Until very recently we ran a 3rd party HR database on an Oracle Unix environment. I have additionally set up various web services that hit stored procedures to carry out a few bespoke processes for our users, and all ran well for years.
However, now that we have moved to Oracle on a Windows environment there is suddenly a big problem.
The best example I have is a VB.Net solution that reads in a 2000 row CSV of employees into a datatable, runs a couple of stored procedures to bring back Post Id etc, populates a database table with the results, then feeds it all back out into a new CSV. This process used to take 1-2 minutes to complete on Unix. It now takes well over 2 hours and kills the server!
The problem manifests by overwhelming the CPU on the database server. Any stored procedure call sends Oracle.EXE into overdrive, completely max-ing out the CPU core that it's using such that no other stored procedures can be run and everything grinds to a halt.
We have run Oracle Enterprise Manager, which suggested the creation of some indexes etc, but nothing will improve the issue. Like I say, the SQL ran fine and swiftly for years, and it hasn't changed at all.
Does anybody know what could be causing this? I am completely at a loss.
The way I see it, it must either be:
1. A CPU/hardware issue (but we have investigated, added extra cores etc to no avail)
2. An Oracle configuration issue?; or
3. An issue with the 3rd party database (which is supposedly identical to what it was on Unix).
Thanks to anyone who read this far.
P.S. I've had a Stack Overflow user account for years but can't get logged into it any more. Back to noobie status for me!
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In my last project we were working on a requirement where huge data (40 million rows) needs to read and for each row we need to trigger a process. As part of design we used multithreading where each thread fetch data for a given partition using Jdbc Cursor with a configurable fetch size. However when we ran the job in the application in the Prod environment, we observed that it is slow as it is taking more time in querying data from database.
As we had very tight time lines on completion of job execution, we have come up with work around where the data is exported from SQL Developer in csv file format and split in to small files. These files are provided to job. This has improved the job performance significantly and helped completing the job on time.
As mentioned above we have used manual step to export the data to the file. If this need to automate this step, executing exporting step from Java App for instance, which one of the below options (which are suggested on the web) will be faster.
sqlplus (Java making native call to sqlplus)
sqlcl parallel spool
pl/sql procedure with utl_file and dbms_parallel_execute
Below link gives some details on the above but does not have stats.
https://asktom.oracle.com/pls/apex/f?p=100:11:0::::P11_QUESTION_ID:9536328100346697722
Please note that currently I don't have access to this Oracle environment, so could not test from my side. Also I am an application developer and don't have much expertise on DB side.
So looking for advise from some one who have worked on similar use case earlier or have relevant expertise.
Thanks in advance.
I have been tasked with creating some backups for some Oracle Apex apps (Application Express v4.1.1.00.23). The request is to back up both the applications & referenced db objects (not sure if this means just structure or structure & data).
On the one hand, I would have expected standard db backups to handle most or all of this but I'm very new to Apex so it's all a learning curve.
I'm currently exporting the application from apex and then exporting (using SQL Developer) all the database object dependencies that Apex gives me - although I see that the list doesn't include functions that are used for auth.
This seems a really clunky process that's very prone to mistakes (miss an object, save something to the wrong place, no guarantees of consistency etc).
Does Apex (my version!) offer something to do the job or is there something else I could be doing? I've had a good google but nothing has stood out.
UPDATE: I realise now that I should have included some extra info. I'm currently at a large organisation & I believe our db backups (which I guess/hope are done using rman) are done by a different department. I think the motivation for the request is so that we have some local, easily accessible backup so that if one of the developers messes something up we don't have to go through multiple layers of organisation (& undoubtedly a lot of time) to sort ourselves out. I suspect that some kind of source control would be a great starting point but I'm not sure how far I'll get with that idea - especially as we seem to have little in the way of autonomy over things like servers.
RMAN is the way to go to backup an oracle database:
https://docs.oracle.com/database/121/BRADV/toc.htm
there are tons of material on the hows and whys online; just google "oracle rman" and you'll find what you need (the documentation should cover you as well of course).
cheers
Standard DB backups will include everything you need.
The Apex applications I develop are static, meaning the end users make no changes to the Apex application, and there is no need to make a specific backup other than to store the original apex application .sql installation files in a safe place.
If you must, you can make an export of the database schemas the application uses. For example with the expdp utility.
IN apex you need to take 2 backups one in the workspace
Second your application
Third is while using export import from the database it tends to loose & character in procedure ..So beter use rman and take a complete backup.
I have found this Oracle white paper Life Cycle Management with Oracle Application Express (Revision 2) which does what it says on the tin - including various strategies for exporting, backing up & managing 'lost application development'. It's a really good read and I'll be using it as a template for suggestions of how we can manage our process in future.
I have an Access application with a SQL server back-end, mixed with quite a few DB objects local to the Access app. I've tried running SQL Profiler, but I got very little except a cryptic sp_execute 2,4288,4289,4290,4291,4292,4293,4294,4295,4296,4297.
I would like a trace tool that is local to the Access DB, so I also pick up any activity that doesn't go back to the SQL server.
