multithreading = sqlserver deadlocks

I created a .net program which uses multithreading. The threads
concurrently access the same db resources. This has generated no end
of sql server deadlocks, which our dba is struggling to resolve.
I am very close to giving up and going ahead and serializing all
database access for the application. This will reduce performance
quite a bit, although it will eliminate all the deadlocks.
Maybe it's our dba's fault, maybe it's sql server's fault, maybe it's
mine for building an app that hits the db so hard, but we are unable
to solve all the deadlocking issues using the errorlog and profiling
combo that has been suggested. We solve one deadlock issue, only to
see another one revealed later, perhaps on different resources,
perhaps not.
I have heard there are many applications that use the Singleton
pattern to serialize db access accross the board, just to avoid
situations like this.
Any feedback welcome.Deadlocks are usually caused by 2 or more users attempting to update the
same set of tables in opposite orders. If you have one sp that updates
Orders and then Details while another updates details first and then orders
this will eventually cause a dead lock. If they are both in the same order
you most likely get only blocking which is normal and can be controlled. Do
you have an example of 2 procedures that deadlock on each other and the
associated DDL for those tables? Deadlocking is almost always a result of a
poor schema or more likely poor data access methods. Serialization is not
the way to go, you should do it right and find the cause so you can fix it.
Maybe these will help:
http://www.support.microsoft.com/?id=224453 Blocking Problems
http://www.support.microsoft.com/?id=271509 How to monitor SQL 2000
Blocking
http://www.amazon.com/exec/obidos/tg/detail/-/B0000W86FY/qid=1077039326//ref=sr_8_xs_ap_i1_xgl14/104-0688407-7232719?v=glance&s=books&n=507846
--
Andrew J. Kelly
SQL Server MVP
"n_o_s_p_a__m" <n_o_s_p_a__m@.mail.com> wrote in message
news:1faa8782.0402170756.4a53601f@.posting.google.com...
> I created a .net program which uses multithreading. The threads
> concurrently access the same db resources. This has generated no end
> of sql server deadlocks, which our dba is struggling to resolve.
> I am very close to giving up and going ahead and serializing all
> database access for the application. This will reduce performance
> quite a bit, although it will eliminate all the deadlocks.
> Maybe it's our dba's fault, maybe it's sql server's fault, maybe it's
> mine for building an app that hits the db so hard, but we are unable
> to solve all the deadlocking issues using the errorlog and profiling
> combo that has been suggested. We solve one deadlock issue, only to
> see another one revealed later, perhaps on different resources,
> perhaps not.
> I have heard there are many applications that use the Singleton
> pattern to serialize db access accross the board, just to avoid
> situations like this.
> Any feedback welcome.|||Can't deadlocking also happen for locks other than tables? It can happen
for RID or KEY locks as well within the same table, can't it?
Christian Smith
"Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
news:OkcJl6X9DHA.548@.TK2MSFTNGP11.phx.gbl...
> Deadlocks are usually caused by 2 or more users attempting to update the
> same set of tables in opposite orders. If you have one sp that updates
> Orders and then Details while another updates details first and then
orders
> this will eventually cause a dead lock. If they are both in the same
order
> you most likely get only blocking which is normal and can be controlled.
Do
> you have an example of 2 procedures that deadlock on each other and the
> associated DDL for those tables? Deadlocking is almost always a result of
a
> poor schema or more likely poor data access methods. Serialization is not
> the way to go, you should do it right and find the cause so you can fix
it.
> Maybe these will help:
>
> http://www.support.microsoft.com/?id=224453 Blocking Problems
> http://www.support.microsoft.com/?id=271509 How to monitor SQL 2000
> Blocking
>
>
http://www.amazon.com/exec/obidos/tg/detail/-/B0000W86FY/qid=1077039326//ref=sr_8_xs_ap_i1_xgl14/104-0688407-7232719?v=glance&s=books&n=507846
> --
> Andrew J. Kelly
> SQL Server MVP
>
> "n_o_s_p_a__m" <n_o_s_p_a__m@.mail.com> wrote in message
> news:1faa8782.0402170756.4a53601f@.posting.google.com...
> > I created a .net program which uses multithreading. The threads
> > concurrently access the same db resources. This has generated no end
> > of sql server deadlocks, which our dba is struggling to resolve.
> >
> > I am very close to giving up and going ahead and serializing all
> > database access for the application. This will reduce performance
> > quite a bit, although it will eliminate all the deadlocks.
> >
> > Maybe it's our dba's fault, maybe it's sql server's fault, maybe it's
> > mine for building an app that hits the db so hard, but we are unable
> > to solve all the deadlocking issues using the errorlog and profiling
> > combo that has been suggested. We solve one deadlock issue, only to
> > see another one revealed later, perhaps on different resources,
> > perhaps not.
> >
> > I have heard there are many applications that use the Singleton
> > pattern to serialize db access accross the board, just to avoid
> > situations like this.
> >
> > Any feedback welcome.
>|||Yes there are other reasons why dead locks occur but the main reason is as I
posted. Without more details it's all a guess so the most logical or common
reason is what I posted.
--
Andrew J. Kelly
SQL Server MVP
"Christian Smith" <csmith@.digex.com> wrote in message
news:uxC%23TGY9DHA.3404@.TK2MSFTNGP09.phx.gbl...
> Can't deadlocking also happen for locks other than tables? It can happen
> for RID or KEY locks as well within the same table, can't it?
> Christian Smith
> "Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
> news:OkcJl6X9DHA.548@.TK2MSFTNGP11.phx.gbl...
> > Deadlocks are usually caused by 2 or more users attempting to update the
> > same set of tables in opposite orders. If you have one sp that updates
> > Orders and then Details while another updates details first and then
> orders
> > this will eventually cause a dead lock. If they are both in the same
> order
> > you most likely get only blocking which is normal and can be controlled.
> Do
> > you have an example of 2 procedures that deadlock on each other and the
> > associated DDL for those tables? Deadlocking is almost always a result
of
> a
> > poor schema or more likely poor data access methods. Serialization is
not
> > the way to go, you should do it right and find the cause so you can fix
> it.
> > Maybe these will help:
> >
> >
> > http://www.support.microsoft.com/?id=224453 Blocking Problems
> > http://www.support.microsoft.com/?id=271509 How to monitor SQL 2000
