we are trying to load the data from sqoop to netezza. And we are facing the following issue.
java.io.IOException: org.netezza.error.NzSQLException: ERROR:
Example Input dataset is as shown below:
1,2,3
1,3,4
sqoop command is as shown below:
sqoop export --table <tablename> --export-dir <path>
--input-fields-terminated-by '\t' --input-lines-terminated-by '\n' --connect
'jdbc:netezza://<host>/<db>' --driver org.netezza.Driver
--username <username> --password <passwrd>
The Sqoop is creating an insert statement in the following way:
insert into (c1,c2,c3) values (1,2,3),(1,3,4).
We are able to load one record but when we try to load the data to multiple records, the error is as said above.
Your help is highly appreciated.
Making sqoop.export.records.per.statement=1 will definitely help but this will make the export process extremely slow if your export record count is very large say "5 Million".
To solve this you need add following things:
1.) A properties file sqoop.properties, it must contain this property jdbc.transaction.isolation=TRANSACTION_READ_UNCOMMITTED (It avoids deadlock during exports)
also in the export command you need to specify this:
--connection-param-file /path/to/sqoop.properties
2.) Also sqoop.export.records.per.statement=100, making this will increase the speed of export.
3.) Third you have to add --batch, Use batch mode for underlying statement execution.
So you final export will look like this,
sqoop export -D sqoop.export.records.per.statement=100 --table <tablename> --export-dir <path>
--input-fields-terminated-by '\t' --input-lines-terminated-by '\n' --connect
'jdbc:netezza://<host>/<db>' --driver org.netezza.Driver
--username <username> --password <passwrd>
--connection-param-file /path/to/sqoop.properties
--batch
Hope this will help.
You can customise the number of rows that will be used in one insert statement with property "sqoop.export.records.per.statement". For example for Netezza you will need to set it to 1:
sqoop export -Dsqoop.export.records.per.statement=1 --connect ...
I would recommend you to also take a look on Apache Sqoop Cookbook where this and many other tips are described.
Related
Have executed a similar kind of sqoop command as shown below. The free form query mentioned below, I wanted to keep it in a file and run the sqoop command since my real time queries are quite complex and bigger.
Wanted to know, Is there a way to keep the query in a file and execute the sqoop command which will refer the free form query inside the file and execute?
like we do for --password-file case. Thanks in advance.
sqoop import --connect "jdbc:mysql://<localhost>:port" --username "admin" --password-file "<passwordfile>" --query "select * from employee" --split-by employee_id --target-dir "<target directory>" --incremental append --check-column employee_id --last-value 0 --fields-terminated-by "|"
The command line options that are not convenient to put in command, can be read using the Sqoop--options-file argument for convenience, hence you can read the query using the options file. Using options file the Sqoop command should be similar to this:
sqoop import --connect $connect_string --username $username --password $pwd --options-file /home/user/sqoop_poc/query.txt --target-dir $target_dir --m 1
Entry in options file should be like this:
--query
select * from TEST_OPTION where ID <= 10 AND $CONDITIONS
More details on options file are available in Sqoop User Guide.
sqoop import --connect \\
jdbc:mysql://localhost:3306/ydb --table yloc --username root -P --check-column rank --incremental append --last-value
We don't know the last value of the previous table. How can I write the query?
You can try to 2 approaches to solve this.
Query into table and get maximum value of last-value column.
Create a job in sqoop and set the column as incremental one and moving forward, your job will run on incremental basis
Go to your pwd
cd .sqoop
open file metastore.db.script using vi or
your fav editor.
search for incremental.last.value
It should be something like
INSERT INTO SQOOP_SESSIONS VALUES('incimpjob','incremental.last.value','2018-09-11 19:20:52.0','SqoopOptions')
Note: I am assuming that you have created a Sqoop Job. The 'incimpjob' is the name of my sqoop job.
I am executing below sqoop command::=
sqoop import --connect 'jdbc:sqlserver://10.xxx.xxx.xx:1435;database=RRAM_Temp' --username DRRM_DATALOADER --password ****** --table T_VND --hive-import --hive-table amitesh_db.amit_hive_test --as-textfile --target-dir amitesh_test_hive -m 1
I have two queries::-
1) what is the relevence of -m 1? as far as I know Its the number of mapper that I am assigning to the sqoop job. If that is true, then, the moment I assign -m 2, the execution start throwing error as below:
ERROR tool.ImportTool: Error during import: No primary key could be found for table xxx. Please specify one with --split-by or perform a sequential import with '-m 1'
Now, I am forced to change my concept, now I see, it has something to do with database primary key. Can somebody help me a logic behind this?
