Starburst Netezza connector#

The Starburst Netezza connector allows querying and creating tables in an external IBM Netezza Database.

Requirements#

To connect to Netezza, you need:

  • Netezza version 11.2.0.0 or higher.

  • Network access from the coordinator and workers to the Netezza Server. Port 5480 is the default port.

  • Netezza JDBC driver, downloaded from IBM Fix Central.

  • A valid Starburst Enterprise license.

Configuration#

You need to add the JDBC driver, before creating catalogs:

  1. Obtain the Netezza JDBC driver.

  2. Add the JDBC JAR file to the SEP plugin/netezza directory on the coordinator and all workers.

  3. Restart SEP on every node.

Create a catalog properties file in etc/catalog named, for example, mynetezza.properties to access the configured Netezza database in the mynetezza catalog. Configure the usage of the connector by specifying the name netezza and replace the connection properties as appropriate for your setup.

connector.name=netezza
connection-url=jdbc:netezza://example.net:5480/database
connection-user=admin
connection-password=secret

More information about the supported JDBC URL format and parameters of the Netezza JDBC driver is available in the Netezza documentation.

General configuration properties#

The following table describes general catalog configuration properties for the connector:

Property name

Description

Default value

case-insensitive-name-matching

Support case insensitive schema and table names.

false

case-insensitive-name-matching.cache-ttl

1m

case-insensitive-name-matching.config-file

Path to a name mapping configuration file in JSON format that allows Trino to disambiguate between schemas and tables with similar names in different cases.

null

case-insensitive-name-matching.refresh-period

Frequency with which Trino checks the name matching configuration file for changes.

0 (refresh disabled)

metadata.cache-ttl

Duration for which metadata, including table and column statistics, is cached.

0 (caching disabled)

metadata.cache-missing

Cache the fact that metadata, including table and column statistics, is not available

false

metadata.cache-maximum-size

Maximum number of objects stored in the metadata cache

10000

write.batch-size

Maximum number of statements in a batched execution. Do not change this setting from the default. Non-default values may negatively impact performance.

1000

dynamic-filtering.enabled

Push down dynamic filters into JDBC queries

true

dynamic-filtering.wait-timeout

Maximum duration for which Trino will wait for dynamic filters to be collected from the build side of joins before starting a JDBC query. Using a large timeout can potentially result in more detailed dynamic filters. However, it can also increase latency for some queries.

20s

Type mapping#

Because SEP and Netezza each support types that the other does not, this connector modifies some types when reading or writing data.

Netezza to SEP type mapping#

The following read type mapping applies when data is read from existing tables in Netezza, or inserted into existing tables in Netezza from SEP.

Netezza to SEP read type mapping#

Netezza type

SEP type

Notes

BOOLEAN, BOOL

BOOLEAN

BYTEINT, INT1

TINYINT

SMALLINT, INT2

SMALLINT

INTEGER, INT, INT4

INTEGER

BIGINT, INT8

BIGINT

DOUBLE PRECISION

DOUBLE

REAL, FLOAT(p)

REAL

Special values Infinity, -Infinity, and NaN are supported.

NUMERIC,(p, s), NUMERIC(p), NUMERIC, DECIMAL(p, s)

DECIMAL(p, s)

CHARACTER(n), CHAR(n), NCHAR(n)

CHAR(n)

CHARACTER VARYING(n), VARCHAR(n), NVARCHAR(n)

VARCHAR(n)

VARBINARY(n)

VARBINARY

ST_GEOMETRY(n) is not supported.

DATE

DATE

TIME

TIME(6)

TIME WITH TIME ZONE

TIME(6) WITH TIME ZONE

TIMESTAMP

TIMESTAMP(6)

JSON, JSONB

JSON

No other types are supported.

SQL support#

The connector provides read and write access to data and metadata in the Netezza database. In addition to the globally available and read operation statements, the connector supports the following features:

SQL DELETE#

If a WHERE clause is specified, the DELETE operation only works if the predicate in the clause can be fully pushed down to the data source.

SEP to Netezza write type mapping#

The following write type mapping applies when tables are created in Netezza from SEP.