> > Blocking
> >
> >
> >
>
http://www.amazon.com/exec/obidos/tg/detail/-/B0000W86FY/qid=1077039326//ref=sr_8_xs_ap_i1_xgl14/104-0688407-7232719?v=glance&s=books&n=507846
> >
> > --
> >
> > Andrew J. Kelly
> > SQL Server MVP
> >
> >
> > "n_o_s_p_a__m" <n_o_s_p_a__m@.mail.com> wrote in message
> > news:1faa8782.0402170756.4a53601f@.posting.google.com...
> > > I created a .net program which uses multithreading. The threads
> > > concurrently access the same db resources. This has generated no end
> > > of sql server deadlocks, which our dba is struggling to resolve.
> > >
> > > I am very close to giving up and going ahead and serializing all
> > > database access for the application. This will reduce performance
> > > quite a bit, although it will eliminate all the deadlocks.
> > >
> > > Maybe it's our dba's fault, maybe it's sql server's fault, maybe it's
> > > mine for building an app that hits the db so hard, but we are unable
> > > to solve all the deadlocking issues using the errorlog and profiling
> > > combo that has been suggested. We solve one deadlock issue, only to
> > > see another one revealed later, perhaps on different resources,
> > > perhaps not.
> > >
> > > I have heard there are many applications that use the Singleton
> > > pattern to serialize db access accross the board, just to avoid
> > > situations like this.
> > >
> > > Any feedback welcome.
> >
> >
>|||One deadlocking situation is fairly simple:
node 1: Select from some_table where rownum = 42
node 2: update some_table with (TABLOCKX) where rownum = 42
"Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message news:<O4PueDZ9DHA.2432@.TK2MSFTNGP09.phx.gbl>...
> Yes there are other reasons why dead locks occur but the main reason is as I
> posted. Without more details it's all a guess so the most logical or common
> reason is what I posted.
> --
> Andrew J. Kelly
> SQL Server MVP
>
> "Christian Smith" <csmith@.digex.com> wrote in message
> news:uxC%23TGY9DHA.3404@.TK2MSFTNGP09.phx.gbl...
> > Can't deadlocking also happen for locks other than tables? It can happen
> > for RID or KEY locks as well within the same table, can't it?
> >
> > Christian Smith
> >
> > "Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
> > news:OkcJl6X9DHA.548@.TK2MSFTNGP11.phx.gbl...
> > > Deadlocks are usually caused by 2 or more users attempting to update the
> > > same set of tables in opposite orders. If you have one sp that updates
> > > Orders and then Details while another updates details first and then
> orders
> > > this will eventually cause a dead lock. If they are both in the same
> order
> > > you most likely get only blocking which is normal and can be controlled.
> Do
> > > you have an example of 2 procedures that deadlock on each other and the
> > > associated DDL for those tables? Deadlocking is almost always a result
> of
> a
> > > poor schema or more likely poor data access methods. Serialization is
> not
> > > the way to go, you should do it right and find the cause so you can fix
> it.
> > > Maybe these will help:
> > >
> > >
> > > http://www.support.microsoft.com/?id=224453 Blocking Problems
> > > http://www.support.microsoft.com/?id=271509 How to monitor SQL 2000
> > > Blocking
> > >
> > >
> > >
> >
> http://www.amazon.com/exec/obidos/tg/detail/-/B0000W86FY/qid=1077039326//ref=sr_8_xs_ap_i1_xgl14/104-0688407-7232719?v=glance&s=books&n=507846
> > >
> > > --
> > >
> > > Andrew J. Kelly
> > > SQL Server MVP
> > >
> > >
> > > "n_o_s_p_a__m" <n_o_s_p_a__m@.mail.com> wrote in message
> > > news:1faa8782.0402170756.4a53601f@.posting.google.com...
> > > > I created a .net program which uses multithreading. The threads
> > > > concurrently access the same db resources. This has generated no end
> > > > of sql server deadlocks, which our dba is struggling to resolve.
> > > >
> > > > I am very close to giving up and going ahead and serializing all
> > > > database access for the application. This will reduce performance
> > > > quite a bit, although it will eliminate all the deadlocks.
> > > >
> > > > Maybe it's our dba's fault, maybe it's sql server's fault, maybe it's
> > > > mine for building an app that hits the db so hard, but we are unable
> > > > to solve all the deadlocking issues using the errorlog and profiling
> > > > combo that has been suggested. We solve one deadlock issue, only to
> > > > see another one revealed later, perhaps on different resources,
> > > > perhaps not.
> > > >
> > > > I have heard there are many applications that use the Singleton
> > > > pattern to serialize db access accross the board, just to avoid
> > > > situations like this.
> > > >
> > > > Any feedback welcome.
> > >
> > >
> >
> >|||Here is the deadlock graph of the previous post:
Wait-for graph
2004-02-18 12:06:37.50 spid4
2004-02-18 12:06:37.50 spid4 Node:1
2004-02-18 12:06:37.51 spid4 KEY: 26:1124251110:2 (130092d8179c)
CleanCnt:1 Mode: U Flags: 0x0
2004-02-18 12:06:37.51 spid4 Grant List 0::
2004-02-18 12:06:37.51 spid4 Owner:0x4fce9ac0 Mode: S
Flg:0x0 Ref:1 Life:00000000 SPID:73 ECID:0
2004-02-18 12:06:37.51 spid4 SPID: 73 ECID: 0 Statement Type:
SELECT Line #: 46
2004-02-18 12:06:37.51 spid4 Input Buf: RPC Event:
S_BPI_BY_BPIID_XML;1
2004-02-18 12:06:37.53 spid4 Requested By:
2004-02-18 12:06:37.53 spid4 ResType:LockOwner Stype:'OR' Mode:
X SPID:57 ECID:0 Ec:(0x53915568) Value:0x558fa140 Cost:(0/3C)
2004-02-18 12:06:37.53 spid4
2004-02-18 12:06:37.53 spid4 Node:2
2004-02-18 12:06:37.53 spid4 KEY: 26:1124251110:1 (4a004cee256c)
CleanCnt:1 Mode: X Flags: 0x0
2004-02-18 12:06:37.53 spid4 Grant List 0::
2004-02-18 12:06:37.53 spid4 Owner:0x4edb17a0 Mode: X
Flg:0x0 Ref:1 Life:02000000 SPID:57 ECID:0
2004-02-18 12:06:37.53 spid4 SPID: 57 ECID: 0 Statement Type:
UPDATE Line #: 347
2004-02-18 12:06:37.53 spid4 Input Buf: RPC Event:
U_FAILED_ELI_CT;1
2004-02-18 12:06:37.53 spid4 Requested By:
2004-02-18 12:06:37.53 spid4 ResType:LockOwner Stype:'OR' Mode:
S SPID:73 ECID:0 Ec:(0x4872B568) Value:0x48b1e3e0 Cost:(0/0)
2004-02-18 12:06:37.53 spid4 Victim Resource Owner:
2004-02-18 12:06:37.53 spid4 ResType:LockOwner Stype:'OR' Mode: S
SPID:73 ECID:0 Ec:(0x4872B568) Value:0x48b1e3e0 Cost:(0/0)
"Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message news:<O4PueDZ9DHA.2432@.TK2MSFTNGP09.phx.gbl>...
> Yes there are other reasons why dead locks occur but the main reason is as I
> posted. Without more details it's all a guess so the most logical or common
> reason is what I posted.
> --
> Andrew J. Kelly
> SQL Server MVP
>
> "Christian Smith" <csmith@.digex.com> wrote in message
> news:uxC%23TGY9DHA.3404@.TK2MSFTNGP09.phx.gbl...
> > Can't deadlocking also happen for locks other than tables? It can happen
> > for RID or KEY locks as well within the same table, can't it?
> >
> > Christian Smith
> >
> > "Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
