Database corruption in NetVoyant

Document ID : KB000044376
Last Modified Date : 14/02/2018
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To address database corruption in NetVoyant, the first tool to use is DBTool.exe to run a repair on the whole database. For NV the command is 'dbtool repair nms2'. See

Then for the specific table/s mentioned in the errors try dbmaintain per the instructions below.


NV has non-standard MySQL tables called Merge tables.

Merge tables can be identified by these endings:





For example the 'reach' (Reachability) dataset, you will have one of each of those tables starting with reach (e.g, reach_rate, reach_ltd, etc.). However the reach_poll table is not a merge table, so the standard repair command should be used on that table, and any other non-merge table.




1. From a command prompt, run ‘dbmaintain -v -repartition all’ or refer to Additional information below for other options

Additional Information:

The typical MySQL command will not work on Merge tables, instead these tools are to be used and that are installed by default.


This tool is used to run a repair of a table.

From the command line (NOT inside MySQL).

dbmaintain -repair <merge_table_name>

Example: for the Interface Statistics LTD merge table you would do:

dbmaintain -repair ifstats_ltd


Sometimes if repartition fails due to mysql errors repeatedly, the merge tables can get large, which in turn can lead to service issues which can lead to mysql corruption. This doesn't always occur, but it is a good idea to repartition any large files to prevent issues.

dbmaintain -v -repartition all

This will run through every table and properly build the daily tables, and also get rid of any tables that have exceeded the retention rate.

Note: This operation is also performed nightly at 12:00 am.