Taking longer than expected (Nov 13, 2014)

Message boards : Technical News : Taking longer than expected (Nov 13, 2014)
Message board moderation

To post messages, you must log in.

AuthorMessage
Eric Korpela Project Donor
Volunteer moderator
Project administrator
Project developer
Project scientist
Avatar

Send message
Joined: 3 Apr 99
Posts: 1382
Credit: 54,506,847
RAC: 60
United States
Message 1600681 - Posted: 13 Nov 2014, 17:14:27 UTC

The Astropulse database fix is taking longer than expected. By one measure (the amount of data written into the new database spaces) we're 70% done. By another measure (the number of table rows showing up in the table stats) we are 25% done. This is after 5 days. I'm inclined to believe the 25% number, in which case we will run out of SETI@home work before Astropulse is back online. If you don't have a low share back-up project, now might be time to add one.

Informix never ceases to astonish me with the way it does things. The table rebuild is neither maxing out CPUs or I/O, primarily because it doesn't seem to be running the table creation in parallel. It's working on one table fragment at a time. It also seems to be making a copy of the data in two places and leaving large portions the allocated data chunks unused. It's certainly not the way I would have written it, but then again I don't write database. The worst case is that these multiple copies of data will cause it to exceed the limits again and we'll have to start over. It looks like we're 68% of the way to exceeding those limits. Hope Informix is smart enough to avoid the problem.
@SETIEric@qoto.org (Mastodon)

ID: 1600681 · Report as offensive
rob smith Crowdfunding Project Donor*Special Project $75 donorSpecial Project $250 donor
Volunteer moderator
Volunteer tester

Send message
Joined: 7 Mar 03
Posts: 22508
Credit: 416,307,556
RAC: 380
United Kingdom
Message 1600685 - Posted: 13 Nov 2014, 17:28:01 UTC

If I recall rightly (and its a good few years since I last did anything in Informix) its ability to create, and then forget, orphan tables during a rebuild was "quite astounding" :-(
I'd believe the 25% figure too, and remember that time is non-linear....
Bob Smith
Member of Seti PIPPS (Pluto is a Planet Protest Society)
Somewhere in the (un)known Universe?
ID: 1600685 · Report as offensive
Profile Raistmer
Volunteer developer
Volunteer tester
Avatar

Send message
Joined: 16 Jun 01
Posts: 6325
Credit: 106,370,077
RAC: 121
Russia
Message 1600790 - Posted: 13 Nov 2014, 21:47:39 UTC

If complete rebuild inevitable maybe it's good time to think about different database engine, more optimal one (if such exits, of course...)
ID: 1600790 · Report as offensive
Eric Korpela Project Donor
Volunteer moderator
Project administrator
Project developer
Project scientist
Avatar

Send message
Joined: 3 Apr 99
Posts: 1382
Credit: 54,506,847
RAC: 60
United States
Message 1600846 - Posted: 14 Nov 2014, 0:19:11 UTC - in response to Message 1600790.  

Good idea. I'll have to dig into what features are found in the various database options.
@SETIEric@qoto.org (Mastodon)

ID: 1600846 · Report as offensive
Profile arkayn
Volunteer tester
Avatar

Send message
Joined: 14 May 99
Posts: 4438
Credit: 55,006,323
RAC: 0
United States
Message 1600901 - Posted: 14 Nov 2014, 3:24:29 UTC - in response to Message 1600846.  

ID: 1600901 · Report as offensive
Profile Cliff Harding
Volunteer tester
Avatar

Send message
Joined: 18 Aug 99
Posts: 1432
Credit: 110,967,840
RAC: 67
United States
Message 1600922 - Posted: 14 Nov 2014, 4:41:29 UTC

Has anyone given any thought to contacting IBM concerning the Infomix limit problem? Maybe, just maybe they might have some insight into the problem, if someone were to ask nicely. Maybe we can get them on as a sponsor at same time.


I don't buy computers, I build them!!
ID: 1600922 · Report as offensive
Thomas
Volunteer tester

Send message
Joined: 9 Dec 11
Posts: 1499
Credit: 1,345,576
RAC: 0
France
Message 1600957 - Posted: 14 Nov 2014, 7:04:05 UTC

Thanks for the heads-up Eric :)
ID: 1600957 · Report as offensive
Cosmic_Ocean
Avatar

Send message
Joined: 23 Dec 00
Posts: 3027
Credit: 13,516,867
RAC: 13
United States
Message 1600960 - Posted: 14 Nov 2014, 7:07:18 UTC - in response to Message 1600922.  

Has anyone given any thought to contacting IBM concerning the Infomix limit problem? Maybe, just maybe they might have some insight into the problem, if someone were to ask nicely. Maybe we can get them on as a sponsor at same time.

That is definitely a good idea. Maybe there's nothing actually wrong with Informix, but S@H may be the first user to run into previously-unknown problems because of the size of the DB and the load and web of cross-references. The DB size and load has been well into "uncharted territory" for quite some time.

I remember reading a news post a few years ago mentioning MySQL was suffering some strange behavior and there were no clear answers as to why, simply because "nobody's ever made a DB that big with MySQL before."

So maybe contacting IBM and asking for some insight could not only resolve your own problems, but also result in preventing future problems for others.
Linux laptop:
record uptime: 1511d 20h 19m (ended due to the power brick giving-up)
ID: 1600960 · Report as offensive
Darth Beaver Crowdfunding Project Donor*Special Project $75 donorSpecial Project $250 donor
Avatar

Send message
Joined: 20 Aug 99
Posts: 6728
Credit: 21,443,075
RAC: 3
Australia
Message 1601024 - Posted: 14 Nov 2014, 10:50:57 UTC

Thanks Eric for the updates .

