Fix excessive read latency during and after shard splits #11059
Merged
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Changelog entry
Fixed excessive read latency during and after some shard splits.
Changelog category
Additional information
It was observed that reads sometimes take seconds during frequent shard splits. Turns out shards replied with an
OVERLOADEDstatus even after split has already finished, which caused KQP to retry reads repeatedly with an exponential backoff, until eventually a guard condition (after multiple seconds) would cause read actor to finally re-resolve the table again. A correctNOT_FOUNDstatus (which indicates the table no longer exists) fixes this problem.Fixes #11036.