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https://dev.mysql.com/doc/refman/8.4/en/example-storage-engine.html
The EXAMPLE storage engine is a stub engine that does nothing. Its purpose is to serve as an example in the MySQL source code that illustrates how to begin writing new storage engines. To enable the EXAMPLE storage engine if you build MySQL from ...
https://dev.mysql.com/doc/refman/8.4/en/examples.html
Some of the examples use the table shop to hold the price of each article (item number) for certain traders (dealers). Here are examples of how to solve some common problems with MySQL. Supposing that each trader has a single fixed price per ...
https://dev.mysql.com/doc/refman/8.4/en/fetching-spatial-data.html
Geometry values stored in a table can be fetched in internal format. Fetching spatial data in internal format: Fetching geometry values using internal format can be useful in table-to-table transfers: CREATE TABLE geom2 (g GEOMETRY) SELECT g FROM ...SELECT ST_AsText(g) FROM geom; Fetching spatial data in WKB format: The ST_AsBinary() function converts a geometry from internal format to a BLOB containing the WKB ...
https://dev.mysql.com/doc/refman/8.4/en/fractional-seconds.html
For example: CREATE TABLE t1 (t TIME(3), dt DATETIME(6)); The fsp value, if given, must be in the range 0 to 6. MySQL has fractional seconds support for TIME, DATETIME, and TIMESTAMP values, with up to microseconds (6 digits) precision: To define a ...
https://dev.mysql.com/doc/refman/8.4/en/group-replication-adding-instances.html
Checking the performance_schema.replication_group_members table again shows that there are now two ONLINE servers in the group. At this point, the group has one member in it, server s1, which has some data in it. It is now time to expand the group ...
https://dev.mysql.com/doc/refman/8.4/en/group-replication-configuring-consistency-guarantees.html
Although the Transaction Synchronization Points section explains that conceptually there are two synchronization points from which you can choose: on read or on write, these terms were a simplification and the terms used in Group Replication are: ...
https://dev.mysql.com/doc/refman/8.4/en/group-replication-server-states.html
The Performance Schema table replication_group_members shows the state for each member in a group. If you see this status for other servers, it can also mean that the member where you query this table is part of a partition, where a subset of the ...
https://dev.mysql.com/doc/refman/8.4/en/index-btree-hash.html
One circumstance under which this occurs is when the optimizer estimates that using the index would require MySQL to access a very large percentage of the rows in the table. (In this case, a table scan is likely to be much faster because it requires ... Understanding the B-tree and hash data structures can help predict how different queries perform on different storage engines that use these data structures in their indexes, particularly for the MEMORY storage engine that lets you choose B-tree or hash ...
https://dev.mysql.com/doc/refman/8.4/en/innochecksum.html
This tool reads an InnoDB tablespace file, calculates the checksum for each page, compares the calculated checksum to the stored checksum, and reports mismatches, which indicate damaged pages. It was originally developed to speed up verifying the ...
https://dev.mysql.com/doc/refman/8.4/en/innodb-buffer-pool-in-core-file.html
The following table shows configuration and MADV_DONTDUMP support scenarios that determine whether core files are generated and whether they include buffer pool pages. The following table provides size reduction examples that you might see for a 1GB ... A core file records the status and memory image of a running ...