[ACCUMULO-2837] Scanning empty table can be optimized

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 1.6.0
• Labels: performance
• Assignee: Keith Turner
• Reporter: Keith Turner
• Created: 23/May/14 16:00
• Updated: 23/Apr/19 15:43
• Resolved: 23/Apr/19 15:43

Description

I wrote an application that repeatedly scanned random rows in an empty table at one point. It did not know the table was empty. I was jstacking the tserver and repeatedly saw stack traces in a few places in the code.

• the audit canScan method
• DefaultConfiguration.get
• Kept seeing Password token ungziping the password??????

After fixing all of these issues (except for system token) I ran a simple test I saw times go from ~1.7s to ~1.3s for a simple test I wrote to recreate this issue.

I am not sure how much of an impact the gziping the password has. I was just sampling the stack traces manually. I seems like I saw the password token gzip stack traces less frequently, but I did catch it multiple jstack calls.

Sub-Tasks

• Use resolved props in DefaultConfiguration.get(): Resolved
• AuditedSecurityOperation canScan is very slow even when not logging: Resolved
• Auditing is not disabled by default in MAC: Resolved