[HUDI-2923] Unable to read from metadata table when a compaction is in progress or has failed

• Type: Bug
• Status: Closed
• Priority: Blocker
• Resolution: Fixed
• Fix Version/s: 0.10.0
• Component/s: compaction, table-service
• Labels: pull-request-available
• Assignee: Prashant Wason
• Reporter: Prashant Wason
• Created: 03/Dec/21 03:44
• Updated: 29/Mar/24 01:25
• Resolved: 29/Mar/24 01:25

Description

When reading from metadata table, the readers are opened with the latest file slices 

When a compaction is in progress, the latest file slice does not have any base-file or log file (yet). Hence we are unable to read data from the metadata table. 

 

There are two cases here:

1. Compaction eventually completes: We will be able to read data from the metadata table.
2. Compaction fails: We will not be able to read data unless the next time compaction runs. This can be a fatal issue if the next writer tries to perform an update which requires listing partition from the metadata table.

 

Relevant logs from a unit test:

 

13084 [main] INFO  org.apache.hudi.common.table.view.AbstractTableFileSystemView  - Pending Compaction instant for (FileSlice {fileGroupId=HoodieFileGroupId

{partitionPath='files', fileId='2733a6ef-4bfd-444d-91bd-b42c3b66a84e-0'}, baseCommitTime=002001, baseFile='null', logFiles='[]'}) is :Option{val=(002001,CompactionOperation{baseInstantTime='001', dataFileCommitTime=Option{val=001}, deltaFileNames=[.2733a6ef-4bfd-444d-91bd-b42c3b66a84e-0_001.log.1_0-34-36], dataFileName=Option{val=2733a6ef-4bfd-444d-91bd-b42c3b66a84e-0_0-16-20_001.hfile}, id='HoodieFileGroupId{partitionPath='files', fileId='2733a6ef-4bfd-444d-91bd-b42c3b66a84e-0'}', metrics={}, bootstrapFilePath=Optional.empty})}

13084 [main] INFO  org.apache.hudi.common.table.view.AbstractTableFileSystemView  - File Slice (FileSlice {fileGroupId=HoodieFileGroupId{partitionPath='files', fileId='2733a6ef-4bfd-444d-91bd-b42c3b66a84e-0'}

, baseCommitTime=002001, baseFile='null', logFiles='[]'}) is in pending compaction

 

13089 [main] INFO  org.apache.hudi.common.table.log.HoodieMergedLogRecordScanner  - Number of log files scanned => 0
13089 [main] INFO  org.apache.hudi.common.table.log.HoodieMergedLogRecordScanner  - MaxMemoryInBytes allowed for compaction => 0
13089 [main] INFO  org.apache.hudi.common.table.log.HoodieMergedLogRecordScanner  - Number of entries in MemoryBasedMap in ExternalSpillableMap => 0
13089 [main] INFO  org.apache.hudi.common.table.log.HoodieMergedLogRecordScanner  - Total size in bytes of MemoryBasedMap in ExternalSpillableMap => 0
13089 [main] INFO  org.apache.hudi.common.table.log.HoodieMergedLogRecordScanner  - Number of entries in DiskBasedMap in ExternalSpillableMap => 0
13089 [main] INFO  org.apache.hudi.common.table.log.HoodieMergedLogRecordScanner  - Size of file spilled to disk => 0
13089 [main] INFO  org.apache.hudi.metadata.HoodieBackedTableMetadata  - Opened metadata log files from [] at instant (dataset instant=002, metadata instant=002) in 2 ms
13089 [main] INFO  org.apache.hudi.metadata.HoodieBackedTableMetadata  - Metadata read for key _all_partitions_ took [baseFileRead, logMerge] [0, 0] ms
13090 [main] INFO  org.apache.hudi.metadata.BaseTableMetadata  - Listed partitions from metadata: #partitions=0

Issue Links

• links to: GitHub Pull Request #4206