http://git-wip-us.apache.org/repos/asf/kudu-site/blob/fee60d98/docs/command_line_tools_reference.html ---------------------------------------------------------------------- diff --git a/docs/command_line_tools_reference.html b/docs/command_line_tools_reference.html new file mode 100644 index 0000000..060f5dd --- /dev/null +++ b/docs/command_line_tools_reference.html @@ -0,0 +1,2304 @@ + + + + + + + + + + Apache Kudu - Apache Kudu Command Line Tools Reference + + + + + + + + + + + + + + + +
+ + + + + + +
+
+
+ +

Apache Kudu Command Line Tools Reference

+
+

Command Hierarchy

+
+
+ +
+
+
+
+

Command Details

+
+
+

cluster: Operate on a Kudu cluster

+
+


+
+
+

ksck: Check the health of a Kudu cluster 

+
+

By default, ksck checks that master and tablet server processes are running, and that table metadata is consistent. Use the 'checksum' flag to check that tablet data is consistent (also see the 'tables' and 'tablets' flags). Use the 'checksum_snapshot' along with 'checksum' if the table or tablets are actively receiving inserts or updates.
+Usage:
+kudu cluster ksck <master_addresses> [-checksum_cache_blocks] [-checksum_scan] [-checksum_scan_concurrency=<concurrency>] [-nochecksum_snapshot] [-color=<color>] [-tables=<tables>] [-tablets=<tablets>] +
+Arguments:

+
+ ++++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
NameDescriptionTypeDefault

master_addresses

Comma-separated list of Kudu Master addresses where each address is of form 'hostname:port'

string

none

checksum_cache_blocks (optional)

Should the checksum scanners cache the read blocks

bool

false

checksum_scan (optional)

Perform a checksum scan on data in the cluster.

bool

false

checksum_scan_concurrency (optional)

Number of concurrent checksum scans to execute per tablet server.

int32

4

checksum_snapshot (optional)

Should the checksum scanner use a snapshot scan

bool

true

color (optional)

Specifies whether output should be colorized. The default value 'auto' colorizes output if the output is a terminal. The other valid values are 'always' or 'never'.

string

auto

tables (optional)

Tables to check (comma-separated list of names). If not specified, checks all tables.

string

none

tablets (optional)

Tablets to check (comma-separated list of IDs) If not specified, checks all tablets.

string

none

+
+


+
+
+
+
+

fs: Operate on a local Kudu filesystem

+
+


+
+
+

format: Format a new Kudu filesystem 

+
+

Usage:
+kudu fs format [-fs_wal_dir=<dir>] [-fs_data_dirs=<dirs>] [-uuid=<uuid>] +
+Arguments:

+
+ ++++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
NameDescriptionTypeDefault

fs_wal_dir (optional)

Directory with write-ahead logs. If this is not specified, the program will not start. May be the same as fs_data_dirs

string

none

fs_data_dirs (optional)

Comma-separated list of directories with data blocks. If this is not specified, fs_wal_dir will be used as the sole data block directory.

string

none

uuid (optional)

The uuid to use in the filesystem. If not provided, one is generated

string

none

+
+


+
+
+
+

dump: Dump a Kudu filesystem

+
+


+
+
+
cfile: Dump the contents of a CFile (column file) 
+
+

Usage:
+kudu fs dump cfile <block_id> [-fs_wal_dir=<dir>] [-fs_data_dirs=<dirs>] [-noprint_meta] [-noprint_rows] +
+Arguments:

+
+ ++++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
NameDescriptionTypeDefault

block_id

block identifier

string

none

fs_wal_dir (optional)

Directory with write-ahead logs. If this is not specified, the program will not start. May be the same as fs_data_dirs

string

none

fs_data_dirs (optional)

Comma-separated list of directories with data blocks. If this is not specified, fs_wal_dir will be used as the sole data block directory.

string

none

print_meta (optional)

Include metadata in output

bool

true

print_rows (optional)

