Hive Connector#

Overview#

The Hive connector allows querying data stored in an Apache Hive data warehouse. Hive is a combination of three components:

Data files in varying formats, that are typically stored in the Hadoop Distributed File System (HDFS) or in object storage systems such as Amazon S3.
Metadata about how the data files are mapped to schemas and tables. This metadata is stored in a database, such as MySQL, and is accessed via the Hive metastore service.
A query language called HiveQL. This query language is executed on a distributed computing framework such as MapReduce or Tez.

Presto only uses the first two components: the data and the metadata. It does not use HiveQL or any part of Hive’s execution environment.

Requirements#

The Hive connector requires a Hive metastore service (HMS), or a compatible implementation of the Hive metastore, such as AWS Glue Data Catalog.

Apache Hadoop 2.x and 3.x are supported, along with derivative distributions, including Cloudera CDH 5 and Hortonworks Data Platform (HDP).

Many distributed storage systems including HDFS, Amazon S3 or S3-compatible systems, Google Cloud Storage, and Azure Storage.

The coordinator and all workers must have network access to the Hive metastore and the storage system.

Supported File Types#

The following file types are supported for the Hive connector:

ORC
Parquet
Avro
RCText (RCFile using ColumnarSerDe)
RCBinary (RCFile using LazyBinaryColumnarSerDe)
SequenceFile
JSON (using org.apache.hive.hcatalog.data.JsonSerDe)
CSV (using org.apache.hadoop.hive.serde2.OpenCSVSerde)
TextFile

Metastore Configuration for Avro#

In order to enable first-class support for Avro tables when using Hive 3.x, you need to add the following property definition to the Hive metastore configuration file hive-site.xml (and restart the metastore service):

<property>
     <!-- https://community.hortonworks.com/content/supportkb/247055/errorjavalangunsupportedoperationexception-storage.html -->
     <name>metastore.storage.schema.reader.impl</name>
     <value>org.apache.hadoop.hive.metastore.SerDeStorageSchemaReader</value>
 </property>

Supported Table Types#

Transactional and ACID Tables#

When connecting to a Hive metastore version 3.x, the Hive connector supports reading from and writing to insert-only and ACID tables, with full support for partitioning and bucketing. Row-level deletes are supported for ACID tables.

ACID tables created with Hive Streaming Ingest are not supported.

Materialized Views#

The Hive connector supports reading from Hive materialized views. In Presto, these views are presented as regular, read-only tables.

Configuration#

Create etc/catalog/hive.properties with the following contents to mount the hive-hadoop2 connector as the hive catalog, replacing example.net:9083 with the correct host and port for your Hive metastore Thrift service:

connector.name=hive-hadoop2
hive.metastore.uri=thrift://example.net:9083

Multiple Hive Clusters#

You can have as many catalogs as you need, so if you have additional Hive clusters, simply add another properties file to etc/catalog with a different name, making sure it ends in .properties. For example, if you name the property file sales.properties, Presto creates a catalog named sales using the configured connector.

HDFS Configuration#

For basic setups, Presto configures the HDFS client automatically and does not require any configuration files. In some cases, such as when using federated HDFS or NameNode high availability, it is necessary to specify additional HDFS client options in order to access your HDFS cluster. To do so, add the hive.config.resources property to reference your HDFS config files:

hive.config.resources=/etc/hadoop/conf/core-site.xml,/etc/hadoop/conf/hdfs-site.xml

Only specify additional configuration files if necessary for your setup. We recommend reducing the configuration files to have the minimum set of required properties, as additional properties may cause problems.

The configuration files must exist on all Presto nodes. If you are referencing existing Hadoop config files, make sure to copy them to any Presto nodes that are not running Hadoop.

HDFS Username and Permissions#

Before running any CREATE TABLE or CREATE TABLE AS statements for Hive tables in Presto, you need to check that the user Presto is using to access HDFS has access to the Hive warehouse directory. The Hive warehouse directory is specified by the configuration variable hive.metastore.warehouse.dir in hive-site.xml, and the default value is /user/hive/warehouse.

