Motivation

Load Action is a synchronous import method where users send requests via HTTP protocol to import local files or data streams into Paimon. Load Action executes the import synchronously and returns the results of the import. Users can directly determine the success of the import from the response body of the request.

Load Action is primarily suitable for importing local files.

SCENARIO

Analysts and business development personnel often encounter temporary small-scale data scenarios in their work. Faced with one or multiple CSV files, these files typically have small data volumes and are scattered across various systems. The traditional process for handling these files involves first uploading them to OSS storage, then using Flink or Hive SQL for table creation and data import, before analysis can begin. This process is not only complex and tedious but also requires specific prior knowledge. To simplify this process, we have introduced the 'Load Action' service. This service enables the rapid import of small-scale data, directly creating Paimon tables, without the dependence on any other data processing engines.

Data is submitted and transmitted via the HTTP protocol. This is demonstrated here using the curl command to show how to submit data for import.

curl -u root -T date -H "label:123" http://abc.com:8030/api/test/date/_load

Overview

How to Load

Users only need to execute an HTTP request with the dataset-related table creation information to complete:

• Verification of user import permissions.
• Creation of a Paimon table according to the table creation information.
• Reading of the uploaded file, data segmentation according to specified separators, followed by batch data import.
• Execution of filtering and adjustment of column positions.

Signature parameters

curl -u user:passwd [-H ""...] -T data.file -XPUT http://load_host:http_port/api/{db}/{table}/_load

• user/passwd: To verify user identity and import permissions.
• label: Identifier of the import task.
• column_separator: Used to specify the column separator in the import file, default is \t.
• line_delimiter: Used to specify the newline character in the import file, default is \n.
• where: Filter condition specified for the import task.
• columns: Names of the column fields of the data to be imported.
• format: Specifies the format of the data to be imported, supports csv and json, default is csv.

Using SQL to Express Load Parameters

It's possible to add a SQL parameter in the Header, which can replace the previous parameters such as column_separator, line_delimiter, where, columns, etc., for convenience of use.

curl -u user:passwd [-H "sql: ${load_sql}"...] -T data.file -XPUT http://load_host:http_port/api/_http_load


# -- load_sql
# insert into db.table (col, ...) select stream_col, ... from http_load("property1"="value1");


# http parameters
# (
#     "column_separator" = ",",
#     "format" = "CSV",
#     ...
# )

Return Results

Since Load Action is a synchronous import method, the results of the import are directly returned to the user through the return value created for the import.

Example:

{
  "Status": "Success",
  "NumberTotalRows": 1000000,
  "NumberFilteredRows": 1,
  "NumberUnselectedRows": 0,
  "LoadTimeMs": 2144
}

The following mainly explains the parameters of the Load Action import results:

• Status: Import completion status.
• NumberTotalRows: Total number of rows processed during import.
• NumberFilteredRows: Number of rows that do not meet data quality standards.
• NumberUnselectedRows: Number of rows filtered by the WHERE condition.
• LoadTimeMs: Import completion time. Unit: milliseconds.

Proposed Changes

In the context of implementing write operations for multiple data formats, the `WriteStrategy` interface defines standards for writing operations and schema retrieval. Specific implementation classes provide dedicated logic for different data formats. For example, the `CsvWriteStrategy` class implements `WriteStrategy`, specifically handling CSV files by parsing and writing data using the provided column separator.

public interface WriteStrategy extends Serializable {

    void writer(BatchTableWrite batchTableWrite, String content, String columnSeparator)
            throws Exception;

    Schema retrieveSchema() throws Exception;
}

Compatibility, Deprecation, and Migration Plan

No

Test Plan

UT and IT

Compatibility, Deprecation, and Migration Plan

This is a new additional feature.