Contents
How can partial indexes improve PostgreSQL database performance?
Partial Indexes: With a partial index, you can reduce the size of your index — it has a “where” clause so that it only covers a small amount of data in your table. As a result, you can scan it faster and improve overall maintenance.
What are the different types of indexes in Postgres?
There are many types of indexes in Postgres, as well as different ways to use them. In this article we give an overview of the types of indexes available, and explain different ways of using and maintaining the most common index type: B-Trees. An index is a way to efficiently retrieve a relatively small number of rows from a table.
Why are PostgreSQL indexes never used in Heroku?
Postgres will decide to perform a sequential scan on any query that will hit a significant portion of a table. If you do have an index on that column, it will be a dead index that’s never used – and indexes are not free: they come at a cost in terms of storage and maintenance.
How to increase the speed of my Postgres select?
The speed of your database generally isn’t your hardware, it’s how well you use the intelligence and features of the engine itself. Try to avoid subselects – especially when dealing with a lot of data. These often can’t be optimised by the query planner.
How to automate the detection of PostgreSQL indexes?
If you wish to automate the detection of such indexes, the pg_catalog table pg_index is a good starting point. As the applications that use the database evolve, so do the queries that they use. Indexes that were added earlier may no longer be used by any query.
When to use generalized inverted indexes in PostgreSQL?
In Postgres 10 and above, hash indexes are now write-ahead logged and replicated to followers. Generalized Inverted Indexes (GIN) are useful when an index must map many values to one row, whereas B-Tree indexes are optimized for when a row has a single key value. GINs are good for indexing array values as well as for implementing full-text search.
Is there a way to stop index creation in PostgreSQL V10?
PostgreSQL v10 has added extended statistics to track how the values in different columns are correlated, but that does not track the distributions of the values, so it will not help us here. There are two workarounds: Drop the index that misleads PostgreSQL.
How to identify PostgreSQL performance issues with slow queries?
OLTP is one of the common use cases for PostgreSQL therefore you want your queries to run as smooth as possible. In this blog we’d like to talk about how you can identify problems with slow queries in PostgreSQL. Generally speaking, the most typical way of identifying performance problems with PostgreSQL is to collect slow queries.
How are indexes used in PostgreSQL for sorting?
PostgreSQL uses the index to find the 1000 rows with category 42, filters out the ones that are not interesting, sorts them and returns the top 20. 5 milliseconds is fine. Now we add an index that can help us with sorting. That is definitely interesting if we often have to find the top 20 results: And suddenly, things are looking worse: