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MySQL NDB Cluster 7.3-7.4  /  NDB Cluster Programs  /  ndb_index_stat — NDB Index Statistics Utility

5.14 ndb_index_stat — NDB Index Statistics Utility

ndb_index_stat provides per-fragment statistical information about indexes on NDB tables. This includes cache version and age, number of index entries per partition, and memory consumption by indexes.

Usage

To obtain basic index statistics about a given NDB table, invoke ndb_index_stat as shown here, with the name of the table as the first argument and the name of the database containing this table specified immediately following it, using the --database (-d) option:

ndb_index_stat table -d database

In this example, we use ndb_index_stat to obtain such information about an NDB table named mytable in the test database:

$> ndb_index_stat -d test mytable
table:City index:PRIMARY fragCount:2
sampleVersion:3 loadTime:1399585986 sampleCount:1994 keyBytes:7976
query cache: valid:1 sampleCount:1994 totalBytes:27916
times in ms: save: 7.133 sort: 1.974 sort per sample: 0.000

NDBT_ProgramExit: 0 - OK

sampleVersion is the version number of the cache from which the statistics data is taken. Running ndb_index_stat with the --update option causes sampleVersion to be incremented.

loadTime shows when the cache was last updated. This is expressed as seconds since the Unix Epoch.

sampleCount is the number of index entries found per partition. You can estimate the total number of entries by multiplying this by the number of fragments (shown as fragCount).

sampleCount can be compared with the cardinality of SHOW INDEX or INFORMATION_SCHEMA.STATISTICS, although the latter two provide a view of the table as a whole, while ndb_index_stat provides a per-fragment average.

keyBytes is the number of bytes used by the index. In this example, the primary key is an integer, which requires four bytes for each index, so keyBytes can be calculated in this case as shown here:

    keyBytes = sampleCount * (4 bytes per index) = 1994 * 4 = 7976

This information can also be obtained using the corresponding column definitions from INFORMATION_SCHEMA.COLUMNS (this requires a MySQL Server and a MySQL client application).

totalBytes is the total memory consumed by all indexes on the table, in bytes.

Timings shown in the preceding examples are specific to each invocation of ndb_index_stat.

The --verbose option provides some additional output, as shown here:

$> ndb_index_stat -d test mytable --verbose
random seed 1337010518
connected
loop 1 of 1
table:mytable index:PRIMARY fragCount:4
sampleVersion:2 loadTime:1336751773 sampleCount:0 keyBytes:0
read stats
query cache created
query cache: valid:1 sampleCount:0 totalBytes:0
times in ms: save: 20.766 sort: 0.001
disconnected

NDBT_ProgramExit: 0 - OK

$>

If the only output from the program is NDBT_ProgramExit: 0 - OK, this may indicate that no statistics yet exist. To force them to be created (or updated if they already exist), invoke ndb_index_stat with the --update option, or execute ANALYZE TABLE on the table in the mysql client.

Options

The following table includes options that are specific to the NDB Cluster ndb_index_stat utility. Additional descriptions are listed following the table.

Table 5.12 Command-line options used with the program ndb_index_stat

Format Description Added, Deprecated, or Removed

--character-sets-dir=path

Directory containing character sets

(Supported in all NDB releases based on MySQL 5.6)

--connect-retries=#

Number of times to retry connection before giving up

ADDED: NDB 7.4.9

--connect-retry-delay=#

Number of seconds to wait between attempts to contact management server

ADDED: NDB 7.4.9

--connect-string=connection_string,

-c connection_string

Same as --ndb-connectstring

(Supported in all NDB releases based on MySQL 5.6)

--core-file

Write core file on error; used in debugging

(Supported in all NDB releases based on MySQL 5.6)

--database=name,

-d name

Name of database containing table

(Supported in all NDB releases based on MySQL 5.6)

--defaults-extra-file=path

Read given file after global files are read

(Supported in all NDB releases based on MySQL 5.6)

--defaults-file=path

Read default options from given file only

(Supported in all NDB releases based on MySQL 5.6)

--defaults-group-suffix=string

Also read groups with concat(group, suffix)

(Supported in all NDB releases based on MySQL 5.6)

--delete

Delete index statistics for table, stopping any auto-update previously configured

(Supported in all NDB releases based on MySQL 5.6)

--dump

Print query cache

(Supported in all NDB releases based on MySQL 5.6)

--help,

-?

Display help text and exit

(Supported in all NDB releases based on MySQL 5.6)

--login-path=path

Read given path from login file

(Supported in all NDB releases based on MySQL 5.6)

--loops=#

Set the number of times to perform given command; default is 0

(Supported in all NDB releases based on MySQL 5.6)

--ndb-connectstring=connection_string,

-c connection_string

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 5.6)

--ndb-mgmd-host=connection_string,

-c connection_string

Same as --ndb-connectstring

(Supported in all NDB releases based on MySQL 5.6)

--ndb-nodeid=#

Set node ID for this node, overriding any ID set by --ndb-connectstring

(Supported in all NDB releases based on MySQL 5.6)

--ndb-optimized-node-selection

Enable optimizations for selection of nodes for transactions. Enabled by default; use --skip-ndb-optimized-node-selection to disable

(Supported in all NDB releases based on MySQL 5.6)

