This tool can be used to check for and remove orphaned BLOB
column parts from NDB
tables, as
well as to generate a file listing any orphaned parts. It is
sometimes useful in diagnosing and repairing corrupted or
damaged NDB
tables containing
BLOB
or
TEXT
columns.
The basic syntax for ndb_blob_tool is shown here:
Press CTRL+C to copyndb_blob_tool [options] table [column, ...]
Unless you use the --help
option, you must specify an action to be performed by including
one or more of the options
--check-orphans
,
--delete-orphans
, or
--dump-file
. These options
cause ndb_blob_tool to check for orphaned
BLOB parts, remove any orphaned BLOB parts, and generate a dump
file listing orphaned BLOB parts, respectively, and are
described in more detail later in this section.
You must also specify the name of a table when invoking
ndb_blob_tool. In addition, you can
optionally follow the table name with the (comma-separated)
names of one or more BLOB
or
TEXT
columns from that table. If
no columns are listed, the tool works on all of the table's
BLOB
and
TEXT
columns. If you need to
specify a database, use the
--database
(-d
) option.
The --verbose
option
provides additional information in the output about the
tool's progress.
All options that can be used with ndb_mgmd are shown in the following table. Additional descriptions follow the table.
Table 5.5 Command-line options used with the program ndb_blob_tool
Format | Description | Added, Deprecated, or Removed |
---|---|---|
Write dummy blob parts to take place of those which are missing | ADDED: NDB 8.0.20 |
|
Directory containing character sets | REMOVED: 8.0.31 |
|
Check for blobs having inline parts but missing one or more parts from parts table | ADDED: NDB 8.0.20 |
|
Check for blob parts having no corresponding inline parts | (Supported in all NDB releases based on MySQL 8.0) |
|
Number of times to retry connection before giving up | (Supported in all NDB releases based on MySQL 8.0) |
|
Number of seconds to wait between attempts to contact management server | (Supported in all NDB releases based on MySQL 8.0) |
|
Same as --ndb-connectstring | (Supported in all NDB releases based on MySQL 8.0) |
|
Write core file on error; used in debugging | REMOVED: 8.0.31 |
|
Database to find the table in | (Supported in all NDB releases based on MySQL 8.0) |
|
Read given file after global files are read | (Supported in all NDB releases based on MySQL 8.0) |
|
Read default options from given file only | (Supported in all NDB releases based on MySQL 8.0) |
|
Also read groups with concat(group, suffix) | (Supported in all NDB releases based on MySQL 8.0) |
|
Delete blob parts having no corresponding inline parts | (Supported in all NDB releases based on MySQL 8.0) |
|
Write orphan keys to specified file | (Supported in all NDB releases based on MySQL 8.0) |
|
Display help text and exit | (Supported in all NDB releases based on MySQL 8.0) |
|
Read given path from login file | (Supported in all NDB releases based on MySQL 8.0) |
|
Set connect string for connecting to ndb_mgmd. Syntax: "[nodeid=id;][host=]hostname[:port]". Overrides entries in NDB_CONNECTSTRING and my.cnf | (Supported in all NDB releases based on MySQL 8.0) |
|
Same as --ndb-connectstring | (Supported in all NDB releases based on MySQL 8.0) |
|
Set node ID for this node, overriding any ID set by --ndb-connectstring | (Supported in all NDB releases based on MySQL 8.0) |
|
Enable optimizations for selection of nodes for transactions. Enabled by default; use --skip-ndb-optimized-node-selection to disable | REMOVED: 8.0.31 |
|
Do not read default options from any option file other than login file | (Supported in all NDB releases based on MySQL 8.0) |
|
Print program argument list and exit | (Supported in all NDB releases based on MySQL 8.0) |
|
Display help text and exit; same as --help | (Supported in all NDB releases based on MySQL 8.0) |
|
Verbose output | (Supported in all NDB releases based on MySQL 8.0) |
|
Display version information and exit | (Supported in all NDB releases based on MySQL 8.0) |
-
Command-Line Format --add-missing
Introduced 8.0.20-ndb-8.0.20 For each inline part in NDB Cluster tables which has no corresponding BLOB part, write a dummy BLOB part of the required length, consisting of spaces.
