Statistics on a boolean function
lab.small(y) is true for 1 percent of 10000 rows. Without statistics the planner guesses 1/3 of the table.
task
Create expression statistics on lab.small(y), ANALYZE, and bring the estimate below 1000 rows.
Play
lessons
aggregates
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btree
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- [ ] b tree meta page
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- [ ] brin ranges
- [ ] gin pending list
- [ ] index only scans and heap fetches
- [ ] is not distinct from reaches the index
- [ ] physical correlation
- [ ] random inserts leave leaf pages loose
- [ ] skip scan on a b tree
- [ ] walk the root page
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m1-catalogs
- [ ] boss one row about a table
- [ ] clear one extended statistics object
- [ ] clear statistics of a missing table
- [ ] column layout in pg attribute
- [ ] count your table s forks
- [ ] extended statistics on virtual generated columns
- [ ] pg stats knows the table oid
- [ ] statistics on a boolean function
- [ ] the index behind a primary key
- [ ] what pg class says about a table
m2-heap-pages
m3-mvcc
m4-vacuum
- [ ] a fresh file after repack
- [ ] a partitioned table needs an index name
- [ ] a read sets all visible without vacuum
- [ ] boss one vacuum cycle
- [ ] dead item memory in vacuum verbose
- [ ] line pointers across delete and vacuum
- [ ] relfrozenxid advances
- [ ] repack concurrently
- [ ] repack using index orders the heap
- [ ] the visibility map after vacuum
- [ ] vacuum full gives the space back
- [ ] which table would autovacuum pick
m5-hot
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null
p10-partitioning
p11-rls-roles
p8-functions-triggers
p9-views
planner
- [ ] an impossible predicate
- [ ] coalesce stops at the first not null argument
- [ ] incremental sort under append
- [ ] is not distinct from reaches the index
- [ ] is null on any not null column of the inner side
- [ ] memoize under an anti join
- [ ] read stream counters in explain io
- [ ] read the memoize estimate
- [ ] turn eager aggregation off
ranges
schema-design
sequences-identity-uuid
set-operations
statistics
subqueries
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wal
what-changed-in-19
- [ ] aggregate support clause
- [ ] base64url token
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- [ ] check not enforced promote
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- [ ] copy header n
- [ ] copy json header error
- [ ] copy multiline header out
- [ ] copy partitioned roundtrip
- [ ] copy set null
- [ ] distinct from null folding
- [ ] eager aggregate
- [ ] grant granted by
- [ ] group subquery expr
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- [ ] notin antijoin
- [ ] notin nullable
- [ ] oid8 validation
- [ ] psql display true
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- [ ] random dates
- [ ] regdatabase lookup
- [ ] repack concurrently
- [ ] repack index order
- [ ] repack partitioned needs index
- [ ] schema forward fk
- [ ] scs always on
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- [ ] skip scan
- [ ] stemmer dictionaries
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- [ ] virtual default
- [ ] virtual set expression
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