Thanks Robert, This information is quite useful.
-----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Robert Hodges Sent: Monday, March 10, 2008 7:45 PM To: Sequoia general mailing list Subject: Re: [Sequoia] SQL Query Hi Jonathan, One more thing: you should not execute reads across databases that hold locks. These need to be executed on the right database in order to allow correct ordering of transactions. For example, you would not want to do the following from VDBA: select * from vdbB.foo for update; Thanks, Robert On 3/10/08 4:15 PM, "Robert Hodges" <[EMAIL PROTECTED]> wrote: > Hi Jonathan, > > You need to be pretty cautious about this but basically if both databases > are up you can select across them. The problem is that if one of your > databases is being recovered or restored, you might get a syntax error (bad) > or inconsistent data due to one database being out of date (worse). > > One of the long-range features I would like to add to Sequoia is ability to > work at the level of a server rather than databases. This requires some > careful thought to ensure we can still recovery everything correctly. For > now you can't update across databases. Selects are ok if you are very > careful. > > Thanks, Robert > > On 3/10/08 12:58 PM, "Jonathan Poole" <[EMAIL PROTECTED]> wrote: > >> Insert's I can understand, how about joins? Can we join tables from >> multiple database connections? >> >> Ie, >> >> Controller -> vdbA -> table 1 >> -> vdbB -> table 2 >> >> So basically we cannot do an insert into table 1, via vdbB's connection. >> This is fine, I understand the table locking, how about reads, or any >> other types of queries. Should I be cautious of other types of queries >> in the future? If so, what types? >> >> Can we do join's of table 1 and table 2, regardless of what connection >> we go down? _______________________________________________ Sequoia mailing list [email protected] https://forge.continuent.org/mailman/listinfo/sequoia _______________________________________________ Sequoia mailing list [email protected] https://forge.continuent.org/mailman/listinfo/sequoia