When not using Kerberos with HDFS, Presto accesses HDFS using the OS user of the Presto process. For example, if Presto is running as nobody, it accesses HDFS as nobody. You can override this username by setting the HADOOP_USER_NAME system property in the Presto JVM Config, replacing hdfs_user with the appropriate username:

-DHADOOP_USER_NAME=hdfs_user

The hive user generally works, since Hive is often started with the hive user and this user has access to the Hive warehouse.

Whenever you change the user Presto is using to access HDFS, remove /tmp/presto-* on HDFS, as the new user may not have access to the existing temporary directories.

Accessing Hadoop clusters protected with Kerberos authentication#

Kerberos authentication is supported for both HDFS and the Hive metastore. However, Kerberos authentication by ticket cache is not yet supported.

The properties that apply to Hive connector security are listed in the Hive Configuration Properties table. Please see the Hive Connector Security Configuration section for a more detailed discussion of the security options in the Hive connector.

Hive Configuration Properties#

Property Name	Description	Default
`hive.config.resources`	An optional comma-separated list of HDFS configuration files. These files must exist on the machines running Presto. Only specify this if absolutely necessary to access HDFS. Example: `/etc/hdfs-site.xml`
`hive.recursive-directories`	Enable reading data from subdirectories of table or partition locations. If disabled, subdirectories are ignored. This is equivalent to the `hive.mapred.supports.subdirectories` property in Hive.	`false`
`hive.ignore-absent-partitions`	Ignore partitions when the file system location does not exist rather than failing the query. This skips data that may be expected to be part of the table.	`false`
`hive.storage-format`	The default file format used when creating new tables.	`ORC`
`hive.compression-codec`	The compression codec to use when writing files. Possible values are `NONE`, `SNAPPY`, `LZ4`, `ZSTD`, or `GZIP`.	`GZIP`
`hive.force-local-scheduling`	Force splits to be scheduled on the same node as the Hadoop DataNode process serving the split data. This is useful for installations where Presto is collocated with every DataNode.	`false`
`hive.respect-table-format`	Should new partitions be written using the existing table format or the default Presto format?	`true`
`hive.immutable-partitions`	Can new data be inserted into existing partitions? If `true` then setting `hive.insert-existing-partitions-behavior` to `APPEND` is not allowed. This also affects the `insert_existing_partitions_behavior` session property in the same way.	`false`
`hive.insert-existing-partitions-behavior`	What happens when data is inserted into an existing partition? Possible values are `APPEND` - appends data to existing partitions `OVERWRITE` - overwrites existing partitions `ERROR` - modifying existing partitions is not allowed	`APPEND`
`hive.create-empty-bucket-files`	Should empty files be created for buckets that have no data?	`false`
`hive.max-partitions-per-writers`	Maximum number of partitions per writer.	100
`hive.max-partitions-per-scan`	Maximum number of partitions for a single table scan.	100,000
