MySQL 9.3 Reference Manual Including MySQL NDB Cluster 9.3
The NDB Cluster restoration program is implemented as a separate
command-line utility ndb_restore, which can
normally be found in the MySQL bin
directory. This program reads the files created as a result of
the backup and inserts the stored information into the database.
ndb_restore must be executed once for each of
the backup files that were created by the
START BACKUP
command used to
create the backup (see
Section 25.6.8.2, “Using The NDB Cluster Management Client to Create a Backup”).
This is equal to the number of data nodes in the cluster at the
time that the backup was created.
Before using ndb_restore, it is recommended that the cluster be running in single user mode, unless you are restoring multiple data nodes in parallel. See Section 25.6.6, “NDB Cluster Single User Mode”, for more information.
Options that can be used with ndb_restore are shown in the following table. Additional descriptions follow the table.
Command-Line Format | --allow-pk-changes[=0|1] |
---|---|
Type | Integer |
Default Value | 0 |
Minimum Value | 0 |
Maximum Value | 1 |
When this option is set to 1
,
ndb_restore allows the primary keys in a
table definition to differ from that of the same table in
the backup. This may be desirable when backing up and
restoring between different schema versions with primary key
changes on one or more tables, and it appears that
performing the restore operation using ndb_restore is
simpler or more efficient than issuing many
ALTER TABLE
statements after
restoring table schemas and data.
The following changes in primary key definitions are
supported by --allow-pk-changes
:
Extending the primary key: A non-nullable column that exists in the table schema in the backup becomes part of the table's primary key in the database.
When extending a table's primary key, any columns
which become part of primary key must not be updated
while the backup is being taken; any such updates
discovered by ndb_restore cause the
restore operation to fail, even when no change in
value takes place. In some cases, it may be possible
to override this behavior using the
--ignore-extended-pk-updates
option; see the description of this option for more
information.
Contracting the primary key (1): A column that is already part of the table's primary key in the backup schema is no longer part of the primary key, but remains in the table.
Contracting the primary key (2): A column that is already part of the table's primary key in the backup schema is removed from the table entirely.
These differences can be combined with other schema differences supported by ndb_restore, including changes to blob and text columns requiring the use of staging tables.
Basic steps in a typical scenario using primary key schema changes are listed here:
Restore table schemas using
ndb_restore
--restore-meta
Alter schema to that desired, or create it
Back up the desired schema
Run ndb_restore
--disable-indexes
using the backup from the previous step, to drop indexes
and constraints
Run ndb_restore
--allow-pk-changes
(possibly along with
--ignore-extended-pk-updates
,
--disable-indexes
,
and possibly other options as needed) to restore all
data
Run ndb_restore
--rebuild-indexes
using the backup made with the desired schema, to
rebuild indexes and constraints
When extending the primary key, it may be necessary for
ndb_restore to use a temporary secondary
unique index during the restore operation to map from the
old primary key to the new one. Such an index is created
only when necessary to apply events from the backup log to a
table which has an extended primary key. This index is named
NDB$RESTORE_PK_MAPPING
, and is created on
each table requiring it; it can be shared, if necessary, by
multiple instances of ndb_restore
instances running in parallel. (Running
ndb_restore
--rebuild-indexes
at the
end of the restore process causes this index to be dropped.)
Command-Line Format | --append |
---|
When used with the --tab
and --print-data
options, this causes the data to be appended to any existing
files having the same names.
--backup-path
=dir_name
Command-Line Format | --backup-path=path |
---|---|
Type | Directory name |
Default Value | ./ |
The path to the backup directory is required; this is
supplied to ndb_restore using the
--backup-path
option, and must include the
subdirectory corresponding to the ID backup of the backup to
be restored. For example, if the data node's
DataDir
is
/var/lib/mysql-cluster
, then the backup
directory is
/var/lib/mysql-cluster/BACKUP
, and the
backup files for the backup with the ID 3 can be found in
/var/lib/mysql-cluster/BACKUP/BACKUP-3
.
The path may be absolute or relative to the directory in
which the ndb_restore executable is
located, and may be optionally prefixed with
backup-path=
.
It is possible to restore a backup to a database with a
different configuration than it was created from. For
example, suppose that a backup with backup ID
12
, created in a cluster with two storage
nodes having the node IDs 2
and
3
, is to be restored to a cluster with
four nodes. Then ndb_restore must be run
twice—once for each storage node in the cluster where
the backup was taken. However,
ndb_restore cannot always restore backups
made from a cluster running one version of MySQL to a
cluster running a different MySQL version. See
Section 25.3.7, “Upgrading and Downgrading NDB Cluster”, for more
information.
It is not possible to restore a backup made from a newer version of NDB Cluster using an older version of ndb_restore. You can restore a backup made from a newer version of MySQL to an older cluster, but you must use a copy of ndb_restore from the newer NDB Cluster version to do so.
For example, to restore a cluster backup taken from a cluster running NDB Cluster 8.4.5 to a cluster running NDB Cluster 8.0.42, you must use the ndb_restore that comes with the NDB Cluster 8.0.42 distribution.
For more rapid restoration, the data may be restored in
parallel, provided that there is a sufficient number of
cluster connections available. That is, when restoring to
multiple nodes in parallel, you must have an
[api]
or [mysqld]
section in the cluster config.ini
file
available for each concurrent ndb_restore
process. However, the data files must always be applied
before the logs.
Command-Line Format | --backup-password=password |
---|---|
Type | String |
Default Value | [none] |
This option specifies a password to be used when decrypting
an encrypted backup with the
--decrypt
option. This
must be the same password that was used to encrypt the
backup.
The password must be 1 to 256 characters in length, and must
be enclosed by single or double quotation marks. It can
contain any of the ASCII characters having character codes
32, 35, 38, 40-91, 93, 95, and 97-126; in other words, it
can use any printable ASCII characters except for
!
, '
,
"
, $
,
%
, \
, and
^
.
