Sizing the Buffer Cache

Data skew and access patterns vary considerably between workloads, making it difficult to predict caching behavior. Consequently, sizing buffer caches is a challenging exercise. As a simple rule of thumb, some people suggest sizing the buffer cache as a proportion of the size of the database. I have read recommendations ranging from 1% to 20% of total database size; the variation in these recommendations highlights the degree of difficulty involved in such a sizing.

Some time ago, Performance and Availability Engineering conducted a study to better understand the relationship between cache sizes and hit rates and the impact of both on performance. As we will see, the optimal buffer cache size was between 10% and 15% of ...

Get Configuring and Tuning Databases on the Solaris™ Platform now with the O’Reilly learning platform.

O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.