`hive.hdfs.authentication.type`	HDFS authentication type. Possible values are `NONE` or `KERBEROS`.	`NONE`
`hive.hdfs.impersonation.enabled`	Enable HDFS end user impersonation.	`false`
`hive.hdfs.presto.principal`	The Kerberos principal that Presto will use when connecting to HDFS.
`hive.hdfs.presto.keytab`	HDFS client keytab location.
`hive.dfs.replication`	Hadoop file system replication factor.
`hive.security`	See Hive Connector Security Configuration.
`security.config-file`	Path of config file to use when `hive.security=file`. See File Based Authorization for details.
`hive.non-managed-table-writes-enabled`	Enable writes to non-managed (external) Hive tables.	`false`
`hive.non-managed-table-creates-enabled`	Enable creating non-managed (external) Hive tables.	`true`
`hive.collect-column-statistics-on-write`	Enables automatic column level statistics collection on write. See Table Statistics for details.	`true`
`hive.s3select-pushdown.enabled`	Enable query pushdown to AWS S3 Select service.	`false`
`hive.s3select-pushdown.max-connections`	Maximum number of simultaneously open connections to S3 for S3 Select Pushdown.	500
`hive.file-status-cache-tables`	Cache directory listing for specific tables. Examples: `fruit.apple,fruit.orange` to cache listings only for tables `apple` and `orange` in schema `fruit` `fruit.,vegetable.` to cache listings for all tables in schemas `fruit` and `vegetable` `*` to cache listings for all tables in all schemas
`hive.file-status-cache-size`	Maximum total number of cached file status entries.	1,000,000
`hive.file-status-cache-expire-time`	How long a cached directory listing should be considered valid.	`1m`
`hive.parquet.time-zone`	Adjusts timestamp values to a specific time zone. For Hive 3.1+, this should be set to UTC.	JVM default
`hive.rcfile.time-zone`	Adjusts binary encoded timestamp values to a specific time zone. For Hive 3.1+, this should be set to UTC.	JVM default
`hive.orc.time-zone`	Sets the default time zone for legacy ORC files that did not declare a time zone.	JVM default
`hive.timestamp-precision`	Specifies the precision to use for columns of type `timestamp`. Possible values are `MILLISECONDS`, `MICROSECONDS` and `NANOSECONDS`. Write operations are only supported for `MILLISECONDS`.	`MILLISECONDS`
`hive.temporary-staging-directory-enabled`	Controls whether the temporary staging directory configured at `hive.temporary-staging-directory-path` should be used for write operations. Temporary staging directory is never used for writes to non-sorted tables on S3, encrypted HDFS or external location. Writes to sorted tables will utilize this path for staging temporary files during sorting operation. When disabled, the target storage will be used for staging while writing sorted tables which can be inefficient when writing to object stores like S3.	`true`
`hive.temporary-staging-directory-path`	Controls the location of temporary staging directory that is used for write operations. The `${USER}` placeholder can be used to use a different location for each user.	`/tmp/${USER}`
`hive.translate-hive-views`	Enable translation for Hive views. (experimental)	`false`
`hive.legacy-hive-view-translation`	Use the legacy algorithm to translate Hive views. You can alternatively set the `legacy_hive_view_translation` session property to `true`.	`false`

