Blocking / deadlock recoveryApparel e-commerce brand, anonymized × red9CS-0668
Brought a high-load ERP server back to steady after a March blow-up, deadlocks down by half and errors 48% lighter
The problem. An apparel and e-commerce company carried a rough March incident into the spring with its ERP production server still unsettled. Deadlocks kept piling onto the box, the error log would not quiet down, and scheduled jobs were failing, a bad spot for a high-load server to sit with a busy retail stretch ahead.
What we did. We ran the recovery by hand: chased the deadlock chains back to the queries and lock ordering feeding them, reworked the worst of those paths, and stood up monitoring to catch the next surge while it is still small. Deadlock counts and error volume were captured before the work began and again once it wrapped.
Red9 · Performance Impact
SQL errors down
48% lower
On the high-load ERP production server after the March incident.
Deadlocks
Halved
Cut to roughly half once the hot paths were reworked.
March incident
closed out
Worked to a finish, with monitoring left running behind it.
SQL errors
48% lower
steadier
Deadlocks
~50% fewer
halved
Monitoring
Standing
early warning
SQL error volume
high-load ERP box
How the figures were taken. The 48% tracks the reduction in logged SQL errors from the first day of the engagement to the last, while the deadlock figure is that same count pulled down to roughly half over the stretch. Each one comes straight from the box's own before-and-after telemetry.
The result. The ERP server settled back down: deadlocks roughly halved, logged errors 48% lighter, and the March incident finally closed, with monitoring now watching for the next spike so a surge surfaces before orders start backing up.
The technical detail
What we uncovered. A handful of hot queries on the ERP database were taking their locks in an order that let concurrent sessions collide as soon as load climbed, so one busy stretch tipped the box into a run of deadlocks and a rising error count.
What we changed (identifiers generalized for privacy):
-- Reworked the hot ERP queries and their indexes so sessions take and
-- release locks fast, breaking the deadlock chains that formed under load.
CREATE NONCLUSTERED INDEX IX_erp_txn_covering
ON dbo.[erp_transaction] (/* filter cols */) INCLUDE (/* output cols */);
-- deadlock capture and alerting left in place; rollback scripts provided
With those paths reworked and lock time trimmed, deadlocks came down by roughly half and logged errors fell 48%, and the alerting now trips on a surge well before it grows into another incident.
