SQL 2016 Query Store: Et si mes queries m'étaient contées...
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This document summarizes Isabelle Van Campenhoudt's presentation on the SQL Server 2016 Query Store at SQLSaturday Paris 2015. The presentation introduced the Query Store, its capabilities for troubleshooting performance regressions, and live demos of using the Query Store. It also covered query optimization, execution plans, live query statistics, and management of the Query Store through T-SQL and extended events.
SQL 2016 Query Store: Et si mes queries m'étaient contées...
- 1. SQLSaturday Paris 2015 SQL 2016 Query Store Et si mes queries m'étaient contées...
- 2. SQLSaturday Paris 2015 Merci à nos sponsors…
- 3. SQLSaturday Paris 2015 Merci à nos volontaires…
- 4. SQLSaturday Paris 2015 Isabelle Van Campenhoudt Isabelle Van Campenhoud t SQL Server MVP, Bruxelles Consultant, speaker, trainer, PASS V-Chapter Leader, GUSS Board member Managing partner de www.ShareQL.com SQL Server depuis 1999 Blog: http://thesqlgrrrl.wordpress.com/ ivc@ShareQL.com @thesqlgrrrl Isabelle Van Campenhoudt 4 globalfrench.sqlpass.org
- 5. SQLSaturday Paris 2015 Introduction Genese d’une requete Plans d’executions Le store Scenarios Conclusions – Q&A Agenda
- 6. SQLSaturday Paris 2015 Si mes queries m’étaient contées Ou pas… Dans le merveilleux monde de la performance…
- 7. SQLSaturday Paris 2015 Tout doucement le matin…. Lenteur de naissance Lenteur soudaine Lenteur lentement plus leeente Row by agonizing row…
- 8. SQLSaturday Paris 2015 Frustrations Qui ??? Pourquoi ???
- 11. SQLSaturday Paris 2015 Algebrization Step 1: Resolution de Nom Step 2: Choix des types Step 3: Aggregation
- 12. SQLSaturday Paris 2015 Du parse à l’arbre logique SELECT P.ProductNumber, P.ProductID, total_qty = SUM(I.Quantity) FROM Production.Product P INNER JOIN Production.ProductInventory AS I ON I.ProductID = P.ProductIDWHERE P.ProductNumber LIKE N'T%'GROUP BY P.ProductID,
- 13. SQLSaturday Paris 2015 Production du plan d’execution
- 14. SQLSaturday Paris 2015 Le Plan d’éxecution Is the plan cheap enough?b Si oui, utilisez-le Si non démarrez l’optimisation Appliquer la simplification Processus de normalisation du query tree et application de transformations basiques Est-ce un plan trivial? Si oui, utilisez-le Si non continuez. Il y a –t-il un plan dans le cache? Si oui, utilisez-le Si non continuez.
- 15. SQLSaturday Paris 2015 Optimisation “cost based” Phase 0 • Explorez les règles fondamentales et les options de jointures hash/nested • le plan a-t-il coût de moins de 0,2 ? Dans l'affirmative, l'utiliser. Si non, continuer. Phase 1 •Explorez plus de règles et modifier l’ordre des jointures. Si le meilleur plan (moins cher) coûte moins de 1.0, utilisez ce plan. •Si non, alors si MAXDOP > 0 et c'est un système SMP et le min coût > coût seuil du parallélisme, puis utilisez un plan parallèle. •Comparer le coût du plan parallèle avec le meilleur plan de série et executer le moins cher des deux phase 2. • Explorer les options et opter pour le plan moins cher après un nombre limité d'explorations.
- 16. SQLSaturday Paris 2015 Bonnes pratiques ou… droit d’influence…. Hints Plan guide TraceFlag Forced Parameterization
- 17. SQLSaturday Paris 2015 DEMO Visualiser les plans d’execution
- 18. SQLSaturday Paris 2015 Live ou Post Mortem Obtenir des informations sur l’execution d’une requête • Set statistics • Trace • Data collector • DMV • Reports • Extended Events….
- 19. SQLSaturday Paris 2015 Live query statistics SET STATISTICS XML ON; or SET STATISTICS PROFILE ON; in the target session. Enable the query_post_execution_showplan extended event. This is a server wide setting that enable live query statistics on all sessions. Not supported • columnstore indexes • memory optimized tables • Natively compiled stored procedures
- 20. SQLSaturday Paris 2015 DEMO Visualiser les plans d’execution en temps réel
- 21. SQLSaturday Paris 2015 Le Candy Query Store
- 22. SQLSaturday Paris 2015 Query Store Qui ??? Pourquoi ???