Print each row in the CFile

bool

true

+
+


+
+
+
+
tree: Dump the tree of a Kudu filesystem 
+
+

Usage:
+kudu fs dump tree [-fs_wal_dir=<dir>] [-fs_data_dirs=<dirs>] +
+Arguments:

+
+ ++++++ + + + + + + + + + + + + + + + + + + + + + + +
NameDescriptionTypeDefault

fs_wal_dir (optional)

Directory with write-ahead logs. If this is not specified, the program will not start. May be the same as fs_data_dirs

string

none

fs_data_dirs (optional)

Comma-separated list of directories with data blocks. If this is not specified, fs_wal_dir will be used as the sole data block directory.

string

none

+
+


+
+
+
+
uuid: Dump the UUID of a Kudu filesystem 
+
+

Usage:
+kudu fs dump uuid [-fs_wal_dir=<dir>] [-fs_data_dirs=<dirs>] +
+Arguments:

+
+ ++++++ + + + + + + + + + + + + + + + + + + + + + + +
NameDescriptionTypeDefault

fs_wal_dir (optional)

Directory with write-ahead logs. If this is not specified, the program will not start. May be the same as fs_data_dirs

string

none

fs_data_dirs (optional)

Comma-separated list of directories with data blocks. If this is not specified, fs_wal_dir will be used as the sole data block directory.

string

none

+
+


+
+
+
+
+
+

local_replica: Operate on local tablet replicas via the local filesystem

+
+


+
+
+

copy_from_remote: Copy a tablet replica from a remote server 

+
+

Usage:
+kudu local_replica copy_from_remote <tablet_id> <source> [-fs_wal_dir=<dir>] [-fs_data_dirs=<dirs>] +
+Arguments:

+
+ ++++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
NameDescriptionTypeDefault

tablet_id

Tablet Identifier

string

none

source

Source RPC address of form hostname:port

string

none

fs_wal_dir (optional)

Directory with write-ahead logs. If this is not specified, the program will not start. May be the same as fs_data_dirs

string

none

fs_data_dirs (optional)

Comma-separated list of directories with data blocks. If this is not specified, fs_wal_dir will be used as the sole data block directory.

string

none

+
+


+
+
+
+

delete: Delete a tablet replica from the local filesystem. By default, leaves a tombstone record. 

+
+

Usage:
+kudu local_replica delete <tablet_id> [-fs_wal_dir=<dir>] [-fs_data_dirs=<dirs>] [-clean_unsafe] +
+Arguments:

+
+ ++++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
NameDescriptionTypeDefault

tablet_id

Tablet Identifier

string

none

fs_wal_dir (optional)

Directory with write-ahead logs. If this is not specified, the program will not start. May be the same as fs_data_dirs

string

none

fs_data_dirs (optional)

Comma-separated list of directories with data blocks. If this is not specified, fs_wal_dir will be used as the sole data block directory.

string

none

clean_unsafe (optional)

Delete the local replica completely, not leaving a tombstone. This is not guaranteed to be safe because it also removes the consensus metadata (including Raft voting record) for the specified tablet, which violates the Raft vote durability requirements.

bool

false

+
+


+
+
+
+

list: Show list of tablet replicas in the local filesystem 

+
+

Usage:
+kudu local_replica list [-fs_wal_dir=<dir>] [-fs_data_dirs=<dirs>] [-list_detail] +
+Arguments:

+
+ ++++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
NameDescriptionTypeDefault

fs_wal_dir (optional)

Directory with write-ahead logs. If this is not specified, the program will not start. May be the same as fs_data_dirs

string

none

fs_data_dirs (optional)

Comma-separated list of directories with data blocks. If this is not specified, fs_wal_dir will be used as the sole data block directory.

string

none

list_detail (optional)

Print partition info for the local replicas

bool

false

+
+


+
+
+
+

cmeta: Operate on a local tablet replica’s consensus metadata file

+
+


+
+
+
print_replica_uuids: Print all tablet replica peer UUIDs found in a tablet’s Raft configuration 
+
+

