Informix News
18 Nov 13 - ZDNet - Top 20 mobile skills in demand... Read
09 Sep 13 - telecompaper - Shaspa and Tatung have shown a new smart home platform at Ifa in Berlin. Powered by the IBM Informix software... Read
06 Sep 13 - IBM data magazine - Mission Accomplished - Miami, Florida will be the backdrop for the 2014 IIUG Informix Conference... Read
01 Feb 13 - IBM Data Magazine - Are your database backups safe? Lester Knutsen (IBM Champion) writes about database back up safety using "archecker"... Read
14 Nov 12 - IBM - IBM's Big Data For Smart Grid Goes Live In Texas... Read
3 Oct 12 - The Financial - IBM and TransWorks Collaborate to Help Louisiana-Pacific Corporation Achieve Supply Chain Efficiency... Read
28 Aug 12 - techCLOUD9 - Splunk kicks up a SaaS Storm... Read
10 Aug 12 - businessCLOUD9 - Is this the other half of Cloud monitoring?... Read
3 Aug 12 - IBM data management - Supercharging the data warehouse while keeping costs down IBM Informix Warehouse Accelerator (IWA) delivers superior performance for in-memory analytics processing... Read
2 Aug 12 - channelbiz - Oninit Group launches Pay Per Pulse cloud-based service... Read
28 May 12 - Bloor - David Norfolk on the recent Informix benchmark "pretty impressive results"... Read
23 May 12 - DBTA - Informix Genero: A Way to Modernize Informix 4GL Applications... Read
9 Apr 12 - Mastering Data Management - Upping the Informix Ante: Advanced Data Tools... Read
22 Mar 12 - developerWorks - Optimizing Informix database access... Read
14 Mar 12 - - International Informix User Group set to meet in San Diego... Read
1 Mar 12 - IBM Data Management - IIUG Heads West for 2012 - Get ready for sun and sand in San Diego... Read
1 Mar 12 - IBM Data Management - Running Informix on Solid-State Drives.Speed Up Database Access... Read
26 Feb 12 - - Better results, lower cost for a broad set of new IBM clients and partners... Read
24 Feb 12 - developerWorks - Informix Warehouse Accelerator: Continuous Acceleration during Data Refresh... Read
6 Feb 12 - PRLOG - Informix port delivers unlimited database scalability for popular SaaS application ... Read
2 Feb 12 - developerWorks - Loading data with the IBM Informix TimeSeries Plug-in for Data Studio... Read
1 Feb 12 - developerWorks - 100 Tech Tips, #47: Log-in to Fix Central... Read
13 Jan 12 - MC Press online - Informix Dynamic Server Entices New Users with Free Production Edition ... Read
11 Jan 12 - Computerworld - Ecologic Analytics and Landis+Gyr -- Suitors Decide to Tie the Knot... Read
9 Jan 12 - - DNS impact on Informix / Impacto do DNS no Informix... Read
8 Sep 11 - - IBM Offers Database Solution to Enable Smart Meter Data Capture... Read
1 Aug 11 - IBM Data Management Magazine - IIUG user view: Happy 10th anniversary to IBM and Informix... Read
8 Jul 11 - Database Trends and Applications - Managing Time Series Data with Informix... Read
31 May 11 - Smart Grid - The meter data management pitfall utilities are overlooking... Read
27 May 11 - IBM Data Management Magazine - IIUG user view: Big data, big time ( Series data, warehouse acceleration, and 4GLs )... Read
16 May 11 - Business Wire - HiT Software Announces DBMoto for Enterprise Integration, Adds Informix. Log-based Change Data Capture... Read
21 Mar 11 - Yahoo! Finance - IBM and Cable&Wireless Worldwide Announce UK Smart Energy Cloud... Read
14 Mar 11 - MarketWatch - Fuzzy Logix and IBM Unveil In-Database Analytics for IBM Informix... Read
11 Mar 11 - InvestorPlace - It's Time to Give IBM Props: How many tech stocks are up 53% since the dot-com boom?... Read
9 Mar 11 - DBTA - Database Administration and the Goal of Diminishing Downtime... Read
2 Feb 11 - DBTAs - Informix 11.7 Flexible Grid Provides a Different Way of Looking at Database Servers... Read
27 Jan 11 - exactsolutions - Exact to Add Informix Support to Database Replay, SQL Monitoring Solutions... Read
25 Jan 11 - PR Newswire - Bank of China in the UK Works With IBM to Become a Smarter, Greener Bank... Read
12 Oct 10 - Database Trends and Applications - Informix 11.7: The Beginning of the Next Decade of IBM Informix... Read
20 Sep 10 - - ITG analyst paper: Cost/Benefit case for IBM Informix as compared to Microsoft SQL Server... Read
20 Jul 10 - IBM Announcements - IBM Informix Choice Edition V11.50 helps deploy low-cost scalable and reliable solutions for Apple Macintosh and Microsoft Windows... Read
20 Jul 10 - IBM Announcements - Software withdrawal: Elite Support for Informix Ultimate-C Edition... Read
24 May 10 - eWeek Europe - IBM Supplies Database Tech For EU Smart Grid... Read
23 May 10 - SiliconIndia - IBM's smart metering system allows wise use of energy... Read
21 May 10 - CNET - IBM to help people monitor energy use... Read
20 May 10 - ebiz - IBM Teams With Hildebrand To Bring Smart Metering To Homes Across Britain... Read
19 May 10 - The New Blog Times - Misurare il consumo energetico: DEHEMS è pronto... Read
19 May 10 - ZDNet - IBM software in your home? Pact enables five-city smart meter pilot in Europe... Read
17 March 10 - ZDNet (blog) David Morgenstern - TCO: New research finds Macs in the enterprise easier, cheaper to manage than... Read
17 March 2010 - Virtualization Review - ...key components of Big Blue's platform to the commercial cloud such as its WebSphere suite of application ser vers and its DB2 and Informix databases... Read
10 February 2010 - The Wall Street Journal - International Business Machines is expanding an initiative to win over students and professors on its products. How do they lure the college crowd?... Read

