Re: [DISCUSSION] Support Database Location Configuration whileCreating Database

Posted by mohdshahidkhan on Oct 12, 2017; 12:36pm
URL: http://apache-carbondata-dev-mailing-list-archive.168.s1.nabble.com/DISCUSSION-Support-Database-Location-Configuration-while-Creating-Database-tp23492p23995.html

Hi Dev,

Please find updated design documents for "Support Database Location Configuration while Creating Database"

Changes:

Carbon will follow the same approach as hive is following.

The table path should be formed from database location or fixed Carbon store location and table name as given below.

There will be three possible scenarios:

   I.  Table path for the databases defined with location attribute.

          tablePath = databaseLocation +”/” + tableName

  II. Table path for the databases defined without location attribute.

         tablePath = carbon.storeLocation + “/” + database_Name+”.db” +”/”  + tableName

  III.  New table path for the default database.

      tablePath = carbon.storeLocation +”/”  + tableName

Regards,

Shahid

On Sat, Oct 7, 2017 at 5:26 PM, Sea <[hidden email]> wrote:

Hi, Shahid:

    I think you misundertood my meaning, the databaseLocation you mentioned is like carbon.storeLocation, not databaseLocation in Hive.

    Your databaseLocation is like `hive.metastore.warehouse.dir`,

     The default behavior in spark(hive):

    If we do not specify database location.

      databaseLocation = hive.metastore.warehouse.dir/spark.sql.warehouse.dir + "/" + databaseName.db + "/" + tableName

      So databaseLocation  is unique.

    If we do not specify table location:

       databaseLocation + '/' + tableName

------------------ Original ------------------

From:  "mohdshahidkhan1987";<[hidden email]>;

Date:  Fri, Oct 6, 2017 08:40 PM

To:  "dev"<[hidden email]>;

Subject:  Re: [DISCUSSION] Support Database Location Configuration whileCreating Database

Hi Sea,

1. create database with location is supported by spark(hive) only, carbon
will not have any own implementation for create database. It is mention here
just for reference regarding the location attribute.
2. Why carbon want to keep tablePath = 'databaseLocation  “/” +
database_Name + "/" + tableName`
   
 There is problem if we keep the tablePath same as hive. For
CarbonFileMetaStore, carbon creates
 the schema file at  <TablePath>/Metadata/schema

If carbon skips adding databaseName, then two table having same name from
two different databases pointing to the same database location will cause
problem during table creation, load and query.

Even in case hive if two tables in different databases with same are
created, then we are showing then when either of the table is queried, the
content from both the tables are shown.

3. What does `Carbon.update.sync.folder` means?
 This is to configure the directory for modifiedTime.mdt.
 Earlier the directory path for modifiedTime.mdt was fixed to
carbon.storeLocation, but what if user           decides to remove the name
service of the  carbon.storeLocation.
 This is required for the federation cluster, where multiple name services
will be available. So if the     nameservice to which the the directory for
modifiedTime.mdt is removed then  the directory could be
 changed.

Regards,
Shahid



--
Sent from: http://apache-carbondata-dev-mailing-list-archive.1130556.n5.nabble.com/