Question : I trying to understand page splits in SQL Server, reading WHAT IS A PAGE SPLIT? WHAT HAPPENS? WHY […]
Category: Database Index
Why would you index text_pattern_ops on a text column?
Question : Today Seven Databases in Seven Weeks introduced me to per-operator indexes. You can index strings for pattern matching […]
Index of which columns are NOT empty
Question : I am trying to enhance the search performance of a table based on whether certain columns contain values. […]
Why is MySQL using this index? Can I force it to use another?
Question : I have a query, and when I call EXPLAIN for it, it appears that my db is using […]
Check int4range includes number using B-tree index
Question : I have a table with two important columns: value and m_range, where value: CREATE TABLE m_filter ( value […]
Creating an index on a really busy table
Question : We have a table with a lot of insertselect every time ( like 100 machines insertingupdating every second). […]
“Recheck Cond:” line in query plans with a bitmap index scan
Question : This is a spin-off from comments to the previous question: Postgres 9.4.4 query takes forever Using PostgreSQL 9.4, […]
Is COW (copy-on-write) based atomic commit widely used in mainstream databases?
Question : The database is not a flat structure like a file system, and generally has three to four levels […]
MongoDB ixscan seems to be scanning more objects than expected
Question : I’m using MongoDB 2.6.12 and a collection has the following index {a: 1, d: -1}. In case the […]
Recommended Postgresql index type to be used with not equal (<>) where condition
Question : I need to query two huge tables (more than milion records). Besides other conditions, there is also a […]