End of Support Dates

IIUG on Facebook IIUG on Twitter

[ View Thread ] [ Post Response ] [ Return to Index ] [ Read Prev Msg ] [ Read Next Msg ]

Classics Forum

Re: ESQL/C Programs take very long time to start u

Posted By: Fernando Nunes
Date: Wednesday, 18 April 2018, at 12:33 p.m.

In Response To: Re: ESQL/C Programs take very long time to start u (RICHARD SPITZ)

On Wed, Apr 18, 2018 at 6:17 PM, RICHARD SPITZ <> wrote:

> Fernando,
> thank you very much for your detailed response. I had written a comment in
> your blog article because that had been the most profound and helpful info
> I
> had found about configuring IDS with PAM support.
> > ESQL/C will most probably (that's what I'd like to test/debug) need
> > to get the user ID *before* trying to connect to IDS. And that's
> > where it's taking time.
> Exactly. I think I had written before in this thread that the delay occurs
> before the database connection is established. What's puzzling me is the
> way
> ESQL/C does this: First it goes through all the "pain" of reading
> /proc/self/loginuid and trying to verify that uid via the mechanisms
> defined
> in /etc/nsswitch.conf (which MUST fail in case of loginuid "-1", and
> causes
> the delay), and then it uses getuid() anyway to continue happily
> everafter.
> > That probably means that the LDAP integration software you're
> > using "hijacks" some internal functions/libraries...
> Well, I'm using a perfectly standard and well documented mechanism for
> that:
> sssd. This is nothing fancy and is integrated into current versions of
> that is also why PAM is not even needed to connect to IDS as an LDAP user.
> > When you say "interactive" may I assume you opened an SSH/telnet
> > to the server using the user name of the user? Or have you done an
> su/sudo?
> Interactive means that I am in a normal user shell (opened via SSH/PuTTY)
> on
> the Linux machine Hosting IDS and executing the shell script that is
> normally
> invoked by the SPL.
> > Assuming you did that directly the login process is going through
> > the authentication and creates the "session context" that makes the
> > calls run fast
> The login process sets /proc/self/loginuid for the shell, which is
> inherited
> by the program or shell script I'm starting.
> > This is not being set when a daemon (Informix) changes a process
> > identity which is what the SYSTEM SPL instruction triggers.
> Exactly. IDS (oninit) is the daemon, and the PAM module is
> designed to set /proc/self/loginuid. That (pseudo) file is writable only
> for
> root, otherwise it would be trivial to write the correct uid to it but of
> course a huge security issue.
> > 1- Understand why the process takes time after trying to get that
> > info from the file. Is it calling a daemon for cache, talking to
> > the LDAP server, etc?. And how can that time be reduced?
> As written before, the problem is that ESQL/C is trying the UID of "-1"
> (read
> from /proc/self/loginuid) to query /etc/passwd and sssd, which MUST be
> unsuccessful. That UID can not be found in any local cache, that's why a
> query
> to the AD servers is done which is of course also unsuccessful. All of
> this
> takes time, a query with a correct UID takes only milliseconds.
> > 2- Check the use of the pam_loginuid in your system.
> That's what I've been doing all along. Is there a mechanism to make IDS
> (and
> other "daemons", like Apache) use that module when invoking subshells or
> processes?
