> Hi,
>
> I found this in the TODO list:
>
> Add API for 64-bit large object access
>
> If this is a still valid TODO item and nobody is working on this, I
> would like to work in this.
Here are the list of functions think we need to change.
1) Frontend lo_* libpq functions(fe-lobj.c)
lo_initialize() need to get backend 64-bit large object handling
function's oid, namely lo_lseek64, lo_tell64, lo_truncate64, loread64,
lowrite64(explained later). If they are not available, use older
32-bit backend functions.
BTW, currently lo_initialize() throws an error if one of oids are not
avilable. I doubt we do the same way for 64-bit functions since this
will make 9.3 libpq unable to access large objects stored in pre-9.2
PostgreSQL servers.
2) Bakend lo_* functions (be-fsstubs.c)
Add lo_lseek64, lo_tell64, lo_truncate64, loread64 and lowrite64 so
that they can handle 64-bit seek position and data lenghth.
3) Backend inv_api.c functions
No need to add new functions. Just extend them to handle 64-bit data.
BTW , what will happen if older 32-bit libpq accesses large objects
over 2GB?
lo_read and lo_write: they can read or write lobjs using 32-bit API as
long as requested read/write data length is smaller than 2GB. So I
think we can safely allow them to access over 2GB lobjs.
lo_lseek: again as long as requested offset is smaller than 2GB, there
would be no problem.
lo_tell:if current seek position is beyond 2GB, returns an error.
Comments, suggestions?
--
Tatsuo Ishii
SRA OSS, Inc. Japan
English: http://www.sraoss.co.jp/index_en.php
Japanese: http://www.sraoss.co.jp
