Cannot allocate memory

[ilsawa]

Emerald daemon shows this error too often on my node:

EXCEPTION: 11DbException
Db::put: Cannot allocate memory
emerald in ProcessMessages()

This error occurs after a certain time regardless of the memory available in the system. I have 26Gb of RAM and about 20Gb of free disk space.
I reloaded the blockсhain and used a new wallet.dat, but there still the same problem.