[HADOOP-17038] Support disabling buffered reads in ABFS positional reads

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.3.1, 3.4.0
• Fix Version/s: 3.3.1, 3.4.0
• Component/s: fs/azure
• Labels: HBase abfsactive pull-request-available
• Target Version/s: 3.3.1, 3.4.0
• Hadoop Flags: Reviewed
• Assignee: Anoop Sam John
• Reporter: Anoop Sam John
• Created: 12/May/20 19:00
• Updated: 12/Feb/24 01:18
• Resolved: 16/Feb/21 17:00

Description

Right now it will do a seek to the position , read and then seek back to the old position. (As per the impl in the super class)
In HBase kind of workloads we rely mostly on short preads. (like 64 KB size by default). So would be ideal to support a pure pos read API which will not even keep the data in a buffer but will only read the required data as what is asked for by the caller. (Not reading ahead more data as per the read size config)

Allow an optional boolean config to be specified while opening file for read using which buffered pread can be disabled.
FutureDataInputStreamBuilder openFile(Path path)

Issue Links

• is related to: HADOOP-16202 Enhance openFile() for better read performance against object stores
• links to: GitHub Pull Request #2206
• links to: GitHub Pull Request #2382
• links to: GitHub Pull Request #2646