FAQ LOGO INFORMIX FAQ $Id: informix.htm,v 1.24 2005/05/15 01:15:00 root Exp $

Frequently Asked Questions about Informix

$Id: informix.htm,v 1.24 2005/05/15 01:15:00 root Exp $

This document answers some of the questions which regularly appear in the Usenet Newsgroup comp.databases.informix. In addition to "frequent" questions I've also included questions which I consider useful or interesting.

Suggestions for improvement are most welcome.

Enjoy yourselves,

Current Maintainer

David Williams (david@smooth1.co.uk)

Previous Maintainers:

Kerry Sainsbury (kerry@kcbbs.gen.nz)

"Creator and Maintainer of the Informix FAQ, 1994-1997". Without Kerry this FAQ would not exist.

PS: Here is Kerry's awesome collection of awards:

Selected by PC Webopaedia


0 FAQ Facts

0.1 What's new in this release of the FAQ?


1.10 How do Informix version numbers work??
4.8.15 Can I declare cursors in SPL?
4.9.2 How do I write a simple program in DBI?
6.3 What do I do if online fails to start?
6.68 Compatibility between NT 4.0 service packs and IDS?
6.69 How do I calculate the network bandwidth required for ER?
6.70 Why do I get out of disk space during a warm restore?
6.71 What is the difference between latches, mutexes and locks?
6.72 What does the output of onstat -C (pre IDS 10.0) mean?
6.73 What does the output at the end of onstat -u mean?
6.74 Why are all sessions hung on the nsf.lock mutex?
6.75 Why does the first CPU VP work harder than the others?
6.76 How do I fix permissions on files under $INFORMIXDIR?
6.77 What is a light scan?
6.78 What happens during an archive?
6.79 How do I disable fuzzy checkpoints?
6.80 How do I see free space in a sbspace?
6.81 Do logical log switches affect Enterprise Replication?
6.82 What is the sh_lock spin lock?
6.83 What does "mt yield n" mean in the wait statistics?
6.84 How do I add more than 10 shared memory segments under AIX?
6.85 What are the fields of the ixbar file?
6.86 Should I use striping?
8.63 Is the High Performance Loader (HPL) really that quick?
8.64 Can I connect to the database server without connecting to a database?
8.65 How do I run HPL job without the GUI?
8.66 Are there any tools that can display table relationships visually?
8.67 Are there any tools that check SQL for portability?
8.68 What is the ISO standard date format?
8.69 What does the "mode" column indicate in the sysprocedures table?
8.70 How can I drop a database in a down dbspace?
8.71 How can I find the number of index and data pages for a table from sysmaster?
8.72 How can I debug dbschema when it fails?
8.73 How can I debug onbar when it fails?
8.74 When should I use varchars?
8.75 How does Enterprise Replication do timestamp conflict resolution?
8.76 How can I calculate the remaining extents for a table?
8.77 Is it ok to use buffered logging for databases?
8.78 Should I fragment my indicies?
8.79 Can I see what temporary tables are in use?
8.80 How can I calculate suggested extent sizes for a table?
8.81 How can I calculate the memory needed for a hash join?
8.82 How do I setup Enterprise Replication (ER)?
8.83 How do I handle a long transaction?
10.12 Are there any notes on onstat?
13.1 How do I write a simple datablade?


1.8 New Features by product (or: Why you should upgrade) Added info from Jonathan Leffler on XPS 8.3. Added info from Raj Muralidharan on max chunk size for XPS 8.3
1.9 How does Informix QA their products? Added info from Madison Pruet on the testing suite Informix use. Added info from Madison Pruet on how porting and betas are done.
1.10 How do Informix version numbers work?? Added info from Andrew Hamm about what does and does not get included in an interim release.
4.8.13 Why does CURRENT always return the same value in SPL? Added info from Leonid Belov on how to get the current datetime from sysmaster.
5.9 How to alter the next SERIAL number Added info from Jonathan Leffler on C-ISAM.
6.32 How do I reduce bufwaits? Added info from Art Kagel that gives more detail.
6.33 What status codes does onstat return? Replaced with info from Mark D. Stock that includes XPS onstat return codes.
6.36 Any fast backup methods under IDS 7.3? Added info from Andrew Hamm (his first mention in the FAQ!) suggesting increasing TAPEBLK and LTAPEBLK.
6.38 Is raw disk faster than cooked files? Added more tests by Toni Arte that show raw disk is faster. Added more tests by Colin Bull that show raw disk is faster.
6.58 Why should I not use RAID 5? Added info from Paul Watson (Another new person in the FAQ!) confirming the disk failures run in batches.
6.61 How do I configure DD_HASHMAX and DD_HASHSIZE? Added info from Michael Mueller.
6.62 How does Online page size vary across platforms? Added info from Obnoxio The Clown that sequent is also a 4K page size. Obnoxio finally gets a credit in the FAQ! Added info from Art Kagel on XPS, that the old Turbo engine on Amdahl mainframes was 4K and that although 5.xx has a PAGESIZE onconfig parameter it should not be changed!
8.13 What undocumented Online things are there? Mentioned NOLRUPRIO. Added info from Stefan Weideneder on WSTATS are how to read the output. (Stefan gets his first entry in the FAQ!) Added info from Glyn Balmer on smartdisk. Added info from Madison Pruet. (Clarence?)
10.11 Are there any notes on sysmaster? Updated URL and Paul Watson's email address.

0.2 How can I get the latest copy of the FAQ?

0.2.1 anonymous ftp

The latest version of this document can be retrieved via anonymous ftp from the USA at ftp://ftp.iiug.org/pub/informix/faq/ifaq.tar.gz

If you've no knowledge of Unix, and have never heard of .gz or .tar formats, just get a copy of WinZip from http://www.winzip.com it's a very sexy Windows95/NT program which can decipher these for you.

0.2.2 World Wide Web

The primary site is London,England at http://www.smooth1.co.uk

Although the Informix-FAQ is available at many other sites on the Web, it is really only the two sites listed below who make an effort to keep their copies up-to-date.

If you are aware of somebody who *does* keep their version current please let me know and I'l be happy to include them in this list.


http://www.iiug.org/techinfo/faq/informix.htm (The International Informix User Group's site)

http://www.garpac.com/informix/ (Contact clay@garpac.com (Clay Irving))

0.2.3 comp.databases.informix

The FAQ is NEVER posted to c.d.i. because it's rather large, and posting hundreds of K into people's mailboxes isn't nice.

0.2.4 email

If you don't have access to FTP try using a FTP-by-mail server. Send a message with "help" in the subject line to the nearest one of:

0.3 Who do I complain to?

David Wiiliams
Home: david@smooth1.co.uk . Ph +44 0208 662 0864 (GMT)