Re: inserts slowing down after 2.5m rows
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
RE: inserts slowing down after 2.5m rows
Another question is why the maximum is set to 1000 pages. Any takers? Because it was a big nice round number? And when I say big, I meant it as it was big enough at the time. Remember that Cloudscape was designed to fill a niche. It was designed to be a small, embeddable engine that was 100% Java. It was not meant as a competitor to the General Purpose RDBMs engines. This is why I've asked that those pushing the Cloudscape development to consider what they want this engine to be. Adding more features creates a larger footprint which has a negative impact on some users who want to embed the engine in a small downloadable app. This is why I recommended that those behind Derby consider building a more modular approach to the engine. Sort of a plug and play for deployment of features. (An example, if you're going to use the engine in an embeddable format, you don't load up a container class that has chunks, page spaces, table spaces, etc. You don't allow containers that utilize raw disks. You don't do portioning. However if someone is going to use this in a more traditional role, you do create the engine and load those classes.) HTH -Mike -Original Message- From: kristian.waa...@sun.com [mailto:kristian.waa...@sun.com] Sent: Tuesday, March 03, 2009 6:19 AM To: Derby Discussion Subject: Re: inserts slowing down after 2.5m rows 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
Re: inserts slowing down after 2.5m rows
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: 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
Re: inserts slowing down after 2.5m rows
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 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
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
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 : 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
RE: inserts slowing down after 2.5m rows
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? 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 : 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
