GitHub user manishgupta88 opened a pull request:
https://github.com/apache/carbondata/pull/2191
[WIP] Improve compaction performance
Problem: Compaction performance is slow as compared to data load
Analysis:
1. During compaction result filling is done in row format. Due to this as
the number of columns increases the dimension and measure data filling time
increases. This happens because in row filling we are not able to take
advantage of OS cacheable buffers as we continuously read data for next column.
2. As compaction uses a page level reader flow wherein both IO and
uncompression is done at page level, the IO and uncompression time increases in
this model.
Solution:
1. Implement a columnar format filling data structure for compaction
process for filling dimension and measure data.
2. Perform IO at blocklet level and uncompression at page level.
**Note:** **This PR contains the solution for point 1**
- [ ] Any interfaces changed?
No
- [ ] Any backward compatibility impacted?
No
- [ ] Document update required?
No
- [ ] Testing done
Manually verified
- [ ] For large changes, please consider breaking it into sub-tasks under
an umbrella JIRA.
NA
You can merge this pull request into a Git repository by running:
$ git pull https://github.com/manishgupta88/carbondata
compaction_columnar_result_filling
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/carbondata/pull/2191.patch
To close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #2191
----
commit a27928e81621cfa1acb72f6545f222d55c02c3f4
Author: m00258959 <manish.gupta@...>
Date: 2018-04-13T14:45:40Z
Problem: Compaction performance is slow as compared to data load
Analysis:
1. During compaction result filling is done in row format. Due to this as
the number of columns increases the dimension and measure data filling time
increases. This happens because in row filling we are not able to take
advantage of OS cacheable buffers as we continuously read data for next column.
2. As compaction uses a page level reader flow wherein both IO and
uncompression is done at page level, the IO and uncompression time increases in
this model.
Solution:
1. Implement a columnar format filling data structure for compaction
process for filling dimension and measure data.
2. Perform IO at blocklet level and uncompression at page level.
----
---
