[Koha] mysql not stable keeps changing on new day.

Hello all, pls kindly help. I noticed that the database in one of my koha installations keeps changing. Once the day change to the following day some operations on koha will disappear and at other time it will appear. I checked the date of the system it was correct, but cant still figure it out why database keeps changing. This affect the charging out and returning library items and fines.I use koha 3.22.04 on Debian 8 OS pls what is the likely reasons and solutions. can it be virus? harddish or RAM.  When i checked the log viewer, the whole day or two days operations are not reflecting at all and some other time it will show. thanksakin