Project: StarRocks (App Definition and Development / Database)
File: paimon_catalog.md

displayed_sidebar: "English" tocmaxheading_level: 5 StarRocks supports Paimon catalogs from v3.1 onwards. A Paimon catalog is a kind of external catalog that enables you to query data from Apache Paimon without ingestion. Also, you can directly transform and load data from Paimon by using based on Paimon catalogs. To ensure successful SQL workloads on your Paimon cluster, your StarRocks cluster must be able to access the storage system and metastore of your Paimon cluster. StarRocks supports the following storage systems and metastores: Distributed file system (HDFS) or object storage like AWS S3, Microsoft Azure Storage, Google GCS, or or other S3-compatible storage system (for example, MinIO) Metastore like your file system or Hive metastore You can only use Paimon catalogs to query data. You cannot use Paimon catalogs to drop, delete, or insert data into your Paimon cluster. Before you create a Paimon catalog, make sure your StarRocks cluster can integrate with the storage system and metastore of your Paimon cluster. If your Paimon cluster uses AWS S3 as storage, choose your suitable authentication method and make the required preparations to ensure that your StarRocks cluster can access the related AWS cloud resources. The following authentication methods are recommended: Instance profile (recommended) Assumed role IAM user Of the above-mentioned three authentication methods, instance profile is the most widely used. For more information, see . If you choose HDFS as storage, configure your StarRocks cluster as follows: (Optional) Set the username that is used to access your HDFS cluster and Hive metastore. By default, StarRocks uses the username of the FE and BE or CN processes to access your HDFS cluster and Hive metastore. You can also set the username by adding `export HADOOPUSERNAME="<username>"` at the beginning of the **fe/conf/hadoopenv.sh file of each FE and at the beginning of the be/conf/hadoopenv.sh** file of each BE or the **cn/conf/hadoopenv.sh file of each CN. After you set the username in these files, restart each FE and each BE or CN to make the parameter settings take effect. You can set only one username for each StarRocks cluster. When you query Paimon data, the FEs and BEs or CNs of your StarRocks cluster use the HDFS client to access your HDFS cluster. In most cases, you do not need to configure your StarRocks cluster to achieve that purpose, and StarRocks starts the HDFS client using the default configurations. You need to configure your StarRocks cluster only in the following situations: High availability (HA) is enabled for your HDFS cluster: Add the hdfs-site.xml file of your HDFS cluster to the $FE_HOME/conf path of each FE and to the $BE_HOME/conf path of each BE or the $CN_HOME/conf path of each CN. View File System (ViewFs) is enabled for your HDFS cluster: Add the core-site.xml file of your HDFS cluster to the $FE_HOME/conf path of each FE and to the $BE_HOME/conf path of each BE or the $CN_HOME/conf path of each CN. NOTE If an error indicating an unknown host is returned when you send a query, you must add the mapping between the host names and IP addresses of your HDFS cluster nodes to the /etc/hosts

If Kerberos authentication is enabled for your HDFS cluster or Hive metastore, configure your StarRocks cluster as follows: Run the `kinit -kt keytab_path principal` command on each FE and each BE or CN to obtain Ticket Granting Ticket (TGT) from Key Distribution Center (KDC). To run this command, you must have the permissions to access your HDFS cluster and Hive metastore. Note that accessing KDC with this command is time-sensitive. Therefore, you need to use cron to run this command periodically. Add `JAVAOPTS="-Djava.security.krb5.conf=/etc/krb5.conf"` to the **$FEHOME/conf/fe.conf file of each FE and to the $BEHOME/conf/be.conf** file of each BE or the **$CNHOME/conf/cn.conf file of each CN. In this example, `/etc/krb5.conf` is the save path of the krb5.conf file. You can modify the path based on your needs. ```SQL CREATE EXTERNAL CATALOG <catalog_name> [COMMENT <comment>] PROPERTIES ( "type" = "paimon", CatalogParams, StorageCredentialParams, ) ``` The name of