GitHub user mohammadshahidkhan reopened a pull request:
https://github.com/apache/carbondata/pull/1418 [WIP] Support db location
**Problem:**
Currently carbon stores the database and tables at the fixed configured location âcarbon.storeLocationâ. So even though in case of federated cluster i.e. multiple independent Namespaces/ Namenodes only one Namespace/ Namenode can be used as storage for the database and tables.
The requirement is to support when create database can specify the LOCATION; the location can be viewfs path, name service path.
Using database location attribute configuration different name nodes can be used to store different databases. Having different name nodes for different databases will scale the read/write throughput.
**Solution:**
Setting the LOCATION attribute for a new database is a way to work with sets of files in an HDFS directory structure outside the fixed carbon store location.
In Create database command user can specify the location, the location where database and table under that database namespace could be stored.
1. The database at specified location could be created at defined location using create database command with location attribute.
Syntax:
CREATE DATABASE [IF NOT EXISTS] database_name[COMMENT 'database_comment'] [LOCATION hdfs_path];
The HDFS path can be viewfs path, nameservice path.
2. The database name and database location will be retrieved from the HiveSessionCatalog. The tables will be retrieved by scanning the table folders.
3. The read/write operation on old databases/ new databases created without specifying the LOCATION attribute should be performed the fixed carbon store location.
4. The table path formation will be same as the hive. The table path should be formed from database location or fixed Carbon store location and table name as given below.
The will be three possible scenarios:
I. Table path for the databases defined with location attribute.
tablePath = databaseLocation +â/â + tableName
II. Table path for the databases defined without location attribute.
tablePath = carbon.storeLocation + â/â + database_Name+â.dbâ +â/â + tableName
III. New table path for the default database.
tablePath = carbon.storeLocation +â/â + tableName
5. The carbon should support hybrid Nameservice path i.e. different operation could be performed in different name service. For example in load command the raw CSV files could be read from the nameservice ns1 i.e. âhdfs://ns1/user/data.csvâ and database location could point to viewfs path âviewfs://federation_cluster/dir1/carbonstoreâ.
Example:
CREATE DATABASE carbon LOCATION âviewfs://federation_cluster/dir1/carbonstoreâ;
CREATE TABLE carbon.carbon_table (c1 string, c2 int) stored by âcarbondataâ;
LOAD DATA INPATH âhdfs://ns1/user/data.csvâ into table carbon.carbon_table;
You can merge this pull request into a Git repository by running:
$ git pull
https://github.com/mohammadshahidkhan/incubator-carbondata support_db_location
Alternatively you can review and apply these changes as the patch at:
https://github.com/apache/carbondata/pull/1418.patchTo close this pull request, make a commit to your master/trunk branch
with (at least) the following in the commit message:
This closes #1418
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commit efc5edb8f721bc22edcaa8af16179b5ed734d32b
Author: mohammadshahidkhan <
[hidden email]>
Date: 2017-10-10T05:20:11Z
Support database location:
The database name and database location will be retrieved from the HiveSessionCatalog. The tables will be retrieved by scanning the table folders.
The read/write operation on old databases/ new databases created without specifying the LOCATION attribute should be performed the fixed carbon store location.
commit bdb11c9a57bb5b7adc77a7d73ff242ef438be7cc
Author: mohammadshahidkhan <
[hidden email]>
Date: 2017-10-10T06:00:43Z
Support configurable path for the store modification info file (modifiedTime.mdt).
commit 8bf6ac4b37d40bde6c9223e2b06609e2c771c004
Author: mohammadshahidkhan <
[hidden email]>
Date: 2017-10-10T10:17:00Z
Fixed drop database issue
commit 6a336153297c6edc38010f6d871511a85b916531
Author: mohammadshahidkhan <
[hidden email]>
Date: 2017-10-11T10:00:51Z
Corrected lock file location
commit b60a874ca6ba60f71ec030c96b397d0d20562fbe
Author: mohammadshahidkhan <
[hidden email]>
Date: 2017-10-16T08:58:07Z
Making carbon table path same as hive.
commit d0d15148c0c4cc3f9a7c53c725138bb64def3e61
Author: mohammadshahidkhan <
[hidden email]>
Date: 2017-10-18T15:31:13Z
fixed failing test cases
commit 3a32d6ba03b1a813cf348db21c9e5190ba442c7f
Author: mohammadshahidkhan <
[hidden email]>
Date: 2017-10-19T10:04:04Z
fixed failing test cases
commit 151f25264e3cc1ecd1a78b051b5b9dc408aa3d90
Author: mohammadshahidkhan <
[hidden email]>
Date: 2017-10-19T14:02:53Z
Added database location test and fixed existing failing test cases
commit 92599d21f06085299aa3357d64c6cc5efd075de9
Author: mohammadshahidkhan <
[hidden email]>
Date: 2017-10-19T18:11:32Z
Fixed alter rename table + Corrected test cases
Fixed drop table issue
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Locked
