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Question 1 of 20
5%
Query Writing
hard
EXPLAIN ANALYZE on a query filtering by email on a 10M-row users table shows a Seq Scan despite an index existing on the email column. What is the most likely root cause?
A
The email column exceeds PostgreSQL's maximum index entry size of 2704 bytes, so the index was silently skipped
B
The query uses ILIKE or LIKE with a leading wildcard such as LIKE '%domain.com', which cannot use a B-tree index
C
The column statistics are stale; running ANALYZE will force the planner to choose the index
D
The planner estimated many rows match, making a sequential scan cheaper than random index access
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