[HUDI-5348] Cache file slices in HoodieBackedTableMetadata

[yihua]

Change Logs

As of now, we only cache the log file reader inside HoodieBackedTableMetadata. Each time the metadata table is looked up with getRecordByKey or getRecordsByKeyPrefixes in HoodieBackedTableMetadata, the corresponding MT partition is listed through HoodieTableMetadataUtil.getPartitionLatestMergedFileSlices because a file system view is constructed each time. This causes repeated FS list calls on MT partitions and increases the latency for reading metadata table and listing files for data table, affecting Presto query latency for example (sample S3 access log from Presto below for listing files partition in MT).

2022-11-24T22:06:43.009Z	INFO	hive-hive-2	org.apache.hudi.common.table.view.AbstractTableFileSystemView	Building file system view for partition (files)
2022-11-24T22:06:43.009Z	DEBUG	hive-hive-2	com.amazonaws.request	Sending Request: GET https://<redacted>.s3.us-east-2.amazonaws.com / Parameters: ({"prefix":["<redacted>/store_sales/.hoodie/metadata/files/"],"delimiter":["/"],"encoding-type":["url"]}Headers: (amz-sdk-invocation-id: 9e963ae0-f2e4-738e-691f-073c5a43264d, Content-Type: application/octet-stream, User-Agent: , aws-sdk-java/1.11.697 Linux/5.4.219-126.411.amzn2.x86_64 OpenJDK_64-Bit_Server_VM/25.342-b07 java/1.8.0_342 vendor/Oracle_Corporation, presto, ) 
2022-11-24T22:06:43.022Z	DEBUG	hive-hive-2	com.amazonaws.request	Received successful response: 200, AWS Request ID: Y4KHZHYVG7SSB0J4

This PR makes the changes to cache the file system view of the metadata table and thus the latest file slices at the partition level for metadata table inside HoodieBackedTableMetadata to avoid FS list calls.

Impact

This PR avoids repeated file listing on the metadata table and thus reduces the latency for reading metadata table. This reduces the latency of the overall metadata-table-based file listing and thus improves the query performance.

Risk level

low

Documentation Update

N/A

Contributor's checklist

• Read through contributor's guide
• Change Logs and Impact were stated clearly
• Adequate tests were added if applicable
• CI passed

[hudi-bot]

CI report:

• 96b2aff Azure: SUCCESS

Bot commands

@hudi-bot supports the following commands:

• @hudi-bot run azure re-run the last Azure build

[nsivabalan]

I am thinking we can cache the file slices also similar to how we cache the file readers. I don't see a reason for file slices to change unless there is a change in timeline on which case entire FileSystemView will be refreshed.

[nsivabalan]

looks like the FileSystemView (MDFSV) caches the entities and so we are good.