Vertica 7.2 - How to identify file associated with a Projection

Hi

Starting 7.2, Vertica uses a new layout. It got rid of second level of the directory hierarchy as well as reduced the number of files

dbadmin=> select projection_id,projection_name,storage_type,storage_oid,sal_storage_id from storage_containers where projection_name = 't1_b0' and node_name = 'v_v720_node0001';
   projection_id   | projection_name | storage_type |    storage_oid    |                  sal_storage_id
-------------------+-----------------+--------------+-------------------+--------------------------------------------------
 45035996273909840 | t1_b0           | ROS          | 45035996273909931 | 02129e327df2e7b8652c6a93107cde9600a00000000320ab
(1 row)

$pwd

/home/dbadmin/v720/v_v720_node0001_data/931
$ls
02129e327df2e7b8652c6a93107cde9600a00000000320ab_0.gt

Hope this helps.

Thanks

Gayatri

Yes Vertica has column oriented on disk physical data structures. There can be many storage containers per projection on a node and each of them has the same number of column files.

Each column file used to have two files, fdb and pidx, but now we store them together in a gt file.

Moreover, if the size of a data file (fdb) falls below a configurable threshold (1MB by default), then it's stored together with other small files (1MB) in that storage container.

Note that we are not changing column oriented format, just many small column files are stored together as one gt file.

Thus this new disk layout reduces the number of files without impacting the benifits of column orientation. 

The query you have shows the file which has the first column data file of that storage container (however size it shows is the total size of all data files in that container).

That storage container could have many files. You have to look at v_internal.vs_ros to figure out what are the files are. 

=> select distinct(salstorageid) from v_internal.vs_ros where delid =45035996273909931;

Note that "931", the folder name, doesn't uniquely identifies a storage container, it's the folder we chose based on part of it's storage id, but there can be many other storage container files stored under that directory.