SEP to Netezza write type mapping#

SEP type

Netezza type

Notes

BOOLEAN

BOOLEAN

TINYINT

BYTEINT

SMALLINT

SMALLINT

INTEGER

INTEGER

BIGINT

BIGINT

REAL

REAL

DOUBLE

DOUBLE PRECISION

DECIMAL(p, s)

DECIMAL(p, s)

CHAR(n)

NCHAR(n)

max n is 16,000

VARCHAR

NVARCHAR(n)

max n is 16,000

VARBINARY

VARBINARY(64000)

DATE

DATE

TIME, TIME(p)

TIME

max supported precision is 6

TIME WITH TIME ZONE, TIME(p) WITH TIME ZONE

TIME WITH TIME ZONE

max supported precision is 6

TIMESTAMP, TIMESTAMP(p)

TIMESTAMP

max supported precision is 6, TIMESTAMP WITH TIME ZONE is not supported

JSON

JSONB

No other type is supported.

Type mapping configuration properties#

The following properties can be used to configure how data types from the connected data source are mapped to Trino data types and how the metadata is cached in Trino.

Property name

Description

Default value

unsupported-type-handling

Configure how unsupported column data types are handled:

  • IGNORE, column is not accessible.

  • CONVERT_TO_VARCHAR, column is converted to unbounded VARCHAR.

The respective catalog session property is unsupported_type_handling.

IGNORE

jdbc-types-mapped-to-varchar

Allow forced mapping of comma separated lists of data types to convert to unbounded VARCHAR

Table functions#

The connector provides specific table functions to access Netezza.

query(varchar) -> table#

The query function allows you to query the underlying database directly. It requires syntax native to the data source, because the full query is pushed down and processed in the data source. This can be useful for accessing native features or for improving query performance in situations where running a query natively may be faster.

The query table function is available in the system schema of any catalog that uses the Netezza connector, such as catalog_example. The following example passes myQuery to the data source. myQuery has to be a valid query for the data source, and is required to return a table as a result:

SELECT
  *
FROM
  TABLE(
    catalog_example.system.query(
      query => 'myQuery'
    )
  );

Performance#

The connector includes a number of performance improvements, detailed in the following sections.

Table statistics#

The Netezza connector can use table and column statistics for cost based optimizations, to improve query processing performance based on the actual data in the data source.

The statistics are collected by Netezza and retrieved by the connector. Read more in Netezza documentation.

Pushdown#

The connector supports pushdown for a number of operations:

Aggregate pushdown for the following functions:

Cost-based join pushdown#

The connector supports cost-based Join pushdown to make intelligent decisions about whether to push down a join operation to the data source.

When cost-based join pushdown is enabled, the connector only pushes down join operations if the available Table statistics suggest that doing so improves performance. Note that if no table statistics are available, join operation pushdown does not occur to avoid a potential decrease in query performance.

The following table describes catalog configuration properties for join pushdown:

Property name

Description

Default value

join-pushdown.enabled

Enable join pushdown. Equivalent catalog session property is join_pushdown_enabled.

true

join-pushdown.strategy

Strategy used to evaluate whether join operations are pushed down. Set to AUTOMATIC to enable cost-based join pushdown, or EAGER to push down joins whenever possible. Note that EAGER can push down joins even when table statistics are unavailable, which may result in degraded query performance. Because of this, EAGER is only recommended for testing and troubleshooting purposes.

AUTOMATIC

Dynamic filtering#

Dynamic filtering is enabled by default. It causes the connector to wait for dynamic filtering to complete before starting a JDBC query.

You can disable dynamic filtering by setting the dynamic-filtering.enabled property in your catalog configuration file to false.

Wait timeout#

By default, table scans on the connector are delayed up to 20 seconds until dynamic filters are collected from the build side of joins. Using a large timeout can potentially result in more detailed dynamic filters. However, it can also increase latency for some queries.