> > news:OkcJl6X9DHA.548@.TK2MSFTNGP11.phx.gbl...
> > > Deadlocks are usually caused by 2 or more users attempting to update the
> > > same set of tables in opposite orders. If you have one sp that updates
> > > Orders and then Details while another updates details first and then
> orders
> > > this will eventually cause a dead lock. If they are both in the same
> order
> > > you most likely get only blocking which is normal and can be controlled.
> Do
> > > you have an example of 2 procedures that deadlock on each other and the
> > > associated DDL for those tables? Deadlocking is almost always a result
> of
> a
> > > poor schema or more likely poor data access methods. Serialization is
> not
> > > the way to go, you should do it right and find the cause so you can fix
> it.
> > > Maybe these will help:
> > >
> > >
> > > http://www.support.microsoft.com/?id=224453 Blocking Problems
> > > http://www.support.microsoft.com/?id=271509 How to monitor SQL 2000
> > > Blocking
> > >
> > >
> > >
> >
> http://www.amazon.com/exec/obidos/tg/detail/-/B0000W86FY/qid=1077039326//ref=sr_8_xs_ap_i1_xgl14/104-0688407-7232719?v=glance&s=books&n=507846
> > >
> > > --
> > >
> > > Andrew J. Kelly
> > > SQL Server MVP
> > >
> > >
> > > "n_o_s_p_a__m" <n_o_s_p_a__m@.mail.com> wrote in message
> > > news:1faa8782.0402170756.4a53601f@.posting.google.com...
> > > > I created a .net program which uses multithreading. The threads
> > > > concurrently access the same db resources. This has generated no end
> > > > of sql server deadlocks, which our dba is struggling to resolve.
> > > >
> > > > I am very close to giving up and going ahead and serializing all
> > > > database access for the application. This will reduce performance
> > > > quite a bit, although it will eliminate all the deadlocks.
> > > >
> > > > Maybe it's our dba's fault, maybe it's sql server's fault, maybe it's
> > > > mine for building an app that hits the db so hard, but we are unable
> > > > to solve all the deadlocking issues using the errorlog and profiling
> > > > combo that has been suggested. We solve one deadlock issue, only to
> > > > see another one revealed later, perhaps on different resources,
> > > > perhaps not.
> > > >
> > > > I have heard there are many applications that use the Singleton
> > > > pattern to serialize db access accross the board, just to avoid
> > > > situations like this.
> > > >
> > > > Any feedback welcome.
> > >
> > >
> >
> >|||Not sure I follow what Node1 & 2 are. Are they 2 different users? Do they
both issue a select and an update? Sometimes it can be more confusing to
only give partial details. There must be more to it than what you show.
Are they wrapped in a transaction and what other statements are between the
begin and commit? But the real question is why on earth are you using a
TABLOCKX?
--
Andrew J. Kelly
SQL Server MVP
"n_o_s_p_a__m" <n_o_s_p_a__m@.mail.com> wrote in message
news:1faa8782.0402201155.64b1af2@.posting.google.com...
> One deadlocking situation is fairly simple:
> node 1: Select from some_table where rownum = 42
> node 2: update some_table with (TABLOCKX) where rownum = 42
>
> "Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
news:<O4PueDZ9DHA.2432@.TK2MSFTNGP09.phx.gbl>...
> > Yes there are other reasons why dead locks occur but the main reason is
as I
> > posted. Without more details it's all a guess so the most logical or
common
> > reason is what I posted.
> >
> > --
> >
> > Andrew J. Kelly
> > SQL Server MVP
> >
> >
> > "Christian Smith" <csmith@.digex.com> wrote in message
> > news:uxC%23TGY9DHA.3404@.TK2MSFTNGP09.phx.gbl...
> > > Can't deadlocking also happen for locks other than tables? It can
happen
> > > for RID or KEY locks as well within the same table, can't it?
> > >
> > > Christian Smith
> > >
> > > "Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
> > > news:OkcJl6X9DHA.548@.TK2MSFTNGP11.phx.gbl...
> > > > Deadlocks are usually caused by 2 or more users attempting to update
the
> > > > same set of tables in opposite orders. If you have one sp that
updates
> > > > Orders and then Details while another updates details first and then
> > orders
> > > > this will eventually cause a dead lock. If they are both in the
same
> > order
> > > > you most likely get only blocking which is normal and can be
controlled.
> > Do
> > > > you have an example of 2 procedures that deadlock on each other and
the
> > > > associated DDL for those tables? Deadlocking is almost always a
result
> > of
> > a
> > > > poor schema or more likely poor data access methods. Serialization
is
> > not
> > > > the way to go, you should do it right and find the cause so you can
fix
> > it.
> > > > Maybe these will help:
> > > >
> > > >
> > > > http://www.support.microsoft.com/?id=224453 Blocking Problems
> > > > http://www.support.microsoft.com/?id=271509 How to monitor SQL
2000
> > > > Blocking
> > > >
> > > >
> > > >
> > >
> >
http://www.amazon.com/exec/obidos/tg/detail/-/B0000W86FY/qid=1077039326//ref=sr_8_xs_ap_i1_xgl14/104-0688407-7232719?v=glance&s=books&n=507846
> > > >
> > > > --
> > > >
> > > > Andrew J. Kelly
> > > > SQL Server MVP
> > > >
> > > >
> > > > "n_o_s_p_a__m" <n_o_s_p_a__m@.mail.com> wrote in message
> > > > news:1faa8782.0402170756.4a53601f@.posting.google.com...
> > > > > I created a .net program which uses multithreading. The threads
> > > > > concurrently access the same db resources. This has generated no
end
> > > > > of sql server deadlocks, which our dba is struggling to resolve.
> > > > >
> > > > > I am very close to giving up and going ahead and serializing all
> > > > > database access for the application. This will reduce performance
> > > > > quite a bit, although it will eliminate all the deadlocks.
> > > > >
> > > > > Maybe it's our dba's fault, maybe it's sql server's fault, maybe
it's
> > > > > mine for building an app that hits the db so hard, but we are
unable
> > > > > to solve all the deadlocking issues using the errorlog and
profiling
> > > > > combo that has been suggested. We solve one deadlock issue, only
to
> > > > > see another one revealed later, perhaps on different resources,
> > > > > perhaps not.
> > > > >
> > > > > I have heard there are many applications that use the Singleton
> > > > > pattern to serialize db access accross the board, just to avoid
> > > > > situations like this.
> > > > >
> > > > > Any feedback welcome.
> > > >
> > > >
> > >
> > >|||In article <1faa8782.0402201155.64b1af2@.posting.google.com>,
n_o_s_p_a__m@.mail.com said...
> One deadlocking situation is fairly simple:
> node 1: Select from some_table where rownum = 42
> node 2: update some_table with (TABLOCKX) where rownum = 42
Actually both would error out because they're not valid SQL statements ;)
Seriously though, why would that deadlock? Whichever grabbed the table
first would finish its work and release it for the other.