Usage:
+kudu local_replica cmeta print_replica_uuids <tablet_id> [-fs_wal_dir=<dir>] [-fs_data_dirs=<dirs>] +
+Arguments:

+
+ ++++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
NameDescriptionTypeDefault

tablet_id

Tablet Identifier

string

none

fs_wal_dir (optional)

Directory with write-ahead logs. If this is not specified, the program will not start. May be the same as fs_data_dirs

string

none

fs_data_dirs (optional)

Comma-separated list of directories with data blocks. If this is not specified, fs_wal_dir will be used as the sole data block directory.

string

none

+
+


+
+
+
+
rewrite_raft_config: Rewrite a tablet replica’s Raft configuration 
+
+

Usage:
+kudu local_replica cmeta rewrite_raft_config <tablet_id> <peers>…​ [-fs_wal_dir=<dir>] [-fs_data_dirs=<dirs>] +
+Arguments:

+
+ ++++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
NameDescriptionTypeDefault

tablet_id

Tablet Identifier

string

none

peers…​

List of peers where each peer is of form 'uuid:hostname:port'

string

none

fs_wal_dir (optional)

Directory with write-ahead logs. If this is not specified, the program will not start. May be the same as fs_data_dirs

string

none

fs_data_dirs (optional)

Comma-separated list of directories with data blocks. If this is not specified, fs_wal_dir will be used as the sole data block directory.

string

none

+
+


+
+
+
+
+

dump: Dump a Kudu filesystem

+
+


+
+
+
block_ids: Dump the IDs of all blocks belonging to a local replica 
+
+

Usage:
+kudu local_replica dump block_ids <tablet_id> [-fs_wal_dir=<dir>] [-fs_data_dirs=<dirs>] +
+Arguments:

+
+ ++++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
NameDescriptionTypeDefault

tablet_id

Tablet Identifier

string

none

fs_wal_dir (optional)

Directory with write-ahead logs. If this is not specified, the program will not start. May be the same as fs_data_dirs

string

none

fs_data_dirs (optional)

Comma-separated list of directories with data blocks. If this is not specified, fs_wal_dir will be used as the sole data block directory.

string

none

+
+


+
+
+
+
meta: Dump the metadata of a local replica 
+
+

Usage:
+kudu local_replica dump meta <tablet_id> [-fs_wal_dir=<dir>] [-fs_data_dirs=<dirs>] +
+Arguments:

+
+ ++++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
NameDescriptionTypeDefault

tablet_id

Tablet Identifier

string

none

fs_wal_dir (optional)

Directory with write-ahead logs. If this is not specified, the program will not start. May be the same as fs_data_dirs

string

none

fs_data_dirs (optional)

Comma-separated list of directories with data blocks. If this is not specified, fs_wal_dir will be used as the sole data block directory.

string

none

+
+


+
+
+
+
rowset: Dump the rowset contents of a local replica 
+
+

Usage:
+kudu local_replica dump rowset <tablet_id> [-dump_data] [-fs_wal_dir=<dir>] [-fs_data_dirs=<dirs>] [-metadata_only] [-nrows=<nrows>] [-rowset_index=<index>] +
+Arguments:

+
+ ++++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
NameDescriptionTypeDefault

tablet_id

Tablet Identifier

string

none

dump_data (optional)

Dump the data for each column in the rowset.

bool

false

fs_wal_dir (optional)

Directory with write-ahead logs. If this is not specified, the program will not start. May be the same as fs_data_dirs

string

none

fs_data_dirs (optional)

Comma-separated list of directories with data blocks. If this is not specified, fs_wal_dir will be used as the sole data block directory.

string

none

metadata_only (optional)

Only dump the block metadata when printing blocks.

bool

false

nrows (optional)

Number of rows to dump

int64

0

rowset_index (optional)

Index of the rowset in local replica, default value(-1) will dump all the rowsets of the local replica

int64

-1

+
+


+
+
+
+
wals: Dump all WAL (write-ahead log) segments of a local replica 
+
+

Usage:
+kudu local_replica dump wals <tablet_id> [-fs_wal_dir=<dir>] [-fs_data_dirs=<dirs>] [-print_entries=<entries>] [-noprint_meta] [-truncate_data=<data>] +
+Arguments:

