Message-ID: <232439a3-af7a-4a13-82ae-33da5520d4bf@postgrespro.ru>
Date: Fri, 26 Jun 2026 18:20:18 +0300
MIME-Version: 1.0
User-Agent: Mozilla Thunderbird
Subject: Re: Add SPLIT PARTITION/MERGE PARTITIONS commands
To: Pavel Borisov <pashkin.elfe@gmail.com>,
 Justin Pryzby <pryzby@telsasoft.com>
Cc: pgsql-hackers@lists.postgresql.org
References: <ZkN6EfjQGz8TOhbL@pryzbyj2023>
 <CAPpHfdvz3S7SoRiaSk9C-Juy2EzHs6NC_c9uUR0i7bymKXkvuQ@mail.gmail.com>
 <ai_c4-v8iLA2kXFV@pryzbyj2023>
 <CAPpHfdvOvaPxMoUp3T6hf4UmAaOhdPCcw71OGUWDjTXvrTZ_JA@mail.gmail.com>
 <CALT9ZEFrDgha=RyOuWru45FTk9Dbj5FF-fTw0NnE8n1FwBb2yg@mail.gmail.com>
 <CAPpHfdvpzvNt=d_Csxe-TCtvF9MRNdeMtfJu3RkmTgBkkQbGUw@mail.gmail.com>
 <CALT9ZEG0YmzH+3M6PixHUNq13pYt+yh8sAgonfaut=g_ij=oZw@mail.gmail.com>
 <CAPpHfdtVp5Xxz59Zse+Gg_oWvZPpwjr+gcVtWq-5pTp0Rsh8gQ@mail.gmail.com>
 <CALT9ZEG39=w6zvDqpKc479WjmeNGFMwdJxi=Ut7z4JUN386URg@mail.gmail.com>
 <CAPpHfdte=WJQnEnEhf8cKZYE1rT-VfQ2mgh=1dCsCCdSYStSow@mail.gmail.com>
 <aj6BPoziSb-F8aJz@pryzbyj2023>
 <CALT9ZEG8F_oTZEp7vpqJH6Y4hGuQ6jEusETk+=C4XciedS0G1w@mail.gmail.com>
Content-Language: en-US, ru
From: Dmitry Koval <d.koval@postgrespro.ru>
In-Reply-To: 
 <CALT9ZEG8F_oTZEp7vpqJH6Y4hGuQ6jEusETk+=C4XciedS0G1w@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit
Archived-At: 
 <https://www.postgresql.org/message-id/232439a3-af7a-4a13-82ae-33da5520d4bf%40postgrespro.ru>
Precedence: bulk

Hi!

If we exclude case with DEFAULT partition, MERGE PARTITIONS command was
intended to be used when an incorrect table partitioning was chosen.
For example, a table was initially partitioned by month, but later we
needed to change table partitioning by quarter. In this case, MERGE
PARTITIONS command should merge several adjacent partitions into one.
Current checks are made for this case.

 >- If there's *no* default partition, then I think the check should be
 >relaxed; it's sufficient to verify that the bounds of the merged
 >partition do not overlap with any partition which is not being merged;

It's probably possible to do this. But in this case, the command will
not exactly be "MERGE PARTITIONS" ("MERGE PARTITIONS & EXPAND"?).

-- 
With best regards,
Dmitry Koval

Postgres Professional: http://postgrespro.com