FreeTDS Development Group

[ZIGLIO Frediano <Frediano.Ziglio AT vodafoneomnitel.it>]

> 
> Hi all,
> 
> I've just checked in some fairly substantial changes to CVS, based 
> largely off of Frediano's patch, but reworked a bit by moi.  

Wow.. I never tough this patch was so important to be included in 0.6
version

> As discussed 
> in the thread with Bill about conversions, each API now has a 
> TDSCONTEXT 
> pointer which maintains a few important items.  This should 
> allow us to 
> modify the handler routines to deal with the lack of a socket 
> structure 
> (dbproc, cs_conn, hdbc).
> 
> The locale structure is now pointed to by the TDSCONTEXT 
> structure and is 
> automatically allocated and read during tds_alloc_context().  
> tds_connect 
> now needs a valid context passed to it instead of a TDSLOCINFO.
> 
> I haven't made all the handler changes yet that I need to, 
> specifically 
> API handlers should do some logic that is a bit like this:
> 
> if (tds_socket) {
> ...
> call the per socket handler if any with tds->msg_info,
> else call the context wide handler with tds->msg_info
> } else {
> call the context wide handler with context->msg_info
> }
> 

I think this is not good. context mantain information per library, msg_info
is not per library (but can be per socket). First strange thing I note in
patch was msg_info in TDSCONTEXT.

> this will allow tds_client_msg() to be called during 
> conversion without a 
> socket structure, in accordance with dblib/ctlib specs.  My 
> big question 
> is that the two threads calling dbconvert simultaneously 
> encounter errors 
> context->msg_info may be overwritten, and the application may 
> receive the 
> same error twice on different threads.  Not exactly sure how 
> to deal with 
> that one yet.
> 

Perhaps best solution is to pass to libraries two parameters
message(TDSSOCKET* ,TDSMSGINFO*), (TDSCONTEXT can be retrieved from
TDSSOKET). Added library information per socket can be retrieved by
tds_socket->parent. 
I think library must be full-multithreaded for socket (I cannot read from a
socket from 2 thread).

> Anyway, beware of CVS over the next couple of days, as this is a big 
> reconoitering and I've still got some work to do yet.  All 
> the unittests 
> programs do pass though (with the exception of most of the 
> dblib ones for 
> reasons stated below) so we hopefully didn't mung things up 
> too badly.  

Mmmm... 
- tds all work (I have also written some fix for problem deleted unexisting
table or other see patch #580272)
- none of ctlib work (see patch #581224 for fix all)
- none of dblib work (see patch #581224 and also as stated below fix calling
to tds_willconvert in dbbind and 17 of them work)

> Note, this is a libtds api change for those working directly 
> with libtds! 
> Stay tuned.
> 
> The other problem is with the implementation of 
> dbwillconvert.  Jim, you 
> got to convert those dblib types to server types before 
> sending them to 
> tds_willconvert.  dbbind also calls dbwillconvert() directly 
> and instead 
> should be calling tds_willconvert because it shouldn't be 
> making the trip 
> from servertype -> dblib type -> servertype.  I just stumbled 
> on this one 
> and haven't had a chance to fix it, and it doesn't look good 
> for tonight.  
> So, the dblib unittests mostly fail on dbbind until further notice.
> 
...
> 
> Jim, I'd say we give 0.60 a couple more weeks to solidify, having the 
> conversion/binding stuff rock solid would be worth the wait, IMO.
> 
> Brian
> 
I think so...

freddy77

PS: I'm glad if someone can check patch #580072 (IMHO another required patch
for 0.6)

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