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Heap cache-hit ratio under 0.90 on a hot table
Part of the Schema & indexes check · fix arrives as a guide
What it is
A frequently-accessed table has a heap cache-hit ratio below 0.90, so more than a tenth of its reads come from disk.
Why it matters
Disk reads are orders of magnitude slower than cache hits, so a hot table missing cache this often sets the floor for every query touching it. It normally means the working set has outgrown the available memory.
How to fix it
Check whether the queries are reading more than they need — a missing index causing a scan pulls the whole table through cache and evicts everything else. If the access pattern is already tight, the instance needs more memory.
Run them all on your app
Connect your repo and your live services with read-only scopes. The first scan is free, and nothing changes without your approval.