db: add regression test for RemoteTablesTotal underflow#5878
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annrpom merged 1 commit intocockroachdb:masterfrom Apr 6, 2026
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Add a regression test verifying that RemoteTablesTotal() returns zero on a local-only DB with virtual sstables. Previously, RemoteTablesTotal() computed remote tables as (total - local) using inconsistent size accounting: totals used virtual table sizes while locals used physical backing sizes. When virtual sstables existed (e.g., from excise during Raft snapshot application), backing sizes could exceed virtual sizes, causing a uint64 underflow. CockroachDB then cast this to int64 for its gauge metric, producing large negative values for storage.sstable.remote.bytes. The underlying bug was fixed in 951fae6 (metrics: redesign disk usage metrics), which rewrote RemoteTablesTotal() to directly sum shared and external placement stats instead of subtracting local from total. Co-Authored-By: roachdev-claude <roachdev-claude-bot@cockroachlabs.com>
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Reviewable status: 0 of 1 files reviewed, all discussions resolved (waiting on xxmplus).
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Add a regression test verifying that RemoteTablesTotal() returns zero on a local-only DB with virtual sstables.
Previously, RemoteTablesTotal() computed remote tables as (total - local) using inconsistent size accounting: totals used virtual table sizes while locals used physical backing sizes. When virtual sstables existed (e.g., from excise during Raft snapshot application), backing sizes could exceed virtual sizes, causing a uint64 underflow. CockroachDB then cast this to int64 for its gauge metric, producing large negative values for storage.sstable.remote.bytes.
The underlying bug was fixed in 951fae6 (metrics: redesign disk usage metrics), which rewrote RemoteTablesTotal() to directly sum shared and external placement stats instead of subtracting local from total.