Database Recovery

You reload the database to initiate database recovery when either all of the data instances are down or all elements in a replica set show the waiting for seed state.

To reload the database:

  1. Run the ttGridAdmin dbStatus -loadReadiness command to see the status of all elements within their respective replica sets.
    % ttGridAdmin dbStatus database1 -loadReadiness
    Data Elements:
    RS DS Instance             State
    -- -- -------------------- --------
     1  1 mysys3host.griddata1 Unloaded
     1  2 mysys4host.griddata2 Unloaded
     1                         Loadable
     2  1 mysys5host.griddata3 Unloaded
     2  2 mysys6host.griddata4 Unloaded
     2                         Loadable
     
    database1 load state: Loadable
    Total Elements Loaded:0/4
  2. Resolve any issues with the elements of the database, as denoted by each element status, as described in Table 13-2.
  3. Run the ttGridAdmin dbload command to reload your database, as described in Reloading a Database into Memory.
    % ttGridAdmin dbLoad database1
    Database database1 load started
  4. Run the ttGridAdmin dbOpen to open the database for user connections.
    % ttGridAdmin dbOpen database1
    Database database1 open started

Note:

If an element of a replica set shows the waiting for seed status, but the seed element does not recover, then evaluate the host and data instance for that element to see if you need to intervene on either a hardware or software error.

If the seed element still does not recover after reloading the database, then evict the down replica set. See Recovering When the Replica Set Has a Permanently Failed Element. If Durability=0, then evict the replica set and then unload and reload the database to perform epoch recovery. See Recovering a Failed Replica Set When Durability=0.