Quick Answer
Common root causes of slow queries: missing or outdated indexes, stale statistics, parameter sniffing, implicit data type conversions, non-SARGable predicates, lock blocking, memory pressure (spills), excessive recompilation, and poorly written loops or cursors instead of set-based operations.
Answer
Slow production queries usually result from:
Missing or poorly designed indexes
Incorrect cardinality estimates
High fragmentation
Outdated statistics
Parameter sniffing issues
Excessive key lookups
TempDB contention or spills
Implicit conversions
Heavy sorts/hashes causing CPU pressure
Blocking or deadlocks
Most performance issues are caused by a combination rather than a single factor.
S
SugharaIQ Editorial Team
Verified Answer
This answer has been peer-reviewed by industry experts holding senior engineering roles to ensure technical accuracy and relevance for modern interview standards.
