Re: Binary difference in pg_internal.init after running pg_initdbmultiple times - Mailing list pgsql-hackers

From Tomas Vondra
Subject Re: Binary difference in pg_internal.init after running pg_initdbmultiple times
Date
Msg-id 485ee630-70d5-d826-6f75-c8cc688e3411@2ndquadrant.com
Whole thread Raw
In response to Binary difference in pg_internal.init after running pg_initdbmultiple times  ("samuel.coulee" <313914592@qq.com>)
List pgsql-hackers
On 07/12/2018 10:08 AM, samuel.coulee wrote:
> Hi,
> 
> In the PG source code function "write_relcache_init_file()", I found that
> the whole 'Relation' structs were directly written into the file
> 'pg_internal.init'. This brings some binary differences of that file,  if we
> run pg_initdb multiple times, because the struct 'Relation' contains some
> pointer fields.
> 
> And my question is : Could we clear the pointer values in 'Relation' before
> calling write_item(...)?
> 
> No benefit regarding function or performance, just for binary
> compatibility...

Binary compatibility with what? Can you describe a scenario where this 
actually matters?

regards

-- 
Tomas Vondra                  http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services


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