2) I have ordered the above sqoop command to save the file as text file format.But when I go to the location suggested by the execution, I find tbl_name.jar. Why, if --as-textfile is a wrong sytax, then what is the right one. Or is there any other location that I can find the file in?
1) To have -m or --num-mappers to be set to a value greater than 1, the table must either have PRIMARY KEY or the sqoop command must be provided with a --split-by column. Controlling Parallelism would explain the logic behind this.
2) The FileFormat of the data imported into the Hive table amit_hive_test would be plain text(--as-textfile). As this is --hive-import, the data will be first imported into the --target-dir and then is loaded (LOAD DATA INPATH) into the Hive table. The resultant data will be inside the table's LOCATION and not in --target-dir.
I have successfully installed SQOOP now the problem is that how to implement it with RDBMS and how to load data from RDBMS to HDFS using SQOOP.
By Using Sqoop You can Load Data directly to Hive Tables or Store the data in Some target Directory in HDFS
If you Need to copy data from RDBMS into Some directory
sqoop import
--connect ConnectionString
--username username
--password Your_Database_Password {In case no password Do not Specify it}
--table tableName
--col column_name(s) {In case you need to call specific columns}
--target-dir '/tmp/myfolder'
--boundary-query 'Select min,max from table name'
--m 5 {set number of mappers to 5}
--fields-terminated-by ',' {how do you want your data to look in target file}
Boundary Query : This is something you can specify. If you do not specify this , then by default this is run in as an inner query which adds up to a complex query.
If you specify this explicitly then this runs as a normal query and hence the performance is increased.
Also you may want to restrict the number of observation ,say based on column ID, and suppose you need data from ID 1 to 1000. Then using Boundary condition and split-by you will be able to restrict your import data.
--boundary-query "select 0,1000 from employee'
--split-by ID
Split-By : You use Split by on a Sqoop import to specify the column on basis of which split is required. By default,if you do not specify this, sqoop pics up table's primary key as the Split_by column.
Split By picks up data from tables and stores them in different folders based on number of mappers. By Default Number of Mappers are 4.
This may seem unwanted but in case you have a composite primary key or no primary key at all, then sqoop fails to pick up data and may error out.
Note: You may not face any issue if you set the number of mappers to 1. In this case, no split by condition is used since there is only one mapper. So query runs fine. This can be done using
--m 1
If you Need to copy data from RDBMS into Hive Table
sqoop import
--connect ConnectionString
--username username
--password Your_Database_Password {In case no password Do not Specify it}
--table tableName
--boundary-query 'Select min,max from table name'
--m 5 {set number of mappers to 5}
--hive-import
--hive-table serviceorderdb.productinfo
--m 1
Running a query instead of calling entire table itself
sqoop import
--connect ConnectionString
--username username
--password Your_Database_Password
--query 'select name from employees where name like '%s' and $CONDITIONS'
--m 5 {set number of mappers to 5}
--target-dir '/tmp/myfolder'
--fields-terminated-by ',' {how do you want your data to look in target file}
You may see $conditions as extra parameter $CONDITIONS. This is because this time you specified no table and specified a query explicity. When Sqoop runs, it searches for a boundary conditions, which it does not find. Then It Searches for a table and a primary key for applying boundary query which again it will not find. Hence we use $CONDITIONS to explicitly specify that we are not using a query and use default boundry condition from query result.
Checking if your connection is set up properly : For this you can just call list databases and if the you see your data populated then your connection is fine.
$ sqoop list-databases
--connect jdbc:mysql://localhost/
--username root
--password pwd
Connection String for Different Databases :
MYSQL: jdbc:mysql://<hostname>:<port>/<dbname>
jdbc:mysql://127.0.0.1:3306/test_database
Oracle :#//host_name:port_number/service_name
jdbc:oracle:thin:scott/tiger#//myhost:1521/myservicename
You may learn more about sqoop imports from : https://sqoop.apache.org/docs/1.4.1-incubating/SqoopUserGuide.html
By using sqoop import command you can import data from RDBMS to HDFS, Hive and HBase
sqoop import --connect jdbc:mysql://localhost:portnumber/DBName --username root --table emp --password root -m1
By using this command data will be stored in HDFS.