It is possible to omit the password, in which case
ndb_restore waits for it to be supplied
from stdin
, as when using
--backup-password-from-stdin
.
--backup-password-from-stdin[=TRUE|FALSE]
Command-Line Format | --backup-password-from-stdin |
---|
When used in place of
--backup-password
, this
option enables input of the backup password from the system
shell (stdin
), similar to how this is
done when supplying the password interactively to
mysql when using the
--password
without supplying
the password on the command line.
--backupid
=#
,
-b
Command-Line Format | --backupid=# |
---|---|
Type | Numeric |
Default Value | none |
This option is required; it is used to specify the ID or
sequence number of the backup, and is the same number shown
by the management client in the Backup
message displayed upon completion of a backup. (See
Section 25.6.8.2, “Using The NDB Cluster Management Client to Create a Backup”.)
backup_id
completed
When restoring cluster backups, you must be sure to restore all data nodes from backups having the same backup ID. Using files from different backups results at best in restoring the cluster to an inconsistent state, and is likely to fail altogether.
Command-Line Format | --character-sets-dir=path |
---|
Directory containing character sets.
--connect
,
-c
Command-Line Format | --connect=connection_string |
---|---|
Type | String |
Default Value | localhost:1186 |
Alias for
--ndb-connectstring
.
Command-Line Format | --connect-retries=# |
---|---|
Type | Integer |
Default Value | 12 |
Minimum Value | 0 |
Maximum Value | 12 |
Number of times to retry connection before giving up.
Command-Line Format | --connect-retry-delay=# |
---|---|
Type | Integer |
Default Value | 5 |
Minimum Value | 0 |
Maximum Value | 5 |
Number of seconds to wait between attempts to contact management server.
Command-Line Format | --connect-string=connection_string |
---|---|
Type | String |
Default Value | [none] |
Same as
--ndb-connectstring
.
Command-Line Format | --core-file |
---|
Write core file on error; used in debugging.
Command-Line Format | --decrypt |
---|
Decrypt an encrypted backup using the password supplied by
the --backup-password
option.
Command-Line Format | --defaults-extra-file=path |
---|---|
Type | String |
Default Value | [none] |
Read given file after global files are read.
Command-Line Format | --defaults-file=path |
---|---|
Type | String |
Default Value | [none] |
Read default options from given file only.
Command-Line Format | --defaults-group-suffix=string |
---|---|
Type | String |
Default Value | [none] |
Also read groups with concat(group, suffix).
Command-Line Format | --disable-indexes |
---|
Disable restoration of indexes during restoration of the
data from a native NDB
backup.
Afterwards, you can restore indexes for all tables at once
with multithreaded building of indexes using
--rebuild-indexes
, which
should be faster than rebuilding indexes concurrently for
very large tables.
This option also drops any foreign keys specified in the backup.
MySQL can open an NDB
table for which one
or more indexes cannot be found, provided the query does not
use any of the affected indexes; otherwise the query is
rejected with
ER_NOT_KEYFILE
. In the
latter case, you can temporarily work around the problem by
executing an ALTER TABLE
statement such as this one:
ALTER TABLE tbl ALTER INDEX idx INVISIBLE;
This causes MySQL to ignore the index idx
on table tbl
. See
Primary Keys and Indexes, for more information,
as well as Section 10.3.12, “Invisible Indexes”.
Command-Line Format | --dont-ignore-systab-0 |
---|
Normally, when restoring table data and metadata,
ndb_restore ignores the copy of the
NDB
system table that is
present in the backup.
--dont-ignore-systab-0
causes the system
table to be restored. This option is intended for
experimental and development use only, and is not
recommended in a production environment.
--exclude-databases
=db-list
Command-Line Format | --exclude-databases=list |
---|---|
Type | String |
Default Value |
|
Comma-delimited list of one or more databases which should not be restored.
This option is often used in combination with
--exclude-tables
; see
that option's description for further information and
examples.
--exclude-intermediate-sql-tables[
=TRUE|FALSE]
Command-Line Format | --exclude-intermediate-sql-tables[=TRUE|FALSE] |
---|---|
Type | Boolean |
Default Value | TRUE |
When performing copying ALTER
TABLE
operations, mysqld
creates intermediate tables (whose names are prefixed with
#sql-
). When TRUE
, the
--exclude-intermediate-sql-tables
option
keeps ndb_restore from restoring such
tables that may have been left over from these operations.
This option is TRUE
by default.
Command-Line Format | --exclude-missing-columns |
---|
It is possible to restore only selected table columns using
this option, which causes ndb_restore to
ignore any columns missing from tables being restored as
compared to the versions of those tables found in the
backup. This option applies to all tables being restored. If
you wish to apply this option only to selected tables or
databases, you can use it in combination with one or more of
the --include-*
or
--exclude-*
options described elsewhere in
this section to do so, then restore data to the remaining
tables using a complementary set of these options.
Command-Line Format | --exclude-missing-tables |
---|
It is possible to restore only selected tables using this option, which causes ndb_restore to ignore any tables from the backup that are not found in the target database.
--exclude-tables
=table-list
Command-Line Format | --exclude-tables=list |
---|---|
Type | String |
Default Value |
|
List of one or more tables to exclude; each table reference
must include the database name. Often used together with
--exclude-databases
.
When --exclude-databases
or --exclude-tables
is used, only those
databases or tables named by the option are excluded; all
other databases and tables are restored by
ndb_restore.
This table shows several invocations of
ndb_restore using
--exclude-*
options (other options possibly
required have been omitted for clarity), and the effects
these options have on restoring from an NDB Cluster backup:
Table 25.23 Several invocations of ndb_restore using --exclude-* options, and the effects these options have on restoring from an NDB Cluster backup.
