HoloWeb supports migrating a table's Table Group (Resharding) through a visual interface. This simplifies the Resharding process and helps you quickly handle any issues that may arise. This topic describes how to perform Table Resharding using HoloWeb. For more information about Table Groups, shard count, and Resharding principles, see Basic Concepts.
Limits
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HoloWeb supports Resharding only for instances running V2.0.24 or later. If your instance runs an earlier version, you must upgrade it or follow the instructions in (Resharding) Migrate tables to a new Table Group to perform Resharding.
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For other Resharding limits, see (Resharding) Migrate tables to a new Table Group.
Create a Table Resharding task
Go to the HoloWeb developer page. For more information, see Connect to HoloWeb.
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In the menu bar at the top of the HoloWeb developer page, click Data Solutions.
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On the Data Solutions page, click Table Resharding in the navigation pane on the left.
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On the Table Resharding page, click Create Table Resharding Task and configure the Resharding task using the following parameters. Keep all other parameters at their default values.
Section
Parameter name
Description
Select instance
Instance name
The name of the destination Hologres instance.
Database
The database in the destination instance.
Settings
Schema
The schema to reshard.
Table
The table to reshard.
Destination Table Group
The Table Group for the destination table.
Import GUC parameter settings
GUC parameters
Optional. Because Resharding involves data import, you might need to adjust certain GUC parameters if memory usage becomes too high. For details, see How to resolve out-of-memory (OOM) errors during import or export.
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Click Submit. You can then view the Resharding task list on the Table Resharding page.
NoteProgress: For partitioned tables, the progress is calculated based on the number of completed child partitions. For non-partitioned tables, the progress is displayed as only 0% or 100%.
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When the task Status changes to Successful, the Resharding task is complete.
Handle failed tasks
During Table Resharding, the system first sets the table to read-only mode and then migrates it to a new Table Group using a temporary table. Because Resharding involves data import, it can take a long time and may encounter issues such as out-of-memory (OOM) errors or manual task termination. In these cases, the task Status becomes Interrupted or Failed. When this happens, the original table remains in read-only mode, and a temporary table named <initial_table_name>_xxxxxxxx appears in the database. Choose one of the following actions:
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Resume the task
If you still want to reshard the table after the task was interrupted by mistake or failed due to an OOM error, you can resume the task. If the task failed due to an OOM error, ensure that you have adjusted the GUC parameters before you resume. To resume the task, click Actions and then Continue to Run. The system resumes the Resharding task from its last progress point.
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Cancel the task
If you no longer need to reshard the table and want to restore its original state, click Actions and then Cancel Task. The system removes the read-only restriction and deletes the temporary table to restore the table to its initial state.