6I2Berkeley DB: DbEnv::set_mp_mmapsize[P

DbEnv::set_mp_mmapsize





#include <db_cxx.h>

$void DbEnv::set_mp_mmapsize(size_t);





Description



IFiles that are opened read-only in the pool (and that satisfy a few otherHcriteria) are, by default, mapped into the process address space insteadKof being copied into the local cache. This can result in better-than-usualIperformance, as available virtual memory is normally much larger than theJlocal cache, and page faults are faster than page copying on many systems.HHowever, in the presence of limited virtual memory it can cause resourceLstarvation, and in the presence of large databases, it can result in immenseprocess sizes.

ESet the maximum file size, in bytes, for a file to be mapped into theFprocess address space. If no value is specified, it defaults to 10Mb.



Class

2DbEnv



See Also

>DbEnv::appinit,>DbEnv::appexit,>DbEnv::version,FDbEnv::get_lg_info,FDbEnv::get_lk_info,FDbEnv::get_mp_info,FDbEnv::get_tx_info,dbenv_set_data_dir,FDbEnv::set_errcall,FDbEnv::set_errfile,NDbEnv::set_error_model,PDbEnv::set_error_stream,DDbEnv::set_errpfx,DDbEnv::set_lg_max,PDbEnv::set_lk_conflicts,JDbEnv::set_lk_detect,HDbEnv::set_lk_modes,DDbEnv::set_lorder,DbEnv::set_mp_mmapsize,FDbEnv::set_mp_size,DDbEnv::set_tx_max,KDbEnv::set_tx_recoverandFDbEnv::set_verbose.
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