When you have multiple different indexes that can be used for a query, MySQL tries to identify the most effective index for the query. It does so by analyzing statistics about the data distribution within each index. In our example, we are looking for all bands that were founded in 1980. Given these requirements, we […]
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If you are unfamiliar with MySQL, or are familiar with other relational database systems, the concept of a storage engine can take some time to understand. In summary, although MySQL communicates and manages data via Structured Query Language (SQL), internally MySQL has different mechanisms to support the storage management and retrieval of the underlying data. […]
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MySQL can use indexes to support a range of different functions. Indexes are not just for optimizing MySQL performance when reading data. These functions include the following: • Maintaining data integrity • Optimizing data access • Improving table joins • Sorting results • Aggregating data Data Integrity MySQL uses both primary and unique keys to […]
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SimpleReach Slide Plugin Version: 0.7.6 You’re still here? Why? There hasn’t been anything new to read here for weeks! Sorry, I’ve been busy, sitting in endless meetings, learning how to play “manager”. It hasn’t been pretty.I’m back, with a new tale of good versus evil. For dramatic effect, I suggest that you read this one […]
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In addition to the potential performance gains for complex views that are frequently referenced in queries, the use of indexed views has several advantages. Learn more.
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Although the SQL Server Database Engine does not have any practical limitations concerning the number of indices, it is advisable to limit them. Learn why.
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Fragmented index data causes the SQL Server Database Engine to perform additional data reads, and decreases performance. To fix this problem, you must rebuild fragmented indexes. Learn more.
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To get information concerning internal index fragmentation in SQL Server, use the DMV sys.dm_db_index_physical_stats. Learn how.
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A nonclustered index in SQL Server has the same index structure as a clustered index, but doesn’t change the physical order of the rows in the table, and the leaf pages consist of an index key plus a bookmark. Learn more.
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A clustered index is built by default for each table for which you define the primary key using the primary key constraint. Learn more.
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SQL Server indices are a separate physical data structure that enables queries to access one or more data rows fast. Proper tuning of indices is key for query performance. Learn why.
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Although SQL Server protects against the Halloween effect, it’s important to keep in mind when considering an indexing strategy. Learn more.
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