--no-defaults

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

(Supported in all NDB releases based on MySQL 5.6)

--print-defaults

Print program argument list and exit

(Supported in all NDB releases based on MySQL 5.6)

--query=#

Perform random range queries on first key attr (must be int unsigned)

(Supported in all NDB releases based on MySQL 5.6)

--sys-drop

Drop any statistics tables and events in NDB kernel (all statistics are lost)

(Supported in all NDB releases based on MySQL 5.6)

--sys-create

Create all statistics tables and events in NDB kernel, if none of them already exist

(Supported in all NDB releases based on MySQL 5.6)

--sys-create-if-not-exist

Create any statistics tables and events in NDB kernel that do not already exist

(Supported in all NDB releases based on MySQL 5.6)

--sys-create-if-not-valid

Create any statistics tables or events that do not already exist in the NDB kernel, after dropping any that are invalid

(Supported in all NDB releases based on MySQL 5.6)

--sys-check

Verify that NDB system index statistics and event tables exist

(Supported in all NDB releases based on MySQL 5.6)

--sys-skip-tables

Do not apply sys-* options to tables

(Supported in all NDB releases based on MySQL 5.6)

--sys-skip-events

Do not apply sys-* options to events

(Supported in all NDB releases based on MySQL 5.6)

--update

Update index statistics for table, restarting any auto-update previously configured

(Supported in all NDB releases based on MySQL 5.6)

--usage,

-?

Display help text and exit; same as --help

(Supported in all NDB releases based on MySQL 5.6)

--verbose,

-v

Turn on verbose output

(Supported in all NDB releases based on MySQL 5.6)

--version,

-V

Display version information and exit

(Supported in all NDB releases based on MySQL 5.6)


  • --character-sets-dir

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

    Directory containing character sets.

  • --connect-retries

    Command-Line Format --connect-retries=#
    Introduced 5.6.28-ndb-7.4.9
    Type Integer
    Default Value 12
    Minimum Value 0
    Maximum Value 12

    Number of times to retry connection before giving up.

  • --connect-retry-delay

    Command-Line Format --connect-retry-delay=#
    Introduced 5.6.28-ndb-7.4.9
    Type Integer
    Default Value 5
    Minimum Value 0
    Maximum Value 5

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

  • --connect-string

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

    Same as --ndb-connectstring.

  • --core-file

    Command-Line Format --core-file

    Write core file on error; used in debugging.

  • --database=name, -d name

    Command-Line Format --database=name
    Type String
    Default Value [none]
    Minimum Value
    Maximum Value

    The name of the database that contains the table being queried.

  • --defaults-extra-file

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

    Read given file after global files are read.

  • --defaults-file

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

    Read default options from given file only.

  • --defaults-group-suffix

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

    Also read groups with concat(group, suffix).

  • --delete

    Command-Line Format --delete

    Delete the index statistics for the given table, stopping any auto-update that was previously configured.

  • --dump

    Command-Line Format --dump

    Dump the contents of the query cache.

  • --help

    Command-Line Format --help

    Display help text and exit.

  • --login-path

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

    Read given path from login file.

  • --loops=#

    Command-Line Format --loops=#
    Type Numeric
    Default Value 0
    Minimum Value 0
    Maximum Value MAX_INT

    Repeat commands this number of times (for use in testing).

  • --ndb-connectstring

    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.

  • --ndb-mgmd-host

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

    Same as --ndb-connectstring.

  • --ndb-nodeid

    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.

  • --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.

  • --query=#

    Command-Line Format --query=#
    Type Numeric
    Default Value 0
    Minimum Value 0
    Maximum Value MAX_INT

    Perform random range queries on first key attribute (must be int unsigned).

  • --sys-drop

    Command-Line Format --sys-drop

    Drop all statistics tables and events in the NDB kernel. This causes all statistics to be lost.

  • --sys-create

    Command-Line Format --sys-create

    Create all statistics tables and events in the NDB kernel. This works only if none of them exist previously.

  • --sys-create-if-not-exist

    Command-Line Format --sys-create-if-not-exist

    Create any NDB system statistics tables or events (or both) that do not already exist when the program is invoked.

  • --sys-create-if-not-valid

    Command-Line Format --sys-create-if-not-valid

    Create any NDB system statistics tables or events that do not already exist, after dropping any that are invalid.

  • --sys-check

    Command-Line Format --sys-check

    Verify that all required system statistics tables and events exist in the NDB kernel.

  • --sys-skip-tables

    Command-Line Format --sys-skip-tables

    Do not apply any --sys-* options to any statistics tables.

  • --sys-skip-events

    Command-Line Format --sys-skip-events

    Do not apply any --sys-* options to any events.

  • --update

    Command-Line Format --update

    Update the index statistics for the given table, and restart any auto-update that was previously configured.

  • --usage

    Command-Line Format --usage

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

  • --verbose

    Command-Line Format --verbose

    Turn on verbose output.

  • --version

    Command-Line Format --version

    Display version information and exit.

ndb_index_stat system options.  The following options are used to generate and update the statistics tables in the NDB kernel. None of these options can be mixed with statistics options (see ndb_index_stat statistics options).

ndb_index_stat statistics options.  The options listed here are used to generate index statistics. They work with a given table and database. They cannot be mixed with system options (see ndb_index_stat system options).