Le pool SQL peut être configuré pour détecter et créer automatiquement des statistiques sur les colonnes. Pour minimiser le risque d’une restauration longue, réduisez si possible les tailles de transactions.To minimize the potential for a long rollback, minimize transaction sizes whenever possible. This can be done by dividing INSERT, UPDATE, and DELETE statements into parts. Consider using a lower granularity than what may have worked for you in SQL Server. To minimize the potential for a long rollback, minimize transaction sizes whenever possible. To get the best performance for queries on columnstore tables, having good segment quality is important. Vous bénéficierez de performances optimales en lançant des mises à jour des statistiques sur les colonnes impliquées dans les jointures, celles utilisées dans la clause WHERE et celles figurant dans GROUP BY. If a CTAS takes the same amount of time, it is a much safer operation to run as it has minimal transaction logging and can be canceled quickly if needed. If your table does not have 6 billion rows in this example, either reduce the number of partitions or consider using a heap table instead. If you enjoyed reading this article about MySQL best practices, you should also read these: Another way to eliminate rollbacks is to use Metadata Only operations like partition switching for data management. However, utilizing larger resource classes reduces concurrency, so you will want to take this impact into consideration before moving all of your users to a large resource class. Étant donné que la qualité des segments columnstore est importante, nous vous conseillons d’utiliser des ID d’utilisateurs qui se trouvent dans la classe de ressource de moyenne ou grande taille pour le chargement des données.Because high-quality columnstore segments are important, it's a good idea to use users IDs that are in the medium or large resource class for loading data. Un autre moyen d’éliminer les restaurations consiste à utiliser des opérations de métadonnées uniquement comme le basculement de partitions pour la gestion des données.Another way to eliminate rollbacks is to use Metadata Only operations like partition switching for data management. I am building my first datawarehouse in SQL 2008/SSIS and I am looking for some best practices around loading the fact tables. This article is a collection of best practices to help you to achieve optimal performance from your dedicated SQL pool (formerly SQL DW) deployment. Voir aussi Index de table, Guide des index columnstore et Reconstruction des index columnstore.See also Table indexes, Columnstore indexes guide, and Rebuilding columnstore indexes. Afficher tous les commentaires de la page, Sélection d’une distribution de tables, Causes de la qualité médiocre des index columnstore, page de questions Microsoft Q&A sur Azure Synapse, Microsoft Q&A question page for Azure Synapse, Forum Stack Overflow sur Azure Synapse Analytics, Azure Synapse Analytics Stack Overflow Forum. When querying a columnstore table, queries will run faster if you select only the columns you need. Azure Synapse est un service d’analytique illimité qui regroupe l’entreposage des données d’entreprise et l’analytique de Big Data. Évitez de définir toutes les colonnes de caractères sur une grande longueur par défaut. If you find it is taking too long to update all of your statistics, you may want to try to be more selective about which columns need frequent statistics updates. It also may not hurt. If you discover data that needs to get incorporated into your Enterprise Data Warehouse, go ahead and update your data model and ETL processes to load the data into either Azure Synapse Analytics or SQL Server running on an Azure VM. Voir aussi Gestion des statistiques sur les tables, CREATE STATISTICS et UPDATE STATISTICS.See also Manage table statistics, CREATE STATISTICS, and UPDATE STATISTICS. In my dw structure, there are a few things I have already applied: For example, rather than execute a DELETE statement to delete all rows in a table where the order_date was in October of 2001, you could partition your data monthly and then switch out the partition with data for an empty partition from another table (see ALTER TABLE examples). Dedicated SQL pool (formerly SQL DW) can be configured to automatically detect and create statistics on columns. For example, if you have an INSERT that you expect to take 1 hour, if possible, break up the INSERT into four parts, which will each run in 15 minutes. Les plans de requête créés par l’optimiseur sont aussi bons que les statistiques disponibles.The query plans created by the optimizer are only as good as the available statistics. This design makes it easy for users to get started creating tables without having to decide how their tables should be distributed. Vous bénéficierez de performances optimales en lançant des mises à jour des statistiques sur les colonnes impliquées dans les jointures, celles utilisées dans la