[CASSANDRA-17588] "Total TrueDiskSpaceUsed" computation does not include manifest and schema files

• Type: Bug
• Status: Resolved
• Priority: Normal
• Resolution: Fixed
• Component/s: Local/Snapshots
• Bug Category: Correctness
• Severity: Low
• Complexity: Normal
• Discovered By: Adhoc Test
• Platform: All
• Assignee: Stefan Miklosovic
• Reporter: Paulo Motta

Authors

Stefan Miklosovic

Reviewers

Paulo Motta

• Created: 29/Apr/22 21:25
• Updated: 24/Jul/24 15:49
• Resolved: 24/Jul/24 15:49

Description

This is the output of nodetool listsnapshots:

Snapshot Details:
Snapshot name                  Keyspace name Column family name True size Size on disk Creation time            Expiration time
test                           ks            indexed_table      1.1 KiB   21.22 KiB    2022-04-26T19:13:20.102Z
test                           ks            my_table           960 bytes 10.76 KiB    2022-04-26T19:13:20.102Z
dropped-1650997415751-my_table ks            my_table           989 bytes 989 bytes    2022-04-26T18:23:35.751Z

Total TrueDiskSpaceUsed: 0 KiB

Total TrueDiskSpaceUsed does not match the sum of "true size on disk" of all snapshots.

The reason for this is because Total TrueDiskSpaceUsed computation does not include the size of snapshot schema and manifest files.

We should fix the Total TrueDiskSpaceUsed computation to include the the size of snapshot schema and manifest files, so it will look like this:

Snapshot Details:
Snapshot name                  Keyspace name Column family name True size Size on disk Creation time            Expiration time
test                           ks            indexed_table      1.1 KiB   21.22 KiB    2022-04-26T19:13:20.102Z
test                           ks            my_table           960 bytes 10.76 KiB    2022-04-26T19:13:20.102Z
dropped-1650997415751-my_table ks            my_table           989 bytes 989 bytes    2022-04-26T18:23:35.751Z

Total TrueDiskSpaceUsed: 3 KiB

Issue Links

• is part of: CASSANDRA-18111 Centralize all snapshot operations to SnapshotManager and cache snapshots
• is related to: CASSANDRA-13338 JMX: EstimatedPartitionCount / SnapshotSize are expensive
• relates to: CASSANDRA-18111 Centralize all snapshot operations to SnapshotManager and cache snapshots
• Testing discovered: CASSANDRA-16843 List snapshots of dropped tables