+
+ ++++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
NameDescriptionTypeDefault

tablet_id

Tablet Identifier

string

none

fs_wal_dir (optional)

Directory with write-ahead logs. If this is not specified, the program will not start. May be the same as fs_data_dirs

string

none

fs_data_dirs (optional)

Comma-separated list of directories with data blocks. If this is not specified, fs_wal_dir will be used as the sole data block directory.

string

none

print_entries (optional)

How to print entries: + false|0|no = don’t print + true|1|yes|decoded = print them decoded + pb = print the raw protobuf + id = print only their ids

string

decoded

print_meta (optional)

Include metadata in output

bool

true

truncate_data (optional)

Truncate the data fields to the given number of bytes before printing. Set to 0 to disable

int32

100

+
+


+
+
+
+
+
+

master: Operate on a Kudu Master

+
+


+
+
+

set_flag: Change a gflag value on a Kudu Master 

+
+

Usage:
+kudu master set_flag <master_address> <flag> <value> [-force] +
+Arguments:

+
+ ++++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
NameDescriptionTypeDefault

master_address

Address of a Kudu Master of form 'hostname:port'. Port may be omitted if the Master is bound to the default port.

string

none

flag

Name of the gflag

string

none

value

New value for the gflag

string

none

force (optional)

If true, allows the set_flag command to set a flag which is not explicitly marked as runtime-settable. Such flag changes may be simply ignored on the server, or may cause the server to crash.

bool

false

+
+


+
+
+
+

status: Get the status of a Kudu Master 

+
+

Usage:
+kudu master status <master_address> +
+Arguments:

+
+ ++++++ + + + + + + + + + + + + + + + + +
NameDescriptionTypeDefault

master_address

Address of a Kudu Master of form 'hostname:port'. Port may be omitted if the Master is bound to the default port.

string

none

+
+


+
+
+
+

timestamp: Get the current timestamp of a Kudu Master 

+
+

Usage:
+kudu master timestamp <master_address> +
+Arguments:

+
+ ++++++ + + + + + + + + + + + + + + + + +
NameDescriptionTypeDefault

master_address

Address of a Kudu Master of form 'hostname:port'. Port may be omitted if the Master is bound to the default port.

string

none

+
+


+
+
+
+
+

pbc: Operate on PBC (protobuf container) files

+
+


+
+
+

dump: Dump a PBC (protobuf container) file 

+
+

Usage:
+kudu pbc dump <path> [-oneline] +
+Arguments:

+
+ ++++++ + + + + + + + + + + + + + + + + + + + + + + +
NameDescriptionTypeDefault

path

path to PBC file

string

none

oneline (optional)

print each protobuf on a single line

bool

false

+
+


+
+
+
+
+

remote_replica: Operate on remote tablet replicas on a Kudu Tablet Server

+
+


+
+
+

check: Check if all tablet replicas on a Kudu Tablet Server are running 

+
+

Usage:
+kudu remote_replica check <tserver_address> +
+Arguments:

+
+ ++++++ + + + + + + + + + + + + + + + + +
NameDescriptionTypeDefault

tserver_address

Address of a Kudu Tablet Server of form 'hostname:port'. Port may be omitted if the Tablet Server is bound to the default port.

string

none

+
+


+
+
+
+

copy: Copy a tablet replica from one Kudu Tablet Server to another 

+
+

Usage:
+kudu remote_replica copy <tablet_id> <src_address> <dst_address> [-force_copy] +
+Arguments:

+
+ ++++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
NameDescriptionTypeDefault

tablet_id

Tablet Identifier

string

none

src_address

Address of a Kudu Tablet Server of form 'hostname:port'. Port may be omitted if the Tablet Server is bound to the default port.

string

none

dst_address

Address of a Kudu Tablet Server of form 'hostname:port'. Port may be omitted if the Tablet Server is bound to the default port.

