ISSUE WITH WORDPRESS - Site Crashing Constantly

ISSUE WITH WORDPRESS - I currently run a jobs board WordPress website with 1000 jobs posted on a monthly basis. Our current volume of users is 90,000 sessions per week and on average we have 200 users on the site at peak times between the hours of 4pm & 11pm. On a regular basis, the site crashes with database issues and needs a full restart of MySQL services to bring the system back up and re-establish a connection between WordPress and database. The database is Mariadb and running on Centos 7 x64 VPS. Rented by OVH. The database currently shows traffic of on average of 30GB an hour at peak time’s which is stressing and collapsing the database which causes the site to lose connection. We do not deliver any media content and most the jobs are redirects to other websites so the possibilities of clients loading 30GB of data an hour is slim. We think the issue is with the coding of the WordPress itself sending constant queries through the database and causing so much traffic. We are looking for someone to track down this issue and make the changes to stop this running so heavy which in time should maximize delivery of our website and shrink the current downtime.