[HDFS-11921] Ozone: KSM: Unable to put keys with zero length

• Type: Sub-task
• Status: Resolved
• Priority: Minor
• Resolution: Not A Problem
• Affects Version/s: HDFS-7240
• Component/s: ozone
• Labels: OzonePostMerge
• Target Version/s: HDFS-7240
• Assignee: Mukul Kumar Singh
• Reporter: Anu Engineer
• Created: 02/Jun/17 18:35
• Updated: 12/Sep/17 16:22
• Resolved: 12/Sep/17 16:22

Description

As part of working on HDFS-11909, I was trying to put zero length keys. I found that put key refuses to do that. Here is the call trace,

at ScmBlockLocationProtocolClientSideTranslatorPB.allocateBlock

we check if the block size is greater than 0, which makes sense since we should not call into SCM to allocate a block of zero size.

However these 2 calls are invoked for creating the key, so that metadata for key can be created, we should probably take care of this behavior here.

ksm.KeyManagerImpl.allocateKey

ksm.KeySpaceManager.allocateKey(KeySpaceManager.java:428)

Another way to fix this might be to just allocate a block with at least 1 byte always, which might be easier than special casing code.

vagarychen Would you like to fix this in the next patch you are working on ?