/*! @page tune_read_only Read-only objects

Cursors opened on checkpoints (either named, or using the special "last
checkpoint" name "WiredTigerCheckpoint") are read-only objects.  Unless
memory mapping is configured off (using the "mmap" configuration string
to ::wiredtiger_open), read-only objects are mapped into process memory
instead of being read through the WiredTiger cache.  Using read-only
objects where possible minimizes the amount of buffer cache memory
required by WiredTiger applications and the work required for buffer
cache management, as well as reducing the number of memory copies from
the operating system buffer cache into application memory.

To open a named checkpoint, use the configuration string "checkpoint"
to the WT_SESSION::open_cursor method:
@snippet ex_all.c open a named checkpoint

To open the last checkpoint taken in the object, use the configuration
string "checkpoint" with the name "WiredTigerCheckpoint" to the
WT_SESSION::open_cursor method:
@snippet ex_all.c open the default checkpoint

Reading from checkpoints is only supported on row- and column-store
objects, LSM cursors cannot be opened with a non-empty \c "checkpoint"
configuration.

 */