[CASSANDRA-3743] Lower memory consumption used by index sampling

• Type: Improvement
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Fix Version/s: 1.1.0
• Labels: optimization
• Assignee: Radim Kolar
• Reporter: Radim Kolar

Authors

Radim Kolar

Reviewers

Yuki Morishita

• Created: 13/Jan/12 19:02
• Updated: 16/Apr/19 09:32
• Resolved: 25/Jan/12 02:18

Description

currently j.o.a.c.io.sstable.indexsummary is implemented as ArrayList of KeyPosition (RowPosition key, long offset)i propose to change it to:

RowPosition keys[]
long offsets[]

and use standard binary search on it. This will lower number of java objects used per entry from 2 (KeyPosition + RowPosition) to 1 (RowPosition).

For building these arrays convenient ArrayList class can be used and then call to .toArray() on it.

This is very important because index sampling uses a lot of memory on nodes with billions rows