[Vertica][VJDBC](5065) ERROR: Too many ROS containers exist for the following projections:
zhaoyunye
Vertica Customer
vertica version: Vertica Analytic Database v10.0.0-0
this is my table:
create table dc_run_job_txn ( id varchar(80) not null primary key, job_definition_id varchar(80) not null, job_definition_snapshot long varchar(1048576) not null, last_job_status varchar(40), last_job_execution_time int, create_time int not null, update_time int not null, last_job_error_detail varchar(1000) );
table projections:
select get_projections('dc_run_job_txn'); Current system K is 0. # of Nodes: 1. Table dc_formula.dc_run_job_txn has 1 projections. Projection Name: [Segmented] [Seg Cols] [# of Buddies] [Buddy Projections] [Safe] [UptoDate] [Stats] ---------------------------------------------------------------------------------------------------- dc_formula.dc_run_job_txn_super [Segmented: Yes] [Seg Cols: "dc_formula.dc_run_job_txn.id"] [K: 0] [No buddy projections] [Safe: Yes] [UptoDate: Yes] [Stats: RowCounts]
The following DML statement will be executed with high frequency:
UPDATE dc_run_job_txn SET last_job_status = 'running', last_job_execution_time = 1592382202606, update_time = 1592382202606 WHERE id = '5ee1b24a78627a71b4477445'
I learned that WOS was abandoned in vertica 10.
Here are some parameters I configured:
ROSPerStratum -1 MoveOutInterval 300 MergeOutInterval 30
We just started using vertica and we are very confused about this issue. Please help us, thank you very much!
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Answers
Can you check the following parameters
select get_config_parameter('ContainersPerProjectionLimit');
select get_config_parameter('FilesPerProjectionLimit');
The error you have mentioned
ERROR 5065: Too many ROS containers exist for the following projections:
This could be because either mergeout is not catching up or you have not committed the transaction or there are lot of partitions (in your case you have not partitioned the table)
Check the commit after the update. Committing often would result in Low ROS count.
In addition, with Vertica you can avoid DELETEs, UPDATEs and MERGE, to reduce delete vectors and improve performance.
I learned this from Maurizio to manage data versioning and save the row “insert/update/delete” time history.
How the method works?
Instead of doing deletes or update to your data, try to use Live Aggregate Projection (LAP) TOP-K with the last version of the data.
In the base (anchor) table you would just do INSERTs.
The anchor table will always increase its size since we insert new data to “replace” or “hide” the old data.
For example:
From time to time (every several months) you can “purge” the anchor table to get rid of old versions of the data.
Like so:
Step1: CREATE TABLE new_base_table AS SELECT * from LAP (you create a new table with the “last version” of the data)
Step2: DROP TABLE base_table CASCADE (drop the old base table, it’s projections and LAP)
Step3: ALTER TABLE new_base_table RENAME base_table (rename the “last version” of the data)
Step4: recreate LAP
From now on you continue INSERTing into the base table as usual.
Please add hint 'direct' while using delete or insert .