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Rework for overlay (should be checked by someone who knows this

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stuff).
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Kurt Zeilenga 2003-12-16 03:59:24 +00:00
parent 5e77767be5
commit 37465b1f3a
1 changed files with 34 additions and 49 deletions
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doc/guide/admin/proxycache.sdf
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@ -49,31 +49,35 @@ expired queries and removes them.
The Proxy Cache paper
({{URL:http://www.openldap.org/pub/kapurva/proxycaching.pdf}}) provides
design/implementation details.
design and implementation details.
H2: Proxy Cache Configuration
The cache configuration specific directives described below must
appear after the {{EX:"database meta"}} directive and before any other
{{EX:"database"}} declaration in {{slapd.conf}}(5).
appear after {{EX:overlay proxycache}} directive within a
{{EX:"database meta"}} or {{EX:database ldap}} section of
the server's {{slapd.conf}}(5) file.
H3: Setting cache parameters
> cacheparams <lo_thresh> <hi_thresh> <numattrsets> <max_entries> <cc_period>
> proxyCache <DB> <maxentries> <nattrsets> <entrylimit> <period>
The directive enables proxy caching and sets general cache parameters.
Cache replacement is invoked when the cache size crosses the
<hi_thresh> bytes and continues till the cache size is greater than
<lo_thresh> bytes. Total number of attributes sets (as specified
by the attrset directive) is given by <numattrsets>. The entry
restriction for cacheable queries is specified by <max_entries>.
Consistency check is performed every <cc_period> duration (specified
in secs). In each cycle queries with expired TTLs are removed.
The <DB> parameter specifies which underlying database is to be
used to hold cached entries. It should be set to {{EX:bdb}},
{{EX:hdb}}, or {{EX:ldbm}}. The <maxentries> parameter specifies
the total number of entries which may be held in the cache. The
<nattrsets> parameter specifies the total number of attribute sets
(as specified by the {{EX:proxyAttrSet}} directive) may be defined.
The <entrylimit> parameter specifies the maximum number of entries
in a cachable query. The <period> specifies the duration consistency
check period (in seconds). In each period, queries with expired
TTLs are removed.
H3: Defining attribute sets
> attrset <index> <attrs...>
> proxyAttrset <index> <attrs...>
Used to associate a set of attributes to an index. Each attribute
set is associated with an index number from 0 to <numattrsets>-1.
@ -82,52 +86,33 @@ cacheable templates.
H3: Specifying cacheable templates
> addtemplate <prototype_string> <attrset_index> <TTL>
> proxyTemplate <prototype_string> <attrset_index> <TTL>
Specifies a cacheable template and the "time to live" (in sec) <TTL>
for queries belonging to the template. A template is described by
its prototype filter string and set of required attributes identified
by <attrset_index>.
H3: Example
An example {{slapd.conf}}(5) for a caching server which proxies for
the backend server {{EX:ldap://server.mydomain.com}} and caches
queries with base object in the {{EX:"dc=example,dc=com"}} subtree
is described below,
An example {{slapd.conf}}(5) database section for a caching server
which proxies for the {{EX:"dc=example,dc=com"}} subtree held
at server {{EX:ldap.example.com}}.
> database meta
> database ldap
> suffix "dc=example,dc=com"
> uri ldap://server.mydomain.com/dc=example,dc=com
> cacheparams 100000 150000 1 50 100
> attrset 0 mail postaladdress telephonenumber
> addtemplate (sn=) 0 3600
> addtemplate (&(sn=)(givenName=)) 0 3600
> addtemplate (&(departmentNumber=)(secretary=*)) 0 3600
A different name space is associated with the local cache database.
E.g if the local database suffix is {{EX:"dc=example,dc=com,cn=cache"}},
then following rewriting rules need to be defined to translate
between master and cache database naming contexts.
> rewriteEngine on
> rewriteContext cacheResult
> rewriteRule "(.*)dc=example,dc=com" "%1dc=example,dc=com,cn=cache" ":"
> rewriteContext cacheBase
> rewriteRule "(.*)dc=example,dc=com" "%1dc=example,dc=com,cn=cache" ":"
> rewriteContext cacheReturn
> rewriteRule "(.*)dc=example,dc=com,cn=cache" "%1dc=example,dc=com" ":"
Finally, the local database for storing cached entries can be declared
as follows:
> database ldbm
> suffix "dc=example,dc=com,cn=cache"
> #other database specific directives
The proxy cache database instance could be either {{TERM:BDB}} or
{{TERM:LDBM}}. A script for demonstrating the proxy cache
({{FILE:test019-proxycaching}}) functionality is provided in the
tests/scripts directory of the distribution.
> uri ldap://ldap.example.com/dc=example,dc=com
> overlay proxycache
> proxycache bdb 100000 1 1000 100
> proxyAttrset 0 mail postaladdress telephonenumber
> proxyTemplate (sn=) 0 3600
> proxyTemplate (&(sn=)(givenName=)) 0 3600
> proxyTemplate (&(departmentNumber=)(secretary=*)) 0 3600
>
> cachesize 20
> directory ./testrun/db.2.a
> index objectClass eq
> index cn,sn,uid,mail pres,eq,sub