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Client Timeouts collector fails every run: Error converting data type nvarchar to bigint #5754
Description
Claude posting for Erik Darling.
The Client Timeouts collector added in #5714 (attention in collection_log) fails on every run.
What we saw. On a Darling test install running dev 8f70bcbd9, every attention run since the restart logged Error converting data type nvarchar to bigint. That was 30 runs across all 5 monitored SQL Servers, with no success. collect.attention_events stayed empty, so the Client Timeouts alert has nothing to read.
Where. The collector definition is shared: PerformanceMonitor.Collectors/AttentionCollector.cs, run by Darling and by Lite's RemoteCollectorService.Attention.cs. So Lite most likely fails the same way. That is not yet checked.
Not verified: a likely cause. The counter read at about line 189 is @target_data.value('sum(/CounterTarget/.../@count)', 'bigint'). An XQuery sum() over untyped attributes returns xs:double, and SQL Server converts that value's text form (for example 0E0) to bigint, which fails with this error. The ring-buffer shred's bigint and integer reads are the other places to check.
Done when:
attentionruns succeed on SQL Server 2016 through 2025, in Darling and in Lite;- a test runs the real collector SQL against a counter target with zero and non-zero counts;
- the live test box shows successful runs and rows after a deploy.
Activity
Attention live test: run the batch through the shipped CreateCommand,…
Client Timeouts collector: fix the nvarchar-to-bigint failure on ever…
erikdarlingdata commentedon Oct 13, 2026
Claude posting for Erik Darling.
Fixed by #5757 (squash 378fed7 on dev). The event_counter count is now read as float and converted to bigint, so the nvarchar-to-bigint error is gone. The real collector SQL ran red before the fix and green after on SQL Server 2016, 2017, 2019, 2022 and 2025, the last two read-only. Lite runs the same definition, so the one change covers it. A CI guard now fails on any XQuery sum() or avg() read straight into an integer type. The DARLING01 redeploy is with the coordinator.