Metastore Configuration Properties#

The required Hive metastore can be configured with a number of properties. Specific properties can be used to further configure the Thrift or Glue metastore.

Property Name	Description	Default
`hive.metastore`	The type of Hive metastore to use. Presto currently supports the default Hive Thrift metastore (`thrift`), and the AWS Glue Catalog (`glue`) as metadata sources.	`thrift`
`hive.metastore-cache-ttl`	Duration how long cached metastore data should be considered valid.	`0s`
`hive.metastore-cache-maximum-size`	Hive metastore cache maximum size.	10000
`hive.metastore-refresh-interval`	Asynchronously refresh cached metastore data after access if it is older than this but is not yet expired, allowing subsequent accesses to see fresh data.
`hive.metastore-refresh-max-threads`	Maximum threads used to refresh cached metastore data.	10
`hive.metastore-timeout`	Timeout for Hive metastore requests.	`10s`
`hive.hide-delta-lake-tables`	Controls whether to hide Delta Lake tables in table listings. Currently applies only when using the AWS Glue metastore.	false

Thrift Metastore Configuration Properties#

Property Name	Description	Default
`hive.metastore.uri`	The URI(s) of the Hive metastore to connect to using the Thrift protocol. If multiple URIs are provided, the first URI is used by default, and the rest of the URIs are fallback metastores. This property is required. Example: `thrift://192.0.2.3:9083` or `thrift://192.0.2.3:9083,thrift://192.0.2.4:9083`
`hive.metastore.username`	The username Presto uses to access the Hive metastore.
`hive.metastore.authentication.type`	Hive metastore authentication type. Possible values are `NONE` or `KERBEROS` (defaults to `NONE`).
`hive.metastore.thrift.impersonation.enabled`	Enable Hive metastore end user impersonation.
`hive.metastore.thrift.delegation-token.cache-ttl`	Time to live delegation token cache for metastore.	`1h`
`hive.metastore.thrift.delegation-token.cache-maximum-size`	Delegation token cache maximum size.	1,000
`hive.metastore.thrift.client.ssl.enabled`	Use SSL when connecting to metastore.	`false`
`hive.metastore.thrift.client.ssl.key`	Path to private key and client certificate (key store).
`hive.metastore.thrift.client.ssl.key-password`	Password for the private key.
`hive.metastore.thrift.client.ssl.trust-certificate`	Path to the server certificate chain (trust store). Required when SSL is enabled.
`hive.metastore.thrift.client.ssl.trust-certificate-password`	Password for the trust store
`hive.metastore.service.principal`	The Kerberos principal of the Hive metastore service.
`hive.metastore.client.principal`	The Kerberos principal that Presto uses when connecting to the Hive metastore service.
`hive.metastore.client.keytab`	Hive metastore client keytab location.

AWS Glue Catalog Configuration Properties#

In order to use a Glue catalog, ensure to configure the metastore with hive.metastore=glue and provide further details with the following properties:

Property Name	Description
`hive.metastore.glue.region`	AWS region of the Glue Catalog. This is required when not running in EC2, or when the catalog is in a different region. Example: `us-east-1`
`hive.metastore.glue.endpoint-url`	Glue API endpoint URL (optional). Example: `https://glue.us-east-1.amazonaws.com`
`hive.metastore.glue.pin-client-to-current-region`	Pin Glue requests to the same region as the EC2 instance where Presto is running, defaults to `false`.
`hive.metastore.glue.max-connections`	Max number of concurrent connections to Glue, defaults to `5`.
`hive.metastore.glue.max-error-retries`	Maximum number of error retries for the Glue client, defaults to `10`.
`hive.metastore.glue.default-warehouse-dir`	Default warehouse directory for schemas created without an explicit `location` property.
`hive.metastore.glue.aws-credentials-provider`	Fully qualified name of the Java class to use for obtaining AWS credentials. Can be used to supply a custom credentials provider.
`hive.metastore.glue.aws-access-key`	AWS access key to use to connect to the Glue Catalog. If specified along with `hive.metastore.glue.aws-secret-key`, this parameter takes precedence over `hive.metastore.glue.iam-role`.
`hive.metastore.glue.aws-secret-key`	AWS secret key to use to connect to the Glue Catalog. If specified along with `hive.metastore.glue.aws-access-key`, this parameter takes precedence over `hive.metastore.glue.iam-role`.
`hive.metastore.glue.catalogid`	The ID of the Glue Catalog in which the metadata database resides.
`hive.metastore.glue.iam-role`	ARN of an IAM role to assume when connecting to the Glue Catalog.
`hive.metastore.glue.external-id`	External ID for the IAM role trust policy when connecting to the Glue Catalog.
`hive.metastore.glue.partitions-segments`	Number of segments for partitioned Glue tables, defaults to `5`.
`hive.metastore.glue.get-partition-threads`	Number of threads for parallel partition fetches from Glue, defaults to `20`.

Google Cloud Storage Configuration#

The Hive connector can access data stored in GCS, using the gs:// URI prefix. Please refer to the Hive Connector GCS Tutorial for step-by-step instructions.

GCS Configuration properties#

Property Name	Description
`hive.gcs.json-key-file-path`	JSON key file used to authenticate with Google Cloud Storage.
`hive.gcs.use-access-token`	Use client-provided OAuth token to access Google Cloud Storage. This is mutually exclusive with a global JSON key file.

Table Statistics#

The Hive connector supports collecting and managing table statistics to improve query processing performance.