Option | Result |
---|---|
--exclude-databases=db1 |
All tables in all databases except db1 are restored;
no tables in db1 are restored |
--exclude-databases=db1,db2 (or
--exclude-databases=db1
--exclude-databases=db2 ) |
All tables in all databases except db1 and
db2 are restored; no tables in
db1 or db2 are
restored |
--exclude-tables=db1.t1 |
All tables except t1 in database
db1 are restored; all other tables
in db1 are restored; all tables in
all other databases are restored |
--exclude-tables=db1.t2,db2.t1 (or
--exclude-tables=db1.t2
--exclude-tables=db2.t1) |
All tables in database db1 except for
t2 and all tables in database
db2 except for table
t1 are restored; no other tables in
db1 or db2 are
restored; all tables in all other databases are
restored |
You can use these two options together. For example, the
following causes all tables in all databases
except for databases
db1
and db2
, and
tables t1
and t2
in
database db3
, to be restored:
$> ndb_restore [...] --exclude-databases=db1,db2 --exclude-tables=db3.t1,db3.t2
(Again, we have omitted other possibly necessary options in the interest of clarity and brevity from the example just shown.)
You can use --include-*
and
--exclude-*
options together, subject to
the following rules:
The actions of all --include-*
and
--exclude-*
options are cumulative.
All --include-*
and
--exclude-*
options are evaluated in
the order passed to ndb_restore, from right to left.
In the event of conflicting options, the first (rightmost) option takes precedence. In other words, the first option (going from right to left) that matches against a given database or table “wins”.
For example, the following set of options causes
ndb_restore to restore all tables from
database db1
except
db1.t1
, while restoring no other tables
from any other databases:
--include-databases=db1 --exclude-tables=db1.t1
However, reversing the order of the options just given
simply causes all tables from database
db1
to be restored (including
db1.t1
, but no tables from any other
database), because the
--include-databases
option, being farthest to the right, is the first match
against database db1
and thus takes
precedence over any other option that matches
db1
or any tables in
db1
:
--exclude-tables=db1.t1 --include-databases=db1
--fields-enclosed-by
=char
Command-Line Format | --fields-enclosed-by=char |
---|---|
Type | String |
Default Value |
|
Each column value is enclosed by the string passed to this
option (regardless of data type; see the description of
--fields-optionally-enclosed-by
).
--fields-optionally-enclosed-by
Command-Line Format | --fields-optionally-enclosed-by |
---|---|
Type | String |
Default Value |
|
The string passed to this option is used to enclose column
values containing character data (such as
CHAR
,
VARCHAR
,
BINARY
,
TEXT
, or
ENUM
).
Command-Line Format | --fields-terminated-by=char |
---|---|
Type | String |
Default Value | \t (tab) |
The string passed to this option is used to separate column
values. The default value is a tab character
(\t
).
Command-Line Format | --help |
---|
Display help text and exit.
Command-Line Format | --hex |
---|
If this option is used, all binary values are output in hexadecimal format.
Command-Line Format | --ignore-extended-pk-updates[=0|1] |
---|---|
Type | Integer |
Default Value | 0 |
Minimum Value | 0 |
Maximum Value | 1 |
When using
--allow-pk-changes
,
columns which become part of a table's primary key must
not be updated while the backup is being taken; such columns
should keep the same values from the time values are
inserted into them until the rows containing the values are
deleted. If ndb_restore encounters
updates to these columns when restoring a backup, the
restore fails. Because some applications may set values for
all columns when updating a row, even when some column
values are not changed, the backup may include log events
appearing to update columns which are not in fact modified.
In such cases you can set
--ignore-extended-pk-updates
to
1
, forcing ndb_restore
to ignore such updates.
When causing these updates to be ignored, the user is responsible for ensuring that there are no updates to the values of any columns that become part of the primary key.
For more information, see the description of
--allow-pk-changes
.
--include-databases
=db-list
Command-Line Format | --include-databases=list |
---|---|
Type | String |
Default Value |
|
Comma-delimited list of one or more databases to restore.
Often used together with
--include-tables
; see
the description of that option for further information and
examples.
Command-Line Format | --include-stored-grants |
---|
ndb_restore does not by default restore
shared users and grants (see
Section 25.6.13, “Privilege Synchronization and NDB_STORED_USER”)
to the ndb_sql_metadata
table. Specifying
this option causes it to do so.
--include-tables
=table-list
Command-Line Format | --include-tables=list |
---|---|
Type | String |
Default Value |
|
Comma-delimited list of tables to restore; each table reference must include the database name.
When --include-databases
or
--include-tables
is
used, only those databases or tables named by the option are
restored; all other databases and tables are excluded by
ndb_restore, and are not restored.
The following table shows several invocations of
ndb_restore using
--include-*
options (other options possibly
required have been omitted for clarity), and the effects
these have on restoring from an NDB Cluster backup:
Table 25.24 Several invocations of ndb_restore using --include-* options, and their effects on restoring from an NDB Cluster backup.
Option | Result |
---|---|
--include-databases=db1 |
Only tables in database db1 are restored; all tables
in all other databases are ignored |
--include-databases=db1,db2 (or
--include-databases=db1
--include-databases=db2 ) |
Only tables in databases db1 and
db2 are restored; all tables in all
other databases are ignored |
--include-tables=db1.t1 |
Only table t1 in database db1 is
restored; no other tables in db1 or
in any other database are restored |
--include-tables=db1.t2,db2.t1 (or
--include-tables=db1.t2
--include-tables=db2.t1 ) |
Only the table t2 in database db1
and the table t1 in database
db2 are restored; no other tables
in db1 , db2 , or
any other database are restored |
You can also use these two options together. For example,
the following causes all tables in databases
db1
and db2
, together
with the tables t1
and
t2
in database db3
, to
be restored (and no other databases or tables):
$> ndb_restore [...] --include-databases=db1,db2 --include-tables=db3.t1,db3.t2
(Again we have omitted other, possibly required, options in the example just shown.)
It also possible to restore only selected databases, or
selected tables from a single database, without any
--include-*
(or
--exclude-*
) options, using the syntax
shown here:
ndb_restoreother_options
db_name
,[db_name
[,...] |tbl_name
[,tbl_name
][,...]]
