mdbm_stat_monitor.pl

SYNOPSIS

mdbm_stat_monitor.pl [-dh] -s ymon-scoreboard-name JSON-file ...

DESCRIPTION

The mdbm_stat_monitor.pl script uses mdbm_stat to extract MDBM structure and data characteristics for one or more MDBMs.

Metric values are emitted to a ymon scoreboard. These Metrics are emitted according to various ordered dimensions defined by A JSON file. If the the metrics for multiple MDBMs are being emitted to the same scoreboard, all MDBMs must use that same setup for dimensions. For example, if one JSON file specifies dataset-name, partition number, and replication number dimensions, then all JSON files must the same dimensions, and in the same order.

Applications should use a cron job to publish these metrics on a regular interval to assist in MDBM capacity planning.

A JSON file contains:

• An MDBM path

• Whether or not to lock the MDBM when using mdbm_stat

• A set of ordered dimensions (minimum of 1 dimension, dataset name, is required).

  • dataset name
  • partition number
  • replica number

• (optional) A page utilization percentage for it to be considered full. This used is computing metrics for MDBM fullness.

A sample JSON file:

{
  "mdbmPath" : "foo.mdbm",
  "lockMdbm" : false,
  "fullPercent" : 85,
  "dimensions" : [{"dataset" : "somedataset"}, {"partition" : 3}, {"replica" : 0}]
}

OPTIONS

-d, --debug	Display debug information.
-h, --help	Shows this help message.
-s, --scoreboard ymon-scoreboard-name
	ymon scoreboards reside in /home/y/var/scoreboards/. Only the basename is used from the ymon-scoreboard parameter.

JSON-file

JSON format files describing ymon metric dimensions for an MDBM. Use multiple JSON files if there are multiple MDBMs. If stats are emitted for multiple MDBMs, they must all use the same dimensions. The JSON “mdbmPath” and “dimensions” settings are required. The JSON “dimensions” setting must specify at least 1 dimension.

RETURN VALUE

Returns 0 upon success, non-zero upon failure.

OUTPUT

Metric values are emitted to a ymon-scoreboard-name.

In the following table, normal pages are pages that are not used for large objects or oversized pages.

Metric Name	YMon Metric	Aggregation	Description
MstatBigPgFull	stat	last	A very rough measure for the number of LOOP pages near full. This count reflects the number of rows (not the number of pages) in the histogram data that are greater than or equal to the JSON “fullPercent” parameter (default is 85%). The “max” value in the histogram’s “Bytes” column is used calculate this percentage.
MstatFrPg	stat	last	Free pages count
MstatKeyAvg	stat	last	Key average bytes
MstatKeyMax	stat	last	Key maximum bytes
MstatKeyMin	stat	last	Key minimum bytes
MstatKvAvg	stat	last	Key+Value average bytes
MstatKvMax	stat	last	Key+Value maximum bytes
MstatKvMin	stat	last	Key+Value minimum bytes
MstatLobAvg	stat	last	Large Object average bytes
MstatLobEnt	stat	last	Large Object Store store entry count
MstatLobMax	stat	last	Large Object maximum bytes
MstatLobMin	stat	last	Large Object minimum bytes
MstatLobSz	stat	last	Large Object store entry bytes
MstatNormEnt	stat	last	Normal store entry count
MstatNormPgFull	stat	last	A very rough indicator for the number of normal (non-LOOP) pages near full. This count reflects the number of rows (not the number of pages) in the histogram data that are greater than or equal to the JSON “fullPercent” parameter (default is 85%). The “max” value in the histogram’s “Bytes” column is used calculate this percentage.
MstatNormSz	stat	last	Normal store entry bytes
MstatOvhSz	stat	last	Overhead bytes
MstatPgEntAvg	stat	last	Entries per page average count
MstatPgEntMax	stat	last	Entries per page maximum count
MstatPgEntMin	stat	last	Entries per page minimum count
MstatTime	stat	last	Elapsed seconds to stat an MDBM
MstatTotEnt	stat	last	Total entry count
MstatTotPg	stat	last	Total number of pages
MstatTotSz	stat	last	Total bytes
MstatTotUtil	stat	last	Total bytes utilization, percentage
MstatValAvg	stat	last	Value average bytes
MstatValMax	stat	last	Value maximum bytes
MstatValMin	stat	last	Value minimum bytes
MstatUsedPg	stat	last	Used pages count
MstatUnusedSz	stat	last	Unused bytes

Unlike other metrics, MstatNormPgFull and MstatBigPgFull are not simply extracted from stat output. Instead, all of histogram data is evaluated to find the various minimum free byte points. That section of the histogram and the configuration input (ex., percent of page is used) is used to determine the number of pages approaching fullness.

EXAMPLES

SEE ALSO

mdbm_check(1), mdbm_compare(1), mdbm_copy(1), mdbm_create(1), mdbm_digest(1), mdbm_dump(1), mdbm_export(1), mdbm_fetch(1), mdbm_import(1), mdbm_purge(1), mdbm_replace(1), mdbm_restore(1), mdbm_save(1), mdbm_stat(1), mdbm_sync(1), mdbm_trunc(1)

CONTACT

mdbm-users <mdbm-users@yahoo-inc.com>