Under 8.1, each working set of buffers protected by the same LRU latch is divided into a hot and cold "half". Blocks are introduced into the MRU end of the cold part of the cache, and age down from there if not touched again. Therefore the effective cache size threshold under 8.1 for a table with the CACHE attribute enabled is the number of buffer in the cold half of its buffer pool. That is set by the _db_percent_hot_default, _db_percent_hot_keep and _db_percent_hot_recycle parameters (which default to 50) in conjunction with the corresponding buffer pool parameters.

Could you explain please the behaviour of cache_size_threshold for 8i? I've read documtentation, it says the parameter obsoleted in 8.1.3, but I can still set CACHE attribute for tables. Is my current understanding correct that now cache_size_threshold has implicit hard setting 10% of db_block_buffers and there is no any way to change it?