mdbx: add auto-readahead note/description.

Change-Id: Ie425416fd1afe9092b73acae4a7e3cdb5c3d8168
This commit is contained in:
Leonid Yuriev 2019-11-09 00:05:30 +03:00
parent 4dfa97cda9
commit bb2d2877c4

6
mdbx.h
View File

@ -973,6 +973,12 @@ LIBMDBX_API const char *mdbx_dump_val(const MDBX_val *key, char *const buf,
* may help random read performance when the DB is larger than RAM and system
* RAM is full.
*
* By default libmdbx dynamically enables/disables readahead depending on the
* actual database size and currently available memory. On the other hand, such
* automation has some limitation, i.e. could be performed only when DB size
* changing but can't tracks and reacts changing a free RAM availability, since
* it changes independently and asynchronously.
*
* NOTE: The mdbx_is_readahead_reasonable() function allows to quickly find out
* whether to use readahead or not based on the size of the data and the
* amount of available memory.