Search Results
https://dev.mysql.com/doc/refman/9.7/en/string-functions.html
If the first argument is a constant string and the second is a column of type SET, the FIND_IN_SET() function is optimized to use bit arithmetic. For functions that operate on string positions, the first position is numbered 1. For functions that ...
https://dev.mysql.com/doc/refman/9.7/en/symbolic-links-to-tables.html
The same is true for the ALTER TABLE, OPTIMIZE TABLE, and REPAIR TABLE statements. Note Symbolic link support as described here, along with the --symbolic-links option that controls it, and is deprecated; expect these to be removed in a future ...
https://dev.mysql.com/doc/refman/9.7/en/table-locking.html
Optimize SELECT statements to run faster so that they lock tables for a shorter time. InnoDB tables use row-level locking so that multiple sessions and applications can read from and write to the same table simultaneously, without making each other ...
https://dev.mysql.com/doc/refman/9.7/en/table-size-limit.html
ALTER TABLE tbl_name MAX_ROWS=1000000000 AVG_ROW_LENGTH=nnn; You have to specify AVG_ROW_LENGTH only for tables with BLOB or TEXT columns; in this case, MySQL cannot optimize the space required based only on the number of rows. The effective ...
https://dev.mysql.com/doc/refman/9.7/en/thread-pool-tuning.html
Optimal performance is often seen with values from 4 to 8. This section provides guidelines on determining the best configuration for thread pool performance, as measured using a metric such as transactions per second. Of chief importance is the ...
https://dev.mysql.com/doc/refman/9.7/en/tracing-memory-usage.html
Each stored trace is a string, which is extended (using realloc()) as optimization progresses by appending more data to it. The optimizer_trace_max_mem_size server system variable sets a limit on the total amount of memory used by all traces ...If ...
https://dev.mysql.com/doc/refman/9.7/en/type-conversion.html
Also, results can be affected by factors such as computer architecture or the compiler version or optimization level. When an operator is used with operands of different types, type conversion occurs to make the operands compatible. For example, ...
https://dev.mysql.com/doc/refman/9.7/en/using-spatial-indexes.html
The optimizer investigates whether available spatial indexes can be involved in the search for queries that use a function such as MBRContains() or MBRWithin() in the WHERE clause. The following query finds all objects that are in the given ...
https://dev.mysql.com/doc/refman/9.7/en/verifying-index-usage.html
Use the EXPLAIN statement, as described in Section 10.8.1, “Optimizing Queries with EXPLAIN”. Always check whether all your queries really use the indexes that you have created in the tables.
https://dev.mysql.com/doc/refman/9.7/en/view-restrictions.html
View processing is not optimized: It is not possible to create an index on a view. The maximum number of tables that can be referenced in the definition of a view is 61. Indexes can be used for views processed using the merge algorithm. However, a ...