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Similaire à PGConf.ASIA 2019 Bali - Upcoming Features in PostgreSQL 12 - John Naylor
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PGConf.ASIA 2019 Bali - Upcoming Features in PostgreSQL 12 - John Naylor
- 2. https://www.2ndQuadrant.com Upcoming Features in PostreSQL 12 PGConf.ASIA 2019
- 3. https://www.2ndQuadrant.com Selamat datang! John Naylor • living in Southeast Asia since 2017 • joined 2ndQuadrant this year • PostgreSQL contributor • system catalogs • query parsing • performance
- 4. https://www.2ndQuadrant.com Where are we? • PostgreSQL major versions released yearly • PG 12 beta4 out Sept 12, please test • PG 12 possibly in October 2019 • no ”killer feature” • many incremental improvements https://www.postgresql.org/docs/12/release-12.html
- 5. https://www.2ndQuadrant.com 1 Performance 2 Administration 3 SQL and Development Features
- 6. https://www.2ndQuadrant.com 1 Performance 2 Administration 3 SQL and Development Features
- 7. https://www.2ndQuadrant.com Partitioning in PostgreSQL • PG 8.1 - inheritance-based partitioning • PG 10 - declarative partitioning • PG 11 - better • PG 12 - faster
- 8. https://www.2ndQuadrant.com Performance of partitioned tables • faster planning with many partitions • increased number of partitions that can be used • faster COPY into partioned tables
- 12. https://www.2ndQuadrant.com Partial de-TOAST • TOAST is a technique for storing large values in a separate table (compressed by default) • PG 11: entire value always decompressed • PG 12: can decompress just the start of the value • useful for: • extracting the start of string • PostGIS spatial joins
- 13. https://www.2ndQuadrant.com Automatic inlining of CTEs • Common table expressions (CTEs) = ”WITH clauses” • PG 11: CTEs are evaluated before the outer query • PG 12: CTEs are inlined into the outer query if: • referenced only once • not RECURSIVE • not overridden by MATERIALIZED • can lead to better query plans
- 14. https://www.2ndQuadrant.com JIT enabled by default • JIT (Just-In-Time) compilation arrived in PG 11 • but disabled by default • used with longer-running queries (> 200ms) • epecially helpful for: • many columns • complex expressions
- 15. https://www.2ndQuadrant.com Parallel query with SERIALIZEABLE PostgreSQL supports three transaction isolation levels: READ COMMITTED, REPEATABLE READ, and SERIALIZABLE • SERIALIZABLE is the strictest possible • Parallel query in PG 9.6, but not with SERIALIZABLE • Now all isolation levels can take advantage of parallelism
- 16. https://www.2ndQuadrant.com Faster float to string conversion • Ryu algorithm: shortest string that represents the value precisely • 3x faster to dump out a table of all float values • Why do this? Because SQL Server was 4x faster
- 17. https://www.2ndQuadrant.com Btree index improvements • 10-40% smaller indexes, especially for: • multicolumn indexes • many duplicates • backward compatible • must REINDEX to remove existing bloat • reduced locking overhead for INSERTs
- 18. https://www.2ndQuadrant.com 1 Performance 2 Administration 3 SQL and Development Features
- 19. https://www.2ndQuadrant.com REINDEX CONCURRENTLY PG11 1 CREATE INDEX CONCURRENTLY idx2 ... 2 DROP INDEX CONCURRENTLY idx1; 3 ALTER INDEX idx2 RENAME TO idx1; 4 constraints? more work PG12 1 REINDEX INDEX CONCURRENTLY idx1;
- 20. https://www.2ndQuadrant.com Recovery configuration in PG11 Configuration • recovery.conf • postgresql.conf Signaling • recovery.conf
- 21. https://www.2ndQuadrant.com Recovery configuration in PG12 Configuration • postgresql.conf Signaling • standby.signal • recovery.signal
