[CASSANDRA-9786] Our index file seeks can be directed to the page most likely to contain the record, and read exactly one page

• Type: Improvement
• Status: Open
• Priority: Normal
• Resolution: Unresolved
• Fix Version/s: 5.x
• Component/s: Legacy/Local Write-Read Paths
• Labels: performance
• Assignee: Unassigned
• Reporter: Benedict Elliott Smith
• Created: 13/Jul/15 09:27
• Updated: 07/Mar/23 10:54

Description

(Perhaps two, if it is likely to cross a page boundary).

This only works if the partitioner is hash based, but if so we can expect the keys to be uniformly distributed, so we can easily calculate the likelihood of finding it on a given page. With CASSANDRA-8931, we can also expect the data to be of a uniform size.

This will require a little bit of index file restructuring, so that each page can be read as a single unit. A follow-up ticket may then permit in-memory binary search within the page for the desired record (with variable key sizes this may be difficult, so perhaps a follow-up).

Issue Links

• is related to: CASSANDRA-8931 IndexSummary (and Index) should store the token, and the minimal key to unambiguously direct a query
• is related to: CASSANDRA-8894 Our default buffer size for (uncompressed) buffered reads should be smaller, and based on the expected record size