The PALI handle get API allocates memory and expects the caller to free it. When WT calls PALI to get the metadata (turtle) page when picking up a checkpoint, it allocates memory in the result buffer using __wt_scr_alloc.

Since PALI overwrites the WT_ITEM->mem field, the scratch allocated memory is lost. Also, PALI zeroes the flags WT_ITEM->flags field, that marks the scratch-allocated WT_ITEM as no longer "in use", so it can be scratch allocated for other uses during the time that the same WT_ITEM filled in by PALI needs to used.

The handle get interface doc is in wiredtiger.in:

     * @param results_array an array of results allocated by the
     *        caller. Each result, up to the returned count, must be
     *        filled in by the implementation.  The implementation
     *        may allocate storage to hold results using the WT_ITEM::mem field,
     *        if that is done, the caller will call free to dispose of the memory
     *        when done.