[HDFS-12423] Ozone: TopN container choosing policy should ignore containers that has no pending deletion blocks

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: HDFS-7240
• Fix Version/s: HDFS-7240
• Component/s: ozone
• Labels: ozoneMerge
• Target Version/s: HDFS-7240
• Hadoop Flags: Reviewed
• Assignee: Yiqun Lin
• Reporter: Yiqun Lin
• Created: 12/Sep/17 03:16
• Updated: 26/Apr/18 21:53
• Resolved: 13/Sep/17 03:00

Description

TopN container choosing policy should ignore unnecessary containers. Currently TopN policy selects specified count of containers but not check the number of pending deletion blocks. So there is a chance there will be some unnecessary containers being chosen. That is say we will choose some containers that don't include any pending deletion blocks. The related output:

17/09/11 02:58:30 INFO impl.TopNOrderedContainerDeletionChoosingPolicy: Select container c7a85e6e-3528-45d1-8063-cd7fec114545 for block deletion, pending deletion blocks num: 1.
17/09/11 02:58:30 INFO impl.TopNOrderedContainerDeletionChoosingPolicy: Select container 1d163265-8d47-4ed3-845f-f7d3eb569b83 for block deletion, pending deletion blocks num: 0.
17/09/11 02:58:30 INFO impl.TopNOrderedContainerDeletionChoosingPolicy: Select container 21017018-be32-44e6-9f62-e7fc9f6a6021 for block deletion, pending deletion blocks num: 0.
17/09/11 02:58:30 INFO impl.TopNOrderedContainerDeletionChoosingPolicy: Select container 4cccadc8-ef5e-466d-bd9e-5b9705f8748c for block deletion, pending deletion blocks num: 0.
17/09/11 02:58:30 INFO impl.TopNOrderedContainerDeletionChoosingPolicy: Select container 55b11be9-f16f-4620-a310-07c9be3bbfee for block deletion, pending deletion blocks num: 0.

We should ignore these containers which pending deletion blocks num is 0, this can reduce some unnecessary block-deletion iterations.