Hi, > How does SERIALIZABLE isolation in MVCC mode compare to SERIALIZABLE_SNAPSHOT? Aren't they the same thing?
I can only refer to Google, which found this: http://blogs.msdn.com/b/craigfr/archive/2007/05/16/serializable-vs-snapshot-isolation-level.aspx Regards, Thomas On Sun, Nov 24, 2013 at 1:10 PM, cowwoc <[email protected]> wrote: > Hi Thomas, > > Thanks for the reply. > > > On 21/11/2013 6:43 AM, Thomas Mueller wrote: > > > Does H2 implement Serializable Snapshot > > Currently not, and I didn't plan to support it. In theory, it could be > supported with the MVStore, but I don't currently think it's very important. > > > How does SERIALIZABLE isolation in MVCC mode compare to > SERIALIZABLE_SNAPSHOT? Aren't they the same thing? > > Thanks, > Gili > > > > Regards, > Thomas > > > > On Sat, Aug 24, 2013 at 8:10 PM, Gili <[email protected]> wrote: > >> Thomas, >> >> Can you please clarify how H2's implementation of MVCC interacts with >> Transaction Isolation? >> >> 1. Is there a practical difference between READ_COMMITTED and >> REPEATABLE_READ in MVCC mode? Doesn't MVCC prevent READ_COMMITTED from >> seeing updates committed by other transactions (after the current >> transaction has already read the row once)? If so, aren't they identical? >> 2. Same question for REPEATABLE_READ and SERIALIZABLE isolation in >> MVCC mode. >> 3. Does H2 implement >> >> http://en.wikipedia.org/wiki/Serializable_Snapshot_Isolation#Serializable_Snapshot_Isolation >> for >> MVCC? If not, do you plan on doing so in the future? >> >> Thank you, >> Gili >> >> >> On Sunday, June 23, 2013 11:23:16 AM UTC-4, Gili wrote: >>> >>> >>> Thanks Thomas. So you're saying I can use other isolation modes with >>> MVCC as I normally would? >>> >>> Gili >>> >>> On 23/06/2013 7:39 AM, Thomas Mueller wrote: >>> >>> Hi, >>> >>> H2 only supports row level locks when using the MVCC mode. By the way, >>> the plan is that in the future (with the MVStore), the MVCC mode will be >>> the default mode. >>> >>> Insert/delete operations don't wait for other operations that do not >>> conflict. They wait for conflicting operations (changes on the same rows). >>> >>> > What happens in the following scenario? >>> >>> H2 uses "read committed" by default, so T1 will see the value from T2. >>> >>> Regards, >>> Thomas >>> >>> >>> >>> >>> On Thu, Jun 20, 2013 at 8:18 PM, Gili <[email protected]> wrote: >>> >>>> Hi, >>>> >>>> Looking at http://www.h2database.com/html/advanced.html#mvcc, >>>> >>>> >>>> 1. Does H2 only support table locks or MVCC? Or is there a way to >>>> get row locks without MVCC? >>>> 2. Using MVCC, do insert/delete operations wait until all open >>>> transactions complete? >>>> 3. Does this imply that open transactions will never experience >>>> insert/delete rows by other threads in mid-transaction? >>>> 4. What happens in the following scenario? >>>> >>>> Database contains a single row: count[value=1] >>>> T1: Open transaction >>>> T2: Open transaction >>>> T2: update count set value=2 where value=1 >>>> T2: commit >>>> T1: select value from count >>>> >>>> Will T1 see a value of 1 or 2? >>>> >>>> Thanks, >>>> Gili >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "H2 Database" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to [email protected]. >>>> To post to this group, send email to [email protected]. >>>> Visit this group at http://groups.google.com/group/h2-database. >>>> For more options, visit https://groups.google.com/groups/opt_out. >>>> >>>> >>>> >>> >>> -- >>> You received this message because you are subscribed to a topic in the >>> Google Groups "H2 Database" group. >>> To unsubscribe from this topic, visit >>> https://groups.google.com/d/topic/h2-database/bGNuMpLr8IY/unsubscribe. >>> To unsubscribe from this group and all its topics, send an email to >>> [email protected]. >>> To post to this group, send email to [email protected]. >>> Visit this group at http://groups.google.com/group/h2-database. >>> For more options, visit https://groups.google.com/groups/opt_out. >>> >>> >>> >>> >>> -- >> You received this message because you are subscribed to the Google Groups >> "H2 Database" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to [email protected]. >> To post to this group, send email to [email protected]. >> Visit this group at http://groups.google.com/group/h2-database. >> For more options, visit https://groups.google.com/groups/opt_out. >> > > -- > You received this message because you are subscribed to a topic in the > Google Groups "H2 Database" group. > To unsubscribe from this topic, visit > https://groups.google.com/d/topic/h2-database/bGNuMpLr8IY/unsubscribe. > To unsubscribe from this group and all its topics, send an email to > [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/h2-database. > For more options, visit https://groups.google.com/groups/opt_out. > > > -- > You received this message because you are subscribed to the Google Groups > "H2 Database" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/h2-database. > For more options, visit https://groups.google.com/groups/opt_out. > -- You received this message because you are subscribed to the Google Groups "H2 Database" group. 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