postgres-xc-developers

[Postgres-xc-developers] Improper locking in GTM again?

[Nikhil S. <ni...@st...>]

Hi,

If I look at GTM_GetTransactionSnapshot() function, it's taking a READ
lock on GTMTransactions.gt_TransArrayLock. After taking that lock it's
modifying fields like

GTMTransactions.gt_recent_global_xmin
GTMTransactions.gt_transactions_array

Hardly READ type of behavior. This behavior particularly seems
dangerous if multiple threads modify the gt_recent_global_xmin value
above while holding read locks.

Regards,
Nikhils
-- 
StormDB - http://www.stormdb.com
The Database Cloud
Postgres-XC Support and Service

Re: [Postgres-xc-developers] Improper locking in GTM again?

[Koichi S. <koi...@gm...>]

Thanks Nikhil.   Recent global xmin needs a bit of improvement.   Lock
should be  fixed also.    I can look into it after I have a bit more
progress on pgxc_ctl C version code.    You're welcome to write the
fix.

Regards;
----------
Koichi Suzuki


2013/3/4 Nikhil Sontakke <ni...@st...>:
> Hi,
>
> If I look at GTM_GetTransactionSnapshot() function, it's taking a READ
> lock on GTMTransactions.gt_TransArrayLock. After taking that lock it's
> modifying fields like
>
> GTMTransactions.gt_recent_global_xmin
> GTMTransactions.gt_transactions_array
>
> Hardly READ type of behavior. This behavior particularly seems
> dangerous if multiple threads modify the gt_recent_global_xmin value
> above while holding read locks.
>
> Regards,
> Nikhils
> --
> StormDB - http://www.stormdb.com
> The Database Cloud
> Postgres-XC Support and Service
>
> ------------------------------------------------------------------------------
> Everyone hates slow websites. So do we.
> Make your web apps faster with AppDynamics
> Download AppDynamics Lite for free today:
> http://p.sf.net/sfu/appdyn_d2d_feb
> _______________________________________________
> Postgres-xc-developers mailing list
> Pos...@li...
> https://lists.sourceforge.net/lists/listinfo/postgres-xc-developers