Github user sgururajshetty commented on a diff in the pull request:
https://github.com/apache/carbondata/pull/1534#discussion_r152480541
--- Diff: docs/data-management-on-carbondata.md ---
@@ -461,25 +461,46 @@ This tutorial is going to introduce all commands and
data operations on CarbonDa
## COMPACTION
-This command merges the specified number of segments into one segment,
compaction help to improve query performance.
-```
+ Compaction help to improve query performance, because frequently load
data, will generate several CarbonData files, because data is sorted only
within each load(per load per segment and one B+ tree index).
+ This means that there will be one index for each load and as number of
data load increases, the number of indices also increases.
+ Compaction feature combines several segments into one large segment by
merge sorting the data from across the segments.
+
+ There are two types of compaction Minor and Major compaction.
+
+ ```
ALTER TABLE [db_name.]table_name COMPACT 'MINOR/MAJOR'
-```
+ ```
- **Minor Compaction**
+
+ In minor compaction the user can specify how many loads to be merged.
+ Minor compaction triggers for every data load if the parameter
carbon.enable.auto.load.merge is set to true.
+ If any segments are available to be merged, then compaction will run
parallel with data load, there are 2 levels in minor compaction:
+ * Level 1: Merging of the segments which are not yet compacted.
+ * Level 2: Merging of the compacted segments again to form a bigger
segment.
+
```
ALTER TABLE table_name COMPACT 'MINOR'
```
- **Major Compaction**
+
+ In Major compaction, many segments can be merged into one big segment.
+ User will specify the compaction size until which segments can be
merged, Major compaction is usually done during the off-peak time.
+ This command merges the specified number of segments into one segment:
+
```
ALTER TABLE table_name COMPACT 'MAJOR'
```
## PARTITION
+ Similar other system's partition features, CarbonData's partition
feature can be used to improve query performance by filtering on the partition
column.
--- End diff --
Similar to other system's partition features, CarbonData's partition
feature also can be used to improve query performance by filtering on the
partition column.
---
