sstabledowngrade

Downgrades the SSTables in the given table or snapshot to the version of Apache Cassandra® that is compatible with the current version of Hyper-Converged Database (HCD) while the HCD node is offline.

Downgrades the SSTables in the given table or snapshot to the version of Cassandra that is compatible with the current version of HCD while the HCD node is offline.

The sstabledowngrade command cannot be used to downgrade system tables or downgrade HCD versions.

Stop HCD before you run this command.

The default location of this SSTable tool depends on your installation type:

Package installations: /usr/bin/
Tarball installations: <installation_location>/resources/cassandra/tools/bin

Synopsis

sstabledowngrade
[--debug]
[-h | --help]
[[-k | --keep-source] | [--keep-generation]]
[-b | --backups]
[-o | --output-dir <output-dir>]
[--schema <schema-file> [--schema <schema-file2> ... ]]
[--sstable-files <sstable>]
[-t | --throughput <rate-limit>]
[--temp-storage <tmp-dir>]
<keyspace_name>
<table_name>
[<snapshot_name>]

SSTable versions

For details on SSTable versions and compatibility, see HCD, Apache Cassandra, CQL, and SSTable compatibility.

Definition

The short- and long-form options are comma-separated.

Command arguments

--debug

Display stack traces.

-h, --help

Print the usage and listing of the commands.

-k, --keep-source

Don’t delete the source SSTables. Don’t use with the --keep-generation option.

-b, --backups

Rewrite incremental backups for the given table. Cannot be combined with the snapshot_name option.

--keep-generation

Keep the generated SSTables. Don’t use with the --keep-source option.

-o, --output-dir

Rewritten files are placed in output-dir/keyspace-name/table-name-and-id.

--schema

Allows upgrading and downgrading SSTables using the schema of the table in a CQL file containing the DDL statements to re-create the schema. Must be a DDL file that allows the recreation of the table including dropped columns. Repeat the option to specify multiple DDL schema files.

Always use the schema.cql from a snapshot of the table so that the DDL has all of the information omitted by DESCRIBE TABLE, including dropped columns.

--sstable-files

Instead of processing all SSTables in the default data directories, process only the tables specified via this option. If a single SSTable file, only that SSTable is processed. If a directory is specified, all SSTables within that directory are processed. Snapshots and backups are not supported with this option.

-t, --throughput

Set to limit the maximum disk read rate in MB/s.

--temp-storage

When used with --schema, specifies location of temporary data. Directory and contents are deleted when the tool terminates. Directory must not be shared with other tools and must be empty. If not specified the default directory is /tmp.

keyspace_name

Keyspace name. Required.

table_name

Table name. Required.

snapshot_name

Snapshot name.

Rewrites only the specified snapshot.
Replaces files in the given snapshot and breaks any hard links to live SSTables.
Required when attempting to restore a snapshot taken in a different HCD version than the one that is currently running.

Examples

The following example demonstrates how to use the sstabledowngrade command.