Hi zoran,
comments below.
/Neel.
On Wednesday 12 August 2015 06:20 PM, Zoran Milinkovic wrote:
> Hi Neelakanta,
>
> What will happen if there is a context-switch between thread1 and thread2
> just after "while(sqliteTransLock) {" when sqliteTransLock == 0 ?
> Then both thread1 and thread2 will pass 'while' loop and both threads will
> increase sqliteTransLock.
In this case, both thread will increment. The result will be one thread
will abort the transaction and other thread will assert when
pbeClosePrepareTrans is called.
> The likelihood that this happen is very very low, but I think that this case
> should also be covered.
yes, the likelihood is very low, but the fix could be check
sqliteTransLock before incrementing.
if(!sqliteTransLock)
++sqliteTransLock; /* Lock is set. */
> Best regards,
> Zoran
>
> -----Original Message-----
> From: Neelakanta Reddy [mailto:[email protected]]
> Sent: Wednesday, August 12, 2015 8:48 AM
> To: Zoran Milinkovic; Anders Björnerstedt; [email protected]
> Cc: [email protected]
> Subject: Re: [PATCH 1 of 1] imm:Decrement sqliteTransLock when BEGIN
> EXCLUSIVE TRANSACTION fails [#1426]
>
> Hi zoran,
>
> In the few line above there is check to verify sqliteTransLock in "
> while(sqliteTransLock) {" .
>
> Multiple threads are present only for 2PBE case. In the 2PBE case if a
> thread1 is waiting for lock and got the lock released, then sqliteTransLock
> will be incremented. If in this time a context-switch happens then the
> thread2 will be spinning in sqliteTransLock.
>
> Decrementing of sqliteTransLock may not be required.
>
> /Neel.
>
>
> On Tuesday 11 August 2015 06:34 PM, Zoran Milinkovic wrote:
>> Hi Neelakanta,
>>
>> Shouldn't sqliteTransLock be also decremented few lines above in "
>> if(sqliteTransLock != 1) {" statement ?
>>
>> Thanks,
>> Zoran
>>
>> -----Original Message-----
>> From: [email protected] [mailto:[email protected]]
>> Sent: Thursday, July 30, 2015 3:47 PM
>> To: Anders Björnerstedt; Zoran Milinkovic; [email protected]
>> Cc: [email protected]
>> Subject: [PATCH 1 of 1] imm:Decrement sqliteTransLock when BEGIN
>> EXCLUSIVE TRANSACTION fails [#1426]
>>
>> osaf/libs/common/immsv/immpbe_dump.cc | 1 +
>> 1 files changed, 1 insertions(+), 0 deletions(-)
>>
>>
>> There is a chance that NFS/shared-storage may re-attach after few
>> seconds, and transaction is not yet started, so decrement the
>> sqliteTransLock in pbeBeginTrans which releases the lock
>>
>> diff --git a/osaf/libs/common/immsv/immpbe_dump.cc
>> b/osaf/libs/common/immsv/immpbe_dump.cc
>> --- a/osaf/libs/common/immsv/immpbe_dump.cc
>> +++ b/osaf/libs/common/immsv/immpbe_dump.cc
>> @@ -2909,6 +2909,7 @@ SaAisErrorT pbeBeginTrans(void* db_handl
>> LOG_ER("SQL statement ('BEGIN EXCLUSIVE TRANSACTION') failed
>> because:\n %s",
>> execErr);
>> sqlite3_free(execErr);
>> + --sqliteTransLock;
>> return SA_AIS_ERR_FAILED_OPERATION;
>> }
>> return SA_AIS_OK;
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