mcsRebuildEM for MariaDB Enterprise ColumnStore 6
This page is part of MariaDB's Documentation.
The parent of this page is: Command-Line Interfaces for MariaDB Enterprise ColumnStore 6
Topics on this page:
Overview
MariaDB Enterprise ColumnStore 6 includes the mcsRebuildEM
utility, which rebuilds the Extent Map from the contents of the database file system.
Reference material is available for MariaDB Enterprise ColumnStore 6.
MariaDB Enterprise ColumnStore 6 is included with MariaDB Enterprise Server 10.6.
USAGE
The mcsRebuildEM
utility should be run from the primary node and requires root
or sudo
or another user with sufficient privileges for /var/lib/columnstore/*
.
The syntax for the mcsRebuildEM
utility is:
mcsRebuildEM [OPTIONS]
DETAILS
The mcsRebuildEM
utility rebuilds or displays the contents of the Extent Map.
MariaDB Enterprise ColumnStore 6 uses the Extent Map to store metadata about the data stored in each extent. There are certain situations when metadata in the Extent Map can become inconsistent with the extents. In these situations, the Extent Map should be rebuilt.
When no options are provided, the mcsRebuildEM
utility rebuilds the Extent Map. It does not check whether the Extent Map is already consistent with the extents. It rebuilds the Extent Map even if the Extent Map is already consistent.
When the -d option is provided, the mcsRebuildEM
utility displays what changes it would make to the Extent Map and exits. This option can be used to test the operation without writing changes to disk.
When the -s option is provided, the mcsRebuildEM
utility displays the current contents of the Extent Map and exits.
The -h option can be used to view the mcsRebuildEM
utility's help output.
The mcsRebuildEM
utility is not supported when MariaDB Enterprise ColumnStore 6 is configured to use Object Storage.
Single-Node ColumnStore using Local Storage
With single-node ColumnStore using Local Storage, the mcsRebuildEM
utility has the following requirements:
The DB Root directory must be available.
mcsRebuildEM Options for MariaDB Enterprise ColumnStore 6
Option | Description |
---|---|
display what would be done--don't do it | |
display this help text | |
show extent map and quit | |
display verbose progress information. More v's, more debug |
To see options supported in other versions, see "mcsRebuildEM Options by MariaDB Enterprise ColumnStore Version".