multithreading = sqlserver deadlocks

I created a .net program which uses multithreading. The threads
concurrently access the same db resources. This has generated no end
of sql server deadlocks, which our dba is struggling to resolve.
I am very close to giving up and going ahead and serializing all
database access for the application. This will reduce performance
quite a bit, although it will eliminate all the deadlocks.
Maybe it's our dba's fault, maybe it's sql server's fault, maybe it's
mine for building an app that hits the db so hard, but we are unable
to solve all the deadlocking issues using the errorlog and profiling
combo that has been suggested. We solve one deadlock issue, only to
see another one revealed later, perhaps on different resources,
perhaps not.
I have heard there are many applications that use the Singleton
pattern to serialize db access accross the board, just to avoid
situations like this.
Any feedback welcome.Deadlocks are usually caused by 2 or more users attempting to update the
same set of tables in opposite orders. If you have one sp that updates
Orders and then Details while another updates details first and then orders
this will eventually cause a dead lock. If they are both in the same order
you most likely get only blocking which is normal and can be controlled. Do
you have an example of 2 procedures that deadlock on each other and the
associated DDL for those tables? Deadlocking is almost always a result of a
poor schema or more likely poor data access methods. Serialization is not
the way to go, you should do it right and find the cause so you can fix it.
Maybe these will help:
http://www.support.microsoft.com/?id=224453 Blocking Problems
http://www.support.microsoft.com/?id=271509 How to monitor SQL 2000
Blocking
http://www.amazon.com/exec/obidos/t...=books&n=507846
Andrew J. Kelly
SQL Server MVP
"n_o_s_p_a__m" <n_o_s_p_a__m@.mail.com> wrote in message
news:1faa8782.0402170756.4a53601f@.posting.google.com...
> I created a .net program which uses multithreading. The threads
> concurrently access the same db resources. This has generated no end
> of sql server deadlocks, which our dba is struggling to resolve.
> I am very close to giving up and going ahead and serializing all
> database access for the application. This will reduce performance
> quite a bit, although it will eliminate all the deadlocks.
> Maybe it's our dba's fault, maybe it's sql server's fault, maybe it's
> mine for building an app that hits the db so hard, but we are unable
> to solve all the deadlocking issues using the errorlog and profiling
> combo that has been suggested. We solve one deadlock issue, only to
> see another one revealed later, perhaps on different resources,
> perhaps not.
> I have heard there are many applications that use the Singleton
> pattern to serialize db access accross the board, just to avoid
> situations like this.
> Any feedback welcome.|||Can't deadlocking also happen for locks other than tables? It can happen
for RID or KEY locks as well within the same table, can't it?
Christian Smith
"Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
news:OkcJl6X9DHA.548@.TK2MSFTNGP11.phx.gbl...
> Deadlocks are usually caused by 2 or more users attempting to update the
> same set of tables in opposite orders. If you have one sp that updates
> Orders and then Details while another updates details first and then
orders
> this will eventually cause a dead lock. If they are both in the same
order
> you most likely get only blocking which is normal and can be controlled.
Do
> you have an example of 2 procedures that deadlock on each other and the
> associated DDL for those tables? Deadlocking is almost always a result of
a
> poor schema or more likely poor data access methods. Serialization is not
> the way to go, you should do it right and find the cause so you can fix
it.
> Maybe these will help:
>
> http://www.support.microsoft.com/?id=224453 Blocking Problems
> http://www.support.microsoft.com/?id=271509 How to monitor SQL 2000
> Blocking
>
>
http://www.amazon.com/exec/obidos/t...=books&n=507846
> --
> Andrew J. Kelly
> SQL Server MVP
>
> "n_o_s_p_a__m" <n_o_s_p_a__m@.mail.com> wrote in message
> news:1faa8782.0402170756.4a53601f@.posting.google.com...
>|||Yes there are other reasons why dead locks occur but the main reason is as I
posted. Without more details it's all a guess so the most logical or common
reason is what I posted.
Andrew J. Kelly
SQL Server MVP
"Christian Smith" <csmith@.digex.com> wrote in message
news:uxC%23TGY9DHA.3404@.TK2MSFTNGP09.phx.gbl...
> Can't deadlocking also happen for locks other than tables? It can happen
> for RID or KEY locks as well within the same table, can't it?
> Christian Smith
> "Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
