A hitchhiker’s guide to SQL/MX Stored Procedures

© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.

A hitchhiker’s guide toSQL/MX Stored ProceduresConnect Advanced Technical BootcampFrans Jongma, ATC / November, 2013


Don’t

Panic!

The Hitchhiker’s guide to the GalaxyDouglas Adams

© Copyright 2012 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.3

Agenda

Intro: Why Stored Procedures?

Architecture:SQL/MX SPJ

Configure:Influencing the SPJ runtime

environment

Optimize:Using Module File Caching

Exceptions:Logging & error reporting


Intro


Why Stored procedures?

A stored procedure is a function or routine available to applications that can access a RDBMS• Typically stored in the database data dictionary• Typically runs “close to the database”

- Within the database engine

- Direct access to the data

• Used to encapsulate business logic • Especially useful in Client-Server environments

• Invoked by CALL or EXECUTE statement• CALL ALERTER ( VALUE_1, VALUE_2, ‘UPDATE’ );


Why Stored procedures?

One problem, different solutions.

•DMBS vendors without a transaction processing engineStored Procedures

•NonStop SQLPrimarily Pathway servers – less immediate need for SPs

•NonStop SQL/MPSP implementation under TS/MP used by ODBC clients

•NonStop SQL/MXStored Procedures in Java (SPJ)


Procedural Languages for SPs

One problem, different programming languages

SP Language SP Language

IBM DB2 JavaSQL PL, close to ANSI SQL/PSM

HP NonStop SQL/MX Java

Microsoft SQL ServerTransact-SQL or .NET

MySQLClose to ANSI SQL/PSM

Oracle Java PL/SQL

Sybase ASE Transact-SQL

(source: Wikipedia)


Architecture


Architecture of SQL/MX SPJ

The three areas of SQL/MX Stored Procedures in Java

• Developing the procedure– Create the Java method in your favorite development environment– Put the compiled Java class on the server

• Defining the procedure in the SQL/MX metadata– CREATE PROCEDURE DDL command

• Invoking the Stored Procedure– Using mxci, rmxci, COBOL, C, Java



Developing the procedure (for example: Vim, Eclipse)import java.sql.*;

public class SP1Reader

{ public static void Reader

(String inString, java.sql.ResultSet[] result)throws Exception {

/* here comes the procedure code*/Connection conn = DriverManager.getConnection("jdbc:default:connection");

}}



Defining the procedure (for example: mxci)

• SQL/MX will try to load the class from the specified location and verify the signature of the SP with the one defined in the DDL.• External path is an OSS filename

create procedure SP1Reader( IN tableName varchar(255) )dynamic result sets 1external name 'SP1Reader.Reader(java.lang.String, java.sql.ResultSet[])'external path '/home/frans/spj/spj.jar'reads SQL DATAlanguage java parameter style java;



Defining the procedure (for example: mxci)

Create procedure SP1 ( ) ….. ;

Procedure SP1 ()external name 'SP1.READER(java.lang.String, java.sql.ResultSet[])'external path '/home/frans/spj/spj.jar‘

SQL CATALOG

/home/frans/spj/spj.jar

OSS Filesystem



Defining the procedureDefinition is stored in the SQL/MX metadata

>>select * from zzprocedures;

SP_NAME SP_LANG SP_TYPE SP_RESULTS SP_PATH

--------------- ------- ------- ----------- ---------------------------------------------

READER Java SQL RO 1 /home/hp/frans/projects/spj/spj.jar/SPreader

READER2 Java SQL RO 1 /home/hp/frans/projects/spj/spj.jar/SPreader

SP1READER Java SQL RO 1 /home/hp/frans/projects/spj/spj.jar/SP1Reader

--- 3 row(s) selected.


Invoke



Invoking the procedure (1)

• In mxci or rmxci – >> call sp1reader ('EMP');

• In Java – CallableStatement cs = conn.prepareCall("{ CALL sp1reader (‘EMP’) }");– boolean rsAvail=cs.execute();– ResultSet rs = cs.getResulSet();



Invoking the procedure (2)

• In Embedded SQL– EXEC SQL CALL SP1READER (:HV1) END EXEC;

• (Note: this is simplified --- the SP needs a cursor)

• In a trigger definition

- create trigger salesalertSP after update of (c2) on B

referencing new as newr , old as oldr for each row

when ( newr.c2 > 500 ) CALL SPalerts (oldr.c1,newr.c2, ‘UPDATE’);



Invoking a normal SQL call

….Select a, b from T….

Table T ;Table T2:

SQL Database

mxcmp for application



Invoking the procedure

/home/frans/spj/spj.jar

OSS Filesystem

MXUDR JVM….

Select x,y from T2 ……

SQL prepare Call SP1();

SQL Execute Call…….

Select a, b from T….