Sample commands to run sqoop import (load data from RDBMS to HDFS):
Postgres
sqoop import --connect jdbc:postgresql://postgresHost/databaseName
--username username --password 123 --table tableName
MySQL
sqoop import --connect jdbc:mysql://mysqlHost/databaseName --username username --password 123 --table tableName
Oracle*
sqoop import --connect jdbc:oracle:thin:#oracleHost:1521/databaseName --username USERNAME --password 123 --table TABLENAME
SQL Server
sqoop import --connect 'jdbc:sqlserver://sqlserverhost:1433;database=dbname;username=<username>;password=<password>' --table tableName
*Sqoop won't find any columns from a table if you don't specify both the username and the table in correct case. Usually, specifying both in uppercase will resolve the issue.
Read the Sqoop User's Guide: https://sqoop.apache.org/docs/1.4.5/SqoopUserGuide.html
I also recommend the Apache Sqoop Cookbook. You will learn how to use import and export tools, do incremental import jobs, save jobs, solve problems with jdbc drivers and much more. http://shop.oreilly.com/product/0636920029519.do
I am trying something on hadoop and its related things. For this, I have configured hadoop, hase, hive, sqoop in Ubuntu machine.
raghu#system4:~/sqoop$ bin/sqoop-import --connect jdbc:mysql://localhost:3306/mysql --username root --password password --table user --hive-import -m 1
All goes fine, but when I enter hive command line and execute show tables, there are nothing. I am able to see that these tables are created in HDFS.
I have seen some options in Sqoop import - it can import to Hive/HDFS/HBase.
When importing into Hive, it is indeed importing directly into HDFS. Then why Hive?
Where can I execute HiveQL to check the data.
From cloudera Support, I understood that I can Hue and check it. But, I think Hue is just an user interface to Hive.
Could someone help me here.
Thanks in advance,
Raghu
I was having the same issue. I was able to work around/through it by importing the data directly into HDFS and then create an External Hive table to point at that specific location in HDFS. Here is an example that works for me.
create external table test (
sequencenumber int,
recordkey int,
linenumber int,
type string)
ROW FORMAT DELIMITED FIELDS TERMINATED BY '\054'
location '/user/hdfs/testdata';
You will need to change your location to where you saved the data in HDFS.
Can you post the output from sqoop? Try using --verbose option.
Here's an example of the command I use, and it does import directly to a Hive table.
sqoop import --hive-overwrite --hive-drop-import-delims --warehouse-dir "/warehouse" --hive-table hive_users --connect jdbc:mysql://$MYSQL_HOST/$DATABASE_NAME --table users --username $MYSQL_USER --password $MYSQL_PASS --hive-import
when we are not giving any database in the sqoop import command,the table will be created in the default database with the same name of the RDBMS table name.
you can specify the database name where you want to import the the RDBMS table in hive by "--hive-database".
Instead of creating the Hive table every time, you can import the table structure in the hive using the create-hive-table command of sqoop. It will import the table as managed_table then you can convert that table to external table by changing the table properties to external table and then add partition. This will reduce the effort of finding the right data type. Please note that there will be precision change
Whenever ,you are using a Sqoop with Hive import option,the sqoop connects directly the corresponding the database's metastore and gets the corresponding table 's metadata(the table's schema),so there is no need to create a table structure in Hive.This schema is then provided to the Hive when used with Hive-import option.
So the output of all the sqoop data on HDFS will by default stored in the default directory .i.e /user/sqoop/tablename/part-m files
with hive import option,the tables will be downloaded directly into the default warehouse direcotry i.e.
/user/hive/warehouse/tablename
command : sudo -u hdfs hadoop fs -ls -R /user/
this lists recursively all the files with in the user.
Now go to Hive and type show databases.if there is only default database,
then type show tables:
remember OK is common default system output and is not part of the command output.
hive> show databases;
OK
default
Time taken: 0.172 seconds
hive> show tables;
OK
genre
log_apache
movie
moviegenre
movierating
occupation
user
Time taken: 0.111 seconds
Try sqoop command like this, its working for me and directly creating hive table, u need not create external table every time
sqoop import --connect DB_HOST --username ***** --password ***** --query "select *from SCHEMA.TABLE where \$CONDITIONS"
--num-mappers 5 --split-by PRIMARY_KEY --hive-import --hive-table HIVE_DB.HIVE_TABLE_NAME --target-dir SOME_DIR_NAME;
The command you are using imports data into the $HIVE_HOME directory. If the HIVE_HOME environment variable is not set or points to a wrong directory, you will not be able to see imported tables.
The best way to find the hive home directory is to use the Hive QL SET command:
hive -S -e 'SET' | grep warehouse.dir
Once you retrieved the hive home directory, append the --hive-home <hive-home-dir>option to your command.
Another possible reason is that in some Hive setups the metadata is cached and you cannot see the changes immediately. In this case you need to flush the metadata cache, using the INVALIDATE METADATA;command.