> news:OkcJl6X9DHA.548@.TK2MSFTNGP11.phx.gbl...
> orders
> order
> Do
of
> a
not
> it.
>
http://www.amazon.com/exec/obidos/t...=books&n=507846
>|||One deadlocking situation is fairly simple:
node 1: Select from some_table where rownum = 42
node 2: update some_table with (TABLOCKX) where rownum = 42
"Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message news:<O4PueDZ9DHA.2432@.
TK2MSFTNGP09.phx.gbl>...
> Yes there are other reasons why dead locks occur but the main reason is as
I
> posted. Without more details it's all a guess so the most logical or comm
on
> reason is what I posted.
> --
> Andrew J. Kelly
> SQL Server MVP
>
> "Christian Smith" <csmith@.digex.com> wrote in message
> news:uxC%23TGY9DHA.3404@.TK2MSFTNGP09.phx.gbl...
> orders
> order
> Do
> of
> a
> not
> it.
> http://www.amazon.com/exec/obidos/t...=books&n=507846|||Here is the deadlock graph of the previous post:
Wait-for graph
2004-02-18 12:06:37.50 spid4
2004-02-18 12:06:37.50 spid4 Node:1
2004-02-18 12:06:37.51 spid4 KEY: 26:1124251110:2 (130092d8179c)
CleanCnt:1 Mode: U Flags: 0x0
2004-02-18 12:06:37.51 spid4 Grant List 0::
2004-02-18 12:06:37.51 spid4 Owner:0x4fce9ac0 Mode: S
Flg:0x0 Ref:1 Life:00000000 SPID:73 ECID:0
2004-02-18 12:06:37.51 spid4 SPID: 73 ECID: 0 Statement Type:
SELECT Line #: 46
2004-02-18 12:06:37.51 spid4 Input Buf: RPC Event:
S_BPI_BY_BPIID_XML;1
2004-02-18 12:06:37.53 spid4 Requested By:
2004-02-18 12:06:37.53 spid4 ResType:LockOwner Stype:'OR' Mode:
X SPID:57 ECID:0 Ec0x53915568) Value:0x558fa140 Cost0/3C)
2004-02-18 12:06:37.53 spid4
2004-02-18 12:06:37.53 spid4 Node:2
2004-02-18 12:06:37.53 spid4 KEY: 26:1124251110:1 (4a004cee256c)
CleanCnt:1 Mode: X Flags: 0x0
2004-02-18 12:06:37.53 spid4 Grant List 0::
2004-02-18 12:06:37.53 spid4 Owner:0x4edb17a0 Mode: X
Flg:0x0 Ref:1 Life:02000000 SPID:57 ECID:0
2004-02-18 12:06:37.53 spid4 SPID: 57 ECID: 0 Statement Type:
UPDATE Line #: 347
2004-02-18 12:06:37.53 spid4 Input Buf: RPC Event:
U_FAILED_ELI_CT;1
2004-02-18 12:06:37.53 spid4 Requested By:
2004-02-18 12:06:37.53 spid4 ResType:LockOwner Stype:'OR' Mode:
S SPID:73 ECID:0 Ec0x4872B568) Value:0x48b1e3e0 Cost0/0)
2004-02-18 12:06:37.53 spid4 Victim Resource Owner:
2004-02-18 12:06:37.53 spid4 ResType:LockOwner Stype:'OR' Mode: S
SPID:73 ECID:0 Ec0x4872B568) Value:0x48b1e3e0 Cost0/0)
"Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message news:<O4PueDZ9DHA.2432@.
TK2MSFTNGP09.phx.gbl>...
> Yes there are other reasons why dead locks occur but the main reason is as
I
> posted. Without more details it's all a guess so the most logical or comm
on
> reason is what I posted.
> --
> Andrew J. Kelly
> SQL Server MVP
>
> "Christian Smith" <csmith@.digex.com> wrote in message
> news:uxC%23TGY9DHA.3404@.TK2MSFTNGP09.phx.gbl...
> orders
> order
> Do
> of
> a
> not
> it.
> http://www.amazon.com/exec/obidos/t...=books&n=507846|||Not sure I follow what Node1 & 2 are. Are they 2 different users? Do they
both issue a select and an update? Sometimes it can be more confusing to
only give partial details. There must be more to it than what you show.
Are they wrapped in a transaction and what other statements are between the
begin and commit? But the real question is why on earth are you using a
TABLOCKX?
Andrew J. Kelly
SQL Server MVP
"n_o_s_p_a__m" <n_o_s_p_a__m@.mail.com> wrote in message
news:1faa8782.0402201155.64b1af2@.posting.google.com...
> One deadlocking situation is fairly simple:
> node 1: Select from some_table where rownum = 42
> node 2: update some_table with (TABLOCKX) where rownum = 42
>
> "Andrew J. Kelly" <sqlmvpnooospam@.shadhawk.com> wrote in message
news:<O4PueDZ9DHA.2432@.TK2MSFTNGP09.phx.gbl>...
as I
common
happen
the
updates
same
controlled.
the
result
is
fix
2000
http://www.amazon.com/exec/obidos/t...=books&n=507846
end
it's
unable
profiling
to|||In article <1faa8782.0402201155.64b1af2@.posting.google.com>,
n_o_s_p_a__m@.mail.com said...
> One deadlocking situation is fairly simple:
> node 1: Select from some_table where rownum = 42
> node 2: update some_table with (TABLOCKX) where rownum = 42
Actually both would error out because they're not valid SQL statements ;)
Seriously though, why would that deadlock? Whichever grabbed the table
first would finish its work and release it for the other.

multi-select MDX issue from a client tool

Hi

This is the sample query which was getting generated by the client tool :
with member [Destination].[Destination].[Sum] as 'Aggregate({[Destination].[Destination].&[12],[Destination].[Destination].&[3]})'
select [Measures].[Value] on columns,
nonempty([Time].[Calendar].allmembers) on rows
from [Consolidation Prototype]
where ([Destination].[Destination].[Sum]

The above query was failing in SSAS. It was failing because of the implicit use of current member somwhere.