the Paimon catalog. The naming conventions are as follows: The name can contain letters, digits (0-9), and underscores (_). It must start with a letter. The name is case-sensitive and cannot exceed 1023 characters in length. The description of the Paimon catalog. This parameter is optional. The type of your data source. Set the value to `paimon`. A set of parameters about how StarRocks accesses the metadata of your Paimon cluster. The following table describes the parameter you need to configure in `CatalogParams`. | Parameter | Required | Description | | | -- | | | paimon.catalog.type | Yes | The type of metastore that you use for your Paimon cluster. Set this parameter to `filesystem` or `hive`. | | paimon.catalog.warehouse | Yes | The warehouse storage path of your Paimon data. | | hive.metastore.uris | No | The URI of your Hive metastore. Format: `thrift://<metastoreIPaddress>:<metastoreport>`. If high availability (HA) is enabled for your Hive metastore, you can specify multiple metastore URIs and separate them with commas (`,`), for example, `"thrift://<metastoreIPaddress1>:<metastoreport1>,thrift://<metastoreIPaddress2>:<metastoreport2>,thrift://<metastoreIPaddress3>:<metastoreport3>"`. | NOTE If you use Hive metastore, you must add the mapping between the host names and IP addresses of your Hive metastore nodes to the `/etc/hosts` path before you query Paimon data. Otherwise, StarRocks may fail to access your Hive metastore when you start a query. A set of parameters about how StarRocks integrates with your storage system. This parameter set is optional. If you use HDFS as storage, you do not need to configure `StorageCredentialParams`. If you use AWS S3, other S3-compatible storage system, Microsoft Azure Storage, or Google GCS as storage, you must configure `StorageCredentialParams`. If you choose AWS S3 as storage for your Paimon cluster, take one of the following actions: To choose the instance profile-based authentication method, configure `StorageCredentialParams` as follows: ```SQL "aws.s3.useinstanceprofile" = "true", "aws.s3.region" = "<awss3region>" ``` To choose the assumed role-based authentication method, configure `StorageCredentialParams` as follows: ```SQL "aws.s3.useinstanceprofile" = "true", "aws.s3.iamrolearn" = "<iamrolearn>", "aws.s3.region" = "<awss3region>" ``` To choose the IAM user-based authentication method, configure `StorageCredentialParams` as follows: ```SQL "aws.s3.useinstanceprofile" = "false", "aws.s3.accesskey" = "<iamuseraccesskey>", "aws.s3.secretkey" = "<iamusersecretkey>", "aws.s3.region" = "<awss3region>" ``` The following table describes the parameters you need to configure in `StorageCredentialParams`. | Parameter | Required | Description | | | -- | | | aws.s3.useinstanceprofile | Yes | Specifies whether to enable the instance profile-based authentication method and the assumed role-based authentication method. Valid values: `true` and `false`. Default value: `false`. | | aws.s3.iamrolearn | No | The ARN of the IAM role that has privileges on your AWS S3 bucket. If you use the assumed role-based authentication method to access AWS S3, you must specify this parameter. | |

| Yes | The region in which your AWS S3 bucket resides. Example: `us-west-1`. | | aws.s3.access_key | No | The access key of your IAM user. If you use the IAM user-based authentication method to access AWS S3, you must specify this parameter. | | aws.s3.secret_key | No | The secret key of your IAM user. If you use the IAM user-based authentication method to access AWS S3, you must specify this parameter. | For information about how to choose an authentication method for accessing AWS S3 and how to configure an access control policy in AWS IAM Console, see . If you choose an S3-compatible storage system, such as MinIO, as storage for your Paimon cluster, configure `StorageCredentialParams` as follows to ensure a successful integration: ```SQL "aws.s3.enable_ssl" = "false", "aws.s3.enablepathstyle_access" = "true", "aws.s3.endpoint" = "<s3_endpoint>", "aws.s3.accesskey" = "<iamuseraccesskey>", "aws.s3.secretkey" = "<iamusersecretkey>" ``` The following table describes the parameters you need to configure in `StorageCredentialParams`. | Parameter | Required | Description | | - | -- | | | aws.s3.enable_ssl | Yes | Specifies whether to enable SSL connection. <br />Valid values: `true` and `false`. Default value: `true`. | | aws.s3.enablepathstyleaccess | Yes | Specifies whether to enable path-style access.