What do you do?  You could tune the existing queries for your publication items to improve sync and MGP performance.  Of course, there is always that poorly written and timed PL/SQL that the junior guy wrote that is inserting/deleting 1 million records in one of your core tables that you are synchronizing to your application, and just when you notice this happening along with syncing or MGP, you notice transactions in C$ALL_CLIENT_ITEMS is blocking all kinds of sessions.  Oracle recommends setting the following in webtogo.ora

SKIP_INQ_CHK_BFR_COMPOSE=NO
DO_APPLY_BFR_COMPOSE=NO

I prefer going to queue based synchronization for situations like this.  Why?   The first things is that it removes triggers on those tables that are usually affected by the blocking locks.  Secondly, if you have bulk operations on a table, the MGP LOG process can get bogged down with logging all the transactions and you often see deadlocks when this happens not to mention blocking locks if the deadlock doesn’t cancel out the MGP process quickly enough.

I am assuming if you are reading this, you are probably familiar with the Mobile Workbench and have created your publication items via that mechanism and felt really good about the fact that you don’t have to write all kinds of stored procedures to perform your synchronizations.  Well, roll up your sleeves, because you will have to write some PL/SQL to get a queue-based refresh working.  In the mobile development kit, there is a tutorial on how to go about creating a queue-based item (Location %ORACLE_HOME%\Mobile\Sdk\samples\Sync\win32\QBasedPI\)

There is a readme.txt in that folder.  I am not going to repost the tutorial, but I will talk about the aspects you should be aware of.  The tutorial basically give a complete-refresh example. This would not be the best example for most applications as there are also bi-directional publication items that you need to worry about.  The real piece of the code you should be concentrating on is the DOWNLOAD_INIT within the package.  This is your download logic.  Your logic should contain the following logic:

• handles physical deletes
• handles inserts
• handles update
• handles logical deletes

Their example only handles inserts.  If you want your publication item to perform incremental syncs, you will need to have a mechanism in that table that indicates records that need to be updated, inserted, or deleted. Here is a template of the mechanism I use.  In our tables, we have an AUDIT_DATE field.  A timestamp or date field is really useful in determining if a record has been updated.  Of course, you may need a trigger on the table or trust those junior developers to have code in place to update that AUDIT_DATE field.

The physical delete:
DELETE CTM$CTM$<TABLE_NAME>
WHERE CLID$$CS = CLIENTID AND DMLTYPE$$ = 'D';

The insert logic:
INSERT INTO CTM$<TABLE_NAME>(CLID$$, FIELDS1, FIELDS2, DMLTYPE$$, TRANSID$$)
SELECT CLIENTID, FIELDS1, FIELDS2, 'I', CURR_TRAN FROM <TABLE_NAME>
WHERE NOT EXISTS (SELECT 'X' FROM CTM$<TABLE_NAME>
WHERE <MATCH PRIMARY KEYS HERE>)

The update logic:
UPDATE CTM$<TABLE_NAME>

The logical delete:
UPDATE CTM$<TABLE_NAME>
SET TRANID$$ = CURR_TRAN,
DMLTYPE$$ = ‘D’
WHERE AUDIT_DATE < TO_CHAR( ADD_MONTHS( SYSDATE, -6 )) AND CLID$$CS = CLIENTID;

Now, in my example, I just keep 6 months of data on the client. At the end of the day, you can decide all aspects of synchronization. Customize the synchronization to fit your business needs.

Lets review the way you create a auto-increment field in Oracle:

//Step 1:
CREATE TABLE TEST_TABLE (
COL1 NUMBER,
COL2 VARCHAR2(20),
CONSTRAINT TEST_TABLE_PK PRIMARY KEY (COL1)
);



//Step 2:
CREATE SEQUENCE TEST_SEQ
START WITH 1
INCREMENT BY 1;



//Step 3:
CREATE TRIGGER TEST_TRIGGER
BEFORE INSERT ON TEST_TABLE
FOR EACH ROW
BEGIN
SELECT TEST_SEQ.NEXTVAL INTO :NEW.COL1 FROM DUAL;
END;


And we are done.

