Is there a significant difference in Memory settings between 9.5 and 12 - Mailing list pgsql-general

From Tory M Blue
Subject Is there a significant difference in Memory settings between 9.5 and 12
Date
Msg-id CAEaSS0aewdAM5REvG7+5vPWGbxYfCq4KvbUsG6CBjX+0gA8y=A@mail.gmail.com
Whole thread Raw
In response to Re: Memory footprint diff between 9.5 and 12  (Tory M Blue <tmblue@gmail.com>)
Responses Re: Is there a significant difference in Memory settings between 9.5 and 12  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-general

Upgraded from 9.5 to 12 and 12 would not start with the current configured Shared Buffers.

Same hardware, same config file.

Which tells me something has changed, are there new default settings in the 12 postgresql.conf file that are not being called out in my 9.5 config file that could be the cause or?

9.5
shared_buffers 10GB

12 
shared_buffers 5GB

12 will not start at 10GB, even though it's the same hardware, same config file, same physical box, same everything, just version 12 vs 9.5

So this tells me that maybe i'm missing a new memory setting in 12 , that is not being overwritten in my local config file (I run an include and my own settings), this worked fine in 9.5 but I'm guessing there is something considerably different between 9.5 and 12 (I'm just not seeing it). Anyone with insight into what memory settings may have been added in 10/11/12 that are significantly different than 9.5?

Thanks
Tory

CentOS 7
Postgresql 9.5.x
Postgresql 12.2


pgsql-general by date:

Previous
From: Matthias Apitz
Date:
Subject: Re: PostgreSQL client hangs sometimes on 'EXEC SQL PREPAREsid_sisisinst FROM :select_anw;'
Next
From: Tom Lane
Date:
Subject: Re: Is there a significant difference in Memory settings between 9.5 and 12