surveillance because you have nothing to hide is no
>> different than making the claim, "I don't care about freedom of
>> speech because I have nothing to say." -- Edward Snowdon
> 
> ------
> Keith Thorne <[email protected]>
> CDS Software Engineer
> LIGO Livingston Laboratory
> Livingston, LA 70754
> Phone: (225)686-3168 Fax: (225)686-7189
> 
> 

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System