- 22. https://www.2ndQuadrant.com Recovery configuration in PG12 Configuration • postgresql.conf • ALTER SYSTEM • some recovery parameters can be changed without server restart Signaling • standby.signal • recovery.signal
- 23. https://www.2ndQuadrant.com Recovery configuration in PG12 Configuration • postgresql.conf • ALTER SYSTEM • some recovery parameters can be changed without server restart Signaling • standby.signal • recovery.signal *Every HA tool and system will need to adapt to this*
- 24. https://www.2ndQuadrant.com More replication • pg_promote function allows promoting a replica from SQL • max_wal_senders not counted as part of max_connections
- 25. https://www.2ndQuadrant.com Functions for inspecting partitioned tables • pg_partition_tree • pg_partition_ancestors • pg_partition_root
- 26. https://www.2ndQuadrant.com Monitoring • log_transaction_sample_rate • log statements from a sample of transactions • in addition to those captured via log_min_statement_duration • system views to track progress of utility statements • pg_stat_progress_create_index • pg_stat_progress_cluster
- 27. https://www.2ndQuadrant.com 1 Performance 2 Administration 3 SQL and Development Features
- 28. https://www.2ndQuadrant.com Partitioning DDL improvements • The tablespace specification for a parent is now inherited by the child • Foreign key constraints can now refer to a partitioned table • ALTER TABLE ... ATTACH PARTITION no longer needs an exclusive lock • does not block writes on parent table • DETACH still needs an exclusive lock
- 29. https://www.2ndQuadrant.com Generated columns • part of SQL:2011 standard • value calculated from other columns • like a view for columns
- 30. https://www.2ndQuadrant.com Generated columns CREATE TABLE mytable ( create_dt date NOT NULL, quarter integer GENERATED ALWAYS AS (date_part('quarter', create_dt)) STORED );
- 31. https://www.2ndQuadrant.com Generated columns • only STORED option this release • not standard but also used by other SQL implementations • VIRTUAL likely in a future release • can index on generated columns • but cannot be a partition key • COPY skips generated columns by default
- 32. https://www.2ndQuadrant.com SQL/JSON Path • JSON support in PostgreSQL since 2012 • SQL:2016 included JSON with a different API • JSON Path is a query language for JSON documents • analogous to XPath for XML • PostgreSQL already has the most complete implementation (14/15 parts)
- 33. https://www.2ndQuadrant.com SQL/JSON Path SELECT jsonb_path_query_array( '{"a":[1,2,3,4,5]}', '$.a[*] ? (@ >= $min && @ <= $max)', '{"min":2,"max":4}'); jsonb_path_query_array ------------------------ [2, 3, 4] (1 row)
- 34. https://www.2ndQuadrant.com SQL/JSON Path SELECT jsonb_path_match( '{"a":[1,2,3,4,5]}', 'exists($.a[*] ? (@ >= $min && @ <= $max))', '{"min":2,"max":4}'); jsonb_path_query ------------------ t (1 row)
- 35. https://www.2ndQuadrant.com SQL/JSON Path SELECT jsonb_path_query( '{"a":[1,2,3,4,5]}', '$.a[*] ? (@ >= $min && @ <= $max)', '{"min":2,"max":4}'); jsonb_path_query ------------------ 2 3 4 (3 rows)
- 36. https://www.2ndQuadrant.com Full text search Stemming support for more languages, including: • Indonesian • Tamil • Nepali • Arabic
- 37. https://www.2ndQuadrant.com Postgres needs your help 9.4 - 90% 9.5 - 84% 9.6 - 80% 10 - 71% 11 - 67% 12 - 64% ???
- 38. https://www.2ndQuadrant.com Postgres needs your help 9.4 - 90% 9.5 - 84% 9.6 - 80% 10 - 71% 11 - 67% 12 - 64% ...percent of user messages translated into Indonesian https://wiki.postgresql.org/wiki/NLS