When writing data, the Hive connector always collects basic statistics (numFiles, numRows, rawDataSize, totalSize) and by default will also collect column level statistics:

Column Type	Collectible Statistics
`TINYINT`	number of nulls, number of distinct values, min/max values
`SMALLINT`	number of nulls, number of distinct values, min/max values
`INTEGER`	number of nulls, number of distinct values, min/max values
`BIGINT`	number of nulls, number of distinct values, min/max values
`DOUBLE`	number of nulls, number of distinct values, min/max values
`REAL`	number of nulls, number of distinct values, min/max values
`DECIMAL`	number of nulls, number of distinct values, min/max values
`DATE`	number of nulls, number of distinct values, min/max values
`TIMESTAMP`	number of nulls, number of distinct values, min/max values
`VARCHAR`	number of nulls, number of distinct values
`CHAR`	number of nulls, number of distinct values
`VARBINARY`	number of nulls
`BOOLEAN`	number of nulls, number of true/false values

Updating table and partition statistics#

If your queries are complex and include joining large data sets, running ANALYZE on tables/partitions may improve query performance by collecting statistical information about the data.

When analyzing a partitioned table, the partitions to analyze can be specified via the optional partitions property, which is an array containing the values of the partition keys in the order they are declared in the table schema:

ANALYZE table_name WITH (
    partitions = ARRAY[
        ARRAY['p1_value1', 'p1_value2'],
        ARRAY['p2_value1', 'p2_value2']])

This query will collect statistics for two partitions with keys p1_value1, p1_value2 and p2_value1, p2_value2.

On wide tables, collecting statistics for all columns can be expensive and can have a detrimental effect on query planning. It is also typically unnecessary - statistics are only useful on specific columns, like join keys, predicates, grouping keys. One can specify a subset of columns to be analyzed via the optional columns property:

ANALYZE table_name WITH (
    partitions = ARRAY[ARRAY['p2_value1', 'p2_value2']],
    columns = ARRAY['col_1', 'col_2'])

This query collects statistics for columns col_1 and col_2 for the partition with keys p2_value1, p2_value2.

Note that if statistics were previously collected for all columns, they need to be dropped before re-analyzing just a subset:

CALL system.drop_stats(schema_name, table_name)

You can also drop statistics for selected partitions only:

CALL system.drop_stats(schema_name, table_name, ARRAY[ARRAY['p2_value1', 'p2_value2']])

Dynamic Filtering#

The Hive connector supports the dynamic filtering optimization. Dynamic partition pruning is supported for partitioned tables stored in any file format for broadcast as well as partitioned joins. Dynamic bucket pruning is supported for bucketed tables stored in any file format for broadcast joins only.

For tables stored in ORC or Parquet file format, dynamic filters are also pushed into local table scan on worker nodes for broadcast joins. Dynamic filter predicates pushed into the ORC and Parquet readers are used to perform stripe or row-group pruning and save on disk I/O. Sorting the data within ORC or Parquet files by the columns used in join criteria significantly improves the effectiveness of stripe or row-group pruning. This is because grouping similar data within the same stripe or row-group greatly improves the selectivity of the min/max indexes maintained at stripe or row-group level.

Delaying execution for dynamic filters#

It can often be beneficial to wait for the collection of dynamic filters before starting a table scan. This extra wait time can potentially result in significant overall savings in query and CPU time, if dynamic filtering is able to reduce the amount of scanned data.

For the Hive connector, a table scan can be delayed for a configured amount of time until the collection of dynamic filters by using the configuration property hive.dynamic-filtering-probe-blocking-timeout in the catalog file or the catalog session property <hive-catalog>.dynamic_filtering_probe_blocking_timeout.

Schema Evolution#

Hive allows the partitions in a table to have a different schema than the table. This occurs when the column types of a table are changed after partitions already exist (that use the original column types). The Hive connector supports this by allowing the same conversions as Hive:

varchar to and from tinyint, smallint, integer and bigint
real to double
Widening conversions for integers, such as tinyint to smallint

Any conversion failure results in null, which is the same behavior as Hive. For example, converting the string 'foo' to a number, or converting the string '1234' to a tinyint (which has a maximum value of 127).

