mcsRebuildEM for MariaDB Enterprise ColumnStore 22.08

This page is part of MariaDB's Documentation.

The parent of this page is: Command-Line Interfaces for MariaDB Enterprise ColumnStore 22.08

Topics on this page:

Overview
USAGE
DETAILS

Overview

MariaDB Enterprise ColumnStore 22.08 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 22.08.

MariaDB Enterprise ColumnStore 22.08 is included with MariaDB Enterprise Server 10.6.

USAGE

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 22.08 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 22.08 is configured to use Object Storage.

ColumnStore Shared Local Storage Topology

In a ColumnStore Shared Local Storage Topology, the mcsRebuildEM utility has the following requirements:

The mcsRebuildEM utility must be executed on the primary node.
The DB Root directories must be available.

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 22.08

Option	Description
-d	display what would be done--don't do it
-h	display this help text
-s	show extent map and quit
-v	display verbose progress information. More v's, more debug

To see options supported in other versions, see "mcsRebuildEM Options by MariaDB Enterprise ColumnStore Version".