<br />Valid values: `true` and `false`. Default value: `false`. For MinIO, you must set the value to `true`.<br /> Path-style URLs use the following format: `https://s3.<regioncode>.amazonaws.com/<bucketname>/<keyname>`. For example, if you create a bucket named `DOC-EXAMPLE-BUCKET1` in the US West (Oregon) Region, and you want to access the `alice.jpg` object in that bucket, you can use the following path-style URL: `https://s3.us-west-2.amazonaws.com/DOC-EXAMPLE-BUCKET1/alice.jpg`. | | aws.s3.endpoint | Yes | The endpoint that is used to connect to your S3-compatible storage system instead of AWS S3. | | aws.s3.access_key | Yes | The access key of your IAM user. | | aws.s3.secret_key | Yes | The secret key of your IAM user. | If you choose Blob Storage as storage for your Paimon cluster, take one of the following actions: To choose the Shared Key authentication method, configure `StorageCredentialParams` as follows: ```SQL "azure.blob.storageaccount" = "<storageaccount_name>", "azure.blob.sharedkey" = "<storageaccountsharedkey>" ``` The following table describes the parameters you need to configure in `StorageCredentialParams`. | Parameter | Required | Description | | -- | -- | -- | | azure.blob.storage_account | Yes | The username of your Blob Storage account. | | azure.blob.shared_key | Yes | The shared key of your Blob Storage account. | To choose the SAS Token authentication method, configure `StorageCredentialParams` as follows: ```SQL "azure.blob.storageaccount" = "<storageaccount_name>", "azure.blob.container" = "<container_name>", "azure.blob.sastoken" = "<storageaccountSAStoken>" ``` The following table describes the parameters you need to configure in `StorageCredentialParams`. | Parameter | Required | Description | | - | -- | | | azure.blob.storage_account| Yes | The username of your Blob Storage account. | | azure.blob.container | Yes | The name of the blob container that stores your data. | | azure.blob.sas_token | Yes | The SAS token that is used to access your Blob Storage account. | If you choose Data Lake Storage Gen2 as storage for your Paimon cluster, take one of the following actions: To choose the Managed Identity authentication method, configure `StorageCredentialParams` as follows: ```SQL "azure.adls2.oauth2usemanaged_identity" = "true", "azure.adls2.oauth2tenantid" = "<serviceprincipaltenant_id>", "azure.adls2.oauth2clientid" = "<serviceclientid>" ``` The following table describes the parameters you need to configure in `StorageCredentialParams`. | Parameter | Required | Description | | | -- | | |

| Yes | Specifies whether to enable the Managed Identity authentication method. Set the value to `true`. | | azure.adls2.oauth2tenantid | Yes | The ID of the tenant whose data you want to access. | | azure.adls2.oauth2clientid | Yes | The client (application) ID of the managed identity. | To choose the Shared Key authentication method, configure `StorageCredentialParams` as follows: ```SQL "azure.adls2.storageaccount" = "<storageaccount_name>", "azure.adls2.sharedkey" = "<storageaccountsharedkey>" ``` The following table describes the parameters you need to configure in `StorageCredentialParams`. | Parameter | Required | Description | | | -- | | | azure.adls2.storage_account | Yes | The username of your Data Lake Storage Gen2 storage account. | | azure.adls2.shared_key | Yes | The shared key of your Data Lake Storage Gen2 storage account. | To choose the Service Principal authentication method, configure `StorageCredentialParams` as follows: ```SQL "azure.adls2.oauth2clientid" = "<serviceclientid>", "azure.adls2.oauth2clientsecret" = "<serviceprincipalclient_secret>", "azure.adls2.oauth2clientendpoint" = "<serviceprincipalclient_endpoint>" ``` The following table describes the parameters you need to configure `in StorageCredentialParams`. | Parameter | Required | Description | | - | -- | | | azure.adls2.oauth2clientid | Yes | The client (application) ID of the service principal. | | azure.adls2.oauth2clientsecret | Yes | The value of