- 23. SQLSaturday Paris 2015 Determiner • Le nombre de fois ou une requete a été exécutée dans une fenetre de temps Identifier • top n requêtes dans les X heures passes (execution time, memory consumption, etc.) in the past x hours. Audit • Historique des plans d’executions d’une requête Analyser • Le profil d’utilisation des ressources d’une database donnée (cpu,ram,io) Regressions • Trouver et corriger une regression de plan d’execution en forcant un plan. Les Scenarios du Query store Qui ??? Pourquoi ???
- 24. SQLSaturday Paris 2015 Les “rayons” du Store
- 25. SQLSaturday Paris 2015 The plan store
- 26. SQLSaturday Paris 2015 The statistics store
- 27. SQLSaturday Paris 2015 Configuration Options • Can be READ_WRITE or READ_ONLY.OPERATION_MODE • Configure the STALE_QUERY_THRESHOLD_DAYS argument to specify the number of days to retain data in the query store.CLEANUP_POLICY • Determines the frequency at which data written to the query store is persisted to disk. To optimize for performance, data collected by the query store is asynchronously written to the disk. The frequency at which this asynchronous transfer occurs is configured via DATA_FLUSH_INTERVAL_SECONDS. DATA_FLUSH_INTERVAL_SECONDS • Configures the maximum size of the query store. If the data in the query store hits the MAX_STORAGE_SIZE_MB limit, the query store automatically changes the state from read-write to read-only and stops collecting new data. MAX_STORAGE_SIZE_MB • Determines the time interval at which runtime execution statistics data is aggregated into the query store. To optimize for space usage, the runtime execution statistics in the Runtime Stats Store are aggregated over a fixed time window. This fixed time window is configured via INTERVAL_LENGTH_MINUTES. INTERVAL_LENGTH_MINUTES • C ontrols whether the cleanup process will be automatically activated when total amount of data gets close to maximum size.SIZE_BASED_CLEANUP_MODE • Designates if the Query Store captures all queries, or relevant queries based on execution count and resource consumption, or stops adding new queries and just tracks current queries.QUERY_CAPTURE_MODE • An integer representing the maximum number of plans maintained for each query.MAX_PLANS_PER_QUERY
- 28. SQLSaturday Paris 2015 DEMO Utiliser le query store
- 29. SQLSaturday Paris 2015 T-SQL management • •sys.database_query_store_options (Transact-SQL) • •sys.query_context_settings (Transact-SQL) • •sys.query_store_plan (Transact-SQL) • •sys.query_store_query (Transact-SQL) • •sys.query_store_query_text (Transact-SQL) • •sys.query_store_runtime_stats (Transact-SQL) • •sys.query_store_runtime_stats_interval (Transact-SQL) • Query Store Stored Procedures 7 vues du catalogue • •sp_query_store_flush_db (Transact-SQL) • •sp_query_store_reset_exec_stats (Transact-SQL) • •sp_query_store_force_plan (Transact-SQL) • •sp_query_store_unforce_plan (Transact-SQL) • •sp_query_store_remove_plan (Transct-SQL) • •sp_query_store_remove_query (Transact-SQL) 6 stored procedures • query_store_background_task_persist_started - Fired if the background task for Query Store data persistence started execution • •query_store_background_task_persist_finished - Fired if the background task for Query Store data persistence is completed successfully • •query_store_load_started - Fired when query store load is started • •query_store_db_data_structs_not_released - Fired if Query Store data structures are not released when feature is turned OFF. • •query_store_db_diagnostics - Periodically fired with Query Store diagnostics on database level. • •query_store_db_settings_changed - Fired when Query Store settings are changed. • •query_store_db_whitelisting_changed - Fired when Query Store database whitelisting state is changed. • •query_store_global_mem_obj_size_kb - Periodically fired with Query Store global memory object size. • •query_store_size_retention_cleanup_started - Fired when size retention policy clean-up task is started. • ………. 19 new extended events:
- 31. SQLSaturday Paris 2015 Pour aller plus loin Optimisateur de requete (webcast GUSS) https://www.youtube.com/watch?v=sMG7v9Y vPX8 https://msdn.microsoft.com/en- us/library/dn817826.aspx https://msdn.microsoft.com/en- us/library/dn818149.aspx
- 32. SQLSaturday Paris 2015 …Et en plus on peut gagner des cadeaux http://GUSS.pro/sqlsat
Editor's Notes
- #5: Rendre sexy
- #12: Confirms that all objects exist and are visible in the security context of the user. This is where the table and column names are checked to ensure that they exist and that the user has access to them 2. Determines the final type for each node in the parse tree 3. Determines where to do any aggregations
- #25: The query store contains two stores; a plan store for persisting the execution plan information, and a runtime stats store for persisting the execution statistics information. The number of unique plans that can be stored for a query in the plan store is limited by the max_plans_per_query configuration option. To enhance performance, the information is written to the two stores asynchronously. To minimize space usage, the runtime execution statistics in the runtime stats store are aggregated over a fixed time window. The information in these stores is visible by querying the query store catalog views.