The error was

The MDX function CURRENTMEMBER failed because the coordinate for the attribute contains a set.

Mosha has written a few blogs over the network explaining the reason for the problem. My guess is that, although, I am not using the currentmember across Destination dimension explicitly in the above query, it is getting used in the MDX script while evaluating the values of the measure [Measures].[Value] .

So while evaluating the currentmember for Destination dimension, its finding 2 current values and fails, because SSAS cannot handle this scenario.

Now the interesting part :

If I replace the slicer clause with this one ({[Destination].[Destination].[Sum]}) i.e just enclosing the calculated member with {}, it works fine.

There is one more solution as well :
If I replace the aggregate statement with the following:

Aggregate({[Destination].[Destination].&[12],[Destination].[Destination].&[3]},[Time].[Calendar].currentmember)

Would anyone be able to explain to me the reason for this kind of behaviour?

ZA

"If I replace the slicer clause with this one ({[Destination].[Destination].[Sum]}) i.e just enclosing the calculated member with {}, it works fine.

There is one more solution as well :
If I replace the aggregate statement with the following:

Aggregate({[Destination].[Destination].&[12],[Destination].[Destination].&[3]},[Time].[Calendar].currentmember) "

Just a guess, but the above tweaks may be enough to stop the replacement that Mosha describes in his blog :

Writing multiselect friendly MDX calculations

...

AS's query engine recognizes the shape of the queries where there is query calculated member doing Aggregate over constant single grain set, and this calculated member (or members if there are multiple multiselects in different hierarchies) is in the WHERE clause. And when AS detects this situation, it replaces the calculated member in the WHERE clause with the corresponding set.

|||I thought so. Thanks anyways, Deepak.

multi-select MDX issue from a client tool

Hi

This is the sample query which was getting generated by the client tool :
with member [Destination].[Destination].[Sum] as 'Aggregate({[Destination].[Destination].&[12],[Destination].[Destination].&[3]})'
select [Measures].[Value] on columns,
nonempty([Time].[Calendar].allmembers) on rows
from [Consolidation Prototype]
where ([Destination].[Destination].[Sum]

The above query was failing in SSAS. It was failing because of the implicit use of current member somwhere.

The error was

The MDX function CURRENTMEMBER failed because the coordinate for the attribute contains a set.

Mosha has written a few blogs over the network explaining the reason for the problem. My guess is that, although, I am not using the currentmember across Destination dimension explicitly in the above query, it is getting used in the MDX script while evaluating the values of the measure [Measures].[Value] .

So while evaluating the currentmember for Destination dimension, its finding 2 current values and fails, because SSAS cannot handle this scenario.

Now the interesting part :

If I replace the slicer clause with this one ({[Destination].[Destination].[Sum]}) i.e just enclosing the calculated member with {}, it works fine.

There is one more solution as well :
If I replace the aggregate statement with the following:

Aggregate({[Destination].[Destination].&[12],[Destination].[Destination].&[3]},[Time].[Calendar].currentmember)

Would anyone be able to explain to me the reason for this kind of behaviour?

ZA

"If I replace the slicer clause with this one ({[Destination].[Destination].[Sum]}) i.e just enclosing the calculated member with {}, it works fine.

There is one more solution as well :
If I replace the aggregate statement with the following:

Aggregate({[Destination].[Destination].&[12],[Destination].[Destination].&[3]},[Time].[Calendar].currentmember) "

Just a guess, but the above tweaks may be enough to stop the replacement that Mosha describes in his blog :

Writing multiselect friendly MDX calculations

...

AS's query engine recognizes the shape of the queries where there is query calculated member doing Aggregate over constant single grain set, and this calculated member (or members if there are multiple multiselects in different hierarchies) is in the WHERE clause. And when AS detects this situation, it replaces the calculated member in the WHERE clause with the corresponding set.

|||I thought so. Thanks anyways, Deepak.sql

multi-select MDX issue from a client tool

Hi

This is the sample query which was getting generated by the client tool :
with member [Destination].[Destination].[Sum] as 'Aggregate({[Destination].[Destination].&[12],[Destination].[Destination].&[3]})'
select [Measures].[Value] on columns,
nonempty([Time].[Calendar].allmembers) on rows
from [Consolidation Prototype]
where ([Destination].[Destination].[Sum]

The above query was failing in SSAS. It was failing because of the implicit use of current member somwhere.

The error was

The MDX function CURRENTMEMBER failed because the coordinate for the attribute contains a set.

Mosha has written a few blogs over the network explaining the reason for the problem. My guess is that, although, I am not using the currentmember across Destination dimension explicitly in the above query, it is getting used in the MDX script while evaluating the values of the measure [Measures].[Value] .

So while evaluating the currentmember for Destination dimension, its finding 2 current values and fails, because SSAS cannot handle this scenario.

Now the interesting part :

If I replace the slicer clause with this one ({[Destination].[Destination].[Sum]}) i.e just enclosing the calculated member with {}, it works fine.

There is one more solution as well :
If I replace the aggregate statement with the following:

Aggregate({[Destination].[Destination].&[12],[Destination].[Destination].&[3]},[Time].[Calendar].currentmember)

Would anyone be able to explain to me the reason for this kind of behaviour?

ZA

"If I replace the slicer clause with this one ({[Destination].[Destination].[Sum]}) i.e just enclosing the calculated member with {}, it works fine.

There is one more solution as well :
If I replace the aggregate statement with the following:

Aggregate({[Destination].[Destination].&[12],[Destination].[Destination].&[3]},[Time].[Calendar].currentmember) "

Just a guess, but the above tweaks may be enough to stop the replacement that Mosha describes in his blog :

Writing multiselect friendly MDX calculations

...

AS's query engine recognizes the shape of the queries where there is query calculated member doing Aggregate over constant single grain set, and this calculated member (or members if there are multiple multiselects in different hierarchies) is in the WHERE clause. And when AS detects this situation, it replaces the calculated member in the WHERE clause with the corresponding set.

|||I thought so. Thanks anyways, Deepak.

Multiple-step OLE DB operation generated errors.

