To ensure that the row has a unique identifier" Rows if you want, but SQL Server adds a suffix to the key internally "SQL Server forces any clustered indexes to be unique. A unique index can be filtered a constraint cannot. Some minor differences are that the constraint has some additional metadata overhead as it is an object in its own right and gets an entry in sys.objects - this metadata can be useful when trying to determine creation or last modified date. There is not much difference in what you choose to enforce this here. A unique constraint will create a unique index implicitly to enforce the constraint efficiently. If you only have one key column then that will enforce only one row per distinct value of that column.Ĭan't we alter the table definition to add a unique constraint to Yes - it enforces that the combination of key values are all DISTINCT. Once I add a person whose age is 22 in the table, I can't add another Wal2json: A JSON Output Plugin for Changeset Extraction - A JSON object is produced per transaction containing both the new and old tuples for updates.What does 'Create Unique NONCLUSTERED Index XXX' do here? Does it mean CREATE A UNIQUE INDEX POSTICO HOW TOFind out why & how to go about it.Ĭomparing Postgres Clients: SQLPro vs Table Plus vs Postico - One developer’s very brief overview of what she liked and disliked about three different GUI apps for working with Postgres and why you might pick each.īarman V2.7 Released: The Backup and Recovery Management Tool - Use this to implement disaster recovery solutions for those all critical production databases. Monitoring PostgreSQL WAL Files - Monitoring Postgres WAL files can lead to a more performant PostgreSQL deployment. The Best Way to Count Distinct Indexed Things - It’s significantly more efficient to do a count of a subquery’s results than to try to do a count with DISTINCT in a single query. Pivotal Launches Its Own Supported Version of Postgres - Pivotal is a well known cloud development company and they’ve created their own commercially supported package of Postgres 11 (for RHEL 7) along with enterprise-style add-ons like a replication manager. There’s more here than you absolutely need to know but it’ll help you understand why indexes sometimes behave the way they do. CREATE A UNIQUE INDEX POSTICO SERIESIndexes in Postgres: A Look at B-Trees - The latest in a series of extensive posts digging into how indexes work in Postgres. Speeding Up GROUP BY - SQL’s GROUP BY is used to group records in a result set together often for summary/aggregation purposes and there’s a way to speed them up and gain some ‘free’ extra performance, claims the author! In related news, Postgres 11 is supported on AWS RDS too!įree eBook: How to Get A 3x Performance Improvement On Your Postgres Database - Learn our best practices for optimizing Postgres query performance for customers like Atlassian and how to reduce data loaded from disk by 500x. PostgreSQL 11 Generally Available on Heroku (and AWS) - Heroku, the cloud application platform, have been huge champions of Postgres over the years and now they’ve made Postgres 11 support generally available across their entire service. Spoiler: Aurora clearly beats RDS performance-wise when it comes to Postgres, although Aurora is quite a different beast. Benchmarking Postgres Cloud Solutions: Amazon RDS - Two weeks ago they benchmarked Amazon Aurora, now it’s RDS’s turn.
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