ggrebalance: Часть 1. Shrink

▤ Summary

This article explains how ggrebalance works in Greengage DB, an open-source fork of Greenplum, when shrinking cluster segment count. It walks through the underlying mechanics, including catalog updates, table rebalancing, segment shutdown, and rollback handling. It compares CTAS and INSERT-based approaches for moving data, then shows why the tool uses a finite-state-machine design in Python. The article also includes command output and examples that demonstrate the shrink process in a live environment. Overall, it is a technical implementation and operations piece for an MPP database platform.

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