mysql temp table performance

When we design the database table structure, we need to pay attention to the performance of the data operation when we operate the database, especially the SQL statements when we look at the table. Here, we're not going to talk too much about optimizations for SQL statements, but only for MySQL, the most Web applicatio

1040 error. The ideal setting isMax_used_connections/max_connections * 100% ≈ 85%.The maximum number of connections accounts for about 85% of the maximum number of connections. If the percentage is less than 10%, the maximum number of connections of the MySQL server is too high.3. Key_buffer_sizeKey_buffer_size is a parameter that has the greatest impact on the performance of the MyISAM

In practical applications, there are 3 ways to analyze a single query SQL performance: Show status, show profiles, and slow query logs. First, use show profile 1, the default is disabled, open in the session #开启profileSet profiling=1; 2. When a query arrives at the server, the tool logs the profiling information to a temporary table and gives the query an integer identifier starting at 1, which can be v

difference is that the table divides the large table into several separate entity tables, while partitioning divides the data into multiple locations, which can be the same disk or on different machines. After partitioning, the surface is still a table, but the data is hashed to multiple locations. When the app reads or writes a large

Six tips for MySQL database performance optimization: bitsCN.com On the surface of the database table, there is an index and error prevention mechanism. However, a simple query takes a long time. Web applications may run well in the development environment, but are equally bad in the product environment. If you are a database administrator, you may have encount

single queue. In this case, write locks and read locks will have the same priority and will be helpful for some applications. Here are some techniques for table locking in MySQL: • You can do parallel operations if you do not mix updates with the choice of checking many rows in the same table. • You can use lock TABLES to improve speed because many updates a

This article introduces the detailed description of MySQL partition performance. For more information, see I, Partition concept PartitionAllows you to allocate multiple parts of a single table across file systems based on specified rules. Different parts of a table are stored as separate tables in different location

-InnoDB-ISAM-NDBCluster[--] Data in MyISAM tables: 889 M (Tables: 479)[--] Data in MEMORY tables: 1 M (Tables: 4)[!] Total fragmented tables: 29 -------- Security Recommendations -------------------------------------------[OK] All database users have passwords assigned -------- Performance Metrics -------------------------------------------------[--] Up for: 12 h 55 m 27 s (4 M q [105.230 qps], 295 K conn, TX: 9B, RX: 546 M)[--] Reads/Writes: 82%/18%[

have explicitly stated that you need to use Query Cache), MySQL will directly HASH the received select statement in string mode based on the preset hash algorithm, then, go to the Query Cache to check whether the data has been cached. That is to say, if the select request is already in the cache, the data will be directly returned, thus omitting all subsequent steps (such as SQL statement parsing, optimizer optimization and data request to the storag

Tags: ISA client interactive range custom Split function query performance efficientFirst, MySQL The main application scenarios 1. Web Site System 2. Logging System 3. Data Warehouse System 4. Embedded system Second, MySQL Frame Composition: Third, MySQL Storage Engine Overview 1 ) MyISAM Storage Engine MyISAM Storag

non-lock reads are used ). However, there is a high price-InnoDB needs to maintain transaction records, from the very beginning it will be recorded, it is very expensive. Even more serious, programs are frequently updated and hot rows-you really don't want InnoDB to process rows. it has hundreds of versions. In terms of performance, both reading and writing can be affected. It is costly to use select queries to traverse multiple rows. for update,

Label:Http://coolshell.cn/articles/1846.html Today, database operations are increasingly becoming a performance bottleneck for the entire application, which is especially noticeable for web applications. It's not just about the performance of the database that DBAs need to worry about, it's something that our programmers need to focus on. When we design the database ta