Database: SQL Server 2000 Standard (works fine)
Database: SQL Server 2005 Standard (fails)
Provider: SQLOLEDB
We can update recordset field (database: MS SQL 2000, client side cursor,
adLockOptimistic), regardless of the recordset's source (query or stored
procedure)
The problem begins with SQL 2005. We cannot update recordset field, if the
recordset is a result of stored procedure.
Error Source: Microsoft Cursor Engine
Error Description: Multiple-step operation generated errors. Check each
status value.> The problem begins with SQL 2005. We cannot update recordset field, if the
> recordset is a result of stored procedure.
Because that's not how you affect data. A recordset is for retrieving and
presenting data. If you want to change the data in the database, use a DML
statement (INSERT/UPDATE/DELETE). Better yet, call a stored procedure that
does that.
A|||Dmitriy Shapiro wrote:
> Database: SQL Server 2000 Standard (works fine)
> Database: SQL Server 2005 Standard (fails)
> Provider: SQLOLEDB
What development platform/language?
> We can update recordset field (database: MS SQL 2000, client side
> cursor, adLockOptimistic), regardless of the recordset's source
> (query or stored procedure)
> The problem begins with SQL 2005. We cannot update recordset field,
> if the recordset is a result of stored procedure.
I'm assuming you've used "SET NOCOUNT ON" in the procedure ...

> Error Source: Microsoft Cursor Engine
> Error Description: Multiple-step operation generated errors. Check
> each status value.
So have you looped through the connection's Errors collection to see the
error message(s)?
If you are developing for ASP, then I will echo Aaron's suggestion: use DML.
If it's a desktop application, then there are some valid reasons (handling
concurrency, etc.) for using a recordset to perform data maintenance.
If none of the above helps, you should post a repro script (DDL and
recordset code) to the group that is focussed on your development platform.
--
Microsoft MVP -- ASP/ASP.NET
Please reply to the newsgroup. The email account listed in my From
header is my spam trap, so I don't check it very often. You will get a
quicker response by posting to the newsgroup.|||Thanks for replies. Our firewall block all notifications. Sorry.
The changes in recordset are not going back to the database. They are only
for UI. This is a legasy code.
Language: VB 6.0
Platform: Windows XP and Win 2003
"Bob Barrows [MVP]" <reb01501@.NOyahoo.SPAMcom> wrote in message
news:ef4gCUrIGHA.3408@.TK2MSFTNGP12.phx.gbl...
> Dmitriy Shapiro wrote:
> What development platform/language?
> I'm assuming you've used "SET NOCOUNT ON" in the procedure ...
>
> So have you looped through the connection's Errors collection to see the
> error message(s)?
> If you are developing for ASP, then I will echo Aaron's suggestion: use
> DML.
> If it's a desktop application, then there are some valid reasons (handling
> concurrency, etc.) for using a recordset to perform data maintenance.
> If none of the above helps, you should post a repro script (DDL and
> recordset code) to the group that is focussed on your development
> platform.
> --
> Microsoft MVP -- ASP/ASP.NET
> Please reply to the newsgroup. The email account listed in my From
> header is my spam trap, so I don't check it very often. You will get a
> quicker response by posting to the newsgroup.
>|||Dmitriy Shapiro wrote:
> Thanks for replies. Our firewall block all notifications. Sorry.
' Data is trnasmitted but error messages are blocked? I don't think this is
possible.

> The changes in recordset are not going back to the database. They are
> only for UI. This is a legasy code.
I'm not sure I understand what you are saying here, or why it is relevant
that the code is legacy.

> Language: VB 6.0
> Platform: Windows XP and Win 2003
>
So you plan to follow up in a VB group ... ?
Try microsoft.public.vb.database or microsoft.public.vb.database.ado.
Also, you might try using SQL Profiler to trace the actual commands being
sent to the database by the application: it may provide a clue.
Bob Barrows
Microsoft MVP -- ASP/ASP.NET
Please reply to the newsgroup. The email account listed in my From
header is my spam trap, so I don't check it very often. You will get a
quicker response by posting to the newsgroup.|||> I'm not sure I understand what you are saying here
Here is an example:
'get recordset from database as result of "stored_procedure"
'GetData executes ADO command, with Client Side Cursor and optimistic
locking option
Set rs = GetData("stored_procedure")
'translate column1 to Spanish
'Our legasy code use this technique to translate some data, before
presenting them to the client
rs("column1").value = trnalsateToSpanish(rs("column1").value)
'show recordset in the grid
Display(rs)
These lines work fine when we connect to SQL Server 2000
They fail with SQL Server 2005

>why it is relevant
> that the code is legacy.
I would like to find solution that will have minimum impact on the code.
"Bob Barrows [MVP]" <reb01501@.NOyahoo.SPAMcom> wrote in message
news:OXigYR1IGHA.2704@.TK2MSFTNGP15.phx.gbl...
> Dmitriy Shapiro wrote:
> ' Data is trnasmitted but error messages are blocked? I don't think this
> is
> possible.
>
> I'm not sure I understand what you are saying here, or why it is relevant
> that the code is legacy.
>
> So you plan to follow up in a VB group ... ?
> Try microsoft.public.vb.database or microsoft.public.vb.database.ado.
> Also, you might try using SQL Profiler to trace the actual commands being
> sent to the database by the application: it may provide a clue.
> Bob Barrows
> --
> Microsoft MVP -- ASP/ASP.NET
> Please reply to the newsgroup. The email account listed in my From
> header is my spam trap, so I don't check it very often. You will get a
> quicker response by posting to the newsgroup.
>|||Dmitriy Shapiro wrote:
<snip>
Microsoft MVP -- ASP/ASP.NET
Please reply to the newsgroup. The email account listed in my From
header is my spam trap, so I don't check it very often. You will get a
quicker response by posting to the newsgroup.|||Dmitriy Shapiro wrote:
> Here is an example:
> 'get recordset from database as result of "stored_procedure"
> 'GetData executes ADO command, with Client Side Cursor and optimistic
> locking option
> Set rs = GetData("stored_procedure")
>
Unless you have set the connection's CursorLocation property to adUseClient,
this line will result in a default server-side forward-only cursor.
To have control over the cursor type, you must:
Set rs= New ADODB.Recordset
rs.CursorLocation=adUseClient
Then either use the command object as the source argument in the recordset's
Open method:
rs.Open cmd
or use the stored-procedure-as-connection-method technique to bypass the
creation of the explicit Command object:
cn.stored_procedure parm1,...parmN, rs
Bob Barrows
--
Microsoft MVP -- ASP/ASP.NET
Please reply to the newsgroup. The email account listed in my From
header is my spam trap, so I don't check it very often. You will get a
quicker response by posting to the newsgroup.|||Bob,

