Postgresql – Query optimization for this table
ID Amount Brand 1 10 NULL 1 20 NULL 2 30 Mazada 2 NULL BMW 3 40 NULL 3 40 KIA 4 NULL Honda 4 NULL Honda Above is the original table, and my goal is to find out any…
Postgresql – Why is a LATERAL JOIN faster than a correlated subquery in Postgres?
I have rewritten the below query from using a correlated subquery to using a LATERAL JOIN. It is now faster, and I would like to understand why? This SO answer says that there is no golden rule and that it…
Terrible performance joining a view to a fast subquery / CTE in PostgreSQL
I have a PostgreSQL (v15) DB view that rolls up a bunch of data per user for a single organization, to display a report of data like fees owed/paid per user, etc. This is executed with an org ID and…
Postgresql – Optimize a query using multicolumn indices
Say you want to optimize a query in a postgres database like: SELECT DISTINCT ON (first) first, second, third FROM my_table WHERE second > 100 AND fourth = 3 ORDER BY first, second DESC, third DESC (EDIT: In this example,…
PostgreSQL better query performance
I have customers and visits table, and I would like to know which of these two queries has the better performance: (I have indexes defined for those columns) Query 1 SELECT customers.id as id, COALESCE(v.count, 0) as visits FROM customers…
Postgresql – Test given IDs for existence in any row of a JSON column
In my Postgres 13.10 database, I have a table menus with a JSON column named dishes. This column contains values in the following format: { "desserts": [ {"id": 1, "name": "chocolate cake"}, {"id": 2, "name": "banana split"} ], "appetizers": […
Postgresql – Postgres – Select Query Optimization
I want to optimize the following DB SELECT query: SELECT ls.caller_id, ls.caller_path_id, ls.caller_path_name, ls.caller_data->>'worker' AS worker, ls.caller_stage, ls.current_status, ls.date_inserted AS date_closed, ls.caller_data->>'name' AS firstname, ls.caller_data->>'surname' AS surname, ls.caller_data->>'cell' AS cell, ls.caller_data->>'home' AS home, ls.caller_data->>'work' AS work, ls.caller_data->>'other' AS other FROM…
Postgresql – Looking for a more performant query
I have 2 tables with flex one-to-many relationship, meaning the parent side may not have any child: Parent_table id dim1 quantity price 1 "abc" 1 1.00 child_table: id parent_id 1 1 2 1 The parent query is very straight forward:…
why Postgresql Explain Cost is Low in Limit and Result Phase but high in Index Scan phase
In the shared plan index scan cost is very high (cost=0.56..696715.50 But Limit (cost=0.56..224.59 is very low and so on result cost Result (cost=224.59..224.60 rows=1 width=8) why it is so? Right now I will consider this query harmless as it…
How to improve or speed up Postgres query with pg_trgm? – Postgresql
Are there any additional steps I can take to speed up query execution? I have a table with more than 100m rows and I need to do search for matching strings. For that I checked two options: Compare text with…