We are using Cloudera CDH 4 and we are able to import tables from our Oracle databases into our HDFS warehouse as expected. The problem is we have 10's of thousands of tables inside our databases and sqoop only supports importing one table at a time.
What options are available for importing multiple tables into HDFS or Hive? For example what would be the best way of importing 200 tables from oracle into HDFS or Hive at a time?
The only solution i have seen so far is to create a sqoop job for each table import and then run them all individually. Since Hadoop is designed to work with large dataset it seems like there should be a better way though.
U can use " import-all-tables " option to load all tables into HDFS at one time .
sqoop import-all-tables --connect jdbc:mysql://localhost/sqoop --username root --password hadoop --target-dir '/Sqoop21/AllTables'
if we want to exclude some tables to load into hdfs we can use " --exclude-tables " option
Ex:
sqoop import-all-tables --connect jdbc:mysql://localhost/sqoop --username root --password hadoop --target-dir '/Sqoop21/AllTables' --exclude-tables <table1>,<tables2>
If we want to store in a specified directory then u can use " --warehouse-dir " option
Ex:
sqoop import-all-tables --connect jdbc:mysql://localhost/sqoop --username root --password hadoop --warehouse-dir '/Sqoop'
Assuming that the sqoop configuration for each table is the same, you can list all the tables you need to import and then iterate over them launching sqoop jobs (ideally launch them asynchronously). You can run the following to fetch the list of tables from Oracle:
SELECT owner, table_name FROM dba_tables reference
Sqoop does offer an option to import all tables. Check this link. There are some limitations though.
Modify sqoop source code and recompile it to your needs. The sqoop codebase is well documented and nicely arranged.
--target-dir is not a valid option when using import-all-tables.
To import all tables in particular directory, Use --warehouse-dir instead of --target-dir.
Example:
$ sqoop import-all-tables --connect jdbc:mysql://localhost/movies --username root --password xxxxx --warehouse-dir '/user/cloudera/sqoop/allMoviesTables' -m 1
The best option is do my shell script
Prepare a inputfile which has list of DBNAME.TABLENAME 2)The shell script will have this file as input, iterate line by line and execute sqoop statement for each line.
while read line;
do
DBNAME=`echo $line | cut -d'.' -f1`
tableName=`echo $line | cut -d'.' -f2`
sqoop import -Dmapreduce.job.queuename=$QUEUE_NAME --connect '$JDBC_URL;databaseName=$DBNAME;username=$USERNAME;password=$PASSWORD' --table $tableName --target-dir $DATA_COLLECTOR/$tableName --fields-terminated-by '\001' -m 1
done<inputFile
You can probably import multiple tables : http://sqoop.apache.org/docs/1.4.2/SqoopUserGuide.html#_literal_sqoop_import_all_tables_literal
You can use Sqoop "import-all-tables" feature to import all the tables in the database. This also has another parameter, --exclude-tables, along with which you can exclude some of the table that you don't want to import in the database.
Note: --exclude-tables only works with import-all-tables command.
importing multiple tables by sqoop if no of tables are very less.
Create sqoop import for each table as below .
sqoop import --connect jdbc:mysql://localhost/XXXX --username XXXX
password=XXXX
--table XXTABLE_1XX*
sqoop import --connect jdbc:mysql://localhost/XXXX --username XXXX
password=XXXX
--table XXTABLE_2XX*
and so on.
But what if no of tables are 100 or 1000 or even more. Below would be ideal solution.
In such scenario, preparing shell script which takes input from text file containing list of table names to be imported, iterate over, run the scoop import job for each table
Related
I know that while importing tables from rdbms to hdfs using sqoop import we can use import-all-tables option to get multiple tables.
But what if I have 30 tables in my rdbms and need to import only 15.
What can be done in that case?
Thanks for suggestions.
add --exclude-tables Comma separated list of tables to exclude from import process
shell script would be like:
#!/bin/bash
exclude="table1,table2"
import-all-tables --connect jdbc:XXXX -username XXX\
-P --warehouse-dir /my/dir --exclude-tables $exclude -m XX
So I'm trying to import-all-tables into hive db, ie, user/hive/warehouse/... on hdfs, using the below command:
sqoop import-all-tables --connect "jdbc:sqlserver://<servername>;database=<dbname>" \
--username "<username>" \
--password "<password>" \
--warehouse-dir "/user/hive/warehouse/" \
--hive-import \
-m 1
In the testdatabase I have 3 tables, when mapreduce runs, the output is success,
ie, the mapreduce job is 100% complete but the file is not found on hive db.
It’s basically getting overwritten by the last table, try removing the forward slash at the end of the directory path. For the tests I would suggest not to use the warehouse directory, use something like ‘/tmp/sqoop/allTables’
There is a another way
1. Create a hive database pointing to a location says "targetLocation"
2. Create hcatalog table in your sqoop import using previously created database.
3. Use target-directory import options to point that targetLocation.
you doesn't need need to define warehouse directory.just define hive database it will automatically find out working directory.
sqoop import-all-tables --connect "jdbc:sqlserver://xxx.xxx.x.xxx:xxxx;databaseName=master" --username xxxxxx --password xxxxxxx --hive-import --create-hive-table --hive-database test -m 1
it will just run like rocket.
hope it work for you....
In Sqoop for Hadoop you can use a parameters file for connection string information.
--connection-param-file filename Optional properties file that provides connection parameters
What is the format of that file?
Say for example I have:
jdbc:oracle:thin:#//myhost:1521/mydb
How should that be in a parameters file?
if you want to give your database connection string and credentials then create a file with those details and use --options-file in your sqoop command
create a file database.props with the following details:
import
--connect
jdbc:mysql://localhost:5432/test_db
--username
root
--password
password
then your sqoop import command will look like:
sqoop --options-file database.props \
--table test_table \
--target-dir /user/test_data
and related to --connection-param-file hope this link will be helpful to understand its usage
It should be same as the command.
Example
import
--connect
jdbc:oracle:thin:#//myhost:1521/mydb
--username
foo
Below is the sample command connecting with mysql server
sqoop list-databases --connect jdbc:mysql://192.168.256.156/test --username root --password root
It will give you the list of databases available at your mysql server
I run a command which exports data from my HDFS to MySql.
But I want to insert data to particular columns at run time, while running the Export Command.
Is this possible?
Or if not, is there any work-around to achieve this?
My command would be like this:
bin/sqoop export --connect jdbc:mysql://my ip/test --username uname --password pwd --table table name --export-dir /MR/part-r-00000 --input-fields-terminated-by ',' --verbose -m 1
(Here I want to supply data for certain columns).
I believe that you can take advantage of parameter --columns to specify subset of table's columns that are available in the input files.
Is it possible to export data from hive to Oracle DB using Sqoop for reporting purpose since i dont want to make any changes in client applications.
Regards,
Bhagwant Bhobe
Use the insert overwrite directory option with Hive for the output of the query to be written to a file and then use the Sqoop export option to insert the data in the file into RDBMs. A work-flow using Oozie or Azkaban (does Azkaban supports Oozie and Hive tasks?) can also be used to automate this.
By using sqoop export command you can export data from hive to oracle DB.
sqoop export --connect jdbc:oracle:thin:#ipaddress:portnumber:DBName --table tableName --export-dir /user/hive/warehouse/emp1 --username uname --password pwd --fields-terminated-by '\001' -m 1
in --export-dir specify the location of hive output directory.