RE: Performance problem: Loading data via insert
- From: "Mark W. Farnham" <mwf@xxxxxxxx>
- To: <abhishek.gurung@xxxxxxxxxxx>, "'Oracle Freelist'" <oracle-l@xxxxxxxxxxxxx>
- Date: Fri, 14 Mar 2014 04:42:33 -0400
Okay, so I think you have written some application.
When some XML file arrives, your application parses the XML file and converts
the file into some set of insert statements.
As the application parses the XML file, it apparently also checks for table and
column references and there is some process by which you discern whether the
table and column references already exist.
If a table does not exist you generate a create table statement and if a column
reference does not exist you generate an alter table statement to add the
column reference.
Then you use something to execute the sql file (does that mean you run sqlplus
and @somefile ?)
Now, in the previous paragraph there a lot of references to “some” that are
undefined. They are probably obvious to you, but I’d be just guessing (such as
the example guess of sqlplus @ for “we execute this sql file.”) so I hope you
don’t think I’m silly for asking.
Speculative wondering:
1) Do you have any instrumentation in your application that informs you as
each step completes?
a. for example, some form of output that you’re about to execute a create
table statement before you do that and that it has completed when it has before
you move on to the next DDL
b. especially wondering if maybe sometimes you’re adding a not null column
to an existing table containing many rows on the “real” system, while the
existing tables are empty or small on the test system.
2) Where does the file exist with respect to your database server?
a. for example if the generated file is remote from the database server,
you may be unintentionally measuring throughput and latency of a network
connection.
b. is the network connection different when considering the difference
between your “fast” experience on your test server and the “slow” experience
for production?
3) Where is your application program executing?
a. some program running on the database server?
b. some program running on a remote client?
i. directly connected
to the database server?
ii. connecting through
some application server or web services layer?
4) Are you generating a list of one row inserts?
a. if so, you would probably be better off generating something in a format
that could either be read as an external table or by loader
b. if so, then you probably don’t want an instrumentation statement before
and after each insert. I’d start with something like before and after each of
your DDL statements and then before and after the first insert to each
different table and then after perhaps 100 rows and after then end of a given
table. Then at least you’ll know if the delay is with respect to some
individual DDL or some particular table.
5) If you’re using sqlplus, did you set arraysize to some reasonable value
in your job stream, or are you relying on a glogin file or default that might
be different on the two servers?
Now it is indeed possible there is something “broken” about your database, but
that should show up in things like the alert log and/or performance monitoring
and/or lock reports on the database.
Instrumenting your application, even just for the elapsed time of major steps,
should give you a pretty good idea where to look next.
Good luck,
mwf
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On
Behalf Of Abhishek Gurung
Sent: Friday, March 14, 2014 3:16 AM
To: Oracle Freelist
Subject: RE: Performance problem: Loading data via insert
Hi Veerabasaiah,
Thanks for replying.
What we do is data comes in XML files we parse them convert them into insert
statement and load those data into
tables. Each of these file contains data for multiple tables. before inserting
data we also Create and alter tables in database,
if we find any new tables or columns in XML file. Then we execute this sql file
containing insert statements to load
data into different tables.
The loading process for all the databases instances start almost at same
time(as soon as they receive the xml file).
We have even try to load the files while no other database loading was going on
but still the loading is taking
same time. So we conclude that there is something wrong with this database
instance but unable to identify it.
Regards
Abhishek
_____
Date: Fri, 14 Mar 2014 10:01:25 +1300
Subject: Re: Performance problem: Loading data via insert
From: veeracb@xxxxxxxxx
To: sameer.choudhari@xxxxxxxxx
CC: carlos.sierra.usa@xxxxxxxxx; abhishek.gurung@xxxxxxxxxxx;
oracle-l@xxxxxxxxxxxxx
Do you always load the data or cleanup some old data before inserting ?
What else is running at the same time the load is running, is something
blocking this load ?
As Carlos suggested, it would be better if you get more data around the problem
and try identify where your time is going.
On Fri, Mar 14, 2014 at 9:42 AM, Sameer Choudhari <sameer.choudhari@xxxxxxxxx>
wrote:
Try tuning your insert statements with hints like PARALLEL NOLOGGING .
On Friday, 14 March 2014, Carlos Sierra <carlos.sierra.usa@xxxxxxxxx> wrote:
Abhishek,
As always, start with the evidence:
What facts have you collected? What is AWR telling you? What are the SQL Traces
telling? Which other diagnostics tools have you used for your case?
Cheers,
Carlos Sierra
blog: carlos-sierra.net
twitter: @csierra_usa
Life's Good!
On Mar 13, 2014, at 6:52 AM, Abhishek Gurung <abhishek.gurung@xxxxxxxxxxx>
wrote:
Hi
We are facing a performance problem but unable to identify where is the problem.
We have a production database server where about 8 database instances of oracle
is running.
Daily we insert in each of these database instances about 1-5 GB of data in
different tables.
All database instances are working fine where we are able to load around 2-3 GB
of data within 1hour except
1 where it is taking about 8 hrs to load only 4 GB of data.
When I try to load the same 4GB of data in another database where only one
instance is running and with
very less configuration as compared to the Production server we were able to
load it in 1hr 45 minutes.
Can anyone suggest how can we proceed to identify the problem?
Regards
Abhishek
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Veerabasaiah C B
"Only put off until tomorrow what you are willing to die having left undone. -
Picasso"
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