Fair prefetching in hybrid column stores

A system, comprising:

• a memory;
• and
• at least one processor coupled to the memory and configured to:
• split a data vector associated with a column of a database table into a first subrange and a second subrange in response to a query;
• perform a first chance prefetch operation on the first subrange based on a first number of rows to prefetch for the first subrange, wherein the first number of rows to prefetch for the first subrange is calculated based on a fixed number of pages, and wherein the performing the first chance prefetch operation on the first subrange loads a first set of pages of the first subrange into the memory;
• perform the first chance prefetch operation on the second subrange based on a second number of rows to prefetch for the second subrange, wherein the second number of rows to prefetch for the second subrange is calculated based on the fixed number of pages, and wherein the performing the first chance prefetch operation on the second subrange loads a second set of pages of the second subrange into the memory;
• perform a second chance prefetch operation on the second subrange based on the performing the first chance prefetch operation on the second subrange, thereby loading a second set of pages of the third subrange into the memory;
• and
• execute the query based on the first set of pages of the first subrange, the second set of pages of the second subrange, and the third set of pages of the second subrange.

A non-transitory computer-readable medium having instructions stored thereon that, when executed by at least one computing device, cause the at least one computing device to perform operations comprising:

• splitting a data vector associated with a column of a database table into a first subrange and a second subrange in response to a query;
• performing a first chance prefetch operation on the first subrange based on a first number of rows to prefetch for the first subrange, wherein the first number of rows to prefetch for the first subrange is calculated based on a fixed number of pages, and wherein the performing the first chance prefetch operation on the first subrange loads a first set of pages of the first subrange into a main memory;
• performing the first chance prefetch operation on the second subrange based on a second number of rows to prefetch for the second subrange, wherein the second number of rows to prefetch for the second subrange is calculated based on the fixed number of pages, and wherein the performing the first chance prefetch operation on the second subrange loads a a second set of pages of the second subrange into the main memory;
• performing a second chance prefetch operation on the second subrange based on the performing the first chance prefetch operation on the second subrange, thereby loading a second set of pages of the third subrange into the main memory;
• and
• executing the query based on the first set of pages of the first subrange, the second set of pages of the second subrange, and the third set of pages of the second subrange.