Transcript Improving Database Performance

Improving Database Performance
Derrick Rapley
[email protected]
www.cfbookmark.com
Agenda
Query Life Cycle
Caching


Variable-based
Query Caching
<CFQueryParam>
Stored Procedures
Block Factor
Caching
 Variable-based
 Query Caching
Using SQL JOINS
Microsoft Access
Query Life Cycle
1.
2.
3.
4.
5.
6.
7.
Request sent to CF to process a template
ColdFusion executes <cfquery>
CF sends SQL statement to the DB
CF waits for a response from the DB
DB parses the SQL statement
DB executes the SQL statement
DB returns record set to CF 1 record at a
time
Caching
Queries that hardly change are perfect
for caching.

I.E. List of Document Types
Queries can be stored in Shared Scope
variables: Session, Application, Server
Queries can be cached based on Results
Variable-based Caching
<CFQUERY name=“Application.doctypes”
datasource=“#datasource#”>
SELECT type_id, doc_type
FROM doctype
</CFQUERY>
<select name=“doctype>
<cfoutput query=“Application.doctypes”>
<option value=“#type_id#”>#doc_type#
</cfoutput>
</select>
Query Caching
Two attributes can be used in <CFQUERY>
 CACHEDWITHIN-caches data for a specified time span
 CACHEDAFTER-caches data until a specific date is
reached.
Queries are only cached if there is enough space. If
not, the query won’t cache and operate as normal.
Perform a Q of Q on a Cached Query for ‘Next N’
records and search results
<CFQUERYPARAM>
Parsing, validating, and analyzing the query can take
longer than actually processing it
Simple queries are easy to cache.
SELECT id, FirstName, LastName
FROM Employees
It’s a waste of time and space to cache dynamic
queries, perfert for cfqueryparam.
SELECT id, FirstName, LastName
FROM Employees
WHERE ID = <cfqueryparam value=“150"
cfsqltype="CF_SQL_NUMERIC">
<CFQUERYPARAM> helps differentiate what is
dynamic in the SQL statement
<CFQUERYPARAM>
Must be used within
<CFQUERY></CFQUERY>
Supports Bind Parameters
Improves Performance
Provides some benefits of Stored Procedures
without using them
Can be used with Stored Procedures when
using <CFQUERY> to call them
Can not be used with Cached Queries
<CFQUERYPARAM VALUE=“150”
CFSQLTYPE=“CF_SQL_INTEGER”>
<CFQUERYPARAM>
<CFQUERY name=“getEmployee”
datasource=“#datasource#”>
SELECT id, FirstName, LastName
FROM Employees
WHERE ID = <CFQUERYPARAM VALUE=“150”
CFSQLTYPE=“CF_SQL_INTEGER”>
</CFQUERY>
<CFQUERYPARAM>
CF_SQL_BIGINT
CF_SQL_BIT
CF_SQL_CHAR
CF_SQL_DATE
CF_SQL_DECIMAL
CF_SQL_DOUBLE
CF_SQL_FLOAT
CF_SQL_IDSTAMP
CF_SQL_INTEGER
CF_SQL_LONGVARCHA
R
CF_SQL_MONEY
CF_SQL_MONEY4
CF_SQL_NUMERIC
CF_SQL_REAL
CF_SQL_REFCURSOR
CF_SQL_SMALLINT
CF_SQL_TIME
CF_SQL_TIMESTAMP
CF_SQL_TINYINT
CF_SQL_VARCHAR
Stored Procedures
Execute faster than SQL from the client

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Precompiled SQL Statements
Stored in the database
Returns the a complete record set as a result
Can execute a block of Statements
Increased Security

Access to tables unavailable to the user
Can use <CFQUERY> and
<CFSTOREDPROC>
<CFQUERY> OR <CFSTOREDPROC>
<CFQUERY>



Can only be used when native driver is
available
It only passes ODBC compliant code to an
ODBC driver
Stored Procedures can vary depending on
which database is being used
<CFSTOREDPROC> can always be used
Block Factor
Rows are retrieved from the database
one row at a time
Block Factor is the number of rows
retrieved at one time (defaults to 1)
Block Factor can hurt performance if too
high of a Block Factor is declared
SQL JOINS
A Relational DB is key to using JOINS
Advantages of Relational DB
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Data does not have to be repeated
Easier to maintain
Uses Less Storage Space
Performs quicker than flat DB
Documents
DocType
Doc_ID
Title
Doc_type_id
Type_ID
Doc_Type
101
Creating A Relational Database
11
11
Word
102
Using Stored Procedures
12
12
PDF
103
Caching Queries
13
XML
104
Joining Tables Together
11
Using Joins
Specify tables in FROM clause
SELECT documents.title, doctype.doc_type
FROM documents, doctype
How does the DB know which rows to join?
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Inner Joins
Right Outer Joins
Left Outer Joins
Full Outer Joins
Using Joins
You must specify the join condition

Can be specified in the WHERE clause
SELECT doc.title, dt.doc_type
FROM documents doc, doctype dt
WHERE doc.doc_type_id = dt.type_id

Can be spcified in the FROM clause
(ANSISQL Standard)
SELECT doc.title, dt.doc_type
FROM documents doc JOIN doctype dt
ON (doc.doc_type_id = dt.type_id)
JOIN sytax is similar in most databases but
can vary
Inner Join
If no Join is specified, then INNER JOIN is assumed
SELECT doc.title, dt.doc_type
FROM documents doc INNER JOIN doctype dt
ON (doc.doc_type_id = dt.type_id)
INNER JOIN only matches rows in both tables
Outer Join
LEFT OUTER JOIN
 Returns all rows from left table
RIGHT OUTER JOIN
 Returns all rows from right table
FULL OUTER JOIN
 Returns all rows from both tables
Microsoft Access
Obtain the latest ODBC drivers
Obtain the latest MDAC
Only allow 5-7 simultaneous (per
Processor) requests to Access
Uncheck ‘Maintain Database
Connection’ in CF Administrator
Max Buffer should be set to 0