Table T ;Table T2:

SQL Database

mxcmp for mxudr

mxcmp for application


Configure


Influencing and Configuring SQL/MX SPJYou do not have to configure the SPJ environment This is a difference from the SQL/MP ODBC environment• where you needed to configure TS/MP

The key component is the MX User Defined Routines MXUDR process

• What is the MXUDR• How does the MXUDR know which configuration options apply• How does is a caller able to set the configuration options


Influencing and Configuring SQL/MX SPJThe MXUDR process provides the run-time SPJ environment

Embedded SQL program CALL lowerprice()

JDBC/MX ApplicationCALL lowerprice()

ODBC/MX client application

CALL lowerprice()

Stored Proceduresamdb.sales.lowerprice()

SPJ MethodSales.lowerPrice()

NonStop SQL database

JDBC Type 2driver

MXUDR embedded JVM


Influencing and Configuring SQL/MX SPJYou do not have to configure the SPJ environment But there are good reasons to do so• Java run -time default: /usr/tandem/java• JDBC T2 driver location default:

/usr/tandem/jdbcMx/current/lib• Class location of the SP (taken from metadata definition)• Catalog and Schema (are the same as the current catalog and schema of the caller)

• Connection pooling and statement caching: set jdbcmx.maxPoolSize and maxStatements property

• Additional class locations: : set java.class.path• Enable MFC : set enableMFC and

compiledModuleLocation• Others like setting JDBC Trace, debugging, logging .


Influencing and Configuring SQL/MX SPJHow to set the UDR_JAVA_OPTIONSUDR_JAVA_OPTIONS contains the set of System properties used by the JVMSQL/MX will pass these parameters when launching the MXUDR object-Djava.class.path=/home/frans/lib/Utils.jar –Djdbcmx.maxPoolsize=100 –D...

• Can be set as a CONTROL QUERY DEFAULT called before the first CALL statement

- CONTROL QUERY DEFAULT UDR_JAVA_OPTIONS

‘-Djdbcmx.maxPoolSize=1 -Djdbcmx.maxStatements=100’;

• Can be set as an MXCS Control

- ADD EVAR $MXOAS.MYDS.UDR_JAVA_OPTIONS, TYPE CONTROL ,

VALUE '-Djdbcmx.maxPoolSize=1 -Djdbcmx.maxStatements=100' ;

• Can be set as an environment variable called _JAVA_OPTIONS where applicable – ENV _JAVA_OPTIONS=”-Djdbcmx.maxPoolSize=1 -Djdbcmx.maxStatements=100”


Optimize


Optimizing with Module File Caching

What again is Module File Caching?In Summary• MFC is an additional SQL/MX SQL Statement cache

– Available for JDBC T2, JDBC T4 and ODBC (Windows) drivers

• Reduces SQL Compilations• Improves application startup times

• Simplifies application tuning– Dynamic SQL statements do not show in MEASURE– MFC Modules appear in Measure SQLSTMT entity


MFC Typical usage

Use in production environments that are relatively stableFirst compilations have overheadStale modules are not automatically removed

Applications use specific compiled_module_locationOne per MXCS server_datasource One per T2 “application class”of JVMs • Multiple instances of JVM executing the same application services• For example: A dedicated location for all the SPJs that are defined in a schema


Configuration options

One: Instruct driver to use MFCT2: -Djdbcmx.enableMFC=ON JVM option• Program can set this property as well

Two: Instruct driver use a location for modules T2: -Djdbcmx.compiledModuleLocation=<full pathname>

– E.g. /home/SPJ/mfc/modules

Combine these options in UDR_JAVA_OPTIONS for use by SPJsUDR_JAVA_OPTIONS “-Djdbcmx.enableMFC=ON -Djdbcmx.compiledModuleLocation=/home/…. “


Logging


Logging and error reporting

Designated SQL/MX error codes for SPJ user exceptionsUse SQLSTATE values 38001 through 38999 to signal user-defined error conditions.• Allows an SPJ to communicate error conditions which may or may not be related to SQL.

if ( condition) )

{

throw new java.sql.SQLException("This exception is thrown upon request", "38088");

}


Logging error and reporting

Using Apache log4jAdd “-Dlog4j.configuration=file:/home/spj/log4j.xml” to the UDR_JAVA_OPTIONS

• Little output: all SPs can log to the one file• Verbose output: Use a specific file for each SPJ instance using the Java properties:

• nsk.process.cpu and nsk.process.pin

• <param name="File“ value="/home/hp/frans/spj/SPJ_${nsk.process.cpu}_${nsk.process.pin}.log"/>


Summary

Intro: Why Stored Procedures?

Architecture:SQL/MX SPJ

Configure:Influencing the SPJ runtime

environment

Optimize:Using Module File Caching

Exceptions:Logging & error reporting


Further reading

Concepts of NonStop SQL/MX Part 5: Stored Procedures HP Technical Whitepaper 4AA4-9428ENW.pdfModule File Caching for NonStop SQL/MX

HP Technical Whitepaper 4AA3-8922ENW.pdfOther

www.hp.com/go/nonstop from here Products NonStop SQL White papers

www.slideshare.net/fjongma All “Concepts of NonStop SQL/MX” papers and more

http://www.hp.com/go/nonstop

http://www.slideshare.net/fjongma


Thank you

“So long and thanks for all the fish”

Technology

A hitchhiker’s guide to SQL/MX Stored Procedures