Now here are the steps for doing it in Oracle Lite:

//Step 1: Create and Compile the Java Code.  Call the Java file JavaTrigger.java.  You may also have to compile using JDK 1.4 as even Oracle 10g is known not to support 1.5 yet.
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
public class JavaTrigger {
   public static void autoIncrement(Connection conn, int newNum[]) throws SQLException {
      try {
         Statement stmt = null;
         ResultSet rs = null;
         stmt = conn.createStatement();
         rs = stmt.executeQuery(”SELECT TEST_SEQ.NEXTVAL FROM DUAL”);
         if (rs.next()) {
            newNum[0] = rs.getInt(1);
         }
      } catch (SQLException e) {
         System.err.println(e.getMessage());
      }
   }
}


//Step 2: Load the file into the database
CREATE JAVA CLASS USING BFILE ('C:\OracleLiteJava\StoredProcedure\Sample\classes\','JavaTrigger.class');



//Step 3: Create a Stored Procedure in the database
CREATE OR REPLACE PROCEDURE AUTO_INCREMENT(NEW_ID IN OUT INT) AS LANGUAGE JAVA NAME 'JavaTrigger.autoIncrement(java.sql.Connection, int[])’;



//Step 4:
CREATE OR REPLACE TRIGGER TEST_TABLE_INSERT_TRIG BEFORE INSERT ON TEST_TABLE FOR EACH ROW AUTO_INCREMENT( NEW.COL1);



//Working Example:
SQL> INSERT INTO TEST_TABLE( COL2) VALUES ('GREG');
1 row(s) created
SQL> DIR TEST_TABLE;
COL1 | COL2
-----+-----
6340 | GREG


For more documentation on Stored Procedures in Oracle Lite, check out the online documentation here.

How do you find the right person.

• Obviously ask them how many projects they have worked on with Oracle Lite or how many years they have working with the product.  Standard question for any technology.
• Ask them the size and scope of the project (users/publications/publication items).
• What technologies within Oracle Lite did they use?  Win32, WinCE, OC4J, Webtogo, Symbian, etc.
• For the more advanced questions, you could ask them about the polite.ini and the webtogo.ora files and what are their functions.
• Asked them if they have used Partition Maps, Shared Maps, Cached Publication Items.  If they have used these, then there is a good chance that they have worked on a system with considerable amounts of data and that they probably have performed query tuning.
• Ask them if they have used CONSPERF and what is it’s function.
• If they have used Oracle Application Server (OAS), then ask them if they have set up a farm and to describe the process.  You may want to ask them what is the function of OPMN, but it’s not as important if they don’t know.  This question will demonstrate their expertise with OAS (But I think Oracle Lite will be using Weblogic starting 10.3.0.3 release for the server).

If you do have an IT project that requires Oracle Lite as your solution, finding a good Oracle Lite resource with experience will be difficult but rewarding.

Here is a picture of a test scenario we had set up. We had 10 laptops and they were synchronizing Webtgo-OC4J and Win32. They were all going through the same router and I think 10 out of 10 succeeded.

Your third option for testing concurrency is by contacting an Oracle Lite guru He might be able to give you a hand with your performance testing.

1. Stopped the server
2. Installed the patch
3. Tried to log into mobile manager
4. Got the following error:
WTG-10118: Mobile Server is not connected to the Repository
WTG-10117: Please contact your system administrator

To find the problem I went to the readme of the patch that stated that the web.xml file might get changed during the install. So, I opened the file and the fix is the following:

Find your web.xml file

<ORACLE_HOME>/mobile/server/admin/repository/webtogo/WEB-INF/web.xml
or
<ORACLE_HOME>/j2ee/mobileserver/applications/mobileserver/webtogo/WEB-INF/web.xml
or
<ORACLE_HOME>/mobile_oc4j/j2ee/mobileserver/applications/mobileserver/webtogo/WEB-INF/web.xml

Modify the line in the file from:

<param-value>%ORACLE_HOME%\mobile\server\bin\webtogo.ora</param-value>

to

<param-value>/export/home/oramobile/mobile/server/bin/webtogo.ora</param-value>

The README.TXT tells me to go into my ./patch_storage/6630384/….. directory.  But I couldn’t find it.  So, if you find yourself in the same situation that I was in, the solution has been posted.

