mysql query performance tuning

size limit (butis Innodb do not know), there is another reason is the convenience of self-maintenance. In addition, INNODB can not only use the textthe original block device, which is what we often call a bare device. when our file table space is about to run out, we have to add data files for it, of course, only sharetable space has this action. Adding a data file to a shared table space is a simple operation, justthe Innodb_data_file_path parameter is followed by a standard format to set the

keys from table_nameTime to create an index:Generally need to be indexed in the where and join clausesConsiderations for Using Indexes:In some cases like needs to be indexed, because in a wildcard % and - start query,mysql Do not use indexesSELECT * from table-name where name like ' % admin'; Besides, there's no way to do the math on the list.SELECT * from Users where Year (adddate) The operation on each

system crashes, some data may be lost, only for the backup node)Innodb_flush_method Fdatasync (in the case of a hardware RAID controller, and a standalone cache with write-back mechanism, with battery power-off protection, configured as O_direct, otherwise, set to Fdatasync)Innodb_log_buffer_size 1M (the default, this configuration determines the cache that is allocated for things that have not been executed, and the default is generally sufficient.) If the object contains a large number of bin

MySQL query cache settings improve MySQL query performance and cache mysql First, let's take a look at the MSYQL logical framework: The image comes from high-performance

In the face of serious performance problems, there are generally several possibilities: 1, the index is not well established; 2, the SQL writing is too complex; 3, configuration error; 4, the machine is really not load; 1, the index is not built wellIf you see the CPU consumed by MySQL is very large, you can use the MySQL client tool to check. Execute on Linux /

) GTID2) in MySQL 5.6 gtid mode synchronous replication error cannot skip the workaround3) Improvement of Gtid replication in MySQL5.74) Gtid Replication traps5) Improvements to Gtid replication in MariaDB 10.1MySQL 5.6/5.7 Security recovery from library crashMariaDB 10.0/10.1 security recovery from vault crashSlave multi-threaded replication from librariesSlave supports multi-source replicationMySQL 5.7 Set synchronous replication filtering without r

. The Block Nested-loop algorithm uses the result set of the driver table (which can be simply understood as the preceding table) as the circular underlying data, and then one article queries the data in that result set by using the data in the resulting dataset as a filter to the next table, and then merges the results. If there is a third participating join, then the join result set of the previous two tables is used as the base data for the join, once again querying the data by looping throug

PHP tutorials and MySQL tutorial performance tuning notes The larger the tmp_table_size=200m tmp_table_size, the smaller the probability of being converted to a disk TMP table PHP Program page MySQL closed in time Set the MySQL timeout timeLow-priority-updates set

waste. Query Cache Fragmentation Rate = Qcache_free_blocks/qcache_total_blocks * 100% If the query cache fragmentation rate exceeds 20%, you can use flush query cache to defragment the cache. Or try reducing query_cache_min_res_unit if your queries are small data volumes. Query Cache utilization = (query_cache_s

Mysql mytop of performance tuning tools installation and use of 1. Mytop of the http://yunpan.cn/cVG3uSs2Jtt9h access Password 7ef1 2. Install Mytop first Necessary Components . Yum-y Install Perl-dbd-mysql Perl-dbiperl-termreadkeyIf you are prompted to locate the installation pack

In the Apache, PHP, MySQL architecture, MySQL has the greatest impact on performance and the key core. For the discuz! Forum program is also the case, MySQL settings are reasonable optimization, directly affect the speed and load of the forum! At the same time, MySQL is also

stored, the maximum value and the pointer to the next primary leaf level block, or a non-leaf level block (pointer), where the pointer is the file number + block number of the block. In the B*tree block of Oracle, the key value of the indexed column is stored +rowid (the file number + block number + slot number of the data row) so that the data rows in the table can easily be found through the index by the key and ROWID values in the B*tree. The data row in the segment in Oracle is the heap str

Tags: purpose reference establishing cost storage combined with different ICA engines6 Query Performance Optimization6.1 Why queries become slowThis illustrates the query execution cycle, from the client to the server side, the server-side resolution, the optimizer generates execution plans, executes (can be subdivided, the general process can be viewed through s

query performance is that there is too much data to access. Most poorly performing queries can be optimized by reducing the amount of data accessed.1. Verify that the application is retrieving a large amount of data than is needed. This usually means that too many rows have been accessed, but sometimes it is possible to access too many columns.2. Verify that the MySQL