As far as I know there is no such facility within Access but, depending on your case, you could try these few things:
Write a wrapper against SQL executables: that would mean replacing all calls to Execute, OpenRecordset etc within your VBA to an alternative version that would log the query.
This isn't going to catch everything obviously but it could help.
Move your local tables to another database and use ODBC to relink them to your original Access application. You can then use ODBC's logging facilities.
This could be the best altenative as it's fairly easy to setup for debugging.
It's not the best solution for a production environment though as all your calls to local tables will in fact go through ODBC, but again, it's a temporary solution for debugging.
Use ShowPlan and ISAMStats to view how Jet/ACE interprets your queries and get other database activity stats.
It's easy to setup by writing a key to the registry and you'll end-up with a log describing how your queries are analysed.
It's more useful for optimisation than logging but again, it could help.
Use Flextracer, a shareware, free for 30 days or so. My colleague here has just found this for us as we were going through a similar situation. Problem solved.
http://www.geardownload.com/development/flextracer-download.html
[]s,
Pedro Carneiro Jr.
pedrokarneiro#hotmail.com
My team inherited an Oracle-based web application and they are fairly inexperienced with Oracle database servers.
The Oracle 10g server is running on a Windows 2003 Server with plenty of disk space and from time to time, all connectivity is lost, the application stops working, not even SQL Plus is able to connect to the database server.
But when we check the Windows Service manager, it says that the service is up and running. A restart usually fixes the problem, but we need to properly troubleshoot it so we know what's causing it and so we can avoid it to happen anymore.
Where should we start looking for clues? What are the criticial log files we should be investigating?
On the server you should have an environment variable called ORACLE_HOME which indicate the root of the Oracle install. Most likely the Oracle trace/dump folders will be under there. Search for a folder called "bdump" (background dump). That's where the main log file, knows as the alert log, will be, as well as trace files generated by background processes. There will be an adjacent file called "udump" which will contain any trace files generated by user processes.
However, my real advice is that you should either hire someone who knows Oracle or get Oracle Support involved.
The alert log would be the first file to check.
It will probably be in $ORACLE_HOME/admin/bdump and (probably) called alert_DATABASE-SID.log
It contains most of the important actions that the database does, as well as any important errors that occur.
I have to agree with cagcowboy. Check your alert logs for errors. If no errors then maintain a sysdba login into the database and when it hangs, attempt to do a hang analysis. See metalink note 215858.1 on hanganalyze.
Have you tried tnsping? We've occasionally run into problems with the listener that requires an assist from our DBA. tnsping is the diagnostic tool we use to do triage.
I would recommend hiring an experienced Oracle DBA if at all possible.
check the alert log to see how the Db is structured. sometimes badly set parameters make hangs or slow performance. or you can shutdown and start in mount mode, then check the v$parameter values for problems. setting total memory is very important.
Is there any technology out there that will allow you to do side-by-side updates of production schemas?
The goal is to have zero down time when applying updates to a schema in production.
Weblogic 10 has a similar feature for their Java EE apps where by you deploy the new version of the app and new connections go to the new app, while the existing connections continue to the old app. When all the old connections complete/timeout, the old app is retired and the new app continues on...zero down time.
Is there something similar in Oracle?
Yes. There is online redefinition package.
DBMS_Redefinition
But I doubt this will give you zero downtime, this doesn't account for every possible change to a schema. This lets you do some table changes. I think you need to define zero and how extensive the changes you want to make. Usually if you change the database, you have to change your client as well. If you changed your database, how would the client switch automatically from the old proc signature to the new proc signature - Instantaneously?
Databases don't work like apps. There either is a FK from tableA to tableB or there isn't... it can't not be there for current connection and exist only for new connection in the same manner as your application can. Databases just aren't the same.
That being said, there is rumor that Oracle is working on package versioning... so you could connect to a specific version of a package to make such a migration simpler. But again... that would work for packages, DBMS_redef would work for tables... but that's not the sum total of your database.
Oracle release today 11gr2, it has edition-based redefinition: http://download.oracle.com/docs/cd/E11882_01/server.112/e10881/chapter1.htm#NEWFTCH1
Depends what you mean, or include, in "schema".
If you want to add or drop an index, that can be done "in-flight", although it will require a lock which may halt activity for a time. In the latest Oracle versions, it doesn't need to hold the lock for the entire time it takes to build the index, just for a moment to lock in the change. If you have short-duration transactions it shouldn't be noticeable.
In some cases that applies to tables as well (eg adding a nullable or default column).
If you use PL/SQL (especially packages), things can be a little more complicated. Enhancements were mooted for 11gR1 to enable the in-flight application upgrade, but it got pushed out and is now expected in 11gR2 (probably out first half next year).
In the meantime, a workaround is a multi-schema solution. Say your data sits in one schema ("yellow") and your current application code is running in "blue" schema, you load your new application into "green schema". You switch your connections, one by one, from blue to green. Once your connections are all using "green", you can retire "blue" until your next upgrade (when "blue" becomes the new app and "green" is retired).
If you have a genuine 24/7 system, you'll probably always have to stage some upgrades. For example, add a new column as optional, upgrade the application to set it, then make it mandatory (possibly with some data change script for pre-existing rows).