In other words, you can specify either of the following to be restored:
All tables from one or more databases
One or more tables from a single database
Command-Line Format | --lines-terminated-by=char |
---|---|
Type | String |
Default Value | \n (linebreak) |
Specifies the string used to end each line of output. The
default is a linefeed character (\n
).
Command-Line Format | --login-path=path |
---|---|
Type | String |
Default Value | [none] |
Read given path from login file.
Command-Line Format | --no-login-paths |
---|
Skips reading options from the login path file.
Command-Line Format | --lossy-conversions |
---|
This option is intended to complement the
--promote-attributes
option. Using --lossy-conversions
allows
lossy conversions of column values (type demotions or
changes in sign) when restoring data from backup. With some
exceptions, the rules governing demotion are the same as for
MySQL replication; see
Section 19.5.1.9.2, “Replication of Columns Having Different Data Types”,
for information about specific type conversions currently
supported by attribute demotion.
This option also makes it possible to restore a
NULL
column as NOT
NULL
. The column must not contain any
NULL
entries; otherwise
ndb_restore stops with an error.
ndb_restore reports any truncation of data that it performs during lossy conversions once per attribute and column.
Command-Line Format | --no-binlog |
---|
This option prevents any connected SQL nodes from writing data restored by ndb_restore to their binary logs.
Command-Line Format | --no-restore-disk-objects |
---|
This option stops ndb_restore from restoring any NDB Cluster Disk Data objects, such as tablespaces and log file groups; see Section 25.6.11, “NDB Cluster Disk Data Tables”, for more information about these.
--no-upgrade
,
-u
Command-Line Format | --no-upgrade |
---|
When using ndb_restore to restore a
backup, VARCHAR
columns
created using the old fixed format are resized and recreated
using the variable-width format now employed. This behavior
can be overridden by specifying
--no-upgrade
.
Command-Line Format | --ndb-connectstring=connection_string |
---|---|
Type | String |
Default Value | [none] |
Set connection string for connecting to
ndb_mgmd. Syntax:
[nodeid=
.
Overrides entries in id
;][host=]hostname
[:port
]NDB_CONNECTSTRING
and my.cnf
.
Command-Line Format | --ndb-mgm-tls=level |
---|---|
Type | Enumeration |
Default Value | relaxed |
Valid Values |
|
Sets the level of TLS support required to connect to the
management server; one of relaxed
or
strict
. relaxed
(the
default) means that a TLS connection is attempted, but
success is not required; strict
means
that TLS is required to connect.
Command-Line Format | --ndb-mgmd-host=connection_string |
---|---|
Type | String |
Default Value | [none] |
Same as
--ndb-connectstring
.
--ndb-nodegroup-map
=map
,
-z
Command-Line Format | --ndb-nodegroup-map=map |
---|
Any value set for this option is ignored, and the option itself does nothing.
Command-Line Format | --ndb-nodeid=# |
---|---|
Type | Integer |
Default Value | [none] |
Set node ID for this node, overriding any ID set by
--ndb-connectstring
.
--ndb-optimized-node-selection
Command-Line Format | --ndb-optimized-node-selection |
---|
Enable optimizations for selection of nodes for
transactions. Enabled by default; use
--skip-ndb-optimized-node-selection
to
disable.
Command-Line Format | --ndb-tls-search-path=list |
---|---|
Type | Path name |
Default Value (Unix) | $HOME/ndb-tls |
Default Value (Windows) | $HOMEDIR/ndb-tls |
Specify a list of directories to search for a CA file. On
Unix platforms, the directory names are separated by colons
(:
); on Windows systems, the semicolon
character (;
) is used as the separator. A
directory reference may be relative or absolute; it may
contain one or more environment variables, each denoted by a
prefixed dollar sign ($
), and expanded
prior to use.
Searching begins with the leftmost named directory and
proceeds from left to right until a file is found. An empty
string denotes an empty search path, which causes all
searches to fail. A string consisting of a single dot
(.
) indicates that the search path
limited to the current working directory.
If no search path is supplied, the compiled-in default value
is used. This value depends on the platform used: On
Windows, this is \ndb-tls
; on other
platforms (including Linux), it is
$HOME/ndb-tls
. This can be overridden by
compiling NDB Cluster using
-DWITH_NDB_TLS_SEARCH_PATH
.
Command-Line Format | --no-defaults |
---|
Do not read default options from any option file other than login file.
--nodeid
=#
,
-n
Command-Line Format | --nodeid=# |
---|---|
Type | Numeric |
Default Value | none |
Specify the node ID of the data node on which the backup was taken; required.
When restoring to a cluster with different number of data nodes from that where the backup was taken, this information helps identify the correct set or sets of files to be restored to a given node. (In such cases, multiple files usually need to be restored to a single data node.) See Restoring to a different number of data nodes, for additional information and examples.
Command-Line Format | --num-slices=# |
---|---|
Type | Integer |
Default Value | 1 |
Minimum Value | 1 |
Maximum Value | 1024 |
When restoring a backup by slices, this option sets the number of slices into which to divide the backup. This allows multiple instances of ndb_restore to restore disjoint subsets in parallel, potentially reducing the amount of time required to perform the restore operation.
A slice is a subset of the data in a
given backup; that is, it is a set of fragments having the
same slice ID, specified using the
--slice-id
option. The
two options must always be used together, and the value set
by --slice-id
must always be less than the
number of slices.
ndb_restore encounters fragments and
assigns each one a fragment counter. When restoring by
slices, a slice ID is assigned to each fragment; this slice
ID is in the range 0 to 1 less than the number of slices.