In the webtogo.ora file:
[WEBTOGO]
DISPLAY_CLIENT_DATA_SIZE=NO
ADMIN_JDBC_URL={changed this to use a RAC URL. Not required in 10.3.0.2 of the product as the installer handles this}
THIN_JDBC_URL={ditto for this URL}

The DISPLAY_CLIENT_DATA_SIZE is meant for OC4J and Webtogo application. If you are not using the customized workspace, Webtogo connects to the remote server and it attempts to determine the number of rows you will be downloading. This is useless, and time consuming. I turn it off.

[CONSOLIDATOR]
RESUME_CLIENT_TIMEOUT=900
MAX_THREADS=8

The RESUME_CLIENT_TIMEOUT variable sets the socket timeout to the number of seconds you specify. Useful in cases where you are having performance issues and you do not want the user to get a network disconnect error.

MAX_THREADS is the number of threads that will concurrently run a MGP cycle. First try 1.5*CPU on the database server. Then back it down to 1*CPU if there are performance issues.

Over to device configuration for Win32, Webtogo, and OC4J:
[SYNC]
TIMEOUT_MAX=900
DEBUG=1
AUTO_COMMIT_COUNT=3000

[All Databases]
MaxSharedMemSize=256

I am not sure if TIMEOUT_MAX is in 10.3.0.2 of the product, but this was around to fix a bug in previous versions. Very similar to the RESUME_CLIENT_TIMEOUT. I set them both to the same value.

DEBUG enables debug of every sync. Very useful in development, but it may cause the overall performance on an initial sync to slow down, especially if you are syncing a large amount of data.

AUTO_COMMIT_COUNT helps in the processing phase. Again, if you are syncing a large amount of data and you are running into memory issues, this is the parameter you want to set to get around those issues. You don’t want to set this too low and you don’t want to set it too high. I usually play with 1000, 3000, or 5000.

If you are running into memory issues due to large initial syncs or large delete/insert scenarios, chances are you will need to set MaxSharedMemSize=256. This controls how many commands can be placed in shared memory, the larger the area, the more commands. Just take not that you will probably have to use AUTO_COMMIT_COUNT if you are using this variable.

Oracle Application Server configuration:
Not too many things here other than changing ports in httpd.conf and changing the following in opmn.xml
< data id=”java-options” value=”
-server -Djava.security.policy=$ORACLE_HOME/j2ee/mobileserver/config/java2.policy -Djava.awt.headless=true
-Xms2048M -Xmx2048M“/>

I always set Xms(Initial Java Heap Size) and Xmx(Maximum Java Heap Size) to be the same. In this case I set them to use 2GB.

Before I do my initial sync on a new server, I make sure these are always set. The other thing you may want to think about doing for your test servers are set them up with the same number of users your production servers will have. Even though you may not be able to test concurrent syncs within your environment, you will be able to see how MGP and your database handle the consolidation.

Which new features in Oracle technologies are you currently finding most valuable? Oracle Database Lite’s automatic sync allows high reliability in mobile applications, while at the same time keeping users working instead of interrupting their current applications to retrieve new applications. Prior releases relied on manual synchronization, and for an organization this caused issues because users’ data could be stale if they waited too long between syncs. Now, an organization can set thresholds around data modified, network connectivity, and even low battery power to sync information.

Name one unique use of Oracle products at your company. We’ve created one of the largest implementations of Oracle Database Lite. We’re synchronizing more than 350 tables, 700 indexes, 60 sequences, and a full-blown OC4J application to field users’ laptop.

What would you like to see Oracle, as a company, do more of? Oracle has many great technologies. What I find most customers have a hard time with is visualizing the integration of those technologies into their businesses. More in-depth case studies of solutions requiring multiple products would help.

Here is a link to the article.

The event will be at the Saint John Trade and Convention Centre October 29-30.
Visitor schedule is posted here.

If all goes well this week, I will be demoing Oracle Lite on my new Samsung ACE SmartPhone.