The Vertica Database Forums

Hi

I am new to vertica can some one help me to understand how the delete vectors will be created in the below example.

I have two projections for a table and I have 1 Million deletes for that table on given date..in this case how many delete vectors will be created means it will be based on no of projections or it is nothing to do with no of projections.

Hi Monica,

Nice to meet you too!

There will be 1 delete vector for each projection...

Example:

dbadmin=> select count(*) from test2;
count
--------
100000
(1 row)

dbadmin=> select count(distinct projection_basename) from projections where anchor_table_name = 'test2';
count
-------
2
(1 row)

dbadmin=> select node_name, projection_name, count(*) from delete_vectors group by node_name, projection_name;
node_name | projection_name | count
-----------+-----------------+-------
(0 rows)

dbadmin=> delete from test2;
OUTPUT
--------
100000
(1 row)

dbadmin=> select node_name, projection_name, count(*) from delete_vectors group by node_name, projection_name;
node_name | projection_name | count
-----------------+-----------------+-------
v_sfdc_node0001 | test2_pr | 1
v_sfdc_node0001 | test2_super | 1
(2 rows)