Delete Vectors

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thanhmy
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Delete Vectors

Post by thanhmy » Thu Sep 21, 2017 8:35 am

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.
tim người giúp việc nhà ở lại dich vu giup viec nha uy tin

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JimKnicely
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Re: Delete Vectors

Post by JimKnicely » Sun Sep 24, 2017 3:21 pm

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)
Jim Knicely

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Note: I work for Vertica. My views, opinions, and thoughts expressed here do not represent those of my employer.

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