-
Command-Line Format --character-sets-dir=path
Removed 8.0.31 Directory containing character sets.
-
Command-Line Format --check-missing
Introduced 8.0.20-ndb-8.0.20 Check for inline parts in NDB Cluster tables which have no corresponding BLOB parts.
-
Command-Line Format --check-orphans
Check for BLOB parts in NDB Cluster tables which have no corresponding inline parts.
-
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
Removed 8.0.31 Write core file on error; used in debugging.
-
Command-Line Format --database=name
Type String Default Value [none]
Specify the database to find the table in.
-
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 --delete-orphans
Remove BLOB parts from NDB Cluster tables which have no corresponding inline parts.
-
Command-Line Format --dump-file=file
Type File name Default Value [none]
Writes a list of orphaned BLOB column parts to
file
. The information written to the file includes the table key and BLOB part number for each orphaned BLOB part. -
Command-Line Format --help
Display help text and exit.
-
Command-Line Format --login-path=path
Type String Default Value [none]
Read given path from login file.
-
Command-Line Format --ndb-connectstring=connection_string
Type String Default Value [none]
Set connect string for connecting to ndb_mgmd. Syntax: "[nodeid=id;][host=]hostname[:port]". Overrides entries in NDB_CONNECTSTRING and my.cnf.
-
Command-Line Format --ndb-mgmd-host=connection_string
Type String Default Value [none]
Same as
--ndb-connectstring
. -
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
Removed 8.0.31 Enable optimizations for selection of nodes for transactions. Enabled by default; use
--skip-ndb-optimized-node-selection
to disable.-
Command-Line Format --no-defaults
Do not read default options from any option file other than login file.
-
Command-Line Format --print-defaults
Print program argument list and exit.
-
Command-Line Format --usage
Display help text and exit; same as --help.
-
Command-Line Format --verbose
Provide extra information in the tool's output regarding its progress.
-
Command-Line Format --version
Display version information and exit.
Example
First we create an NDB
table in the
test
database, using the
CREATE TABLE
statement shown
here:
Press CTRL+C to copyUSE test; CREATE TABLE btest ( c0 BIGINT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY, c1 TEXT, c2 BLOB ) ENGINE=NDB;
Then we insert a few rows into this table, using a series of statements similar to this one:
Press CTRL+C to copyINSERT INTO btest VALUES (NULL, 'x', REPEAT('x', 1000));
When run with
--check-orphans
against
this table, ndb_blob_tool generates the
following output:
Press CTRL+C to copy$> ndb_blob_tool --check-orphans --verbose -d test btest connected processing 2 blobs processing blob #0 c1 NDB$BLOB_19_1 NDB$BLOB_19_1: nextResult: res=1 total parts: 0 orphan parts: 0 processing blob #1 c2 NDB$BLOB_19_2 NDB$BLOB_19_2: nextResult: res=0 NDB$BLOB_19_2: nextResult: res=0 NDB$BLOB_19_2: nextResult: res=0 NDB$BLOB_19_2: nextResult: res=0 NDB$BLOB_19_2: nextResult: res=0 NDB$BLOB_19_2: nextResult: res=0 NDB$BLOB_19_2: nextResult: res=0 NDB$BLOB_19_2: nextResult: res=0 NDB$BLOB_19_2: nextResult: res=0 NDB$BLOB_19_2: nextResult: res=0 NDB$BLOB_19_2: nextResult: res=1 total parts: 10 orphan parts: 0 disconnected
The tool reports that there are no NDB
BLOB
column parts associated with column c1
, even
though c1
is a
TEXT
column. This is due to the
fact that, in an NDB
table, only
the first 256 bytes of a BLOB
or
TEXT
column value are stored
inline, and only the excess, if any, is stored separately; thus,
if there are no values using more than 256 bytes in a given
column of one of these types, no BLOB
column
parts are created by NDB
for this column. See
Data Type Storage Requirements, for more information.