@hackage rolling-queue0.1

Bounded channel for STM that discards old entries when full

This package provides a FIFO channel for STM supporting a size limit. When this limit is reached, older entries are discarded to make way for newer entries.

The motivation for this is logging. If log entries are written to a plain TChan, the program will use a lot of memory if it produces log entries faster than they can be processed. If log entries are written to a bounded channel where writes block (e.g. the stm-chans package), the program may deadlock if the log channel fills up. With Data.STM.RollingQueue, old entries will be discarded instead.

Possible improvements (not available in Data.STM.RollingQueue) include:

  • Discard lower-priority entries first.

  • Discard every other entry, so some of the older entries will still be available.