For a table that is not a
BLOB
table, the slice to
which a given fragment belongs is determined using the
formula shown here:
[slice_ID
] = [fragment_counter
] % [number_of_slices
]
For a BLOB
table, a fragment
counter is not used; the fragment number is used instead,
along with the ID of the main table for the
BLOB
table (recall that
NDB
stores
BLOB
values in a separate table
internally). In this case, the slice ID for a given fragment
is calculated as shown here:
[slice_ID
] = ([main_table_ID
] + [fragment_ID
]) % [number_of_slices
]
Thus, restoring by N
slices means
running N
instances of
ndb_restore, all with
--num-slices=
(along with any other necessary options) and one each with
N
--slice-id=1
,
--slice-id=2
,
--slice-id=3
, and so on through
slice-id=
.
N
-1
Example.
Assume that you want to restore a backup named
BACKUP-1
, found in the default
directory
/var/lib/mysql-cluster/BACKUP/BACKUP-3
on the node file system on each data node, to a cluster
with four data nodes having the node IDs 1, 2, 3, and 4.
To perform this operation using five slices, execute the
sets of commands shown in the following list:
Restore the cluster metadata using ndb_restore as shown here:
$> ndb_restore -b 1 -n 1 -m --disable-indexes --backup-path=/home/ndbuser/backups
Restore the cluster data to the data nodes invoking ndb_restore as shown here:
$>ndb_restore -b 1 -n 1 -r --num-slices=5 --slice-id=0 --backup-path=/var/lib/mysql-cluster/BACKUP/BACKUP-1
$>ndb_restore -b 1 -n 1 -r --num-slices=5 --slice-id=1 --backup-path=/var/lib/mysql-cluster/BACKUP/BACKUP-1
$>ndb_restore -b 1 -n 1 -r --num-slices=5 --slice-id=2 --backup-path=/var/lib/mysql-cluster/BACKUP/BACKUP-1
$>ndb_restore -b 1 -n 1 -r --num-slices=5 --slice-id=3 --backup-path=/var/lib/mysql-cluster/BACKUP/BACKUP-1
$>ndb_restore -b 1 -n 1 -r --num-slices=5 --slice-id=4 --backup-path=/var/lib/mysql-cluster/BACKUP/BACKUP-1
$>ndb_restore -b 1 -n 2 -r --num-slices=5 --slice-id=0 --backup-path=/var/lib/mysql-cluster/BACKUP/BACKUP-1
$>ndb_restore -b 1 -n 2 -r --num-slices=5 --slice-id=1 --backup-path=/var/lib/mysql-cluster/BACKUP/BACKUP-1
$>ndb_restore -b 1 -n 2 -r --num-slices=5 --slice-id=2 --backup-path=/var/lib/mysql-cluster/BACKUP/BACKUP-1
$>ndb_restore -b 1 -n 2 -r --num-slices=5 --slice-id=3 --backup-path=/var/lib/mysql-cluster/BACKUP/BACKUP-1
$>ndb_restore -b 1 -n 2 -r --num-slices=5 --slice-id=4 --backup-path=/var/lib/mysql-cluster/BACKUP/BACKUP-1
$>ndb_restore -b 1 -n 3 -r --num-slices=5 --slice-id=0 --backup-path=/var/lib/mysql-cluster/BACKUP/BACKUP-1
$>ndb_restore -b 1 -n 3 -r --num-slices=5 --slice-id=1 --backup-path=/var/lib/mysql-cluster/BACKUP/BACKUP-1
$>ndb_restore -b 1 -n 3 -r --num-slices=5 --slice-id=2 --backup-path=/var/lib/mysql-cluster/BACKUP/BACKUP-1
$>ndb_restore -b 1 -n 3 -r --num-slices=5 --slice-id=3 --backup-path=/var/lib/mysql-cluster/BACKUP/BACKUP-1
$>ndb_restore -b 1 -n 3 -r --num-slices=5 --slice-id=4 --backup-path=/var/lib/mysql-cluster/BACKUP/BACKUP-1
$>ndb_restore -b 1 -n 4 -r --num-slices=5 --slice-id=0 --backup-path=/var/lib/mysql-cluster/BACKUP/BACKUP-1
$>ndb_restore -b 1 -n 4 -r --num-slices=5 --slice-id=1 --backup-path=/var/lib/mysql-cluster/BACKUP/BACKUP-1
$>ndb_restore -b 1 -n 4 -r --num-slices=5 --slice-id=2 --backup-path=/var/lib/mysql-cluster/BACKUP/BACKUP-1
$>ndb_restore -b 1 -n 4 -r --num-slices=5 --slice-id=3 --backup-path=/var/lib/mysql-cluster/BACKUP/BACKUP-1
$>ndb_restore -b 1 -n 4 -r --num-slices=5 --slice-id=4 --backup-path=/var/lib/mysql-cluster/BACKUP/BACKUP-1
All of the commands just shown in this step can be
executed in parallel, provided there are enough slots
for connections to the cluster (see the description for
the --backup-path
option).
Restore indexes as usual, as shown here:
$> ndb_restore -b 1 -n 1 --rebuild-indexes --backup-path=/var/lib/mysql-cluster/BACKUP/BACKUP-1
Finally, restore the epoch, using the command shown here:
$> ndb_restore -b 1 -n 1 --restore-epoch --backup-path=/var/lib/mysql-cluster/BACKUP/BACKUP-1
You should use slicing to restore the cluster data only; it
is not necessary to employ
--num-slices
or
--slice-id
when
restoring the metadata, indexes, or epoch information. If
either or both of these options are used with the
ndb_restore options controlling
restoration of these, the program ignores them.
The effects of using the
--parallelism
option on
the speed of restoration are independent of those produced
by slicing or parallel restoration using multiple instances
of ndb_restore
(--parallelism
specifies the number of
parallel transactions executed by a
single ndb_restore
thread), but it can be used together with either or both of
these. You should be aware that increasing
--parallelism
causes
ndb_restore to impose a greater load on
the cluster; if the system can handle this, restoration
should complete even more quickly.
The value of --num-slices
is not directly
dependent on values relating to hardware such as number of
CPUs or CPU cores, amount of RAM, and so forth, nor does it
depend on the number of LDMs.
