v.25.7New Feature

Add support for lightweight updates for MergeTree-family

Official CH changelog text
Added support for lightweight updates for MergeTree-family tables. Lightweight updates can be used by a new syntax: UPDATE <table> SET col1 = val1, col2 = val2, ... WHERE <condition>. Added implementation of lightweight deletes via lightweight updates. It can be enabled by setting lightweight_delete_mode = 'lightweight_update'. #82004 (Anton Popov).
Added support for lightweight updates in MergeTree-family tables, allowing efficient UPDATE and lightweight deletes using a new, simplified syntax.

Why it matters

This feature addresses the need for efficient row-level updates and deletes in MergeTree-family tables without heavy overhead. It simplifies data modification by enabling lightweight updates that optimize performance and reduce resource consumption compared to traditional methods.

How to use it

Use the new UPDATE syntax as follows:

UPDATE &lt;table&gt; SET col1 = val1, col2 = val2, ... WHERE &lt;condition&gt;


To enable lightweight deletes via lightweight updates, set the table setting lightweight_delete_mode to 'lightweight_update'.

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