RE: Need help with a regex pattern

I was using the SQL version and performance landed on its face.

Using this in my join of two tables...

left join source on Regexp_like(srcdta,
'[^A-Za-z0-9_@#$]'||trim(field)||'[^A-Za-z0-9_@#$]','i')

it runs for about 5 minutes.

Switching to this (which only finds ACCT and doesn't eliminate prefixed or
suffixed values such as ACCT01)

left join source on srcdta like '%'||trim(field)||'%'

it runs in about 5 seconds.

These times are pretty consistent over multiple tests (alternating which is
executed first) so it is not caching or CPU bog down or any of that.

So. I thought I would switch to use the later and then then add the RegEx to
my RPG for the other part and see what that does.

-----Original Message-----
From: RPG400-L <rpg400-l-bounces@xxxxxxxxxxxxxxxxxx> On Behalf Of David
Gibbs via RPG400-L
Sent: Tuesday, June 4, 2019 11:29 AM
To: RPG programming on IBM i <rpg400-l@xxxxxxxxxxxxxxxxxx>
Cc: David Gibbs <david@xxxxxxxxxxxx>
Subject: Re: Need help with a regex pattern

On Tue, Jun 4, 2019 at 10:23 AM <smith5646midrange@xxxxxxxxx> wrote:

Is there a way to build an expression so I can provide a variable
value at run time rather than freeing and recompiling the pattern
every time the variable changes?

Are you using the regex api's directly?

If so, I suggest you take a look at the SQL regexp_* functions.

https://www.ibm.com/support/knowledgecenter/ssw_ibm_i_72/db2/rbafzscaregexp_
substr.htm

They are much easier to work with IMO.

david


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