[ACCUMULO-3033] SiteConfiguration gets invoked frequently and scans all configuration items

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Cannot Reproduce
• Affects Version/s: 1.5.0, 1.5.1, 1.6.0
• Assignee: Josh Elser
• Reporter: Josh Elser
• Created: 31/Jul/14 15:36
• Updated: 23/Apr/19 21:16
• Resolved: 23/Apr/19 21:16

Description

I noticed yesterday that SiteConfiguration#getProperties(Map, PropertyFilter) is invoked very frequently (at least 30 times a second on my single machine) to extract the Iterator configurations before a table scan happens. Printing a stack trace shows that this is the dominating caller of getProperties is IteratorUtil#parseIterConf().

What this translates to is repeatedly reading, filtering and adding the same elements to a map to satisfy the AccumuloConfiguration#getPropertiesWithPrefix from an immutable source (accumulo-site.xml). While this is probably not a huge time waste in terms of actual time spent, it's repeatedly happening and will slow things down (especially when the underlying Hadoop Configuration is creating a new HashMap with the contents of the accumulo-site.xml for every call).

Need to think about some options for making the "extract keys with this prefix" case faster from SiteConfiguration.

Issue Links

• relates to: ACCUMULO-2838 Use resolved props in DefaultConfiguration.get()
• relates to: ACCUMULO-4041 Java reflection eats too much CPU