It is possible to employ different values for this option on different data nodes as part of the same restoration; doing so should not in and of itself produce any ill effects.
--parallelism
=#
,
-p
Command-Line Format | --parallelism=# |
---|---|
Type | Numeric |
Default Value | 128 |
Minimum Value | 1 |
Maximum Value | 1024 |
ndb_restore uses single-row transactions to apply many rows concurrently. This parameter determines the number of parallel transactions (concurrent rows) that an instance of ndb_restore tries to use. By default, this is 128; the minimum is 1, and the maximum is 1024.
The work of performing the inserts is parallelized across
the threads in the data nodes involved. This mechanism is
employed for restoring bulk data from the
.Data
file—that is, the fuzzy
snapshot of the data; it is not used for building or
rebuilding indexes. The change log is applied serially;
index drops and builds are DDL operations and handled
separately. There is no thread-level parallelism on the
client side of the restore.
--preserve-trailing-spaces
,
-P
Command-Line Format | --preserve-trailing-spaces |
---|
Cause trailing spaces to be preserved when promoting a
fixed-width character data type to its variable-width
equivalent—that is, when promoting a
CHAR
column value to
VARCHAR
, or a
BINARY
column value to
VARBINARY
. Otherwise, any
trailing spaces are dropped from such column values when
they are inserted into the new columns.
Command-Line Format | --print |
---|
Causes ndb_restore to print all data,
metadata, and logs to stdout
. Equivalent
to using the
--print-data
,
--print-meta
, and
--print-log
options
together.
Use of --print
or any of the
--print_*
options is in effect performing
a dry run. Including one or more of these options causes
any output to be redirected to stdout
;
in such cases, ndb_restore makes no
attempt to restore data or metadata to an NDB Cluster.
Command-Line Format | --print-data |
---|
Cause ndb_restore to direct its output to
stdout
. Often used together with one or
more of --tab
,
--fields-enclosed-by
,
--fields-optionally-enclosed-by
,
--fields-terminated-by
,
--hex
, and
--append
.
TEXT
and
BLOB
column values are always
truncated. Such values are truncated to the first 256 bytes
in the output. This cannot currently be overridden when
using --print-data
.
Command-Line Format | --print-defaults |
---|
Print program argument list and exit.
Command-Line Format | --print-log |
---|
Cause ndb_restore to output its log to
stdout
.
Command-Line Format | --print-meta |
---|
Print all metadata to stdout
.
Command-Line Format | --print-sql-log |
---|
Log SQL statements to stdout
. Use the
option to enable; normally this behavior is disabled. The
option checks before attempting to log whether all the
tables being restored have explicitly defined primary keys;
queries on a table having only the hidden primary key
implemented by NDB
cannot be converted to
valid SQL.
This option does not work with tables having
BLOB
columns.
Command-Line Format | --progress-frequency=# |
---|---|
Type | Numeric |
Default Value | 0 |
Minimum Value | 0 |
Maximum Value | 65535 |
Print a status report each N
seconds while the backup is in progress. 0 (the default)
causes no status reports to be printed. The maximum is
65535.
Command-Line Format | --promote-attributes |
---|
ndb_restore supports limited
attribute promotion in
much the same way that it is supported by MySQL replication;
that is, data backed up from a column of a given type can
generally be restored to a column using a “larger,
similar” type. For example, data from a
CHAR(20)
column can be restored to a
column declared as VARCHAR(20)
,
VARCHAR(30)
, or
CHAR(30)
; data from a
MEDIUMINT
column can be
restored to a column of type
INT
or
BIGINT
. See
Section 19.5.1.9.2, “Replication of Columns Having Different Data Types”,
for a table of type conversions currently supported by
attribute promotion.
This option also makes it possible to restore a NOT
NULL
column as NULL
.
Attribute promotion by ndb_restore must be enabled explicitly, as follows:
Prepare the table to which the backup is to be restored.
ndb_restore cannot be used to
re-create the table with a different definition from the
original; this means that you must either create the
table manually, or alter the columns which you wish to
promote using ALTER TABLE
after restoring the table metadata but before restoring
the data.
Invoke ndb_restore with the
--promote-attributes
option (short form -A
) when restoring
the table data. Attribute promotion does not occur if
this option is not used; instead, the restore operation
fails with an error.
When converting between character data types and
TEXT
or BLOB
, only
conversions between character types
(CHAR
and
VARCHAR
) and binary types
(BINARY
and
VARBINARY
) can be performed
at the same time. For example, you cannot promote an
INT
column to
BIGINT
while promoting a
VARCHAR
column to TEXT
in the same invocation of ndb_restore.
Converting between TEXT
columns using different character sets is not supported, and
is expressly disallowed.
When performing conversions of character or binary types to
TEXT
or BLOB
with
ndb_restore, you may notice that it
creates and uses one or more staging tables named
.
These tables are not needed afterwards, and are normally
deleted by ndb_restore following a
successful restoration.
table_name
$STnode_id
Command-Line Format | --rebuild-indexes |
---|
Enable multithreaded rebuilding of the ordered indexes while
restoring a native NDB
backup. The number
of threads used for building ordered indexes by
ndb_restore with this option is
controlled by the
BuildIndexThreads
data node configuration parameter and the number of LDMs.
It is necessary to use this option only for the first run of
ndb_restore; this causes all ordered
indexes to be rebuilt without using
--rebuild-indexes
again when restoring
subsequent nodes. You should use this option prior to
inserting new rows into the database; otherwise, it is
possible for a row to be inserted that later causes a unique
constraint violation when trying to rebuild the indexes.
Building of ordered indices is parallelized with the number
of LDMs by default. Offline index builds performed during
node and system restarts can be made faster using the
BuildIndexThreads
data node configuration parameter; this parameter has no
effect on dropping and rebuilding of indexes by
ndb_restore, which is performed online.
