A number of configuration variables in Hive can be used by the administrator to change the behavior for their installations and user sessions. These variables can be configured in any of the following ways, shown in the order of preference:
Using the set command in the cli for setting session level values for the configuration variable for all statements subsequent to the set command. e.g.
sets the scratch directory (which is used by hive to store temporary output and plans) to
/tmp/mydirfor all subseq
--hiveconfoption on the cli for the entire session. e.g.
hive-site.xml. This is used for setting values for the entire Hive configuration. e.g.
hive-default.xml.template contains the default values for various configuration variables that come prepackaged in a Hive distribution. In order to override any of the values, create
hive-site.xml instead and set the value in that file as shown above. Please note that this template file is not used by Hive at all (as of Hive 0.9.0) and so it might be out of date or out of sync with the actual values. The canonical list of configuration options is now only managed in the
HiveConf java class.
hive-default.xml.template is located in the
conf directory in your installation root.
hive-site.xml should also be created in the same directory.
The administrative configuration variables are listed below.
Hive uses temporary folders both on the machine running the Hive client and the default HDFS instance. These folders are used to store per-query temporary/intermediate data sets and are normally cleaned up by the hive client when the query is finished. However, in cases of abnormal hive client termination, some data may be left behind. The configuration details are as follows:
- On the HDFS cluster this is set to /tmp/hive-<username> by default and is controlled by the configuration variable hive.exec.scratchdir
- On the client machine, this is hardcoded to /tmp/<username>
Note that when writing data to a table/partition, Hive will first write to a temporary location on the target table's filesystem (using hive.exec.scratchdir as the temporary location) and then move the data to the target table. This applies in all cases - whether tables are stored in HDFS (normal case) or in file systems like S3 or even NFS.
Hive client produces logs and history files on the client machine. Please see Error Logs for configuration details.
Derby Server Mode
Broadly the configuration variables for Hive administration are categorized into:
Hive Configuration Variables
The data format to use for DDL output (e.g.
Wrapper around any invocations to script operator e.g. if this is set to python, the script passed to the script operator will be invoked as
This directory is used by Hive to store the plans for different map/reduce stages for the query as well as to stored the intermediate outputs of these stages.
/tmp/<user.name>/hive (Hive 0.8.0 and earlier)
This directory is used for temporary files when Hive runs in local mode. (as of Hive 0.10.0)
Determines whether the map/reduce jobs should be submitted through a separate jvm in the non local mode.
false - By default jobs are submitted through the same jvm as the compiler
Maximum number of serialization errors allowed in a user script invoked through
Determines whether the output of the final map/reduce job in a query is compressed or not.
Determines whether the output of the intermediate map/reduce jobs in a query is compressed or not.
The location of hive_cli.jar that is used when submitting jobs in a separate jvm.
The location of the plugin jars that contain implementations of user defined functions and serdes.
A strict value for this variable indicates that an error is thrown by the compiler in case no partition predicate is provided on a partitioned table. This is used to protect against a user inadvertently issuing a query against all the partitions of the table.
Determines whether the map side aggregation is on or not.
Default file format for CREATE TABLE statement. Options are TextFile, SequenceFile, RCFile, and Orc.
Merge small files at the end of a map-only job.
Merge small files at the end of a map-reduce job.
Size of merged files at the end of the job.
When the average output file size of a job is less than this number, Hive will start an additional map-reduce job to merge the output files into bigger files. This is only done for map-only jobs if hive.merge.mapfiles is true, and for map-reduce jobs if hive.merge.mapredfiles is true.
Whether to log the plan's progress every time a job's progress is checked. These logs are written to the location specified by
Directory where structured hive query logs are created. One file per session is created in this directory. If this variable set to empty string structured log will not be created.
The interval to wait between logging the plan's progress in milliseconds. If there is a whole number percentage change in the progress of the mappers or the reducers, the progress is logged regardless of this value. The actual interval will be the ceiling of (this value divided by the value of
A flag to gather statistics automatically during the INSERT OVERWRITE command. (as of Hive 0.7.0)
The default database that stores temporary hive statistics. Valid values are
The default connection string for the database that stores temporary hive statistics. (as of Hive 0.7.0)
The JDBC driver for the database that stores temporary hive statistics. (as of Hive 0.7.0)
Whether queries will fail because stats cannot be collected completely accurately. If this is set to true, reading/writing from/into a partition may fail becuase the stats could not be computed accurately (as of Hive 0.10.0)
If enabled, enforces inserts into bucketed tables to also be bucketed
Substitutes variables in Hive statements which were previously set using the
The maximum replacements the substitution engine will do. (as of Hive 0.10.0)
Hive Metastore Configuration Variables
Please see Hive Metastore Administration for information about the configuration variables used to set up the metastore in local, remote, or embedded mode. Also see descriptions in the Metastore section of the Language Manual's Hive Configuration Properties.
Hive Configuration Variables Used to Interact with Hadoop
The location of hadoop script which is used to submit jobs to hadoop when submitting through a separate jvm.
The location of the configuration directory of the hadoop installation
The url to the jobtracker. If this is set to local then map/reduce is run in the local mode.
The number of reducers for each map/reduce stage in the query plan.
The name of the map/reduce job
Hive Variables Used to Pass Run Time Information
The id of the Hive Session.
The query string passed to the map/reduce job.
The id of the plan for the map/reduce stage.
The maximum length of the jobname.
The name of the hive table. This is passed to the user scripts through the script operator.
The name of the hive partition. This is passed to the user scripts through the script operator.
The alias being processed. This is also passed to the user scripts through the script operator.
Configuring HCatalog and WebHCat
Starting in Hive release 0.11.0, HCatalog is installed and configured with Hive. The HCatalog server is the same as the Hive metastore.
- See Hive Metastore Administration for metastore configuration properties.
- See HCatalog Installation from Tarball for additional information.
For Hive releases prior to 0.11.0, see the "Thrift Server Setup" section in the HCatalog 0.5.0 document Installation from Tarball.
For information about configuring WebHCat, see WebHCat Configuration.