Contents
Which is the best index for between queries in MySQL?
Best index for BETWEEN queries are B-TREE indices. See MySQL docs on that Topic. If you create an index for start_ip and one for end_ip, I found I could get comparable results to Jeshurun’s results without doing the order by, using an inner join with the same table:
When to use Index on start _ IP, end _ IP?
First, let’s dissect the query. so the engine will first use the index on start_ip, end_ip to fetch all rows for which start_ip is smaller than C, and then further filter out the rows for which end_ip is also bigger than C.
Why is MySQL unable to index between queries?
MySQL seems to be unable to use the indexes for most of my queries, as the where clause uses a between that falls somewhere between start_ip and end_ip: The table has a few million records.
Why does MySQL use partial index instead of full index?
Also you will find MySQL uses a partial index instead of reporting a full-index scan which is more comforting to me. Adding indices will help. , a INDEX (x, y) will not improve the performance, but two seperate indices for x and y will.
Can you use an index with a prefix length?
An index declared with a prefix length can only be used for lookups, not for sorting, and not as a covering index, since it doesn’t contain the full column value, by definition. Also, the above queries were run on an InnoDB table, but running them on a MyISAM table yields virtually identical results.
When to add columns to index in MySQL?
In most cases, conditions such as name = ‘John’ will allow the database to filter many of the rows from the table and go through a small amount of rows to return the required results. Therefore, we should start indexing by adding these columns to the index.
What to do if there is no Index in MySQL?
The index cannot be used. (If there are no “=” parts AND’d in the WHERE clause, move on to step 2 without any columns in your putative INDEX.) Find the first of 2a / 2b / 2c that applies; use it; then quit. If none apply, then you are through gathering columns for the index.
When to apply limit to index in MySQL?
The following are especially good. Normally a LIMIT cannot be applied until after lots of rows are gathered and then sorted according to the ORDER BY. But, if the INDEX gets all they way through the ORDER BY, only (OFFSET + LIMIT) rows need to be gathered.