5.3.2 Buffer Cache and Prefetching

The messages that are read are kept in the cache buffer so as to make the behavior fast when you are to read the message again. It is called `buffer cache'. The number of cache buffer is specified by wl-message-buffer-cache-size.

There are message prefetching mechanism in the Wanderlust that prefetches next message while you are reading.

You can control the message prefetching mechanism by these two variables.

wl-message-buffer-prefetch-folder-type-list

The initial setting is '(imap4 nntp). If it is a list of folder types, it specifies the folder types in which message prefetching is enabled. In initial setting, messages are prefetch only in the nntp and imap4 folders. In this case, multi folder that contains localdir and imap4 prefetches only imap4 messages. This variable precedes the value of wl-message-buffer-prefetch-folder-list. To prefetch messages in all folder types, specify t.

wl-message-buffer-prefetch-folder-list

The initial setting is nil. A list of regexp of folders to enable message prefetching.

wl-message-buffer-prefetch-depth

The initial setting is 1. The number of messages for automatical prefetch.

wl-message-buffer-prefetch-idle-time

The initial setting is 1 (in seconds). The period of automatical prefetch.

wl-message-buffer-prefetch-threshold

The initial setting is 30000 (bytes). If prefetching message has larger size than this value, Wanderlust does not prefetch automatically. If wl-message-buffer-prefetch-threshold is nil, the message is not checked for the size.

wl-auto-prefetch-first

The initial setting is nil. If non-nil, first message is automatically prefetched to the buffer when you enter the folder.