If the AHM is not advancing, troubleshoot using this checklist:
| Step | Task | Results |
|---|---|---|
| 1 | Check whether the Last Good Epoch (LGE) is advancing.
=> SELECT CURRENT_EPOCH, LAST_GOOD_EPOCH, AHM_EPOCH FROM SYSTEM; |
If the LGE is advancing, go to Step 2. If the LGE is not advancing, go to Step 5. |
| 2 | Check whether all nodes are UP.
=> SELECT * FROM NODES WHERE NODE_STATE = 'UP'; |
If all the nodes are UP, go to Step 3.
If one or more node is DOWN, bring all the nodes UP.
$ admintools -t restart_node -d <database name> -s <node_name>
Then proceed to Step 4. |
| 3 | Check for unrefreshed projections.
=> SELECT PROJECTION_NAME, NODE_NAME, IS_UP_TO_DATE
FROM PROJECTIONS WHERE IS_UP_TO_DATE != 't'; |
If one or more of your projections is out of date (IS_UP_TO_DATE is f), do one of the following tasks:
|
| 4 | Did the AHM advance? => SELECT GET_AHM_EPOCH(); | If yes, this is the end of your checklist. If no, start this checklist again to find an alternative path. If the AHM continues not to advance, contact Vertica Support. |
| 5 | Check whether there is data in WOS.
=> SELECT sum (wos_used_bytes) from projection_storage; |
If there is data in WOS, force a MOVEOUT.
=> SELECT DO_TM_TASK('moveout');If there is no data in WOS, go to Step 6. |
| 6 | Check for a node where LGE is behind others.
=> SELECT GET_EXPECTED_RECOVERY_EPOCH(); |
If one node’s LGE is older than another node’s LGE, go to Step 7. If all the nodes have the same LGE, open a ticket with Vertica Technical Support. |
| 7 | Check whether moveout is executing and move-out is not slow due to replay-deletes.
=> SELECT OPERATION_START_TIMESTAMP, NODE_NAME,
OPERATION_NAME, OPERATION_STATUS, TABLE_SCHEMA,
PROJECTION_NAME FROM TUPLE_MOVER_OPERATIONS
WHERE IS_EXECUTING; |
If moveout is executing and the AHM advanced
=> SELECT GET_AHM_EPOCH();
This is end of your checklist.If moveout is not executing, open a ticket with Vertica Technical Support. |
Learn More
Learn more about Epochs in the Vertica Documentation.About the Author
Soniya Shah
Information Developer
Currently, a first year law student with a background in science and technology. Experienced technical writer, with specializations in software documentation, big data, blog development, and website development. I build user-centered content to communicate complex and technical information more easily.
I used to work for Vertica full time for about 3 years. I still work at Vertica part time while going to law school.
Update: Soniya is now doing her law internship, and no longer working at Vertica. Good luck, Soniya!
