HI
How Exactly data is compressed in Multinode Vertica set up ? Is there any difference in Compression ratio with number of nodes ?
Compression Ratio varies with number of nodes
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Re: Compression Ratio varies with number of nodes
Reply soon !!!!!!
- JimKnicely
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Re: Compression Ratio varies with number of nodes
Hi,
I don't think the compression ratio would change significantly based on the number of nodes. That is, the sum of the compressed data on all nodes should have a similar size to the compressed data on a single node. But that's assuming you have optimized projections. Default super projections might not optimize database performance, resulting in slow query performance and low data compression.
I don't think the compression ratio would change significantly based on the number of nodes. That is, the sum of the compressed data on all nodes should have a similar size to the compressed data on a single node. But that's assuming you have optimized projections. Default super projections might not optimize database performance, resulting in slow query performance and low data compression.
Jim Knicely
Note: I work for Vertica. My views, opinions, and thoughts expressed here do not represent those of my employer.
Note: I work for Vertica. My views, opinions, and thoughts expressed here do not represent those of my employer.
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Re: Compression Ratio varies with number of nodes
i have loaded 39 GB of raw data
In single node it is compressed to 5.1 GB and in 3 node it is compressed to 12.01 GB with K safety 1 (Original data + 1 backup copy)
1 GB differece .....
All Table structure , Optimized Query , Db designs are same in both the single and 3 node Vertica ..
why this large difference ?
In single node it is compressed to 5.1 GB and in 3 node it is compressed to 12.01 GB with K safety 1 (Original data + 1 backup copy)
1 GB differece .....
All Table structure , Optimized Query , Db designs are same in both the single and 3 node Vertica ..
why this large difference ?
- JimKnicely
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Re: Compression Ratio varies with number of nodes
Are you sure the physical designs are the same?
What are the projection counts from PROJECTIONS table in each solution? What are the projection counts where the is_super_projection = t?
On the single node I bet all projections are super projections that can be poorly compressed as expressed by the documentation.
What are the projection counts from PROJECTIONS table in each solution? What are the projection counts where the is_super_projection = t?
On the single node I bet all projections are super projections that can be poorly compressed as expressed by the documentation.
Jim Knicely
Note: I work for Vertica. My views, opinions, and thoughts expressed here do not represent those of my employer.
Note: I work for Vertica. My views, opinions, and thoughts expressed here do not represent those of my employer.
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Re: Compression Ratio varies with number of nodes
IN single node vertica , For super projection Compression ratio was 12.71 GB .
Re: Compression Ratio varies with number of nodes
So now the compression size is matching in your single node and your 3 node cluster.