Hi, That's interesting, I didn't know. I believe the MVStore (the 1.4 version of H2) no longer relies on the space to be filled with zeroes.
For your file system implementation, what I would do is provide a compatibility flag that fills the space with zeroes. Regards, Thomas On Wed, May 14, 2014 at 2:36 PM, PN <pingnik...@gmail.com<javascript:_e(%7B%7D,'cvml','pingnik...@gmail.com');> > wrote: > I believe, I've found out the cause of the problem. > > When H2 seeks beyond the current file-size and tries to write at the new > channel position, it creates a hole in the file. So far, so good. > > However, it then erroneously assumes (in its page-allocation internals > somewhere) that this hole would always be initialized to zero's, which may > or may not be the case, especially for custom file-systems like the one I'm > dealing with right now. For sake of efficiency, this file-system does not > -- and similarly many others may not -- initialize this hole to zero. > > Even the Java 7 spec on FileChannel.position(long) > <http://docs.oracle.com/javase/7/docs/api/java/nio/channels/FileChannel.html#position(long)>has > this to say: > > * "Setting the position to a value that is greater than the file's > current size is legal but does not change the size of the file. A later > attempt to read bytes at such a position will immediately return an > end-of-file indication. A later attempt to write bytes at such a position > will cause the file to be grown to accommodate the new bytes; the values of > any bytes between the previous end-of-file and the newly-written bytes are > unspecified."* > > I have verified now... > 1. that the default file/channel implementation in Java 7 does indeed > initialize this hole to zero's, This could cease being the case in future. > 2. that when I initialize this hole to zero's in my file-system code, > both the corruption and the file-increase problems do indeed disappear. > > So, H2 is reading some junk in this hole as valid data and (rightly) > throwing corruption-exception. > > I am aware by now that H2 uses its own channel and does not use the Java 7 > semantics but... Do you agree with the above? If yes, would a fix for > this be available soon? > > Regards, > /PN > > > > -- > 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<javascript:_e(%7B%7D,'cvml','h2-database%2bunsubscr...@googlegroups.com');> > . > To post to this group, send email to > h2-database@googlegroups.com<javascript:_e(%7B%7D,'cvml','h2-database@googlegroups.com');> > . > Visit this group at http://groups.google.com/group/h2-database. > For more options, visit https://groups.google.com/d/optout. > -- 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/d/optout.
