Hi, > is LOG=2 enough?
To prevent corruptions from power failure, the default settings are enough. > Which version should we use? 172, nightly, wait for the next one? Yes, there is one bugfix related to corruption fixed in the nightly build, it is "Fix corruption resulting from a mix of the "WRITE_DELAY=0" option and "SELECT DISTINCT" queries". But it only applies to queries that don't fit in memory, so if you don't use such queries then you should be fine with version 1.3.172. > Will it make any difference if I create indexes? Does them increase the "exposed area" for corruptions? In theory yes, but the added risk is very small. If you want to decrease the risk, you might want to backup the database from time to time (for example using the online backup feature, or even better using the "script to" statement if the database isn't too big), and append the SQL statements that modify the data since the last backup to a text file. Regards, Thomas On Sun, Jul 7, 2013 at 1:42 PM, Ryan How <r...@exemail.com.au> wrote: > I shut it down about 50 times a day uncleanly during development and never > had an issue. As the database gets larger startup time takes longer. I > guess as it checks the database. It all happens automatically. > > I can't vouch for ext4, I've had a lot of corruptions on that (not H2, but > just the system in general). So in terms of the entire system going down > and not just killing the H2 process, I'm not sure. > > > On 7/07/2013 5:40 PM, Germano Rizzo wrote: > >> Hi all, >> we're about to implement a project that uses H2 on board of some >> RFID readers, for a steel factory. The database will be used to store RFID >> readings, so we will write few datas relatively often (2 records/second, >> maybe). >> >> Problem is, being an "embedded" scenario, the readers will usually go >> down without a proper, clean shutdown, at a frequency of 3-4 times per day. >> There's really no way to avoid the possibility that the power-off happens >> during a write. >> >> OS is Linux, with a proper journaled filesystem (EXT4) stored on a >> micro-sd card; CPU is an Atom processor. Supplier assures me that as far as >> the operating system is concerned, this scenario is O.K. >> >> Which is the best way to avoid corruptions of H2, detect them and recover >> from them, in a programmatical way? No user interaction should be required. >> >> In particular: >> >> - Which url parameters should we use? is LOG=2 enough? >> - Which version should we use? 172, nightly, wait for the next one? >> Project will be rolled out at 20 of july. >> - Will it make any difference if I create indexes? Does them increase the >> "exposed area" for corruptions? >> - Which is the worst-case scenario for this? I'm ok losing the last few >> writes. >> >> Thanks a lot, >> >> Germano >> -- >> 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 >> h2-database+unsubscribe@**googlegroups.com<h2-database%2bunsubscr...@googlegroups.com> >> . >> To post to this group, send email to h2-database@googlegroups.com. >> Visit this group at >> http://groups.google.com/**group/h2-database<http://groups.google.com/group/h2-database> >> . >> For more options, visit >> https://groups.google.com/**groups/opt_out<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 > h2-database+unsubscribe@**googlegroups.com<h2-database%2bunsubscr...@googlegroups.com> > . > To post to this group, send email to h2-database@googlegroups.com. > Visit this group at > http://groups.google.com/**group/h2-database<http://groups.google.com/group/h2-database> > . > For more options, visit > https://groups.google.com/**groups/opt_out<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 h2-database+unsubscr...@googlegroups.com. To post to this group, send email to h2-database@googlegroups.com. Visit this group at http://groups.google.com/group/h2-database. For more options, visit https://groups.google.com/groups/opt_out.