>Unless you have set the connection's CursorLocation property to
>adUseClient,
> this line will result in a default server-side forward-only cursor.
I do have MyDBConnection.CursorLocation = adUseClient
Before I was unable to update recordset regardless if was result of stored
procedure or query.
Now I can only do it if it result of the query.
This code works:
Set rs = GetData("select column1 from table1")
rs("column1").value = "abc"
And this code does not work with new SQL Server 2005, but works with SQL
Server 2000:
Set rs = GetData("stored_procedure")
rs("column1").value = "abc"
Thank you.
"Bob Barrows [MVP]" <reb01501@.NOyahoo.SPAMcom> wrote in message
news:epIvE21IGHA.208@.tk2msftngp13.phx.gbl...
> Dmitriy Shapiro wrote:
> Unless you have set the connection's CursorLocation property to
> adUseClient,
> this line will result in a default server-side forward-only cursor.
> To have control over the cursor type, you must:
> Set rs= New ADODB.Recordset
> rs.CursorLocation=adUseClient
> Then either use the command object as the source argument in the
> recordset's
> Open method:
> rs.Open cmd
> or use the stored-procedure-as-connection-method technique to bypass the
> creation of the explicit Command object:
> cn.stored_procedure parm1,...parmN, rs
> Bob Barrows
> --
> Microsoft MVP -- ASP/ASP.NET
> Please reply to the newsgroup. The email account listed in my From
> header is my spam trap, so I don't check it very often. You will get a
> quicker response by posting to the newsgroup.
>|||Dmitriy Shapiro wrote:
> Bob,
>
> I do have MyDBConnection.CursorLocation = adUseClient
> Before I was unable to update recordset regardless if was result of
> stored procedure or query.
> Now I can only do it if it result of the query.
> This code works:
> Set rs = GetData("select column1 from table1")
> rs("column1").value = "abc"
> And this code does not work with new SQL Server 2005, but works with
> SQL Server 2000:
> Set rs = GetData("stored_procedure")
>
I'm sorry, but without knowing what the GetData function and the stored
procedure look like, nobody will be able to help you. An I'm sure you are
going to be able to get more help from thhe VB experts in one of the VB
newsgroups.
Microsoft MVP -- ASP/ASP.NET
Please reply to the newsgroup. The email account listed in my From
header is my spam trap, so I don't check it very often. You will get a
quicker response by posting to the newsgroup.

Multiple-step OLE DB operation generated errors

I'm trying to view a report on Report Manager (Reporting Services 2000) that displays Analysis Services (2000) data. I keep getting the following error message:

An error has occurred during report processing. (rsProcessingAborted) Get Online Help

Cannot create a connection to data source 'CubeName'. (rsErrorOpeningConnection) Get Online Help

Multiple-step OLE DB operation generated errors. Check each OLE DB status value, if available. No work was done.

I am using Visual Studio 2003 to build the report and I can successfully view the cube and pull data but when I deploy the report and data source to Report Manager I keep getting this error message. I am not using my credentials for the data source I am using a SQL account that is a sys admin and has access to the cube I am trying to view.

Additional Information: Visual Studio - local machine
SQL Server/Analysis Services - Machine A
Reporting Services - Machine B

See this http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=706585&SiteID=1 is any help.

Multiple-step OLE DB operation generated errors

Hello....

I have two linked server... (ServerB and ServerC) which reside on ServerA. I am able to connect to the remote database using "Select" statements without any issues.

When I run this query, It is successful:

delete [SERVERB].MyDatabase.dbo.TableName
from [SERVERB].MyDatabase.dbo.TableName t1
Left join MyDatabase.dbo.TableName t2 on ( t1.ID = t2.ID and
t1.EmployeeNumber = t2.EmployeeNumber and
t1.AccountNumber = t2.AccountNumber)
where t2.ID is null;

However, when I change [SERVERB] to [SERVERC], I receive two errors:

"Could not find server 'ELEARN-FRM-BETA' in sysservers. Execute sp_addlinkedserver to add the server to sysservers."

And

OLE DB provider "SQLNCLI" for linked server "ELEARN-FRM-BETA" returned message "Multiple-step OLE DB operation generated errors. Check each OLE DB status value, if available. No work was done.".

When I run profiler on ServerC, I see traffic... mainly a whole bunch of exec "sp_cursorfetch" operations, so I know the connection is valid.

Any ideas?

Forch

Sorry... I forgot to mention that all three servers are SQL Server 2005 x64 edition with SP1.

Forch

sql

Multiple-step OLE DB operation generated errors

I'm trying to view a report on Report Manager (Reporting Services 2000) that displays Analysis Services (2000) data. I keep getting the following error message:

An error has occurred during report processing. (rsProcessingAborted) Get Online Help

Cannot create a connection to data source 'CubeName'. (rsErrorOpeningConnection) Get Online Help Multiple-step OLE DB operation generated errors. Check each OLE DB status value, if available. No work was done.

I am using Visual Studio 2003 to build the report and I can successfully view the cube and pull data but when I deploy the report and data source to Report Manager I keep getting this error message. I am not using my credentials for the data source I am using a SQL account that is a sys admin and has access to the cube I am trying to view.

Additional Information: Visual Studio - local machine
SQL Server/Analysis Services - Machine A
Reporting Services - Machine B

See this http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=706585&SiteID=1 is any help.

Multiple step OLEDB Error

The error message is

-2147217887 - Multiple-step OLE DB operation generated errors. Check each OLE DB status value, if available. No work was done.

It is hard to pinpoint the exact problem w/o any additional info other than just the error msg here.

The error msg itself basically indicates that the application program was passing in an OLEDB property set, one or more of the properties were causing problem. What you should do is to enumerate through the property set and examine the corresponding status value, the error status should shed light on what went wrong.