Performance Tuning · PostgreSQL
Index and Plan Reading for Performance
Six weeks dedicated to query plans, index design, and the careful art of measuring before you change. Bring three slow queries and leave with three fast ones.
About this cohort
This is the cohort for the operator who has read the documentation and still cannot make a particular query behave. We treat performance work as a craft of measurement: the first session is entirely about reading EXPLAIN output across PostgreSQL, MySQL, and SQL Server, and only in week two do we start changing anything. You will learn when to add a covering index and when to stop adding indexes; how to interpret latch waits and lock waits without conflating them; and how to write a small benchmark that gives the team enough confidence to deploy a change. Bring three real slow queries from your environment — anonymised — and we work them with you.
Inclusions
- Side-by-side reading of plans across PostgreSQL, MySQL, and SQL Server
- Index design clinic on your own anonymised schemas
- Microbenchmark template using pgbench, sysbench, and ostress
- Wait-statistics walkthroughs grounded in real captured traces
- Pull-request style review of every plan change you propose
- Reference cards on index types, sargability, and parameter sniffing
By the end you can
- 01 Read a query plan on three engines and explain it to a non-DBA colleague
- 02 Design and validate an index change against a representative workload
- 03 Run a small benchmark and report a result the team can act on
Programme lead
Lee Min-jae
Program Director and former platform reliability engineer. He runs the pacing of every cohort and keeps the curriculum honest about what fits in six weeks.
Common questions
From the cohort
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I spent two evenings on parameter sniffing alone and finally have language for what we were observing in production.
Ji-eunJi-eun
Senior DBA 4.8/5 · internal feedback
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Honest, careful, and unflashy. The mentor review on my second slow query identified a redundant sort I had ignored for a year.
Tae-minTae-min
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Wish I had taken this two roles ago.
Practitioner in a logistics companyPractitioner in a logistics company
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Solid material; the wait-statistics chapter felt slightly compressed, though the references compensate.
Hyun-wooHyun-woo
4.5/5