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Posted to commits@carbondata.apache.org by ku...@apache.org on 2019/05/16 09:36:46 UTC
[carbondata] branch master updated: [DOC] Update doc for
sort_columns modification
This is an automated email from the ASF dual-hosted git repository.
kunalkapoor pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/carbondata.git
The following commit(s) were added to refs/heads/master by this push:
new fa91d02 [DOC] Update doc for sort_columns modification
fa91d02 is described below
commit fa91d02af8d8f4cba26ff5bd7e0581c592b50573
Author: QiangCai <qi...@qq.com>
AuthorDate: Mon May 6 10:39:19 2019 +0800
[DOC] Update doc for sort_columns modification
Update doc for sort_columns modification
This closes #3203
---
docs/ddl-of-carbondata.md | 21 +++++++++++++++++++++
1 file changed, 21 insertions(+)
diff --git a/docs/ddl-of-carbondata.md b/docs/ddl-of-carbondata.md
index 88615a2..5bc8f10 100644
--- a/docs/ddl-of-carbondata.md
+++ b/docs/ddl-of-carbondata.md
@@ -793,6 +793,27 @@ Users can specify which columns to include and exclude for local dictionary gene
ALTER TABLE tablename UNSET TBLPROPERTIES('SORT_SCOPE')
```
+ - ##### SORT COLUMNS
+ Example to SET SORT COLUMNS:
+ ```
+ ALTER TABLE tablename SET TBLPROPERTIES('SORT_COLUMNS'='column1')
+ ```
+ After this operation, the new loading will use the new SORT_COLUMNS. The user can adjust
+ the SORT_COLUMNS according to the query, but it will not impact the old data directly. So
+ it will not impact the query performance of the old data segments which are not sorted by
+ new SORT_COLUMNS.
+
+ UNSET is not supported, but it can set SORT_COLUMNS to empty string instead of using UNSET.
+ ```
+ ALTER TABLE tablename SET TBLPROPERTIES('SORT_COLUMNS'='')
+ ```
+
+ **NOTE:**
+ * The future version will enhance "custom" compaction to sort the old segment one by one.
+ * The streaming table is not supported for SORT_COLUMNS modification.
+ * If the inverted index columns are removed from the new SORT_COLUMNS, they will not
+ create the inverted index. But the old configuration of INVERTED_INDEX will be kept.
+
### DROP TABLE
This command is used to delete an existing table.