Altering Column Families
About this task
Modifying a Column Family Using the MapR Control System
Procedure
- Go to the table information page.
-
Click Column Families tab.
The page displays:
- Default column family permissions
- All the column families for the table
-
Click the name of the column family to modify.
The Edit Column Family page displays.
-
Make changes to the following properties (under PROPERTIES) as desired.
Column Family Name The name of the column family. Compression The compression setting to use for the column family. Valid options are off, lzf, lz4, and zlib. The default setting is the same as the compression setting for the directory where the table is located. To find out whether a directory is compressed and the type of compression, see Turning Compression On or Off on Directories Using the CLI. In Memory Determines whether preference is given to values of this column family for storage with row keys. Because row keys are cached in memory in preference to row data, column-family data that is stored inline with the row keys is also cached in memory. For all column families in a table together, up to 200 bytes of row data will be stored inline with each row key. Storing data inline with a row key might speed retrieval of the data from a column family because disk access can often be avoided. For each column family, up to 32 bytes can be stored inline with each row key even if this is disabled (No), but preference will be given to column families where this is enabled (Yes). A column family can have more than 32 bytes stored inline if this is enabled.
If the total number of bytes for all column families together exceeds 200 for a row, then preference for inclusion within the inline storage for that row is given to column families that have this enabled.
NOTE: All of the data for a column family will be stored in-line with the row key, or none will be. If the contents in a column family for a particular row are larger than the maximum number of bytes that are allowed to be stored for that column family, no data will be stored in-line for that column family.By default, this is enabled.Column Family Name The name of the column family. Version - Minimum — The minimum number of versions of column values to keep. The default is zero.
- Maximum — Maximum number of versions of column values to keep. The default is one.
Compression The compression setting to use for the column family. Valid options are off, lzf, lz4, and zlib. The default setting is the same as the compression setting for the directory where the table is located. To find out whether a directory is compressed and the type of compression, see Turning Compression On or Off on Directories Using the CLI. Time-to-Live Specifies whether to purge data when the age of the data in this column family exceeds the value specified here. Data can remain forever or can be purged after specified amount of time (in seconds). Setting the value to 0 is equivalent to allowing data to remain indefinitely or forever. In Memory Determines whether preference is given to values of this column family for storage with row keys. Because row keys are cached in memory in preference to row data, column-family data that is stored inline with the row keys is also cached in memory. For all column families in a table together, up to 200 bytes of row data will be stored inline with each row key. Storing data inline with a row key might speed retrieval of the data from a column family because disk access can often be avoided. For each column family, up to 32 bytes can be stored inline with each row key even if this is disabled (No), but preference will be given to column families where this is enabled (Yes). A column family can have more than 32 bytes stored inline if this is enabled.
If the total number of bytes for all column families together exceeds 200 for a row, then preference for inclusion within the inline storage for that row is given to column families that have this enabled.
NOTE: All of the data for a column family will be stored in-line with the row key, or none will be. If the contents in a column family for a particular row are larger than the maximum number of bytes that are allowed to be stored for that column family, no data will be stored in-line for that column family.By default, this is enabled. -
Make changes to permissions as desired.
To grant or block access to users, groups, and/or roles, from the:
- Basic settings, select the type — public, (OR) user, group, or role — from the drop-down
menu, specify the name of the user, group, or role, and select one or more checkbox to
grant permissions.TIP: Click to create a copy of the associated access control setting. Click to remove the associated access control expression.To add access control expressions for another user, group, or role, click Add Another and repeat this step.
- Advanced settings, or specify public (
p
) or user (u
), group (g
), and/or role (r
) who have and/or do not have the type of access using the following boolean expressions and subexpressions:!
— Negation operator.&
— AND operation.|
— OR operation.
()
, parentheses, for subexpressions.NOTE: You cannot specify user, group, or role individually if access is granted to all users (public).Alternatively, click associated with the type of access to use the Access Control Expression window to define access for public or users, group, and/or role. See Defining ACEs for more information.
NOTE: If you switch from Basic to Advanced, the basic settings, if any, will be carried over to the advanced settings. If you switch from Advanced to Basic, all the settings will be lost because the subexpressions and AND (&
) and negation (!
) operations that are supported by advanced settings are not supported in the basic settings. - Basic settings, select the type — public, (OR) user, group, or role — from the drop-down
menu, specify the name of the user, group, or role, and select one or more checkbox to
grant permissions.
- Click Save Changes for the changes to take effect.
Modifying a Column Family Using the CLI or REST API
About this task
maprcli table cf edit -path <path> -cfname <name_of_column_family> options
For
the full list of options for this command, see table cf edit
.The format of the value of the -path
parameter depends on whether you
are creating a table on a local cluster or a remote cluster:
- For a path on the local cluster, start the path at the volume mount point. For
example, for a table named
test
under a volume with a mount point at /volume1, specify the following path:/volume1/test
- For a path on a remote cluster, you must also specify the cluster name in the
path. For example, for a table named
customer
undervolume1
in thesanfrancisco
cluster, specify the following path:/mapr/sanfrancisco/volume1/customer
NOTE: You cannot use the following characters in the table name:To use the following characters in the table name, enclose them either in single or double quotes:< > ? % \
For example:; | ( ) /
maprcli table create -path "/設備^=#;{}&()/" (or) maprcli table create -path '/設備^=#;{}&()/'
To use either the ' or the " character in the table name, enclose:For example:- the ' character within double quotes (")
- the " character within single quote (')
maprcli table create -path "/'設備^=#;{}&()/" (or) maprcli table create -path '/"設備^=#;{}&()/'
Modifying a Column Family in a Binary Table Using HBase shell
About this task
After starting the HBase shell, run the alter
command. Type
help
to see a list of commands and their syntax.