FreeTDS Development Group

[Frediano Ziglio <freddy77 AT gmail.com>]

Went into stable (ftp://ftp.freetds.org/pub/freetds/stable/)

2012/12/5 "Tony" Yu Jiang <yujiang99 AT gmail.com>:
> Hi Frediano,
>
> That patch is almost exactly the same as mine - so I guess mine is
> unnecessary anymore.
>
> I think this patch is perfectly safe to backport to 0.91 since the change
> is so small and so clearly defined. It shouldn't affect anything else.
>
> Thanks!
> Tony
>
>
>
> On Wed, Dec 5, 2012 at 9:00 AM, <freetds-request AT lists.ibiblio.org> wrote:
>
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>> Today's Topics:
>>
>>    1. Enable freebcp to specify target database on command line
>>       ("Tony" Yu Jiang)
>>    2. Re: Enable freebcp to specify target database on command  line
>>       (Frediano Ziglio)
>>    3. Re: Memory problems with dbcmd (Frediano Ziglio)
>>    4. Re: Memory problems with dbcmd (Alberto Pulvirenti)
>>
>>
>> ----------------------------------------------------------------------
>>
>> Message: 1
>> Date: Tue, 4 Dec 2012 10:24:27 -0800
>> From: "\"Tony\" Yu Jiang" <yujiang99 AT gmail.com>
>> Subject: [freetds] Enable freebcp to specify target database on
>>         command line
>> To: freetds AT lists.ibiblio.org
>> Message-ID:
>>         <CAD9rgJ=
>> 9HQjzYjAF-M0gUEg0QEFCf5+3MjDyHWdE_tg_OoPoLw AT mail.gmail.com>
>> Content-Type: text/plain; charset=ISO-8859-1
>>
>> Hi there,
>>
>> This patch allows the user to specify a target database on freebcp command
>> line. This is especially useful when accessing SQL Azure, which always
>> returns a connection to a system database.
>>
>> The patch is here:
>>
>> https://github.com/tonyjiang/freetds/commit/4d50f8835f584b042fabe42510f1cede24e5d938
>>
>> It'd be great if you can merge it into freebcp.
>>
>> Cheers,
>> Tony
>>
>>
>> ------------------------------
>>
>> Message: 2
>> Date: Tue, 4 Dec 2012 19:27:59 +0000
>> From: Frediano Ziglio <freddy77 AT gmail.com>
>> Subject: Re: [freetds] Enable freebcp to specify target database on
>>         command line
>> To: FreeTDS Development Group <freetds AT lists.ibiblio.org>
>> Message-ID:
>>         <CAHt6W4fuBAfg=
>> j+aJ7gUW5tC1HGCib2+Rvqtd-OdbGNMYM_sgw AT mail.gmail.com>
>> Content-Type: text/plain; charset=UTF-8
>>
>> 2012/12/4 "Tony" Yu Jiang <yujiang99 AT gmail.com>:
>> > Hi there,
>> >
>> > This patch allows the user to specify a target database on freebcp
>> command
>> > line. This is especially useful when accessing SQL Azure, which always
>> > returns a connection to a system database.
>> >
>> > The patch is here:
>> >
>> https://github.com/tonyjiang/freetds/commit/4d50f8835f584b042fabe42510f1cede24e5d938
>> >
>> > It'd be great if you can merge it into freebcp.
>> >
>> > Cheers,
>> > Tony
>>
>> Thanks for the patch, on official master branch we have a similar patch:
>>
>>
>> http://gitorious.org/freetds/freetds/commit/c34afafd2fec4cbba9b245e4f13a5471c6fb8041
>>
>> Do you think we should backport it on 0.91branch? Usually we do not
>> backport new feature on stable branch but this seems quite safe to me.
>>
>> James fixed the snapshot generation a week ago so snapshots have this
>> patch.
>>
>> Regards,
>>   Frediano
>>
>>
>> ------------------------------
>>
>> Message: 3
>> Date: Tue, 4 Dec 2012 19:30:58 +0000
>> From: Frediano Ziglio <freddy77 AT gmail.com>
>> Subject: Re: [freetds] Memory problems with dbcmd
>> To: FreeTDS Development Group <freetds AT lists.ibiblio.org>
>> Message-ID:
>>         <
>> CAHt6W4fLnOS3AuypN8pRALr1rRsQeHAcNxoyLBNx4quE0dqGNg AT mail.gmail.com>
>> Content-Type: text/plain; charset=UTF-8
>>
>> 2012/12/4 Alberto Pulvirenti <alberto.pulvirenti AT crowdengineering.com>:
>> > Dear all,
>> >
>> > unfortunately, searching on google seemed to be unsuccessful for this,
>> and
>> > I didn't find any help looking ad previous discussions (maybe since I
>> > subscribed this mailing list).
>> >
>> > I have manage to set up a connection to a MS SQL database server using
>> > freeTDS, but it sometimes (seldom, fortunately) happens that a dbcmd
>> fails.
>> > Looking at the various documentations, it should be a problem of memory
>> > allocation, but this happened even for extremely simple queries like a
>> > "begin transaction", and not always for the same query: it just happened
>> in
>> > a given moment, and it was not either possible to reproduce this problem,
>> > but I remained afraid that it can appear again.
>> > I don't really understand how can dbcmd fail with such a simple query
>> when
>> > the machine is not stuck (which I would think if it is a problem is so
>> > serious that even such a small string cannot be allocated).
>> >
>> > The MS SQL server stays in another machine to which I must connect
>> through
>> > network, although it is a machine internal to the location where all this
