Advance Caching Techniques

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Advance Caching Techniques
SCCFUG Winter 2002 Conference

• Keen Haynes
• MKAD
• khaynes_at_mkad.com

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Introduction

• What is caching?
• Why is it important to me?
• What can I cache?
• How do I leverage caching

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Introduction (cont.)

• Template Cache
• Trusted Cache
• Database Connection Cache or Pooling
• Query Caching

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Template Cache

• Cache the HTML generated by a template
• Cache for a specified period
• Caching can be client-side, server-side or both

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ltCFCACHEgt

• Speeds up page rendering when dynamic content
  does not have to be retrieved each time a user
  accesses the page. To accomplish this, cfcache
  creates temporary files that contain the static
  HTML returned from a ColdFusion page.

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ltCFCACHEgt (cont.)

• ltcfcache
• action "cache" or "flush" or "clientCache" or
  "optimal"
• username "username"
• password "password"
• protocol "protocol name"
• timeout timeout date-time"
• directory "directory name for map file"
• cacheDirectory directory name for cached
  pages"
• expireURL "wildcarded URL reference"
• port "port-number"gt

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ltCFCACHEgt (cont.)

• Client-side caching
• ltCFCACHE ACTIONCLIENTCACHE
• Server-side caching
• ltCFCACHE ACTIONCACHE
• Optimal combination of client server
• ltCFCACHE ACTIONOPTIMAL
• Refresh a cached page
• ltCFCACHE ACTIONFLUSH

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ltCFCACHEgt (cont.)

• ltCFCACHE ACTIONCACHE
• TIMEOUTDateAdd(h, -4, Now())gt
• ltCFCACHE ACTIONFLUSH
• EXPIREURLCustomer.cfm?

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Trusted Cache

• When checked, any requested files found to
  currently reside in the template cache will not
  be inspected for potential updates recommended
  for sites that do not update during the life of
  the server.

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Trusted Cache (cont.)

• Refreshing the template cache
• Uncheck the 'Trusted Cache' option in the
  ColdFusion Administrator.
• Click Apply.
• Check the "Trusted Cache" option.
• Click Apply.

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Caching and CF Admin
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Database Connection Caching

• If "Maintain Database Connections" is enabled for
  a data source, CF keeps the connection open after
  its first connection to the database. It does not
  log out of the database after this first
  connection.
• Will create a new connection if a request is
  using a data source connection that is already
  opened, and another request is received
• The connection pool can increase up to the
  setting for simultaneous connections limit which
  is set for each data source.

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Database Connection Caching (cont.)
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Caching and database queries

• What does ColdFusion do when it sees a query?
• ltCFQUERYgt
• Cachedwithin
• Cachedafter

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Caching and database queries (cont)

• What does ColdFusion do when it sees a
• query?
• Passes SQL content to appropriate driver (handled
  by a thread)
• Waits for results to return before processing
  rest of tag
• Will use existing instance of driver if data
  source already in use
• Will cache connection information if Maintain
  Database Connections is selected

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Caching and database queries (cont)

• ltCFQUERY NameStates DATASOURCEtest
• CACHEDWITHINCreateTimeSpan(0,1,0,0)gt
• SELECT state_name FROM tbl_state
• lt/CFQUERYgt
• CACHEDWITHIN (TIMESPAN) caches the query
  results for a specified time
• CACHEDAFTER (DATE) caches the query based on a
  particular date and time

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Caching and database queries (cont)

• ltCFQUERY Nameus_states DATASOURCEStates
• SELECT
• FROM us_states
• ORDER BY State
• lt/CFQUERYgt

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Caching and database queries (cont)

• ltCFQUERY Nameus_states DATASOURCEStates
• CACHEDWITHINCreateTimeSpan(0,1,0,0)gt
• SELECT
• FROM us_states
• ORDER BY State
• lt/CFQUERYgt

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Caching and database queries (cont)

• Points to remember
• Queries are cached on a server-wide basis
• Documentation states query must use same SQL
  statement, data source, query name, user name,
  password, and DBTYPE (I did not find this to be
  true for query name )
• SQL statements must be exactly the same this
  includes even tabbing

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Caching and database queries (cont)

• ltCFQUERY NameStates DATASOURCEtest
• CACHEDWITHINCreateTimeSpan(0,1,0,0)gt
• SELECT state_name FROM tbl_state
• lt/CFQUERYgt
• IS NOT THE SAME QUERY AS
• ltCFQUERY NameStates DATASOURCEtest2
• CACHEDWITHINCreateTimeSpan(0,1,0,0)gt
• SELECT state_name FROM tbl_state
• lt/CFQUERYgt

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Caching and database queries (cont)

• ltCFQUERY NameStates DATASOURCEtest
• CACHEDWITHINCreateTimeSpan(0,1,0,0)gt
• SELECT state_name FROM tbl_state
• lt/CFQUERYgt
• IS NOT THE SAME QUERY AS
• ltCFQUERY NameStates DATASOURCEtest
• CACHEDWITHINCreateTimeSpan(0,1,0,0)gt
• SELECT state_name
• FROM tbl_state
• lt/CFQUERYgt

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Caching and database queries (cont)

• ltcfquery name"us_states" datasource"States"
• CACHEDWITHINCreateTimeSpan(0,1,0,0)gt
• SELECT (Note tabbing)
• FROM us_states
• ORDER BY State
• lt/cfquerygt

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Caching and database queries (cont)

• More points to remember
• Queries containing dynamic values will result in
  an instance of each record setting being cached
• Max limit of 100 cached queries was removed with
  CF4.5
• Cached queries will not reflect changes to the
  database until the cache interval has expired.

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Caching and database queries (cont)

• Forcing an update of cached queries
• This can be accomplished by following queries
  that
• effect changes with a CFQUERY that contains a
  negative
• CACHEDWITHIN value
• ltCFQUERY NameCustomers DATASOURCEtest
• CACHEDWITHINCreateTimeSpan(0,0,0,-1)gt
• SELECT customer_name FROM tbl_customer
• lt/CFQUERYgt

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Caching and database queries (cont)

• ltCFQUERY NameUpdateCustomer DATASOURCEtestgt
• UPDATE
• lt/CFQUERYgt
• ltCFQUERY NameCustomers DATASOURCEtest
• CACHEDWITHINCreateTimeSpan(0,0,0,-1)gt
• SELECT customer_name FROM tbl_customer
• lt/CFQUERYgt

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Advance Security Caching and CF Admin

• Security Server Policy Store Cache caches
  Advanced security information. By default, it is
  notified of administrative changes to the policy
  store once every minute. Using this cache
  provides the most noticeable performance
  improvements with Advanced security.
• Security Server Authorization Cache caches each
  unique isAuthorized call.
• ColdFusion Server Cache caches isAuthorized and
  isProtected requests.

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Advance Security Caching and CF Admin (cont.)
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Advance Security Caching and CF Admin (cont.)
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ltCFOBJECTCACHEgt

• The CFML Language Reference ommitssic a new
  ColdFusion Server 5 tag, cfobjectcache. It
  clears, or flushes, the entire query cache.
• ltcfobjectcache action"clear"gt The action
  attribute must be set to clear. No other values
  are supported.
• http//livedocs.macromedia.com/cf50docs/CFML_Refer
  ence/Tags78.jsp1102316

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Summary

• Things to consider
• Overhead
• Need for current information
• Identify candidates for caching both long
  running and frequently called queries and
  templates
• Testing to verify expected results

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• ltCFQUESTIONSgt
• ?
• lt/CFQUESTIONSgt