clause WHERE et celles figurant dans GROUP BY.You will gain the most benefit by having updated statistics on columns involved in joins, columns used in the WHERE clause, and columns found in GROUP BY. Additionally, consider encryption within the data warehouse. For example, if you have an INSERT, which you expect to take 1 hour, if possible, break up the INSERT into four parts, which will each run in 15 minutes. Si vous trouvez que la mise à jour de toutes vos statistiques prend trop de temps, vous souhaiterez peut-être sélectionner les colonnes nécessitant des mises à jour fréquentes des statistiques.If you find it is taking too long to update all of your statistics, you may want to try to be more selective about which columns need frequent statistics updates. See also Table overview, Table data types, CREATE TABLE. Un trop grand nombre de partitions peut également réduire l’efficacité des index columnstore en cluster si chaque partition possède moins d’1 million de lignes.Having too many partitions can also reduce the effectiveness of clustered columnstore indexes if each partition has fewer than 1 million rows. Pour les tables non partitionnées, utilisez une instruction CTAS pour écrire les données que vous souhaitez conserver dans une table plutôt que l’instruction DELETE. Data Sharing for Dummies. Par exemple, utilisez plutôt des partitions hebdomadaires ou mensuelles plutôt que des partitions quotidiennes.For example, consider using weekly or monthly partitions rather than daily partitions. It also may be worth experimenting to see if better performance can be gained with a heap table with secondary indexes rather than a columnstore table. This step helps you avoid client-side issues caused by large query result. Moins d’étapes signifie une requête plus rapide. I just now do a data warehouse with a data load of 150gb. Since columnstore tables generally won't push data into a compressed columnstore segment until there are more than 1 million rows per table and each SQL pool table is partitioned into 60 tables, generally, columnstore tables won't benefit a query unless the table has more than 60 million rows. Nous vous recommandons d’activer AUTO_CREATE_STATISTICS pour vos bases de données et de conserver les statistiques mises à jour quotidiennement ou après chaque charge pour vous assurer que les statistiques sur les colonnes utilisées dans vos requêtes sont toujours à jour.We recommend that you enable AUTO_CREATE_STATISTICS for your databases and keep the statistics updated daily or after each load to ensure that statistics on columns used in your queries are always up to date. To maximize throughput when using gzip text files, break up files into 60 or more files to maximize parallelism of your load. Évitez de définir toutes les colonnes de caractères sur une grande longueur par défaut.Avoid defining all character columns to a large default length. For detailed explanation of what SQL Data Warehouse is and what it is not, check out Azure SQL Data Warehouse … For example, if you have an orders table, which is distributed by order_id, and a transactions table, which is also distributed by order_id, when you join your orders table to your transactions table on order_id, this query becomes a pass-through query, which means we eliminate data movement operations. Pour une table comportant moins de 60 millions de lignes, il n’est pas judicieux d’avoir un index columnstore. By default, tables in dedicated SQL pool are created as Clustered ColumnStore. Cette approche est particulièrement importante pour les colonnes CHAR et VARCHAR. Leverage special Minimal Logging cases, like CTAS, TRUNCATE, DROP TABLE, or INSERT to empty tables, to reduce rollback risk. Clustered columnstore indexes are one of the most efficient ways you can store your data in dedicated SQL pool. The purpose of this article is to give you some basic guidance and highlight important areas of focus. Cet article fournit des conseils et décrit les meilleures pratiques à adopter quand vous développez votre solution de pool SQL.This article describes guidance and best practices as you develop your SQL pool solution. PolyBase supports a variety of file formats including Gzip files. N’oubliez pas que, en arrière-plan, le pool SQL partitionne vos données en 60 bases de données, donc si vous créez une table avec 100 partitions, cela produit en réalité 6 000 partitions. By default, tables in dedicated SQL pool are created as Clustered ColumnStore. See the Causes of poor columnstore index quality in the Table indexes article for step-by-step instructions on detecting and improving segment quality for clustered columnstore tables. See also Load data, Guide for using PolyBase, Dedicated SQL pool loading patterns and strategies, Load Data with Azure Data Factory, Move data with Azure Data Factory, CREATE EXTERNAL FILE FORMAT, and Create table as select (CTAS).

sql data warehouse best practices

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