What Does Sargeable Mean?
A sargeable query, in the context of a relational database, is one where indexes can improve the speed and efficiency of a query. As a result, it is highly desireable to have sargeable SQL queries.
Sargeable is derived from a contraction of Search ARGument ABLE.
Techopedia Explains Sargeable
There are several circumstances where non-sargeable queries creep in:
- Whether predicates in WHERE clauses and JOIN clauses will prevent the use of an index
- Where a function is included in the left part of a condition of a WHERE clause
- When the time required to perform a SEEK on a table is greater than scanning an index when joining one table or result set onto another. Usually a seek is much faster than scanning a whole table, but when you have to seek a lot of rows, a scan could be more efficient.
In most cases, the databases management system's query optimizer will identify opportunities to improve queries by making them sargeable.