Percona's MySQL & InnoDB performance and scalability blog
…in the table above you can with default buffer size of 256K, MariaDB 5.5 shows that Handler_mrr_rowid_refills = 1, which means the…the PK column value in the index record to make a lookup in the PK. Both these lookups are performed in a single call to the…
…MySQL optimizer restrictions in how well it can deal with primary key appended to the index column, especially in such case as you’re suggesting. In the…The table is only used to record a user_id and competition_id, nothing more. Would doing a SELECT competition_id, COUNT…
…table, every column, and every index in that table. Once you get the output, you just DROP the table…
…of the tables had timestamp fields and were set to a default value of CURRENT_TIMESTAMP. From the manual, here is how MySQL…each time, the checksum will change. However, the underlying data isn’t touched and remains the same. In…
…in practice, most tables are both read and written. The first write query to each table will immediately block against the…localhost | test | Query | 80 | Sending data | select count(*) …MySQL command-line client that wasn’t started with -A, and it’s trying to get a list of tables and columns in the…
…the table does not contain a suitable column,” but there are only a handful of references to FTS_DOC_ID found when searching the MySQL…
…the number of rows in the table orders (left operand), and so MySQL 5.5 prefers to do a PRIMARY index scan of the table orders resulting in…
…the FlightDate column in the WHERE clause instead of Year. Each iteration reads an additional year of data. That is, the first query reads one year, and the…
…the InnoDB versions are only available on 64 bit instances. MySQL will fail to start on a micro instance, simply decrease the values in the…in the EC2 console. That the “private ip” field is selected in the list of columns to show (click show/hide to change the columns) That the…
… little rule of thumb I sometimes use to decide which columns should come first in an index. This is not specific to MySQL, it’s generally applicable to any database server with b-tree indexes. And there are a bunch of subtleties… those for the sake of simplicity. Let’s start with this query, which returns zero rows but does a full table scan. EXPLAIN…
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