1 Optimizing Your ColdFusion Applications for Oracle Justin Fidler, CNA, CPS, CCFD Chief Technology Officer Bantu, Inc. 8 May 2001

2 Overview  Why Oracle?  Configuring Your Platform  Query Tuning  CFQUERYPARAM  Special Coding Techniques  NULL Handling  Lists of Values  Date Handling  BLOCKFACTOR  Further Reading, Questions

3 Why Oracle?  Industry-accepted platform  Runs on virtually any server platform  Large base of Oracle knowledge  Robust, scalable, proven technology  Widely supported  BUT.. It won’t be cheap!

4 Configuring Your Platform -- Database  Oracle 8i is the current popular version  Standard vs. Enterprise Edition  Beware of “App Server” focus  Have a DBA to help with configuration  Use an internal-address NIC (security)  Don’t skimp on hardware -- typically single point of failure  Perform routine maintenance (tablespace sizing, init settings, backups, table index analysis)

5 Configuring Your Platform -- ColdFusion  Only the Enterprise Edition provides native Oracle drivers  Use and enable connection pooling  Set connection pooling similar to simultaneous request limit, in most cases  Beware of running out of connections -- have a DBA look at settings  Use a separate NIC for the database traffic

6 Query Tuning  Most poor database performance results from poorly- designed queries  EXPLAIN PLAN will solve most of your problems  Use TKPROF in severe cases  Have your DBA closely check and monitor Oracle performance statistics

7 Query Tuning - EXPLAIN PLAN Bad Query: SELECT u.gender FROM users u, user_chat_preferences ucp WHERE ucp.user_id = u.user_id AND u.logon_id='justin’ Output: SELECT STATEMENT Cost= 4806 NESTED LOOPS TABLE ACCESS FULL USERS TABLE ACCESS FULL USER_CHAT_PREFERENCES

8 Query Tuning - EXPLAIN PLAN Good Query: SELECT u.gender FROM users u, user_chat_preferences ucp WHERE ucp.user_id = u.user_id AND u.logon_id='justin’ Output: SELECT STATEMENT Cost= 4 NESTED LOOPS TABLE ACCESS BY INDEX ROWID USERS INDEX UNIQUE SCAN UK_USERS_LOGON_ID INDEX UNIQUE SCAN PK_USER_CHAT_PREFERENCES

9 CFQUERYPARAM  Introduced in CF4.5  Enormous performance improvement  Works with any database that supports “bind” variables  Oracle SQL statement cache is literal and case- sensitive  Statement cache determines execution plans

10 CFQUERYPARAM Before Example Your Code before CFQUERYPARAM: SELECT username FROM users WHERE user_id=#SESSION.USER_ID# In the Database before CFQUERYPARAM: SELECT username FROM users WHERE user_id=2236

11 CFQUERYPARAM After Example Your Code after CFQUERYPARAM: SELECT username FROM users WHERE user_id= In the Database after CFQUERYPARAM: SELECT username FROM users WHERE user_id=:1

12 CFQUERYPARAM Summary  Works with all datatypes except BLOBS, including dates, characters, numbers  Null handling is done with the NULL=“YES” parameter  Can be used on UPDATEs, INSERTs, SELECTs, DELETEs  Should be used for all literal and dynamic values (parameterized values)  Bind variable enumeration will appear in debug output  No reason not to use CFQUERYPARAM

13 Special Coding Techniques  SELECTs should use listed field names instead of “SELECT *”  SELECTs should only select the fields needed for the query  INSERT statements should list field names explicitly: INSERT INTO tablename(field1,field2,…) VALUES (value1,value2,…)  Explicit field listing helps with different database field ordering (production vs. development)

14 More Coding Techniques  SIMPLE computations can be done in the query: SELECT product_id, price*1.05 as taxprice FROM products WHERE category_id=6  Complex operations should be avoided  Correlated Subqueries  GROUP BY, HAVING, UNION (temp sort area)  Many table complex joins  Aggregate functions, whenever possible  Stored Procedures, when applicable

15 NULL Handling  Evaluation of NULLs can often be misleading (IS NULL vs. = NULL, GTE evaluations)  NULLs can’t be indexed  Aggregate queries like MAX and MIN may return NULL  Try to design your data model so that NULLs aren’t allowed  Use other identifiers for NULL  Start with no columns nullable, then make a case for each to allow NULLs

16 NULL with NVL Use in a general query: SELECT product_id, NVL(price,-1) as NULLprice FROM products WHERE category_id=6 Use in an aggregate function (note placement of NVL): SELECT NVL(MAX(price),0) as maxprice FROM products WHERE category_id=6

17 Lists of Values  Improved performance over a join, if you can enumerate the items in code SELECT DECODE(gender,'M','Male','F','Female','N','Unknown') as fullgender FROM users

18 Date Handling  Do not assume CF will handle date conversion  Non-literal date conversion depends on server locale settings  Oracle in-line date conversion functions are very fast  Bind variables are supported (use character type)  Multi-lingual conversion is supported

19 Date Handling Examples SELECT event_id FROM calendar WHERE start_date > TO_DATE('#DateFormat(l_In_Date,"MMDDYYYY")#','MMDDYYYY') SELECT TO_CHAR(sale_date, 'Day DD Month YYYY HH24:MI:SS') as nice_sale_date FROM sales WHERE sales_id=3939 Nice_sale_date Wednesday 25 October :16:13

20 More Date Handling Examples In French: SELECT TO_CHAR(sale_date,'Day DD Month YYYY HH24:MI:SS','NLS_DATE_LANGUAGE= FRENCH') as nice_sale_date FROM sales WHERE sales_id=3939 Nice_sale_date Mercredi 25 Octobre :16:13

21 BLOCKFACTOR  Directive for database fetch size  Only applies to SELECT statements SELECT product_id, product_name FROM products

22 Further Reading  Oracle Technet --  Allaire Developer Exchange  Oracle MetaLink (part of Oracle Support)  Many good Oracle books (O’Reilly, Oracle Press) Questions?