[OAK-6912] Cold standby performance regression due to segment caching

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.7.0
• Fix Version/s: 1.7.12, 1.8.0
• Component/s: segment-tar, tarmk-standby
• Labels: cold-standby performance scalability
• Assignee: Andrei Dulceanu
• Reporter: Andrei Dulceanu
• Created: 07/Nov/17 11:47
• Updated: 08/Dec/17 14:23
• Resolved: 14/Nov/17 14:43

Description

The changes to the segment cache introduced in r1793527 [0] introduced a performance regression on the primary for the case in which a standby is attached to it. Below a benchmark duration comparison between primary w/o and w/ standby for r1793527 (after the segment cache changes) and r1793526 (before the changes) :

Oak 1.6 r1793527 (20170502)	# BasicWriteTest C min 10% 50% 90% max N Oak-Segment-Tar 1 19 21 22 26 160 2491 Oak-Segment-Tar-DS 1 56 59 63 70 181 919 Oak-Segment-Tar-Cold(Shared DS) 1 58 66 159 177 372 302
Oak 1.6 r1793526 (20170502)	# BasicWriteTest C min 10% 50% 90% max N Oak-Segment-Tar 1 19 21 22 25 52 2584 Oak-Segment-Tar-DS 1 56 60 63 69 158 925 Oak-Segment-Tar-Cold(Shared DS) 1 57 60 64 70 122 915

[0] https://github.com/apache/jackrabbit-oak/commit/efafa4e1710621b7f3b8e92d0b2681669185fcd4

Issue Links

• is blocked by: OAK-6915 Minimize the amount of uncached segment reads