Don't understand a word you said but nice to know your on top of it.....:)
ID: 1601024 · Report as offensive
Profile Dimly Lit Lightbulb 😀
Volunteer tester
Avatar

Send message
Joined: 30 Aug 08
Posts: 15399
Credit: 7,423,413
RAC: 1
United Kingdom
Message 1601056 - Posted: 14 Nov 2014, 12:21:22 UTC - in response to Message 1601024.  

Thanks Eric for the updates .

Don't understand a word you said but nice to know your on top of it.....:)

I think it's like packing a suitcase when you go on holiday, first time you can't close it. Then you fold things differently and move stuff about till you can :)

Good luck with it Eric :)

Member of the People Encouraging Niceness In Society club.

ID: 1601056 · Report as offensive
Profile Cliff Harding
Volunteer tester
Avatar

Send message
Joined: 18 Aug 99
Posts: 1432
Credit: 110,967,840
RAC: 67
United States
Message 1601070 - Posted: 14 Nov 2014, 13:35:34 UTC - in response to Message 1600960.  
Last modified: 14 Nov 2014, 14:13:55 UTC

Has anyone given any thought to contacting IBM concerning the Infomix limit problem? Maybe, just maybe they might have some insight into the problem, if someone were to ask nicely. Maybe we can get them on as a sponsor at same time.

That is definitely a good idea. Maybe there's nothing actually wrong with Informix, but S@H may be the first user to run into previously-unknown problems because of the size of the DB and the load and web of cross-references. The DB size and load has been well into "uncharted territory" for quite some time.

I remember reading a news post a few years ago mentioning MySQL was suffering some strange behavior and there were no clear answers as to why, simply because "nobody's ever made a DB that big with MySQL before."

So maybe contacting IBM and asking for some insight could not only resolve your own problems, but also result in preventing future problems for others.


I'm more familiar with DB2 than Informix as a database manager. Both have been used in data warehousing for years, DB2 has been using terabyte databases in particular. Unfortunately, DB2 requires a more hands on DBA. Since SQL is basically the same across all platforms and management systems, and MySQL is essentially using an extension of SQL; I would love to take a peek at our database/table schemas.

Another big problem that I see occurring is that Informix making data copies in multiple places while rebuilding the database, I've never heard or experienced that when rebuilding/restoring DB2 tables/databases. Since the rebuild/restore source is essentially the last full image copy (backup) merged with the succeeding incremental image copies, prior to the actual rebuild; then essentially it should be just a matter of copying one to another in an sequential manner. Once this is accomplished, there should be a log somewhere that has all of the current updates that were made to the table/database up to the time of the stoppage. Applying the log (LOGAPPLY) to the table/database will bring it current status. If necessary, the indices can be rebuilt using a REBUILD utility.


I don't buy computers, I build them!!
ID: 1601070 · Report as offensive
David S
Volunteer tester
Avatar

Send message
Joined: 4 Oct 99
Posts: 18352
Credit: 27,761,924
RAC: 12
United States
Message 1601092 - Posted: 14 Nov 2014, 16:03:02 UTC

Thanks for the update, Eric. I wish I understood it on more than the most basic level.
David
Sitting on my butt while others boldly go,
Waiting for a message from a small furry creature from Alpha Centauri.

ID: 1601092 · Report as offensive
Profile Angela Special Project $75 donor
Volunteer moderator
Volunteer tester
Avatar

Send message
Joined: 16 Oct 07
Posts: 13131
Credit: 39,854,104
RAC: 31
United States
Message 1601293 - Posted: 15 Nov 2014, 2:24:09 UTC

New game for the Cafe... TLPTGAWUW!!!
(The last person to get a work unit wins)
ID: 1601293 · Report as offensive
Profile Uli
Volunteer tester
Avatar

Send message
Joined: 6 Feb 00
Posts: 10923
Credit: 5,996,015
RAC: 1
Germany
Message 1601299 - Posted: 15 Nov 2014, 2:43:52 UTC

I like that idea!
Pluto will always be a planet to me.

Seti Ambassador
Not to late to order an Anni Shirt
ID: 1601299 · Report as offensive
Profile HAL9000
Volunteer tester
Avatar

Send message
Joined: 11 Sep 99
Posts: 6534
Credit: 196,805,888
RAC: 57
United States
Message 1601307 - Posted: 15 Nov 2014, 4:29:41 UTC - in response to Message 1601293.  

New game for the Cafe... TLPTGAWUW!!!
(The last person to get a work unit wins)

I thought we were already playing "First one to infinity wins" :P
SETI@home classic workunits: 93,865 CPU time: 863,447 hours
Join the [url=http://tinyurl.com/8y46zvu]BP6/VP6 User Group[
ID: 1601307 · Report as offensive
Profile Dimly Lit Lightbulb 😀
Volunteer tester
Avatar

Send message
Joined: 30 Aug 08
Posts: 15399
Credit: 7,423,413
RAC: 1
United Kingdom
Message 1601322 - Posted: 15 Nov 2014, 5:09:42 UTC - in response to Message 1601293.  

New game for the Cafe... TLPTGAWUW!!!
(The last person to get a work unit wins)

Done :)

Member of the People Encouraging Niceness In Society club.

ID: 1601322 · Report as offensive

Message boards : Technical News : Taking longer than expected (Nov 13, 2014)


 
©2024 University of California
 
SETI@home and Astropulse are funded by grants from the National Science Foundation, NASA, and donations from SETI@home volunteers. AstroPulse is funded in part by the NSF through grant AST-0307956.