Brian Peterson wrote:
I thought I read in the documentation that 1000 was the max initial
pages you could allocate, and after that, Derby allocates a page at a
time. Is there some other setting for getting it to allocate more at a time?
Another question is why the maximum is set to 1000 pages.
Any takers?
If the property can be set higher and controlled on a per conglomerate
(table or index) basis, it can be a nice tool for those who require or
want to use such tuning.
--
Kristian
Brian
*From:* Michael Segel [mailto:mse...@segel.com] *On Behalf Of
*de...@segel.com
*Sent:* Friday, February 27, 2009 9:59 PM
*To:* 'Derby Discussion'
*Subject:* RE: inserts slowing down after 2.5m rows
Ok,
For testing, if you allocate 2000 pages, then if my thinking is ok, then
you'll fly along until you get until 2100 pages.
It sounds like you're hitting a bit of a snag where after your initial
allocation of pages, Derby is only allocating a smaller number of pages
at a time.
I would hope that you could configure the number of pages to be
allocated in blocks as the table grows.
------------------------------------------------------------------------
*From:* publicay...@verizon.net [mailto:publicay...@verizon.net]
*Sent:* Friday, February 27, 2009 8:48 PM
*To:* Derby Discussion
*Subject:* Re: inserts slowing down after 2.5m rows
I've increased the log size and the checkpoint interval, but it doesn't
seem to help.
It looks like the inserts begin to dramatically slow down once the table
reaches the initial allocation of pages. Things just fly along until it
gets to about 1100 pages (I've allocated an initial 1000 pages, pages
are 32k).
Any suggestions on how to keep the inserts moving quickly at this point?
Brian
On Fri, Feb 27, 2009 at 3:41 PM, publicay...@verizon.net wrote:
The application is running on a client machine. I'm not sure how to
tell if there's a different disk available that I could log to.
If checkpoint is causing this delay, how to a manage that? Can I turn
checkpointing off? I already have durability set to test; I'm not
concerned about recovering from a crashed db.
Brian
On Fri, Feb 27, 2009 at 9:34 AM, Peter Ondruška wrote:
Could be checkpoint.. BTW to speed up bulk load you may want to use
large log files located separately from data disks.
2009/2/27, Brian Peterson < dianeay...@verizon.net
<mailto:dianeay...@verizon.net>>:
I have a big table that gets a lot of inserts. Rows are inserted 10k at a
time with a table function. At around 2.5 million rows, inserts slow down
from 2-7s to around 15-20s. The table's dat file is around 800-900M.
I have durability set to "test", table-level locks, a primary key
index and
another 2-column index on the table. Page size is at the max and page
cache
set to 4500 pages. The table gets compressed (inplace) every 500,000
rows.
I'm using Derby 10.4 with JDK 1.6.0_07, running on Windows XP. I've ruled
out anything from the rest of the application, including GC (memory usage
follows a consistent pattern during the whole load). It is a local file
system. The database has a fixed number of tables (so there's a fixed
number
of dat files in the database directory the whole time). The logs are
getting
cleaned up, so there's only a few dat files in the log directory as well.
Any ideas what might be causing the big slowdown after so many loads?
Brian