the new client (application) secret created. | | azure.adls2.oauth2clientendpoint | Yes | The OAuth 2.0 token endpoint (v1) of the service principal or application. | If you choose Data Lake Storage Gen1 as storage for your Paimon cluster, take one of the following actions: To choose the Managed Service Identity authentication method, configure `StorageCredentialParams` as follows: ```SQL "azure.adls1.usemanagedservice_identity" = "true" ``` The following table describes the parameters you need to configure in `StorageCredentialParams`. | Parameter | Required | Description | | - | -- | | | azure.adls1.usemanagedservice_identity | Yes | Specifies whether to enable the Managed Service Identity authentication method. Set the value to `true`. | To choose the Service Principal authentication method, configure `StorageCredentialParams` as follows: ```SQL "azure.adls1.oauth2clientid" = "<applicationclientid>", "azure.adls1.oauth2credential" = "<applicationclient_credential>", "azure.adls1.oauth2endpoint" = "<OAuth2.0authorizationendpoint_v2>" ``` The following table describes the parameters you need to configure in `StorageCredentialParams`. | Parameter | Required | Description | | -- | -- | | | azure.adls1.oauth2clientid | Yes | The client (application) ID of the service principal. | | azure.adls1.oauth2_credential | Yes | The value of the new client (application) secret created. | | azure.adls1.oauth2_endpoint | Yes | The OAuth 2.0 token endpoint (v1) of the service principal or application. | If you choose Google GCS as storage for your Paimon cluster, take one of the following actions: To choose the VM-based authentication method, configure `StorageCredentialParams` as follows: ```SQL "gcp.gcs.usecomputeengineserviceaccount" = "true" ``` The following table describes the parameters you need to configure in `StorageCredentialParams`. | Parameter | Default value | Value example | Description | | | - | - | | | gcp.gcs.usecomputeengineserviceaccount | FALSE | TRUE | Specifies whether to directly use the service account that is bound to your Compute Engine. | To choose the service account-based authentication method, configure `StorageCredentialParams` as follows: ```SQL "gcp.gcs.serviceaccountemail" = "<googleserviceaccount_email>", "gcp.gcs.serviceaccountprivatekeyid" = "<googleserviceprivatekeyid>", "gcp.gcs.serviceaccountprivatekey" = "<googleserviceprivatekey>" ``` The following table describes the parameters you need to configure in `StorageCredentialParams`. | Parameter | Default value | Value example | Description | | -- | - | | | | gcp.gcs.serviceaccountemail | "" | "" | The email address in the JSON file generated at the creation of the service account. | |

| "" | "61d257bd8479547cb3e04f0b9b6b9ca07af3b7ea" | The private key ID in the JSON file generated at the creation of the service account. | | gcp.gcs.serviceaccountprivate_key | "" | "--BEGIN PRIVATE KEY-xxxx--END PRIVATE KEY--\n" | The private key in the JSON file generated at the creation of the service account. | To choose the impersonation-based authentication method, configure `StorageCredentialParams` as follows: Make a VM instance impersonate a service account: ```SQL "gcp.gcs.usecomputeengineserviceaccount" = "true", "gcp.gcs.impersonationserviceaccount" = "<assumedgoogleserviceaccountemail>" ``` The following table describes the parameters you need to configure in `StorageCredentialParams`. | Parameter | Default value | Value example | Description | | | - | - | | | gcp.gcs.usecomputeengineserviceaccount | FALSE | TRUE | Specifies whether to directly use the service account that is bound to your Compute Engine. | | gcp.gcs.impersonationserviceaccount | "" | "hello" | The service account that you want to impersonate. | Make a service account (temporarily named as meta service account) impersonate another service account (temporarily named as data service account): ```SQL "gcp.gcs.serviceaccountemail" = "<googleserviceaccount_email>", "gcp.gcs.serviceaccountprivatekeyid" = "<metagoogleserviceaccountemail>", "gcp.gcs.serviceaccountprivatekey" = "<metagoogleserviceaccount_email>", "gcp.gcs.impersonationserviceaccount" = "<datagoogleserviceaccountemail>" ``` The following table describes the parameters you need to configure in `StorageCredentialParams`. | Parameter | Default value | Value example | Description | | -- | - | | | | gcp.gcs.serviceaccountemail | "" | "" | The email address in the JSON file generated at the creation of the meta service account. | | gcp.gcs.serviceaccountprivatekeyid | "" | "61d257bd8479547cb3e04f0b9b6b9ca07af3b7ea" | The private key ID in the JSON file generated at the creation of the meta service account. | | gcp.gcs.serviceaccountprivate_key | "" | "--BEGIN PRIVATE KEY-xxxx--END PRIVATE KEY--\n" | The private key in the JSON file generated at the creation of the meta service account. | | gcp.gcs.impersonationserviceaccount | "" | "hello" | The data service account that you want to impersonate. | The following examples create a Paimon catalog named `paimoncatalogfs` whose metastore type `paimon.catalog.type` is set to `filesystem` to query data from your Paimon cluster. If you choose the instance profile-based authentication method, run a command like below: ```SQL CREATE EXTERNAL CATALOG paimoncatalogfs PROPERTIES ( "type" = "paimon", "paimon.catalog.type" = "filesystem", "paimon.catalog.warehouse" = "<s3paimonwarehouse_path>", "aws.s3.useinstanceprofile" = "true", "aws.s3.region" = "us-west-2" ); ``` If you choose the assumed role-based authentication method, run a command like below: ```SQL CREATE EXTERNAL CATALOG paimoncatalogfs PROPERTIES ( "type" = "paimon", "paimon.catalog.type" = "filesystem", "paimon.catalog.warehouse" = "<s3paimonwarehouse_path>", "aws.s3.useinstanceprofile" = "true", "aws.s3.iamrolearn" = "arn:aws:iam::081976408565:role/tests3role", "aws.s3.region" = "us-west-2" ); ``` If you choose the IAM user-based authentication method, run a command like below: ```SQL CREATE EXTERNAL CATALOG paimoncatalogfs PROPERTIES ( "type" = "paimon", "paimon.catalog.type" = "filesystem", "paimon.catalog.warehouse" = "<s3paimonwarehouse_path>", "aws.s3.useinstanceprofile" = "false", "aws.s3.accesskey" = "<iamuseraccesskey>", "aws.s3.secretkey" = "<iamusersecretkey>", "aws.s3.region" = "us-west-2" ); ``` Use MinIO as an example. Run a command like below: ```SQL CREATE EXTERNAL CATALOG paimoncatalogfs PROPERTIES ( "type" = "paimon", "paimon.catalog.type" = "filesystem", "paimon.catalog.warehouse" = "<paimonwarehousepath>", "aws.s3.enable_ssl" = "true", "aws.s3.enablepathstyle_access" = "true", "aws.s3.endpoint" = "<s3_endpoint>", "aws.s3.accesskey" = "<iamuseraccesskey>", "aws.s3.secretkey" = "<iamusersecretkey>" ); ``` If you choose the Shared Key authentication method, run a command like below: ```SQL CREATE EXTERNAL CATALOG paimoncatalogfs PROPERTIES ( "type" = "paimon", "paimon.catalog.type" = "filesystem", "paimon.catalog.warehouse" = "<blobpaimonwarehouse_path>", "azure.blob.storageaccount" = "<blobstorageaccountname>", "azure.blob.sharedkey" = "<blobstorageaccountshared_key>" ); ``` If you choose the SAS Token authentication method, run a command like below: ```SQL CREATE EXTERNAL CATALOG paimoncatalogfs PROPERTIES ( "type" = "paimon", "paimon.catalog.type" = "filesystem", "paimon.catalog.warehouse" = "<blobpaimonwarehouse_path>", "azure.blob.storageaccount" = "<blobstorageaccountname>", "azure.blob.container" = "<blobcontainername>",

= "<blobstorageaccountSAS_token>" ); ``` If you choose the Managed Service Identity authentication method, run a command like below: ```SQL CREATE EXTERNAL CATALOG paimoncatalogfs PROPERTIES ( "type" = "paimon", "paimon.catalog.type" = "filesystem", "paimon.catalog.warehouse" = "<adls1paimonwarehouse_path>", "azure.adls1.usemanagedservice_identity" = "true" ); ``` If you choose the Service Principal authentication method, run a command like below: ```SQL CREATE EXTERNAL CATALOG paimoncatalogfs PROPERTIES ( "type" = "paimon", "paimon.catalog.type" = "filesystem", "paimon.catalog.warehouse" = "<adls1paimonwarehouse_path>", "azure.adls1.oauth2clientid" = "<applicationclientid>", "azure.adls1.oauth2credential" = "<applicationclient_credential>", "azure.adls1.oauth2endpoint" = "<OAuth2.0authorizationendpoint_v2>" ); ``` If you choose the Managed Identity authentication method, run a command like below: ```SQL CREATE EXTERNAL CATALOG paimoncatalogfs PROPERTIES ( "type" = "paimon", "paimon.catalog.type" = "filesystem", "paimon.catalog.warehouse" = "<adls2paimonwarehouse_path>", "azure.adls2.oauth2usemanaged_identity" = "true", "azure.adls2.oauth2tenantid" = "<serviceprincipaltenant_id>", "azure.adls2.oauth2clientid" = "<serviceclientid>" ); ``` If you choose the Shared Key authentication method, run a command like below: ```SQL CREATE EXTERNAL CATALOG paimoncatalogfs PROPERTIES ( "type" = "paimon", "paimon.catalog.type" = "filesystem", "paimon.catalog.warehouse" = "<adls2paimonwarehouse_path>", "azure.adls2.storageaccount" = "<storageaccount_name>", "azure.adls2.sharedkey" = "<sharedkey>" ); ``` If you choose the Service Principal authentication method, run a command like below: ```SQL CREATE EXTERNAL CATALOG paimoncatalogfs PROPERTIES ( "type" = "paimon", "paimon.catalog.type" = "filesystem", "paimon.catalog.warehouse" = "<adls2paimonwarehouse_path>", "azure.adls2.oauth2clientid" = "<serviceclientid>", "azure.adls2.oauth2clientsecret" = "<serviceprincipalclient_secret>", "azure.adls2.oauth2clientendpoint" = "<serviceprincipalclient_endpoint>" ); ``` If you choose the VM-based authentication method, run a command like below: ```SQL CREATE EXTERNAL CATALOG paimoncatalogfs PROPERTIES ( "type" = "paimon", "paimon.catalog.type" = "filesystem", "paimon.catalog.warehouse" = "<gcspaimonwarehouse_path>", "gcp.gcs.usecomputeengineserviceaccount" = "true" ); ``` If you choose the service account-based authentication method, run a command like below: ```SQL CREATE EXTERNAL CATALOG paimoncatalogfs PROPERTIES ( "type" = "paimon", "paimon.catalog.type" = "filesystem", "paimon.catalog.warehouse" = "<gcspaimonwarehouse_path>", "gcp.gcs.serviceaccountemail" = "<googleserviceaccount_email>", "gcp.gcs.serviceaccountprivatekeyid" = "<googleserviceprivatekeyid>", "gcp.gcs.serviceaccountprivatekey" = "<googleserviceprivatekey>" ); ``` If you choose the impersonation-based authentication method: If you make a VM instance impersonate a service account, run a command like below: ```SQL CREATE EXTERNAL CATALOG paimoncatalogfs PROPERTIES ( "type" = "paimon", "paimon.catalog.type" = "filesystem", "paimon.catalog.warehouse" = "<gcspaimonwarehouse_path>", "gcp.gcs.usecomputeengineserviceaccount" = "true", "gcp.gcs.impersonationserviceaccount" = "<assumedgoogleserviceaccountemail>" ); ``` If you make a service account impersonate another service account, run a command like below: ```SQL CREATE EXTERNAL CATALOG paimoncatalogfs PROPERTIES ( "type" = "paimon", "paimon.catalog.type" = "filesystem", "paimon.catalog.warehouse" = "<gcspaimonwarehouse_path>", "gcp.gcs.serviceaccountemail" = "<googleserviceaccount_email>", "gcp.gcs.serviceaccountprivatekeyid" = "<metagoogleserviceaccountemail>", "gcp.gcs.serviceaccountprivatekey" = "<metagoogleserviceaccount_email>", "gcp.gcs.impersonationserviceaccount" = "<datagoogleserviceaccountemail>" ); ``` You can use to query all catalogs in the current StarRocks cluster: ```SQL SHOW CATALOGS; ``` You can also use to query the creation statement of an external catalog. The following example queries the creation statement of a Paimon catalog named `paimoncatalogfs`: ```SQL SHOW CREATE CATALOG paimoncatalogfs; ``` You can use to drop an external catalog. The following example drops a Paimon catalog named `paimoncatalogfs`: ```SQL DROP Catalog paimoncatalogfs; ``` You can use one of the following syntaxes to view the schema of a Paimon table: View schema ```SQL DESC[RIBE] <catalogname>.<databasename>.<table_name>; ``` View schema and location from the CREATE statement ```SQL SHOW CREATE TABLE <catalogname>.<databasename>.<table_name>; ``` Use to view the databases in your Paimon cluster: ```SQL SHOW DATABASES FROM <catalog_name>; ``` Use to switch to the destination catalog in the current session: ```SQL SET CATALOG <catalog_name>; ``` Then, use to specify the active database in the current session: ```SQL USE <db_name>; ``` Or, you can use to directly specify the active database in the destination catalog: ```SQL USE <catalogname>.<dbname>; ``` Use to query the destination table in the specified database: ```SQL SELECT count(*) FROM <table_name> LIMIT 10; ``` Suppose you have an OLAP table named `olap_tbl`, you can transform and load data like below: ```SQL INSERT INTO defaultcatalog.olapdb.olaptbl SELECT * FROM paimontable; ```