You can configure the dynamic-filtering.wait-timeout property in your catalog properties file:

dynamic-filtering.wait-timeout=1m

You can use the dynamic_filtering_wait_timeout catalog session property in a specific session:

SET SESSION catalogname.dynamic_filtering_wait_timeout = 1s;

Compaction#

The maximum size of dynamic filter predicate, that is pushed down to the connector during table scan for a column, is configured using the domain-compaction-threshold property in the catalog properties file:

domain-compaction-threshold=100

You can use the domain_compaction_threshold catalog session property:

SET SESSION domain_compaction_threshold = 10;

By default, domain-compaction-threshold is set to 32. When the dynamic predicate for a column exceeds this threshold, it is compacted into a single range predicate.

For example, if the dynamic filter collected for a date column dt on the fact table selects more than 32 days, the filtering condition is simplified from dt IN ('2020-01-10', '2020-01-12',..., '2020-05-30') to dt BETWEEN '2020-01-10' AND '2020-05-30'. Using a large threshold can result in increased table scan overhead due to a large IN list getting pushed down to the data source.

Metrics#

Metrics about dynamic filtering are reported in a JMX table for each catalog:

jmx.current."io.trino.plugin.jdbc:name=catalogname,type=dynamicfilteringstats"

Metrics include information about the total number of dynamic filters, the number of completed dynamic filters, the number of available dynamic filters and the time spent waiting for dynamic filters.

JDBC connection pooling#

When JDBC connection pooling is enabled, each node creates and maintains a connection pool instead of opening and closing separate connections to the data source. Each connection is available to connect to the data source and retrieve data. After completion of an operation, the connection is returned to the pool and can be reused. This improves performance by a small amount, reduces the load on any required authentication system used for establishing the connection, and helps avoid running into connection limits on data sources.

JDBC connection pooling is disabled by default. You can enable JDBC connection pooling by setting the connection-pool.enabled property to true in your catalog configuration file:

connection-pool.enabled=true

The following catalog configuration properties can be used to tune connection pooling:

JDBC connection pooling catalog configuration properties#

Property name

Description

Default value

connection-pool.enabled

Enable connection pooling for the catalog.

false

connection-pool.max-size

The maximum number of idle and active connections in the pool.

10

connection-pool.max-connection-lifetime

The maximum lifetime of a connection. When a connection reaches this lifetime it is removed, regardless of how recently it has been active.

30m

connection-pool.pool-cache-max-size

The maximum size of the JDBC data source cache.

1000

connection-pool.pool-cache-ttl

The expiration time of a cached data source when it is no longer accessed.

30m

Security#

The connector includes a number of security-related features, detailed in the following sections.

Kerberos authentication#

The connector supports Kerberos authentication. Use the following properties in the catalog properties file to configure it.

netezza.authentication.type=KERBEROS
kerberos.client.principal=example@example.com
kerberos.client.keytab=etc/kerberos/example.keytab
kerberos.config=etc/kerberos/krb5.conf

In this example the user example@example.com, as defined in the kerberos.client.principal property, is used to connect to the database. The related Kerberos service ticket is located in the file defined in the kerberos.client.keytab property.

Kerberos credential pass-through#

The connector can be configured to pass through Kerberos credentials, received by SEP, to the Netezza database. This allows you to apply Kerberos-defined permissions to Netezza connections through SEP.

To configure credential pass-through in Kerberos and SEP, see Kerberos credential pass-through.

After you configure Kerberos and SEP, edit the catalog properties file to enable the connector to pass the credentials to the Netezza database. Configure the following Kerberos client configuration properties in the catalog properties file:

netezza.authentication.type=KERBEROS_PASS_THROUGH
http.authentication.krb5.config=/etc/krb5.conf
http-server.authentication.krb5.service-name=exampleServiceName
http-server.authentication.krb5.keytab=/path/to/Keytab/File

Any Netezza database accessed using SEP is now subject to the Kerberos-defined data access restrictions and permissions.

Password credential pass-through#

The connector supports password credential pass-through. To enable it, edit the catalog properties file to include the authentication type:

netezza.authentication.type=PASSWORD_PASS_THROUGH

For more information about configurations and limitations, see Password credential pass-through.

User impersonation#

The Netezza connector supports user impersonation.

User impersonation can be enabled in the catalog properties file:

netezza.impersonation.enabled=true

User impersonation in the connector is based on Netezza’s masquerading feature, which uses the EXECUTE AS command. For more information, see Netezza masquerading.