Apache Module mod_mem_cache

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Description:	Content cache keyed to URIs
Status:	Experimental
Module Identifier:	mem_cache_module
Source File:	mod_mem_cache.c

Summary

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- This module is experimental. Documentation is still under - development... -

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This module requires the service of mod_cache. It acts as a support module for mod_cache and provides a memory based storage manager. - mod_mem_cache can be configured to operate in two - modes: caching open file descriptors or caching objects in heap storage. - mod_mem_cache is most useful when used to cache locally - generated content or to cache backend server content for mod_proxy configured for ProxyPass (aka reverse proxy).

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Content is stored in and retrieved from the cache using URI based - keys. Content with access protection is not cached.

MCacheMaxObjectCount Directive

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Description:	The maximum number of objects allowed to be placed in the -cache
Syntax:	`MCacheMaxObjectCount value`
Default:	`MCacheMaxObjectCount 1009`
Context:	server config
Status:	Experimental
Module:	mod_mem_cache

The MCacheMaxObjectCount directive sets the - maximum number of objects to be cached. The value is used to create the - open hash table. If a new object needs to be inserted in the cache and - the maximum number of objects has been reached, an object will be - removed to allow the new object to be cached. The object to be removed - is selected using the algorithm specified by MCacheRemovalAlgorithm.

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Example

- MCacheMaxObjectCount 13001 -

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MCacheMaxObjectSize Directive

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Description:	The maximum size (in bytes) of a document allowed in the -cache
Syntax:	`MCacheMaxObjectSize bytes`
Default:	`MCacheMaxObjectSize 10000`
Context:	server config
Status:	Experimental
Module:	mod_mem_cache

The MCacheMaxObjectSize directive sets the - maximum allowable size, in bytes, of a document for it to be considered - cacheable.

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Example

- MCacheMaxObjectSize 6400000 -

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Note

The value of MCacheMaxObjectSize must be - greater than the value specified by the MCacheMinObjectSize directive.

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MCacheMaxStreamingBuffer Directive

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Description:	Maximum amount of a streamed response to buffer in memory -before declaring the response uncacheable
Syntax:	`MCacheMaxStreamingBuffer size_in_bytes`
Default:	`MCacheMaxStreamingBuffer the smaller of 100000 or MCacheMaxObjectSize`
Context:	server config
Status:	Experimental
Module:	mod_mem_cache

The MCacheMaxStreamingBuffer directive - specifies the maximum number of bytes of a streamed response to - buffer before deciding that the response is too big to cache. - A streamed response is one in which the entire content is not - immediately available and in which the Content-Length - may not be known. Sources of streaming responses include proxied - responses and the output of CGI scripts. By default, a streamed - response will not be cached unless it has a - Content-Length header. The reason for this is to - avoid using a large amount of memory to buffer a partial response - that might end up being too large to fit in the cache. - The MCacheMaxStreamingBuffer directive allows - buffering of streamed responses that don't contain a - Content-Length up to the specified maximum amount of - space. If the maximum buffer space is reached, the buffered - content is discarded and the attempt to cache is abandoned.

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Note:

Using a nonzero value for MCacheMaxStreamingBuffer - will not delay the transmission of the response to the client. - As soon as mod_mem_cache copies a block of streamed - content into a buffer, it sends the block on to the next output - filter for delivery to the client.

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- # Enable caching of streamed responses up to 64KB: - MCacheMaxStreamingBuffer 65536 -

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MCacheMinObjectSize Directive

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Description:	The minimum size (in bytes) of a document to be allowed in the -cache
Syntax:	`MCacheMinObjectSize bytes`
Default:	`MCacheMinObjectSize 0`
Context:	server config
Status:	Experimental
Module:	mod_mem_cache

The MCacheMinObjectSize directive sets the - minimum size in bytes of a document for it to be considered - cacheable.

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Example

- MCacheMinObjectSize 10000 -

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MCacheRemovalAlgorithm Directive

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Description:	The algorithm used to select documents for removal from the -cache
Syntax:	`MCacheRemovalAlgorithm LRU\|GDSF`
Default:	`MCacheRemovalAlgorithm GDSF`
Context:	server config
Status:	Experimental
Module:	mod_mem_cache

The MCacheRemovalAlgorithm directive specifies - the algorithm used to select documents for removal from the cache. - Two choices are available:

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LRU (Least Recently Used): LRU removes the documents that have not been accessed - for the longest time.
GDSF (GreadyDual-Size): GDSF assigns a priority to cached documents based - on the cost of a cache miss and the size of the document. Documents - with the lowest priority are removed first.

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Example

- MCacheRemovalAlgorithm GDSF - MCacheRemovalAlgorithm LRU -

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MCacheSize Directive

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Description:	The maximum amount of memory used by the cache in -KBytes
Syntax:	`MCacheSize KBytes`
Default:	`MCacheSize 100`
Context:	server config
Status:	Experimental
Module:	mod_mem_cache

The MCacheSize directive sets the maximum - amount of memory to be used by the cache, in KBytes (1024-byte units). - If a new object needs to be inserted in the cache and the size of the - object is greater than the remaining memory, objects will be removed - until the new object can be cached. The object to be removed is - selected using the algorithm specified by MCacheRemovalAlgorithm.

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Example

- MCacheSize 700000 -

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Note

The MCacheSize value must be greater than - the value specified by the MCacheMaxObjectSize directive.

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Apache Module mod_mem_cache

Summary

Directives

See also

MCacheMaxObjectCount Directive

Example

MCacheMaxObjectSize Directive

Example

Note

MCacheMaxStreamingBuffer Directive

Note:

MCacheMinObjectSize Directive

Example

MCacheRemovalAlgorithm Directive

Example

MCacheSize Directive

Example

Note