[HIVE-24353] performance: Refactor TimestampTZ parsing

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 4.0.0-alpha-1
• Labels: pull-request-available
• Assignee: Vincenz Priesnitz
• Reporter: Vincenz Priesnitz
• Created: 03/Nov/20 19:15
• Updated: 17/Nov/22 08:48
• Resolved: 02/Feb/21 19:01

Description

I found that for datasets that contain a lot of timestamps (without timezones) hive spends the majority of time in TimestampTZUtil.parse, in particular constructing stractraces for the try-catch blocks. 

When parsing TimestampTZ we are currently using a fallback chain with several try-catch blocks. For a common timestamp string without a timezone, we currently throw and catch 2 exceptions, and actually parse the string twice. 

I propose a refactor, that parses the string once and then expresses the fallback chain with queries to the parsed TemporalAccessor. 

 

Update: I added a PR that resolves this issue: https://github.com/apache/hive/pull/1650 

 

 

Issue Links

• relates to: HIVE-24693 Convert timestamps to zoned times without string operations
• links to: GitHub Pull Request #1650