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MySQL 9.2 Reference Manual  / ...  / MySQL NDB Cluster 9.2  / NDB Cluster Programs  /  ndb_blob_tool — Check and Repair BLOB and TEXT columns of NDB Cluster Tables

25.5.6 ndb_blob_tool — Check and Repair BLOB and TEXT columns of NDB ClusterTables

This tool can be used to check for and remove orphaned BLOB column parts fromNDB tables, as well as to generate a file listing any orphaned parts. It is sometimes useful in diagnosing and repairing corrupted or damagedNDB tables containingBLOB orTEXT columns.

The basic syntax forndb_blob_tool is shown here:

ndb_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 causendb_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 invokingndb_blob_tool. In addition, you can optionally follow the table name with the (comma-separated) names of one or moreBLOB orTEXT columns from that table. If no columns are listed, the tool works on all of the table'sBLOB andTEXT 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 withndb_mgmd are shown in the following table. Additional descriptions follow the table.

  • --add-missing

    Command-Line Format--add-missing

    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.

  • --character-sets-dir

    Command-Line Format--character-sets-dir=path

    Directory containing character sets.

  • --check-missing

    Command-Line Format--check-missing

    Check for inline parts in NDB Cluster tables which have no corresponding BLOB parts.

  • --check-orphans

    Command-Line Format--check-orphans

    Check for BLOB parts in NDB Cluster tables which have no corresponding inline parts.

  • --connect-retries

    Command-Line Format--connect-retries=#
    TypeInteger
    Default Value12
    Minimum Value0
    Maximum Value12

    Number of times to retry connection before giving up.

  • --connect-retry-delay

    Command-Line Format--connect-retry-delay=#
    TypeInteger
    Default Value5
    Minimum Value0
    Maximum Value5

    Number of seconds to wait between attempts to contact management server.

  • --connect-string

    Command-Line Format--connect-string=connection_string
    TypeString
    Default Value[none]

    Same as--ndb-connectstring.

  • --core-file

    Command-Line Format--core-file

    Write core file on error; used in debugging.

  • --database=db_name,-d

    Command-Line Format--database=name
    TypeString
    Default Value[none]

    Specify the database to find the table in.

  • --defaults-extra-file

    Command-Line Format--defaults-extra-file=path
    TypeString
    Default Value[none]

    Read given file after global files are read.

  • --defaults-file

    Command-Line Format--defaults-file=path
    TypeString
    Default Value[none]

    Read default options from given file only.

  • --defaults-group-suffix

    Command-Line Format--defaults-group-suffix=string
    TypeString
    Default Value[none]

    Also read groups with concat(group, suffix).

  • --delete-orphans

    Command-Line Format--delete-orphans

    Remove BLOB parts from NDB Cluster tables which have no corresponding inline parts.

  • --dump-file=file

    Command-Line Format--dump-file=file
    TypeFile name
    Default Value[none]

    Writes a list of orphaned BLOB column parts tofile. The information written to the file includes the table key and BLOB part number for each orphaned BLOB part.

  • --help

    Command-Line Format--help

    Display help text and exit.

  • --login-path

    Command-Line Format--login-path=path
    TypeString
    Default Value[none]

    Read given path from login file.

  • --no-login-paths

    Command-Line Format--no-login-paths

    Skips reading options from the login path file.

  • --ndb-connectstring

    Command-Line Format--ndb-connectstring=connection_string
    TypeString
    Default Value[none]

    Set connection string for connecting tondb_mgmd. Syntax:[nodeid=id;][host=]hostname[:port]. Overrides entries inNDB_CONNECTSTRING andmy.cnf.

  • --ndb-mgm-tls

    Command-Line Format--ndb-mgm-tls=level
    TypeEnumeration
    Default Valuerelaxed
    Valid Values

    relaxed

    strict

    Sets the level of TLS support required to connect to the management server; one ofrelaxed orstrict.relaxed (the default) means that a TLS connection is attempted, but success is not required;strict means that TLS is required to connect.

  • --ndb-mgmd-host

    Command-Line Format--ndb-mgmd-host=connection_string
    TypeString
    Default Value[none]

    Same as--ndb-connectstring.

  • --ndb-nodeid

    Command-Line Format--ndb-nodeid=#
    TypeInteger
    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.

  • --ndb-tls-search-path

    Command-Line Format--ndb-tls-search-path=list
    TypePath 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.

  • --no-defaults

    Command-Line Format--no-defaults

    Do not read default options from any option file other than login file.

  • --print-defaults

    Command-Line Format--print-defaults

    Print program argument list and exit.

  • --usage

    Command-Line Format--usage

    Display help text and exit; same as --help.

  • --verbose

    Command-Line Format--verbose

    Provide extra information in the tool's output regarding its progress.

  • --version

    Command-Line Format--version

    Display version information and exit.

Example

First we create anNDB table in thetest database, using theCREATE TABLE statement shown here:

USE 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:

INSERT INTO btest VALUES (NULL, 'x', REPEAT('x', 1000));

When run with--check-orphans against this table,ndb_blob_tool generates the following output:

$> ndb_blob_tool --check-orphans --verbose -d test btestconnectedprocessing 2 blobsprocessing blob #0 c1 NDB$BLOB_19_1NDB$BLOB_19_1: nextResult: res=1total parts: 0orphan parts: 0processing blob #1 c2 NDB$BLOB_19_2NDB$BLOB_19_2: nextResult: res=0NDB$BLOB_19_2: nextResult: res=0NDB$BLOB_19_2: nextResult: res=0NDB$BLOB_19_2: nextResult: res=0NDB$BLOB_19_2: nextResult: res=0NDB$BLOB_19_2: nextResult: res=0NDB$BLOB_19_2: nextResult: res=0NDB$BLOB_19_2: nextResult: res=0NDB$BLOB_19_2: nextResult: res=0NDB$BLOB_19_2: nextResult: res=0NDB$BLOB_19_2: nextResult: res=1total parts: 10orphan parts: 0disconnected

The tool reports that there are noNDB BLOB column parts associated with columnc1, even thoughc1 is aTEXT column. This is due to the fact that, in anNDB table, only the first 256 bytes of aBLOB orTEXT 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, noBLOB column parts are created byNDB for this column. SeeSection 13.7, “Data Type Storage Requirements”, for more information.