string

none

force_copy (optional)

Force the copy when the destination tablet server has this replica

bool

false

+
+


+
+
+
+

delete: Delete a tablet replica from a Kudu Tablet Server 

+
+

Usage:
+kudu remote_replica delete <tserver_address> <tablet_id> <reason> +
+Arguments:

+
+ ++++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
NameDescriptionTypeDefault

tserver_address

Address of a Kudu Tablet Server of form 'hostname:port'. Port may be omitted if the Tablet Server is bound to the default port.

string

none

tablet_id

Tablet Identifier

string

none

reason

Reason for deleting the replica

string

none

+
+


+
+
+
+

dump: Dump the data of a tablet replica on a Kudu Tablet Server 

+
+

Usage:
+kudu remote_replica dump <tserver_address> <tablet_id> +
+Arguments:

+
+ ++++++ + + + + + + + + + + + + + + + + + + + + + + +
NameDescriptionTypeDefault

tserver_address

Address of a Kudu Tablet Server of form 'hostname:port'. Port may be omitted if the Tablet Server is bound to the default port.

string

none

tablet_id

Tablet Identifier

string

none

+
+


+
+
+
+

list: List all tablet replicas on a Kudu Tablet Server 

+
+

Usage:
+kudu remote_replica list <tserver_address> +
+Arguments:

+
+ ++++++ + + + + + + + + + + + + + + + + +
NameDescriptionTypeDefault

tserver_address

Address of a Kudu Tablet Server of form 'hostname:port'. Port may be omitted if the Tablet Server is bound to the default port.

string

none

+
+


+
+
+
+
+

table: Operate on Kudu tables

+
+


+
+
+

delete: Delete a table 

+
+

Usage:
+kudu table delete <master_addresses> <table_name> +
+Arguments:

+
+ ++++++ + + + + + + + + + + + + + + + + + + + + + + +
NameDescriptionTypeDefault

master_addresses

Comma-separated list of Kudu Master addresses where each address is of form 'hostname:port'

string

none

table_name

Name of the table to delete

string

none

+
+


+
+
+
+

list: List all tables 

+
+

Usage:
+kudu table list <master_addresses> [-list_tablets] +
+Arguments:

+
+ ++++++ + + + + + + + + + + + + + + + + + + + + + + +
NameDescriptionTypeDefault

master_addresses

Comma-separated list of Kudu Master addresses where each address is of form 'hostname:port'

string

none

list_tablets (optional)

Include tablet and replica UUIDs in the output

bool

false

+
+


+
+
+
+
+

tablet: Operate on remote Kudu tablets

+
+


+
+
+

leader_step_down: Force the tablet’s leader replica to step down 

+
+

Usage:
+kudu tablet leader_step_down <master_addresses> <tablet_id> +
+Arguments:

+
+ ++++++ + + + + + + + + + + + + + + + + + + + + + + +
NameDescriptionTypeDefault

master_addresses

Comma-separated list of Kudu Master addresses where each address is of form 'hostname:port'

string

none

tablet_id

Tablet Identifier

string

none

+
+


+
+
+
+

change_config: Change a tablet’s Raft configuration

+
+


+
+
+
add_replica: Add a new replica to a tablet’s Raft configuration 
+
+

Usage:
+kudu tablet change_config add_replica <master_addresses> <tablet_id> <replica_uuid> <replica_type> +
+Arguments:

+
+ ++++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
NameDescriptionTypeDefault

master_addresses

Comma-separated list of Kudu Master addresses where each address is of form 'hostname:port'

string

none

tablet_id

Tablet Identifier

string

none

replica_uuid

New replica’s UUID

string

none

replica_type

New replica’s type. Must be VOTER or NON-VOTER.

string

none

+
+


+
+
+
+
change_replica_type: Change the type of an existing replica in a tablet’s Raft configuration 
+
+

Usage:
+kudu tablet change_config change_replica_type <master_addresses> <tablet_id> <replica_uuid> <replica_type> +
+Arguments:

+
+ ++++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
NameDescriptionTypeDefault

master_addresses

Comma-separated list of Kudu Master addresses where each address is of form 'hostname:port'

string

none

tablet_id

Tablet Identifier

string

none

replica_uuid

Existing replica’s UUID

string

none

replica_type

Existing replica’s new type. Must be VOTER or NON-VOTER.

string

none

+
+


+
+
+
+
remove_replica: Remove an existing replica from a tablet’s Raft configuration 
+
+

Usage:
+kudu tablet change_config remove_replica <master_addresses> <tablet_id> <replica_uuid> +
+Arguments:

+
+ ++++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
NameDescriptionTypeDefault

master_addresses

Comma-separated list of Kudu Master addresses where each address is of form 'hostname:port'

string

none

tablet_id

Tablet Identifier

string

none

replica_uuid

Existing replica’s UUID

string

none

+
+


+
+
+
+
+
+

test: Run various tests against a Kudu cluster

+
+


+
+
+

loadgen: Run load generation test with optional scan afterwards 

+
+

Run load generation tool which inserts auto-generated data into already existing or auto-created table as fast as possible. If requested, also run scan over the inserted rows to check whether the actual count or inserted rows matches the expected one.
+Usage:
+kudu test loadgen <master_addresses> [-buffer_flush_watermark_pct=<pct>] [-buffer_size_bytes=<bytes>] [-buffers_num=<num>] [-flush_per_n_rows=<rows>] [-keep_auto_table] [-num_rows_per_thread=<thread>] [-num_threads=<threads>] [-run_scan] [-seq_start=<start>] [-show_first_n_errors=<errors>] [-string_fixed=<fixed>] [-string_len=<len>] [-table_name=<name>] [-table_num_buckets=<buckets>] [-table_num_replicas=<replicas>] [-use_random] +
+Arguments:

+
+ ++++++ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +
NameDescriptionTypeDefault

master_addresses

Comma-separated list of master addresses to run against. Addresses are in 'hostname:port' form where port may be omitted if a master server listens at the default port.

string

none

buffer_flush_watermark_pct (optional)

Mutation buffer flush watermark, in percentage of total size.

double

0.5

buffer_size_bytes (optional)

Size of the mutation buffer, per session (bytes).

int32

4194304

buffers_num (optional)

Number of mutation buffers per session.

int32

2

flush_per_n_rows (optional)

Perform async flush per given number of rows added. Setting to non-zero implicitly turns on manual flush mode.

int32

0

keep_auto_table (optional)

If using the auto-generated table, enabling this option retains the table populated with the data after the test finishes. By default, the auto-generated table is dropped after sucessfully finishing the test. NOTE: this parameter has no effect if using already existing table (see the '--table_name' flag): the existing tables nor their data are never dropped/deleted.

bool

false

num_rows_per_thread (optional)

Number of rows each thread generates and inserts; 0 means unlimited. All rows generated by a thread are inserted in the context of the same session.

uint64

1000

num_threads (optional)

Number of generator threads to run. Each thread runs its own KuduSession.

int32

2

run_scan (optional)

Whether to run post-insertion scan to verify that the count of the inserted rows matches the expected number. If enabled, the scan is run only if no errors were encountered while inserting the generated rows.

bool

false

seq_start (optional)

Initial value for the generator in sequential mode. This is useful when running multiple times against already existing table: for every next run, set this flag to (num_threads * num_rows_per_thread * column_num + seq_start).

uint64

0

show_first_n_errors (optional)

Output detailed information on the specified number of first n errors (if any).

int32

0

string_fixed (optional)

Pre-defined string to write into binary and string columns. Client generates more data per second using pre-defined string compared with auto-generated strings of the same length if run with the same CPU/memory configuration. If left empty, then auto-generated strings of length specified by the '--string_len' parameter are used instead.

string

none

string_len (optional)

Length of strings to put into string and binary columns. This parameter is not in effect if '--string_fixed' is specified.