Experimental Physics and
Industrial Control System

On 07.05.19 19:58, Johnson, Andrew N. wrote:

and for every link field (DB or CA) it performs a record-name lookup on the PV name in that link (which requires calculating a hash of the name and checking the names in that hash bucket, which may have several records in it so does several string comparisons, most of which are going to fail).

I don't think so. I do epicsStrGlobMatch(), but that does not look up records by name or calculate hashes. Still it fails on most records, of course. Like dbgrep does. I don't think that I can avoid the glob match, even when iterating target records instead of links, but the number of matches performed may be smaller. In particular when I only check records that are known to have links pointing to them.

If you use the new BKLNK field in the record you will still have to look through every record instance, but for each record you immediately know how many DB links point back to this record, which in most cases will be a small number or 0.

Yes, that may shortcut things. Unfortunately it does not give me the name of the link field. But searching the record were the link came from is not too difficult.

Now this doesn't give you CA links

Which is a pity. I understand why, as it was implemented to handle lock sets. But for my use case it would be really helpful to get all types of links.

Can you tell me what link type PN_LINK is? It seems to be used only in dev*SoftCallback.c but I found no documentation about it.

-- 
Complexity comes for free, Simplicity you have to work for.