Performance service level agreements in multi-tenant database systems

A multi-tenant database system, comprising:

• a resource of hardware;
• at least one processor;
• and
• memory that comprises computer-executable instructions that, when executed by the at least one processor, cause the at least one processor to perform acts including:
• evaluating, for a workload of a tenant and disparate workloads of disparate tenants, performance degradations between actual performance metrics of the resource of the hardware and baseline performance metrics of the resource of the hardware;
• and
• allocating the resource of the hardware between the workload of the tenant and the disparate workloads of the disparate tenants based on the performance degradations for the workload of the tenant and the disparate workloads of the disparate tenants;
• wherein a performance service level agreement (SLA) for the tenant and disparate performance SLAs for the disparate tenants comprise terms that set performance criteria as though corresponding levels of the resource of the hardware are respectively dedicated for the tenant and each of the disparate tenants;
• and
• wherein the baseline performance metrics of the resource of the hardware for the workload of the tenant and the disparate workloads of the disparate tenants are based on simulations of utilizations of the levels of the resource of the hardware respectively dedicated for the tenant and each of the disparate tenants set in the performance SLA and the disparate performance SLAs for the workload of the tenant and the disparate workloads of the disparate tenants.

A computer-readable storage medium including computer-executable instructions that, when executed by a processor, cause the processor to perform acts including:

• measuring a number of pages accessed by a workload of a tenant in a multi-tenant database system;
• for each of the pages accessed by the workload of the tenant, determining whether the page is found in buffer pool memory of the multi-tenant database system, the buffer pool memory of the multi-tenant database system being shared with a concurrently executing workload of a disparate tenant;
• computing an actual hit rate as a fraction of the pages accessed by the workload of the tenant that are found in the buffer pool memory;
• simulating page replacement that would have been carried out for the workload of the tenant in dedicated buffer pool memory, the page replacement simulated based on the workload of the tenant and an amount of the dedicated buffer pool memory specified in a performance service level agreement (SLA) as being dedicated to the tenant, wherein the page replacement is simulated in a baseline buffer pool based on a page replacement policy;
• for each of the pages accessed by the workload of the tenant, determining whether the page is found in the baseline buffer pool;
• computing a baseline hit rate as a fraction of the pages accessed by the workload of the tenant that are found in the baseline buffer pool;
• comparing the actual hit rate with the baseline hit rate to evaluate a hit rate degradation;
• and
• evicting a selected page from the buffer pool memory of the multi-tenant database system based on the hit rate degradation and a penalty function specified in the performance SLA.