- Specifies the behavior of the target connector component
- Configures how data is transformed
- Configures the underlying link data transportation layer
- Affects how the initiator connector performs
Links are named configurations that include an initiating connector and a target connector. If the same property is set for a link and a connector, the link setting overrides the connector setting.
Basic Tab
Presto Connector | ||||
---|---|---|---|---|
Name | Default | Description | Overridable? Property Name |
Connector Type |
Server | None | Used to connect to the target database as part of the JDBC connection string. This is the IP address or DNS name of the target host. For AWS CFT, use the IP portion of the PrestoCoordinatorURL (given as an output value after CloudFormation stack creation). | Target | |
Port | 8090 | Sometimes set to 8080. This is a required setting. Valid values are 1026–65535. The default value can be overridden. |
Target | |
Catalog Name | hive | Name of the catalog for the Presto connector. | Target | |
Schema Name | default | Name of the schema used for the Presto connector. | Target |
Security Tab
Presto Connector | ||||
---|---|---|---|---|
Name | Default | Description | Overridable? Property Name |
Connector Type |
Authentication Mechanism | None | Indicates the authentication mechanism used on the target data source. Valid values are None, Kerberos, and LDAP/Okta. This is a required setting. |
Target | |
Username | None | Name of the user. Maximum length is 255 characters. A username added for a connector or target connector link must be included in Allowed OS users. This NVP is saved in the QueryGrid Manager configuration and is required when the initiator does not support a mechanism to provide user credentials. The username is also used for connectivity diagnostic checks. |
Target | |
Password | None | User password. Maximum length is 255 characters. Password must not be set when using Kerberos. |
Target | |
Kerberos Keytab | None | Absolute path to the Kerberos keytab file. QueryGrid only uses the keytab file for authentication if the user does not provide a username and password. | Target | |
Kerberos Realm | None | Kerberos realm. | Target | |
Kerberos Service Name | Trino | Must match the http-server.authentication.krb5.service-name set in the Presto coordinator config.properties file if using Kerberos. | Target | |
Role Support | False | Enable user role support for the target system. This feature is only available when Presto with Sentry is being used. When set to true, the user role from the initiator or target is applied to the target system based on role mapping, if any. If the cluster is configured to support roles, errors are returned back to the user. If the cluster is not configured to support roles, the user role is not applied. When set to false, roles are not applied to the target system. |
● roleSupport |
Target |
SSL Trust or Key Store Path | None | SSL truststore or keystore path for Kerberos or LDAP/Okta authentication on Presto. | Target | |
SSL Trust or Key Store Password | None | SSL truststore or keystore password for Kerberos or LDAP/Okta authentication on Presto. | Target |
Query Engine Tab
Presto Connector | ||||
---|---|---|---|---|
Name | Default | Description | Overridable? Property Name |
Connector Type |
Explain Kind | LOGICAL | Defines the flavor of the explain for the EXPLAIN SQL statement for a remote Presto query. Valid values are logical or distributed. |
● explainKind |
Target |
Presto Reader Task Concurrency | 8 | Number of parallel concurrent readers in Presto per worker per query. Valid values are 1–32. |
● prestoReaderTaskConcurrency |
Target |
Presto Writer Count | 8 | Number of parallel writers in Presto or concurrent writer threads per worker per query. Valid values are 1–32. |
● prestoWriterCount |
Target |
Advanced Tab
Presto Connector | ||||
---|---|---|---|---|
Name | Default | Description | Overridable? Property Name |
Connector Type |
Temporary Schema Name | None | Specified database name for creating temporary tables/views. If you do not provide a database name in this property, QueryGrid creates the temporary view in the default database assigned to the user. |
● tempDbName |
Target |
Enable Logging | INFO | Logging level for the connector or link properties. User level log settings can be explicitly set through the add or edit link page in the QueryGrid portlet. This setting applies to both the initiating and target connector. The logging level for the initiator connector in the link takes precedence if set differently. Valid values are NONE, WARN, INFO, and DEBUG. |