Avro Schema Evolution#

Presto supports querying and manipulating Hive tables with the Avro storage format, which has the schema set based on an Avro schema file/literal. Presto is also capable of creating the tables in Presto by infering the schema from a valid Avro schema file located locally, or remotely in HDFS/Web server.

To specify that the Avro schema should be used for interpreting table’s data one must use avro_schema_url table property. The schema can be placed remotely in HDFS (e.g. avro_schema_url = 'hdfs://user/avro/schema/avro_data.avsc'), S3 (e.g. avro_schema_url = 's3n:///schema_bucket/schema/avro_data.avsc'), a web server (e.g. avro_schema_url = 'http://example.org/schema/avro_data.avsc') as well as local file system. This URL, where the schema is located, must be accessible from the Hive metastore and Presto coordinator/worker nodes.

The table created in Presto using avro_schema_url behaves the same way as a Hive table with avro.schema.url or avro.schema.literal set.

Example:

CREATE TABLE hive.avro.avro_data (
   id bigint
 )
WITH (
   format = 'AVRO',
   avro_schema_url = '/usr/local/avro_data.avsc'
)

The columns listed in the DDL (id in the above example) is ignored if avro_schema_url is specified. The table schema matches the schema in the Avro schema file. Before any read operation, the Avro schema is accessed so the query result reflects any changes in schema. Thus Presto takes advantage of Avro’s backward compatibility abilities.

If the schema of the table changes in the Avro schema file, the new schema can still be used to read old data. Newly added/renamed fields must have a default value in the Avro schema file.

The schema evolution behavior is as follows:

Column added in new schema: Data created with an older schema produces a default value when table is using the new schema.
Column removed in new schema: Data created with an older schema no longer outputs the data from the column that was removed.
Column is renamed in the new schema: This is equivalent to removing the column and adding a new one, and data created with an older schema produces a default value when table is using the new schema.
Changing type of column in the new schema: If the type coercion is supported by Avro or the Hive connector, then the conversion happens. An error is thrown for incompatible types.

Limitations#

The following operations are not supported when avro_schema_url is set:

CREATE TABLE AS is not supported.
Using partitioning(partitioned_by) or bucketing(bucketed_by) columns are not supported in CREATE TABLE.
ALTER TABLE commands modifying columns are not supported.

Procedures#

system.create_empty_partition(schema_name, table_name, partition_columns, partition_values)

Create an empty partition in the specified table.
system.sync_partition_metadata(schema_name, table_name, mode, case_sensitive)

Check and update partitions list in metastore. There are three modes available:
- ADD : add any partitions that exist on the file system, but not in the metastore.
- DROP: drop any partitions that exist in the metastore, but not on the file system.
- FULL: perform both ADD and DROP.
The case_sensitive argument is optional. The default value is true for compatibility with Hive’s MSCK REPAIR TABLE behavior, which expects the partition column names in file system paths to use lowercase (e.g. col_x=SomeValue). Partitions on the file system not conforming to this convention are ignored, unless the argument is set to false.
system.drop_stats(schema_name, table_name, partition_values)

Drops statistics for a subset of partitions or the entire table. The partitions are specified as an array whose elements are arrays of partition values (similar to the partition_values argument in create_empty_partition). If partition_values argument is omitted, stats are dropped for the entire table.

system.register_partition(schema_name, table_name, partition_columns, partition_values, location)

Registers existing location as a new partition in the metastore for the specified table.

When the location argument is omitted, the partition location is constructed using partition_columns and partition_values.

Due to security reasons, the procedure is enabled only when hive.allow-register-partition-procedure is set to true.

system.unregister_partition(schema_name, table_name, partition_columns, partition_values)

Unregisters given, existing partition in the metastore for the specified table. The partition data is not deleted.

