improve performance of page allocation
--------------------------------------
Key: DERBY-888
URL: http://issues.apache.org/jira/browse/DERBY-888
Project: Derby
Type: Improvement
Reporter: Mike Matrigali
Assigned to: Mike Matrigali
Priority: Minor
Improve performance of page allocation by no longer requiring sync of the
allocated pages. The reason for the sync
currently is so that during redo recovery we did not have to handle the case of
redoing the allocate and finding no space
available on the disk. During tasks like single user load this sync
allocation is a significant performance issue - in the
case where one does 1000 insert per transaction the total time aproaches very
close to durability=test where no syncing
is done in the whole system.
For instance in a test of loading a 150 meg db with a number of tables and
indexes, on a 1.7 ghz laptop with one ide disk,
sun jdk1.4.2, windows XP
i got the following types of results:
default system: 6 minutes
no alloc sync: 1 minute, 43 seconds
no syncing: 1 minute , 1 second
Once syncing is disabled then recovery must be enhanced to handle the possible
out of space condition. Recovery already
handles out of space during undo, so this will just handle the error the same
as that. It will stop recovery and produce an error
indicating that user must add disk space and rerun recovery before system can
be brought online. I actually think on most
JVM's/OS's this won't happen as the system will still be asking the JVM/OS for
the space, just not syncing the values in those
pages to disk. Most OS's at this point will reserve the space in the file
tables and not let others grab that space.
This project will make sure that out of space recovery path has tests. It will
also make sure that redo recovery encountering garbage
in a newly allocated page during redo of an create page is tested.
--
This message is automatically generated by JIRA.
-
If you think it was sent incorrectly contact one of the administrators:
http://issues.apache.org/jira/secure/Administrators.jspa
-
For more information on JIRA, see:
http://www.atlassian.com/software/jira