Initiator, Target | |
Disable Pushdown | False | When set to true, disables the pushdown of all query conditions to the target system. Certain system-level, session-level, and column-level query attributes, such as CASESPECIFIC, can affect character string comparison results. These attributes can cause some queries to return incorrect results due to incorrect row filtering on the target system. To avoid incorrect results caused by condition pushdown in situations where the settings on the initiating system do not match the settings on the target system, you can disable the pushdown of all conditions to the target system. If designated as Overridable, this property can only be overridden at the session level from false to true (indicating you are disabling pushdown), but cannot be changed from true to false. |
● disablePushdown |
Initiator |
16.20+ LOB Support | True | On Teradata systems version 16.20 and later, the STRING and BINARY columns on Presto are mapped to CLOB and BLOB by default. Deselect this option to map the STRING and BINARY columns to VARCHAR and VARBYTE, respectively. Disable this option if there are a large number of STRING/BINARY columns in the Presto table. |
● lobSupport |
Target |
Default String Size | 32000 characters | The VARCHAR truncation size. This is the size at which data imported from or exported to string columns is truncated. The value represents the maximum number of Unicode characters to import, and defaults to 32000 characters. QueryGrid truncates the string columns at the default value set in defaultStringSize if less than the actual column size. Valid values are 1–1048544000 characters. This is for a Teradata-to-Presto link and is used by the target Presto connector and is applicable when the initiating Teradata system does not support the CLOB data type with QueryGrid. With CLOB support, the default string size is not used. |
● defaultStringSize |
Target |
Default Binary Size | 64000 bytes | The default truncation size for the VARBINARY types. Valid values are 1–2097088000 bytes. This is for a Teradata-to-Presto link and is used by the target Presto connector and is applicable when the initiating Teradata system does not support BLOB data types with QueryGrid. With BLOB support, the default binary size is not used. |
● defaultBinarySize |
Target |
Timestamp Timezone | None | Calculate the timestamp using a specified timezone. The timezone property value must exist in the TimeZone.getAvailableIDs() list returned by Java. | ● TimestampTimezone |
Target |
Link Buffer Count | 4 | Maximum number of write buffers available on a single channel at one time. Link Buffer Count overrides the default internal fabric property shmDefaultNumMemoryBuffers.
Valid values are 4–8. |
● linkBufferCount |
Initiator, Target |
Link Buffer Size | 1048576 | Maximum size of the write buffers to allocate for row handling and message exchange. Valid values are 73728–10485760 bytes. |
● linkBufferSize |
Initiator |
Response Timeout | 86400000 | The number of milliseconds to wait for the target query to complete before timing out and stopping the operation. The fabric stops and releases all resources associated with queries whose duration exceeds the value set on the target link properties or the target connector properties. Connectors timeout when responses from the fabric exceed their response timeout value. Valid values are 300000–172800000. |
● responseTimeout |
Initiator, Target |
Connection Max Idle Time | 86400 seconds | The maximum idle time for the connection cache object, after which the object is closed and removed from the cache. Use this property when there are multiple concurrent users and queries running on the system that might lead to starvation of connection objects. Valid values are 1–86400 seconds. |
Target | |
Connection Pool Size | 100 | Maximum number of connection objects that can be stored in a connection pool. When acquiring a new connection, the connector checks for an available space in the pool. If no space is available in the connection pool, the connection fails after 5 minutes. Only one connection pool and username per connector configuration is allowed. Valid values are 1–10000. |
Target | |
Connection Evict Frequency | 30 minutes | Frequency of eviction checks. Connection objects from the pool are checked, closed, and removed if the idle time (current time - last time of use) of a connection object is greater than the Connection Max Idle Time setting. Reduce the time between checks if there are multiple concurrent users running queries to clear the connections more frequently. Valid values are 1–1440 minutes. |
Target |