Rebuilding of unique indexes uses disk write bandwidth for
redo logging and local checkpointing. An insufficient amount
of this bandwidth can lead to redo buffer overload or log
overload errors. In such cases you can run
ndb_restore
--rebuild-indexes
again; the process
resumes at the point where the error occurred. You can also
do this when you have encountered temporary errors. You can
repeat execution of ndb_restore
--rebuild-indexes
indefinitely; you may be
able to stop such errors by reducing the value of
--parallelism
. If the
problem is insufficient space, you can increase the size of
the redo log
(FragmentLogFileSize
node configuration parameter), or you can increase the speed
at which LCPs are performed
(MaxDiskWriteSpeed
and related parameters), in order to free space more
quickly.
--remap-column=
db
.tbl
.col
:fn
:args
Command-Line Format | --remap-column=string |
---|---|
Type | String |
Default Value | [none] |
When used together with
--restore-data
, this
option applies a function to the value of the indicated
column. Values in the argument string are listed here:
db
: Database name, following
any renames performed by
--rewrite-database
.
tbl
: Table name.
col
: Name of the column to be
updated. This column must be of type
INT
or
BIGINT
. The column can
also be but is not required to be
UNSIGNED
.
fn
: Function name; currently,
the only supported name is offset
.
args
: Arguments supplied to
the function. Currently, only a single argument, the
size of the offset to be added by the
offset
function, is supported.
Negative values are supported. The size of the argument
cannot exceed that of the signed variant of the
column's type; for example, if
col
is an
INT
column, then the allowed range of
the argument passed to the offset
function is -2147483648
to
2147483647
(see
Section 13.1.2, “Integer Types (Exact Value) - INTEGER, INT, SMALLINT, TINYINT,
MEDIUMINT, BIGINT”).
If applying the offset value to the column would cause
an overflow or underflow, the restore operation fails.
This could happen, for example, if the column is a
BIGINT
, and the option attempts to
apply an offset value of 8 on a row in which the column
value is 4294967291, since 4294967291 + 8
= 4294967299 > 4294967295
.
This option can be useful when you wish to merge data stored in multiple source instances of NDB Cluster (all using the same schema) into a single destination NDB Cluster, using NDB native backup (see Section 25.6.8.2, “Using The NDB Cluster Management Client to Create a Backup”) and ndb_restore to merge the data, where primary and unique key values are overlapping between source clusters, and it is necessary as part of the process to remap these values to ranges that do not overlap. It may also be necessary to preserve other relationships between tables. To fulfill such requirements, it is possible to use the option multiple times in the same invocation of ndb_restore to remap columns of different tables, as shown here:
$> ndb_restore --restore-data --remap-column=hr.employee.id:offset:1000 \
--remap-column=hr.manager.id:offset:1000 --remap-column=hr.firstaiders.id:offset:1000
(Other options not shown here may also be used.)
--remap-column
can also be used to update
multiple columns of the same table. Combinations of multiple
tables and columns are possible. Different offset values can
also be used for different columns of the same table, like
this:
$> ndb_restore --restore-data --remap-column=hr.employee.salary:offset:10000 \
--remap-column=hr.employee.hours:offset:-10
When source backups contain duplicate tables which should
not be merged, you can handle this by using
--exclude-tables
,
--exclude-databases
, or
by some other means in your application.
Information about the structure and other characteristics of
tables to be merged can obtained using
SHOW CREATE TABLE
; the
ndb_desc tool; and
MAX()
,
MIN()
,
LAST_INSERT_ID()
, and other
MySQL functions.
Replication of changes from merged to unmerged tables, or from unmerged to merged tables, in separate instances of NDB Cluster is not supported.
--restore-data
,
-r
Command-Line Format | --restore-data |
---|
Output NDB
table data and logs.
--restore-epoch
,
-e
Command-Line Format | --restore-epoch |
---|
Add (or restore) epoch information to the cluster
replication status table. This is useful for starting
replication on an NDB Cluster replica. When this option is
used, the row in the
mysql.ndb_apply_status
having
0
in the id
column is
updated if it already exists; such a row is inserted if it
does not already exist. (See
Section 25.7.9, “NDB Cluster Backups With NDB Cluster Replication”.)
--restore-meta
,
-m
Command-Line Format | --restore-meta |
---|
This option causes ndb_restore to print
NDB
table metadata.
The first time you run the ndb_restore
restoration program, you also need to restore the metadata.
In other words, you must re-create the database
tables—this can be done by running it with the
--restore-meta
(-m
)
option. Restoring the metadata need be done only on a single
data node; this is sufficient to restore it to the entire
cluster.
ndb_restore uses the default number of partitions for the target cluster, unless the number of local data manager threads is also changed from what it was for data nodes in the original cluster.
When using this option, it is recommended that auto
synchronization be disabled by setting
ndb_metadata_check=OFF
until ndb_restore has completed restoring
the metadata, after which it can it turned on again to
synchronize objects newly created in the NDB dictionary.
The cluster should have an empty database when starting to
restore a backup. (In other words, you should start the
data nodes with --initial
prior to performing the restore.)
--rewrite-database
=olddb,newdb
Command-Line Format | --rewrite-database=string |
---|---|
Type | String |
Default Value | none |
This option makes it possible to restore to a database
having a different name from that used in the backup. For
example, if a backup is made of a database named
products
, you can restore the data it
contains to a database named inventory
,
use this option as shown here (omitting any other options
that might be required):
$> ndb_restore --rewrite-database=product,inventory
The option can be employed multiple times in a single
invocation of ndb_restore. Thus it is
possible to restore simultaneously from a database named
db1
to a database named
db2
and from a database named
db3
to one named db4
using --rewrite-database=db1,db2
--rewrite-database=db3,db4
. Other
ndb_restore options may be used between
multiple occurrences of --rewrite-database
.
