Question : Our site has a chronological event feed that uses MySQL. We have noticed that some of the queries […]
Tag: index-tuning
How to determine if an Index is uselss in Percona MySQL?
Question : Using Percona Server 5.5 I’ve a table which stores user activty (lets call it user_activity). It was created […]
What strategy does MySQL optimizer use when choosing between two indexes?
Question : In question: Optimize a query with two range conditions the OP wanted to know if there were a […]
Search for nested values in jsonb array with greater operator
Question : Here is the table definition (simplified): CREATE TABLE documents ( document_id int4 NOT NULL GENERATED BY DEFAULT AS […]
Oracle not using index when > used in where clause
Question : We have a relatively classic scenario where the date clause of the query generated by the application uses […]
Does the length of the index name have any performance impact?
Question : This may seem silly, but in trying to stick to my standard nomenclature when naming indexes in our […]
Index Maintenance on busy OLTP database
Question : I have a database where constant read writes happening all the time. Searches are being done with wild […]
PostgreSQL is not using index with large data
Question : Enviroment My PostgreSQL (9.2) schema looks like this: CREATE TABLE first ( id_first bigint NOT NULL, first_date timestamp […]
MySQL using a index referencing a different column
Question : I have a large table which uses a versioning system in the table. When a record is updated […]
How to optimize a query for < operator
Question : I have a SELECT that is very slow when using < operator I’m looking for fixes or workarounds […]