That select statement is not my cursor, that's just one of the many 600 lines
of code that the cursor is evaluating. The cursor itself would not be
index-able as it contains >=, not null, etc....
I mean, yes, I could look at the many, many select statements within the loop
(my wild guess is that there's around 50 of them) and maybe there would be 10
or 15 different potential compound indexes. I'm not sure if there's a
practical limit to the number of compound indexes you could create on a single
table (there would be probably 10 different "lookup" tables).
So yeah, good idea, I'll look at all the lookups and check indexing. But I'm
assuming that compounds would only work in instances where all of the
components are using "=", right?
Karen
-----Original Message-----
From: Albert Berry <alb...@albertberry.com>
To: rbase-l <rbase-l@googlegroups.com>
Sent: Mon, Apr 24, 2017 9:40 am
Subject: Re: [RBASE-L] - Thoughts on speeding up a cursor?
Karen - wild thought. Would a compound index work here?
CREATE INDEX LoopTroubles (PolicyID,AgentNo,Policy,CovCode)
This would enable an index only retrieval.
Albert
On Apr 24, 2017, at 8:26 AM, karentellef via RBASE-L <rbase-l@googlegroups.com>
wrote:
Dan:
I had actually posted here on the list a few years ago when, as the business
grew, our cursor (which used to process about 25K rows) started randomly
crashing in the 30K or 40K range. Several people here recommended to replace
the while loop with goto/label, so that's what I did. The goto works fine, so
I'm not interested in revisiting a while loop.
I'm not understanding what you're suggesting on a temp table. I would have to
create a temp table that would hold probably 30K rows, and my "select into"
would simply operate against a temp table rather than the permanent table. Are
you saying selecting against a temp table would be faster than a permanent
table?
One thing that I've asked permission to try -- that is to avoid a "declare
cursor" altogether, which puts an hours-long "cursor lock" against a very
heavily used table.
I'm thinking I could create a 40K row temp table with the policyID I'm to
process (the PK), with an autonumber column, such as:
1111 1
1222 2
3535 3
Then using my goto/label block, I could (just quick code here, not 100% right)
set var vcount int = 1
label top
select policyid into vid from temptable where autonumbercol = .vcount
if vid is null then ; quit ; return
select .... into ..... from policytable where policyid = .vid (this
replaces the "fetch")
-- do all the "cursor" loop stuff
set var vcount = (.vcount + 1)
goto top
I don't know if this will speed up the code, but it prevents the routine from
putting ANY locks on the main table.
Karen
-----Original Message-----
From: Dan Goldberg <d...@lancecamper.com>
To: rbase-l <rbase-l@googlegroups.com>
Sent: Mon, Apr 24, 2017 8:34 am
Subject: RE: [RBASE-L] - Thoughts on speeding up a cursor?
I would find out why the while loop never completes. I have 9 level while loops
for my BOM to break down the assemblies into a parts list that runs every night
and it always runs.
There are many tricks on speeding up processing. Sometimes using temp tables to
reduce the amount of items in the where clause usually speeds things up. This
is only one of them I use.
Example, maybe use a temp table for the select statement below. I am assuming
the select statement runs many times.
--create temp table to hold values filtering out the standard items
Create temp table tmpagtcomm (agentno integer, policy_no text, covcode integer)
Insert into tmpagtcomm select agentno, policy_no, covcode from agtcomm where
polyr = 1 and agtcomm < 0 and paidtoagton is not null
--While loop
SELECT agtcomm INTO vtestagtcomm +
FROM tmpagtcomm +
WHERE agentno = .vagentno AND policy_no = .vpolicy_no +
AND covcode = .vcovcode
This way it is not looking at all the where parameters which might slow it down.
Not sure if this helps. I usually trace it as well to see what is slowing it
down.
Dan Goldberg
From: karentellef via RBASE-L [mailto:rbase-l@googlegroups.com]
Sent: Monday, April 24, 2017 6:14 AM
To: rbase-l@googlegroups.com
Subject: [RBASE-L] - Thoughts on speeding up a cursor?
I inherited a monster program. It's 800 physical lines of code, separated like
this:
100 lines of pre-processing code before we set a cursor
600 lines of code that are within a DECLARE CURSOR that processes 40,000
records. We cannot use a "while" loop because it never completed, so we use a
"goto / label" structure to move around, and it always completes fine.
100 lines of post-cursor code.
I am trying to speed up this cursor as it now takes hours to process. There
are no "run" statements within this program, no printing of reports other than
post-cursor.
Within that cursor loop, there are many "goto" statements to move around within
that cursor loop.
My assumption: when the program hits a "goto" command, it must run through
every line of code, one line at a time, to find the "label". It would go all
the way to the end of the program, and if it cannot find the label, it then
goes back up to line 1 of the program and scans every line until it finally
hits the label. In this program, sometimes these labels are after the goto,
sometimes they are "above" it.
So question 1: is my assumption correct?
If it is: Let's say for readability that a line has been separated into
multiple lines, such as this:
SELECT agtcomm INTO vtestagtcomm +
FROM agtcomm +
WHERE agentno = .vagentno AND policy_no = .vpolicy_no +
AND covcode = .vcovcode AND polyr = 1 AND agtcomm < 0 +
AND paidtoagton IS NOT NULL
As it searches for a matching "label", is RBase evaluating 5 lines of code, one
at a time? Or is it "smart" enough to know it's one command and evaluates it
just once?
So IOW: if I was to retype this command so that it takes just one really long
line, or maybe just 2 lines, would it be "quicker" for RBase to search for a
label? I wouldn't normally be so anal about it, but when you're doing this
40,000 times.....
Karen
--
You received this message because you are subscribed to the Google Groups
"RBASE-L" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to rbase-l+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
--
You received this message because you are subscribed to the Google Groups
"RBASE-L" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to rbase-l+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
--
You received this message because you are subscribed to the Google Groups
"RBASE-L" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to rbase-l+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
--
You received this message because you are subscribed to the Google Groups
"RBASE-L" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to rbase-l+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
--
You received this message because you are subscribed to the Google Groups
"RBASE-L" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to rbase-l+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