>> > stuff runs. Can it happen that a sudden and momentary communication
>> failure
>> > causes dbcmd() to fail? Or its failure are only due to memory allocation
>> > problems?
>> >
>> > Is there any way I can adopt to deeper check this problem?
>> >
>> > Thanks
>> >
>> > Alberto
>>
>> Personally I would exclude a memory problem. If the system fails to
>> allocate few bytes of memory you should note other problems (unless
>> you set some limits on your program for instance using PHP module
>> which limit memory itself).
>>
>> It's possible that connection got broken for some reason (a simple
>> service restart or a backup schedule which put database in some
>> particular state). Or even that server disconnect you cause you where
>> idle for too time (see recent keepalive discussion).
>>
>> Frediano
>>
>>
>> ------------------------------
>>
>> Message: 4
>> Date: Wed, 5 Dec 2012 10:38:18 +0100
>> From: Alberto Pulvirenti <alberto.pulvirenti AT crowdengineering.com>
>> Subject: Re: [freetds] Memory problems with dbcmd
>> To: FreeTDS Development Group <freetds AT lists.ibiblio.org>
>> Message-ID:
>>         <
>> CAJNp6N3tbXidcTW9iaEM6Lo+wxCLOFTTCHL9n1BsH+7zGx6u+w AT mail.gmail.com>
>> Content-Type: text/plain; charset=ISO-8859-1
>>
>> Hi,
>>
>> maybe I forgot to clarify a point. The failure I mention refers to the
>> function dbcmd().
>> I checked with a personal MS SQL Server I use for testing and I saw that
>> when the connection is faulty or the DB server is down, what happens is
>> that either the dbsqlsend() fails (and then I catch it) or the dbsqlok()
>> stays pending for a long time.
>> Whenever I try to switch off the server, it stops always there, never at
>> the dbcmd() level.
>>
>> In all the documentations I see, when dbcmd fails it is always explained as
>> a memory problem, and it happens before one tries to send to the server
>> itself. That's what confused me.
>>
>> It is surely possible that in a moment a memory occupancy spike took place
>> which caused this momentary failure (because, maybe I didn't stress this
>> point, but this failure was not a persistent condition, it happened just
>> once or twice and then the communication succeeded).
>>
>> Thanks for any advice.
>>
>> Alberto
>>
>> 2012/12/4 Frediano Ziglio <freddy77 AT gmail.com>
>>
>> > 2012/12/4 Alberto Pulvirenti <alberto.pulvirenti AT crowdengineering.com>:
>> > > Dear all,
>> > >
>> > > unfortunately, searching on google seemed to be unsuccessful for this,
>> > and
>> > > I didn't find any help looking ad previous discussions (maybe since I
>> > > subscribed this mailing list).
>> > >
>> > > I have manage to set up a connection to a MS SQL database server using
>> > > freeTDS, but it sometimes (seldom, fortunately) happens that a dbcmd
>> > fails.
>> > > Looking at the various documentations, it should be a problem of memory
>> > > allocation, but this happened even for extremely simple queries like a
>> > > "begin transaction", and not always for the same query: it just
>> happened
>> > in
>> > > a given moment, and it was not either possible to reproduce this
>> problem,
>> > > but I remained afraid that it can appear again.
>> > > I don't really understand how can dbcmd fail with such a simple query
>> > when
>> > > the machine is not stuck (which I would think if it is a problem is so
>> > > serious that even such a small string cannot be allocated).
>> > >
>> > > The MS SQL server stays in another machine to which I must connect
>> > through
>> > > network, although it is a machine internal to the location where all
>> this
>> > > stuff runs. Can it happen that a sudden and momentary communication
>> > failure
>> > > causes dbcmd() to fail? Or its failure are only due to memory
>> allocation
>> > > problems?
>> > >
>> > > Is there any way I can adopt to deeper check this problem?
>> > >
>> > > Thanks
>> > >
>> > > Alberto
>> >
>> > Personally I would exclude a memory problem. If the system fails to
>> > allocate few bytes of memory you should note other problems (unless
>> > you set some limits on your program for instance using PHP module
>> > which limit memory itself).
>> >
>> > It's possible that connection got broken for some reason (a simple
>> > service restart or a backup schedule which put database in some
>> > particular state). Or even that server disconnect you cause you where
>> > idle for too time (see recent keepalive discussion).
>> >
>> > Frediano
>> > _______________________________________________
>> > FreeTDS mailing list
>> > FreeTDS AT lists.ibiblio.org
>> > http://lists.ibiblio.org/mailman/listinfo/freetds
>> >
>>
>>
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>> End of FreeTDS Digest, Vol 119, Issue 3
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