In the event of conflicts between multiple
--rewrite-database
options, the last
--rewrite-database
option used, reading
from left to right, is the one that takes effect. For
example, if --rewrite-database=db1,db2
--rewrite-database=db1,db3
is used, only
--rewrite-database=db1,db3
is honored, and
--rewrite-database=db1,db2
is ignored. It
is also possible to restore from multiple databases to a
single database, so that --rewrite-database=db1,db3
--rewrite-database=db2,db3
restores all tables and
data from databases db1
and
db2
into database db3
.
When restoring from multiple backup databases into a
single target database using
--rewrite-database
, no check is made for
collisions between table or other object names, and the
order in which rows are restored is not guaranteed. This
means that it is possible in such cases for rows to be
overwritten and updates to be lost.
Command-Line Format | --skip-broken-objects |
---|
This option causes ndb_restore to ignore
corrupt tables while reading a native
NDB
backup, and to continue
restoring any remaining tables (that are not also
corrupted). Currently, the
--skip-broken-objects
option works only in
the case of missing blob parts tables.
Command-Line Format | --skip-table-check |
---|
It is possible to restore data without restoring table metadata. By default when doing this, ndb_restore fails with an error if a mismatch is found between the table data and the table schema; this option overrides that behavior.
Some of the restrictions on mismatches in column definitions
when restoring data using ndb_restore are
relaxed; when one of these types of mismatches is
encountered, ndb_restore does not stop
with an error as it did previously, but rather accepts the
data and inserts it into the target table while issuing a
warning to the user that this is being done. This behavior
occurs whether or not either of the options
--skip-table-check
or
--promote-attributes
is
in use. These differences in column definitions are of the
following types:
Different COLUMN_FORMAT
settings
(FIXED
, DYNAMIC
,
DEFAULT
)
Different STORAGE
settings
(MEMORY
, DISK
)
Different default values
Different distribution key settings
Command-Line Format | --skip-unknown-objects |
---|
This option causes ndb_restore to ignore
any schema objects it does not recognize while reading a
native NDB
backup. This can be
used for restoring a backup made from a cluster running (for
example) NDB 7.6 to a cluster running NDB Cluster 7.5.
Command-Line Format | --slice-id=# |
---|---|
Type | Integer |
Default Value | 0 |
Minimum Value | 0 |
Maximum Value | 1023 |
When restoring by slices, this is the ID of the slice to
restore. This option is always used together with
--num-slices
, and its
value must be always less than that of
--num-slices
.
For more information, see the description of the
--num-slices
elsewhere
in this section.
--tab
=dir_name
,
-T
dir_name
Command-Line Format | --tab=path |
---|---|
Type | Directory name |
Causes --print-data
to
create dump files, one per table, each named
.
It requires as its argument the path to the directory where
the files should be saved; use tbl_name
.txt.
for the
current directory.
Command-Line Format | --timestamp-printouts{=true|false} |
---|---|
Type | Boolean |
Default Value | true |
Causes info, error, and debug log messages to be prefixed with timestamps.
This option is enabled by default. Disable it with
--timestamp-printouts=false
.
Command-Line Format | --usage |
---|
Display help text and exit; same as
--help
.
Command-Line Format | --verbose=# |
---|---|
Type | Numeric |
Default Value | 1 |
Minimum Value | 0 |
Maximum Value | 255 |
Sets the level for the verbosity of the output. The minimum is 0; the maximum is 255. The default value is 1.
Command-Line Format | --version |
---|
Display version information and exit.
Command-Line Format | --with-apply-status |
---|
Restore all rows from the backup's
ndb_apply_status
table (except for the
row having server_id = 0
, which is
generated using
--restore-epoch
). This
option requires that
--restore-data
also be
used.
If the ndb_apply_status
table from the
backup already contains a row with server_id =
0
, ndb_restore
--with-apply-status
deletes it. For this
reason, we recommend that you use
ndb_restore
--restore-epoch
after invoking
ndb_restore with the
--with-apply-status
option. You can also
use --restore-epoch
concurrently with the
last of any invocations of ndb_restore
--with-apply-status
used to restore the
cluster.
For more information, see ndb_apply_status Table.
Typical options for this utility are shown here:
ndb_restore [-cconnection_string
] -nnode_id
-bbackup_id
\ [-m] -r --backup-path=/path/to/backup/files
Normally, when restoring from an NDB Cluster backup,
ndb_restore requires at a minimum the
--nodeid
(short form:
-n
),
--backupid
(short form:
-b
), and
--backup-path
options.
The -c
option is used to specify a connection
string which tells ndb_restore
where to
locate the cluster management server (see
Section 25.4.3.3, “NDB Cluster Connection Strings”). If this
option is not used, then ndb_restore attempts
to connect to a management server on
localhost:1186
. This utility acts as a
cluster API node, and so requires a free connection
“slot” to connect to the cluster management server.
This means that there must be at least one
[api]
or [mysqld]
section
that can be used by it in the cluster
config.ini
file. It is a good idea to keep
at least one empty [api]
or
[mysqld]
section in
config.ini
that is not being used for a
MySQL server or other application for this reason (see
Section 25.4.3.7, “Defining SQL and Other API Nodes in an NDB Cluster”).
ndb_restore can decrypt an encrypted backup
using --decrypt
and
--backup-password
. Both
options must be specified to perform decryption. See the
documentation for the START
BACKUP
management client command for information on
creating encrypted backups.
You can verify that ndb_restore is connected
to the cluster by using the
SHOW
command in the
ndb_mgm management client. You can also
accomplish this from a system shell, as shown here:
$> ndb_mgm -e "SHOW"
Error reporting.
ndb_restore reports both temporary and
permanent errors. In the case of temporary errors, it may able
to recover from them, and reports Restore successful,
but encountered temporary error, please look at
configuration
in such cases.
After using ndb_restore to initialize an
NDB Cluster for use in circular replication, binary logs on
the SQL node acting as the replica are not automatically
created, and you must cause them to be created manually. To
cause the binary logs to be created, issue a
SHOW TABLES
statement on that
SQL node before running START
REPLICA
. This is a known issue in NDB Cluster.