PDF (US Ltr)
- 35.1Mb
PDF (A4)
- 35.2Mb
Man Pages (TGZ)
- 256.4Kb
Man Pages (Zip)
- 361.2Kb
Info (Gzip)
- 3.4Mb
Info (Zip)
- 3.4Mb
Search Results
https://dev.mysql.com/doc/refman/5.7/en/mysql-cluster-limitations-transactions.html
This issue does not occur for queries that use index or table scans, even against NDB tables having BLOB or TEXT columns. You can help minimize issues with shared read locks by avoiding queries that use unique key lookups that retrieve BLOB or TEXT ... A number of limitations exist in NDB Cluster with regard to the handling of ...
https://dev.mysql.com/doc/refman/5.7/en/mysql-indexes.html
Indexes are used to find rows with specific column values quickly. Without an index, MySQL must begin with the first row and then read through the entire table to find the relevant rows. If the table has an index for the columns in question, MySQL ...
https://dev.mysql.com/doc/refman/5.7/en/mysqladmin.html
Questions The number of questions (queries) from clients since the server was started. Slow queries The number of queries that have taken more than long_query_time seconds. You can use it to check the server's configuration and current status, to ...
https://dev.mysql.com/doc/refman/5.7/en/no-matching-rows.html
If you have a complicated query that uses many tables but that returns no rows, you should use the following procedure to find out what is wrong: Test the query with EXPLAIN to check whether you can find something that is obviously wrong. Select ...
https://dev.mysql.com/doc/refman/5.7/en/optimizing-subqueries.html
See also Section 8.2.2, “Optimizing Subqueries, Derived Tables, and View References”. For example, try this: SELECT DISTINCT column1 FROM t1 WHERE t1.column1 IN ( SELECT column1 FROM t2); Instead of this: SELECT DISTINCT t1.column1 FROM t1, t2 ... Development is ongoing, so no optimization tip is reliable for the long ...
https://dev.mysql.com/doc/refman/5.7/en/partitioning-limitations-partitioning-keys-unique-keys.html
This section discusses the relationship of partitioning keys with primary keys and unique keys. The rule governing this relationship can be expressed as follows: All columns used in the partitioning expression for a partitioned table must be part ...
https://dev.mysql.com/doc/refman/5.7/en/stored-objects-security.html
If the account you are searching for does not exist, any objects displayed by those queries are orphan objects. Stored programs (procedures, functions, triggers, and events) and views are defined prior to use and, when referenced, execute within a ...
https://dev.mysql.com/doc/refman/5.7/en/user-resources.html
The following statement changes the query limit for francis to 100: mysql> ALTER USER 'francis'@'localhost' WITH MAX_QUERIES_PER_HOUR 100; The statement modifies only the limit value specified and leaves the account otherwise unchanged. Similarly, ... One means of restricting client use of MySQL server resources is to set the global max_user_connections system variable to a nonzero ...
https://dev.mysql.com/doc/refman/5.7/en/where-optimization.html
You might be tempted to rewrite your queries to make arithmetic operations faster, while sacrificing readability. Each table index is queried, and the best index is used unless the optimizer believes that it is more efficient to use a table scan.
https://dev.mysql.com/doc/refman/5.7/en/charset-collation-information-schema.html
The preceding behavior occurs because the utf8_general_ci collation is not used for INFORMATION_SCHEMA queries when searching for values that correspond to objects represented in the file system. For information about these optimizations, see ...