Special Columns#

In addition to the defined columns, the Hive connector automatically exposes metadata in a number of hidden columns in each table. You can use these columns in your SQL statements like any other column, e.g., they can be selected directly or used in conditional statements.

$bucket: Bucket number for this row
$path: Full file system path name of the file for this row
$file_modified_time: Date and time of the last modification of the file for this row
$file_size: Size of the file for this row
$partition: Partition name for this row

Special Tables#

Table Properties#

The raw Hive table properties are available as a hidden table, containing a separate column per table property, with a single row containing the property values. The properties table name is the same as the table name with $properties appended.

You can inspect the property names and values with a simple query:

SELECT * FROM hive.web."page_views$properties";

Examples#

The Hive connector supports querying and manipulating Hive tables and schemas (databases). While some uncommon operations need to be performed using Hive directly, most operations can be performed using Presto.

Create a new Hive schema named web that stores tables in an S3 bucket named my-bucket:

CREATE SCHEMA hive.web
WITH (location = 's3://my-bucket/')

Create a new Hive table named page_views in the web schema that is stored using the ORC file format, partitioned by date and country, and bucketed by user into 50 buckets. Note that Hive requires the partition columns to be the last columns in the table:

CREATE TABLE hive.web.page_views (
  view_time timestamp,
  user_id bigint,
  page_url varchar,
  ds date,
  country varchar
)
WITH (
  format = 'ORC',
  partitioned_by = ARRAY['ds', 'country'],
  bucketed_by = ARRAY['user_id'],
  bucket_count = 50
)

Drop a partition from the page_views table:

DELETE FROM hive.web.page_views
WHERE ds = DATE '2016-08-09'
  AND country = 'US'

Add an empty partition to the page_views table:

CALL system.create_empty_partition(
    schema_name => 'web',
    table_name => 'page_views',
    partition_columns => ARRAY['ds', 'country'],
    partition_values => ARRAY['2016-08-09', 'US']);

Drop stats for a partition of the page_views table:

CALL system.drop_stats(
    schema_name => 'web',
    table_name => 'page_views',
    partition_values => ARRAY['2016-08-09', 'US']);

Query the page_views table:

SELECT * FROM hive.web.page_views

List the partitions of the page_views table:

SELECT * FROM hive.web."page_views$partitions"

Create an external Hive table named request_logs that points at existing data in S3:

CREATE TABLE hive.web.request_logs (
  request_time timestamp,
  url varchar,
  ip varchar,
  user_agent varchar
)
WITH (
  format = 'TEXTFILE',
  external_location = 's3://my-bucket/data/logs/'
)

Collect statistics for the request_logs table:

ANALYZE hive.web.request_logs;

The examples shown here should work on Google Cloud Storage after replacing s3:// with gs://.

Cleaning up#

Drop the external table request_logs. This only drops the metadata for the table. The referenced data directory is not deleted:

DROP TABLE hive.web.request_logs

Drop a schema:

DROP SCHEMA hive.web

Hive Connector Limitations#

DELETE is only supported if the WHERE clause matches entire partitions.
ALTER SCHEMA usage fails, since the Hive metastore does not support renaming schemas.

For security reasons, the sys system catalog is not accessible.
Hive’s timestamp with local zone data type is not supported. It is possible to read from a table with a column of this type, but the column data is not accessible. Writing to such a table is not supported.
Due to Hive issues HIVE-21002 and HIVE-22167, Presto does not correctly read timestamp values from Parquet, RCBinary, or Avro file formats created by Hive 3.1 or later. When reading from these file formats, Presto returns different results than Hive.
CREATE TABLE AS can be used to create transactional tables in ORC format like this:
```
CREATE TABLE <name>
WITH (
    format='ORC',
    transactional=true,
)
AS <query>
```
Presto does not support gathering table statistics for Hive transactional tables. You need to use Hive to gather table statistics with ANALYZE TABLE COMPUTE STATISTICS after table creation.