Re: does failure of write to memstore has any impact on response code from hbase
On Thu, Aug 8, 2019 at 11:49 AM Jean-Marc Spaggiari wrote: > Don't we first write to WAL and then memstore? Getting confused here, > sorry. > > You are right JMS. IIRC, Udai is correct for older versions of HBase; the memstore update would get rolled back if the concurrent WAL write failed. S > JMS > > Le mer. 7 août 2019 13 h 22, Udai Bhan Kashyap (BLOOMBERG/ PRINCETON) < > [email protected]> a écrit : > > > memstore is written first and if write(s) to WAL fails, they are rolled > > back. > > > > From: [email protected] At: 08/07/19 13:15:27To: > [email protected] > > Subject: Re: does failure of write to memstore has any impact on response > > code from hbase > > > > On Mon, Aug 5, 2019 at 9:36 PM Maneesh Bhunwal < > [email protected]> > > wrote: > > > > > Hi Team, > > > > > > First fo all thanks for the awesome product. > > > > > > Can you please help me with how will application behave when write to > > > memstore fails but write to WAL has succeeded already,will we return > > > success to the user or failure? > > > > > > Failure. Client will get an exception that varies dependent on failure > > type. > > > > > > > Also what if db crashes after writing to WAL, when db will come up > after > > > crash, it will assume that whatever is there in WAL has been > replicated, > > > but that may not be the case. > > > > > > > > DB does not make progress until the write to the DB has been sync'd > (which > > means the edit has been replicated). So on crash, the WAL will be > replayed. > > The edit that was written to the WAL but not to the memstore on which the > > client received an exception, will perpetuate. > > > > S > > > > > > > Can you please help me with the above? > > > > > > Regards > > > Maneesh Bhunwal > > > > > > > > > >
Re: does failure of write to memstore has any impact on response code from hbase
Don't we first write to WAL and then memstore? Getting confused here, sorry. JMS Le mer. 7 août 2019 13 h 22, Udai Bhan Kashyap (BLOOMBERG/ PRINCETON) < [email protected]> a écrit : > memstore is written first and if write(s) to WAL fails, they are rolled > back. > > From: [email protected] At: 08/07/19 13:15:27To: [email protected] > Subject: Re: does failure of write to memstore has any impact on response > code from hbase > > On Mon, Aug 5, 2019 at 9:36 PM Maneesh Bhunwal > wrote: > > > Hi Team, > > > > First fo all thanks for the awesome product. > > > > Can you please help me with how will application behave when write to > > memstore fails but write to WAL has succeeded already,will we return > > success to the user or failure? > > > > Failure. Client will get an exception that varies dependent on failure > type. > > > > Also what if db crashes after writing to WAL, when db will come up after > > crash, it will assume that whatever is there in WAL has been replicated, > > but that may not be the case. > > > > > DB does not make progress until the write to the DB has been sync'd (which > means the edit has been replicated). So on crash, the WAL will be replayed. > The edit that was written to the WAL but not to the memstore on which the > client received an exception, will perpetuate. > > S > > > > Can you please help me with the above? > > > > Regards > > Maneesh Bhunwal > > > > >
Re: does failure of write to memstore has any impact on response code from hbase
memstore is written first and if write(s) to WAL fails, they are rolled back. From: [email protected] At: 08/07/19 13:15:27To: [email protected] Subject: Re: does failure of write to memstore has any impact on response code from hbase On Mon, Aug 5, 2019 at 9:36 PM Maneesh Bhunwal wrote: > Hi Team, > > First fo all thanks for the awesome product. > > Can you please help me with how will application behave when write to > memstore fails but write to WAL has succeeded already,will we return > success to the user or failure? > > Failure. Client will get an exception that varies dependent on failure type. > Also what if db crashes after writing to WAL, when db will come up after > crash, it will assume that whatever is there in WAL has been replicated, > but that may not be the case. > > DB does not make progress until the write to the DB has been sync'd (which means the edit has been replicated). So on crash, the WAL will be replayed. The edit that was written to the WAL but not to the memstore on which the client received an exception, will perpetuate. S > Can you please help me with the above? > > Regards > Maneesh Bhunwal >
Re: does failure of write to memstore has any impact on response code from hbase
On Mon, Aug 5, 2019 at 9:36 PM Maneesh Bhunwal wrote: > Hi Team, > > First fo all thanks for the awesome product. > > Can you please help me with how will application behave when write to > memstore fails but write to WAL has succeeded already,will we return > success to the user or failure? > > Failure. Client will get an exception that varies dependent on failure type. > Also what if db crashes after writing to WAL, when db will come up after > crash, it will assume that whatever is there in WAL has been replicated, > but that may not be the case. > > DB does not make progress until the write to the DB has been sync'd (which means the edit has been replicated). So on crash, the WAL will be replayed. The edit that was written to the WAL but not to the memstore on which the client received an exception, will perpetuate. S > Can you please help me with the above? > > Regards > Maneesh Bhunwal >
