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Is there a way to improve Postgres database performance?
It still has a very noticeable impact on Postgres performance. Remember that the query is quite simple. It’s a primary key lookup so there aren’t many obvious ways to fix it without dramatically re-architecting the database or the application. We turned to the community for help via the PGSQL-Performance mailing list.
How long does it take Postgres to respond to a query?
In 99.9% of accounts these queries would be zippy. In a few cases where the number of tags used to annotate metrics is large, these queries would take up to 20 seconds. That much time spent in a database meant that someone was waiting in front of their browser for the graph editor to respond.
Which is the fastest way to count rows in PostgreSQL?
When all rows to be counted can fit in work_mem then PostgreSQL uses a hash table to get distinct values: This is the fastest way discussed thus far to get distinct values. It takes an average of 372 ms for n and 23 seconds for s.
Which is the best validation query for MySQL?
Similarly, Apache Commons DBCP has validationQuery. Many example queries I’ve seen are for MySQL and recommend using SELECT 1; as the value for the test query. However, this query doesn’t work on some databases (e.g. HSQLDB, for which SELECT 1 expects a FROM clause).
How does loading in memory affect Postgres performance?
All this “loading in memory” and “checking individual row” takes time (the Recheck Cond in the plan). Luckily for us the table is 30% loaded in RAM so it is not as bad as retrieving the rows from disk. It still has a very noticeable impact on Postgres performance.
Is the slow PostgreSQL query still in effect?
The slow Postgres query is gone. The 0.1% unlucky few who would have been affected by the issue are happy too. Seeing the impact of the change using Datadog allowed us to instantly validate that altering that part of the query was the right thing to do.
How big is the Postgres database in GB?
The amount of time invested will pay off a hundred times over. The Postgres community is your second best friend. Earlier this week the performance of one of our (many) databases was plagued by a few pathologically large, primary-key queries in a smallish table (10 GB, 15 million rows) used to feed our graph editor.