From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
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To: | Sairam Gaddam <gaddamsairam(at)gmail(dot)com> |
Cc: | pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: Is there any way to access heap_open() from _PG_init ?? |
Date: | 2017-05-12 14:30:58 |
Message-ID: | 18569.1494599458@sss.pgh.pa.us |
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Lists: | pgsql-hackers |
Sairam Gaddam <gaddamsairam(at)gmail(dot)com> writes:
> During startup (_PG_init), I need to access some meta info of
> table/relation (like PK Column Position, FK Column Positions, Index Column
> Positions etc...) and load it into memory.
Why not fetch that info at first use, instead?
If you insist on doing it at _PG_init, you'll never be able to make the
extension work as a shared_preload_libraries item, where _PG_init
would be run in the postmaster. (I think local_preload_libraries would
be problematic too; not sure that you're inside a transaction there.)
You won't be able to retry after an error, or more generally to cope with
post-load-time changes in the data you want to cache.
It's probably possible to make it work as long as the library gets loaded
during a transaction, ie in response to some SQL command. Without seeing
your code we can't guess why its crashing though.
regards, tom lane
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