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Program Agenda 1 Connections Hard and Soft Parses LOB Operations Result Set Cache Array Operations/Stored Procedures Questions 2 3 4 5 6

Program Agenda 1 Connections Hard and Soft Parses LOB Operations Result Set Cache Array Operations/Stored Procedures Questions

Calls for a Connection Strategy Creating a DB connection is an expensive database operation Spawn O/S process, network connection, several roundtrips Associated database authentication and session creation Database Connections are expensive to tear down! Repeated Connection/Disconnection can be a huge scaling issue Calls for a Connection Strategy

Connection Management Strategy Client Side Connection Pool; Frequent short term connection usage Use Universal Connection Pool (UCP) Very large scale deployment Use Database Resident Connection Pool Single Instance and multiple databases Use Multi-tenant Database Multiple instances, single database scenario RAC Architecture

Planned Maintenance Development Steps Universal Connection Pool (UCP) Most convenient and works with most of the application containers such as Weblogic, Tomcat, Websphere, JBOSS etc., Built-in Failover mechanisms which makes it easier to use with RAC, RAC one etc., PoolDataSource pds = PoolDataSourceFactory.getPoolDataSource(); …. Connection conn = pds.getConnection(); Set the below UCP properties for better performance (1) Each 12c DB transaction is associated with a logical transaction ID (LTXID) (2) The main and only purpose of LTXIDs is to help make a reliable determination of the outcome of the last COMMIT statement (see Transaction Guard) (3) LTXIDs are issued by the RDBMS at the beginning of each transaction and changed only by when the transaction is committed or rolled back. UCP Properties Description setInitialPoolSize(), setMinPoolSize(), setMaxPoolSize() Set the Pool size based on your application setTimeToLiveConnectionTimeout() , setAbandonConnectionTimeout() Set the Connection Timeout appropriately setMaxStatements() Enable Statement Caching

Very Large Scale Deployment Database Resident Connection Pool (DRCP) Problem to Solve: eCommerce-style deployment => thousands of mid- tiers, each with it’s own client-side pool Database Resident Connection Pool (DRCP) Thousands of clients requiring database server session for a short period of time Applications mostly have same DB credentials & have identical session settings Specify (SERVER=POOLED) in short URL to enable DRCP Example: jdbc:oracle:thin:@//localhost:5221/orcl:POOLED Overwhlem the database Only 5 – 10% connbections in use => waste of memory and system resources

RAC for Scalability RAC, RAC one customers New Retry while service is unavailable alias = (DESCRIPTION_LIST= (LOAD_BALANCE=off) (FAILOVER=on) (DESCRIPTION=(CONNECT_TIMEOUT=90)(TRANSPORT_CONNECT_TIMEOUT=10)(RETRY_COUNT=10)(RETRY_DELAY=3) (ADDRESS_LIST= (LOAD_BALANCE=on) (ADDRESS=(PROTOCOL=TCP)(HOST=RAC-scan)(PORT=1521))) (CONNECT_DATA=(SERVICE_NAME=gold))) (DESCRIPTION=(CONNECT_TIMEOUT=90)(TRANSPORT_CONNECT_TIMEOUT=10)(RETRY_COUNT=10)(RETRY_DELAY=10) (ADDRESS=(PROTOCOL=TCP)(HOST= DG-scan)(PORT=1521))) (CONNECT_DATA=(SERVICE_NAME=gold)))) Connect time Load Balancing Safe for logon storms Balance IP’s in Scan Talk about Connect Time Load Balancing Vs Run time Load Balancing. The above URL is for customers using RAC, RAC One etc., Talk about the LOAD_BALANCE = ON and how it does the load balancing between the cluster

Program Agenda Connections Hard and Soft Parses LOB Operations Result Set Cache Array Operations/Stored Procedures Questions 2

Hard Parses About Hard Parse Parse structure and Execution Plan is thrown out when the statement is closed Problems to solve Causes library cache latch contention Causes shared pool contention Causes scalability issues Very bad on the server Solution Avoid Hard Parsing using Prepared Statement & Bind Variables Reduces hard parses on the server Reduces risk of SQL Injection: Potential Security issues.

Hard Parses An Example Instead of: Change to: String query = "SELECT EMPLOYEE_ID, LAST_NAME, SALARY FROM "+"EMPLOYEES WHERE EMPLOYEE_ID = " + generateNumber(MIN_EMPLOYEE_ID, MAX_EMPLOYEE_ID); pstmt = connection.prepareStatement(query); rs = pstmt.executeQuery(); Change to: String query = "SELECT EMPLOYEE_ID, LAST_NAME, SALARY FROM "+"EMPLOYEES WHERE EMPLOYEE_ID = ?"; pstmt = connection.prepareStatement(query); pstmt.setInt(1, n); rs = pstmt.executeQuery();

Soft Parses About Soft Parse Parse structure and Execution Plan are saved and re-used. Session executes a statement that exists in shared pool Creates session specific cursor context Metadata processing Problems to solve Though light weight, can take more time Solution Enable Statement caching oracleDataSource.setImplicit CachingEnabled(true) Choose the correct cache size to best utilize the memory connection.setStatementCac heSize(10);

Program Agenda Connections Hard and Soft Parses LOB Operations Result Set Cache Array Operations/Stored Procedures Questions 3

Large Objects (LOBs) LOB API Data API Recommended for offset based access Use for large LOBs (MBs) Data API Handle LOBs like LONG or LONG RAW columns Recommended for small LOBs No extra roundtrips Oracle Database 11g Improvements for LOBs BASIC LOBs: Tune SDU & Use PreFetching SECUREFILES LOBs: Vectored I/O (a.k.a. Zero Copy network transfer)

Program Agenda Connections Hard and Soft Parses LOB Operations Result Set Cache Array Operations/Stored Procedures Questions 4

Result Set Caching Shared across multiple connections from the same Data Source in the middle tier Faster access to frequently queried data Some of the benchmarks showed 3x improvement Server side configuration to enable Result Set Caching RESULT_CACHE_MAX_SIZE – Should be set to 0 RESULT_CACHE_REMOTE_EXPIRATION – Specifies expiration time (in minutes) for a result in the server result cache

Result Set Caching Problems to Solve Avoid Wasteful Re-execution Faster access to frequently queried data Some of the benchmarks showed 3x improvement Server side configuration to enable Result Set Caching RESULT_CACHE_MAX_SIZE – Should be set to 0 RESULT_CACHE_REMOTE_EXPIRATION – Specifies expiration time (in minutes) for a result in the server result cache

Program Agenda Connections Hard and Soft Parses LOB Operations Result Set Cache Array Operations/Stored Procedures Questions 5

Stored Procedures Best Practices Bundle multiple SQL statements in one call Use anonymous blocks or stored procedures Eliminates roundtrips to database Eliminates moving data between database and client Can improve performance dramatically Monitor roundtrips and bytes transferred stats High values may indicate optimization opportunities Oracle furnishes Java and PL/SQL Stored Procedures

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