MapR-DB verifyindex

Describes how to use the MapR-DB verifyindex command to verify that the data in a secondary index is consistent with its JSON table.

Syntax

mapr verifyindex
        -path < table path >
        -index < index name >
        -first_exit < true | false >
        -numthreads < thread number >  

Parameters

Parameter Description
path (Required) Path to where the table exists.
index (Required) Name of the secondary index on the table.
first_exit (Optional) Exit when the first difference is found. Options: true or false. Default: false.
numthreads (Optional) Number of parallel threads to use for the verification. Default: 16

Example

The following example creates a table, creates a secondary index on the table, inserts some documents, and then runs the verifyindex command to verify that there is data consistency between the JSON table and the secondary index. See Troubleshooting Secondary Indexes for an example where verifyindex detects data inconsistency.

// Create a table using dbshell add
# mapr dbshell
      
maprdb root:> create /t1
Table /t1 created.

        
// Create an index using maprcli table index add
# maprcli table index add -path /t1 -index i1 -indexedfields a -json
{
"timestamp":1499788406380,
"timeofday":"2017-07-11 08:53:26.380 GMT-0700",
"status":"OK",
"total":0,
"data":[ ]
}


// Insert documents into the table using dbshell insert
# mapr dbshell

maprdb root:> insert /t1 --v {"a":1,"b":2} --id 1
Document with id: "1" inserted.

maprdb root:> insert /t1 --v {"a":"mapr","b":3} --id 2
Document with id: "2" inserted.
 
maprdb root:> insert /t1 --v {"a":{"$numberLong":3},"b":4} --id 4
Document with id: "4" inserted.


// Run verifyindex to verify indexed data
# mapr verifyindex -path /t1 -index i1

Number of rows in table but not in index: 0
Number of rows in index but not in table: 0
Mismatch row count: 0

Troubleshooting Use Cases

Situations where you can use this command are as follows:

  • Examine details on updates that have not yet propagated from a JSON table to one of its indexes.
  • Detect if there are documents that are missing from an index.
  • Detect other data consistency issues between an index and its parent JSON table.

See Troubleshooting Secondary Indexes for more information on these use cases.