> > I suppose the delay is also noticeable when you do the login.
> No, a valid user login works instantly, no noticeable delay.
> > 1- Can you change the ESQL/C to CONNECT with a specific user?
> > Maybe in that case it doesn't need to get the UID?
> Tried both implicit and explicit connections, no difference in behaviour.
> > 2- You probably can reproduce this by scheduling the process in the
> > crontab.
> crond is PAM-enabled and uses, so /proc/self/loginuid is
> set
> to the correct UID. I already verified that by scheduling the ESQL/C
> program
> in cron.
> > 3- On many ocassions this weird delays are caused by issues in reverse
> > lookups (IP to names).
> No problem there, I can assure you.
> > I honestly don't know (strace should help) what ESQL/C calls when it
> > starts....
> I can send you a complete strace output, but I already mentioned the
> relevant
> parts in this thread.
> > I'm sure Jonathan Leffler would be able to provide some more
> > info on this, but I haven't seen him here for a while.
> Honestly, I had hoped that he might read this...
> > Note that in noway ESQL/C directly accesses the /proc/self/loginuid.
> > That's a consequence on a system call and your system configuration....
> Sorry, but I think you're wrong. The strace traces prove that the ESQL/C
> program itself reads /proc/self/loginuid, and that ONLY happens if the
> program
> establishes a database connection somewhere later in the program. I wrote
> a
> dummy ESQL/C program that doesn't open a database connection, and this
> dummy
> program doesn't read /proc/self/loginuid and does no user verification at
> all.
> Regards, Richard
No. I understand you got that from strace. And I didn't mean that the
ESQL/C process does not read the file.
What I mean is that ESQL/C only calls "standard" POSIX functions. And this
functions in your system (Linux + kernel version + configuration +
whatever) trigger those operations.
We would need to understand what call triggers that and if there's a way to
workaround it.
I thought, apprently wrongly, that it was the call to getuid which I
confirmed happens on an ESQL/C process. That's why I sent you a test case
with that call.
A possible way to try to find that would be to run the ESQL/C program in a
debugger and set a couple of breakpoints in OS functions close to the
sequence where it has delays.
When the program stops and returns control to the debugger try to run a
"where" and see what's in there. An example with getuid():> gdb ./test.exe
GNU gdb (GDB) Red Hat Enterprise Linux 7.6.1-100.el7_4.1
Copyright (C) 2013 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-redhat-linux-gnu".
For bug reporting instructions, please see:
Reading symbols from /tmp/test.exe...(no debugging symbols found)...done.
(gdb) break getuid
Function "getuid" not defined.
Make breakpoint pending on future shared library load? (y or [n]) y
Breakpoint 1 (getuid) pending.
(gdb) run
Starting program: /tmp/./test.exe
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/".

Breakpoint 1, 0x00007ffff640b080 in getuid () from /lib64/
Missing separate debuginfos, use: debuginfo-install
glibc-2.17-196.el7_4.2.x86_64 nss-softokn-freebl-3.28.3-8.el7_4.x86_64
(gdb) where
#0 0x00007ffff640b080 in getuid () from /lib64/
#1 0x00007ffff79597e7 in cmInit () from
#2 0x00007ffff7950ddf in asfInit () from
#3 0x00007ffff795196b in ASF_Call () from
#4 0x00007ffff7b99a88 in asf_init () from
#5 0x00007ffff7b9ce0d in sqli_connect_open () from
#6 0x0000000000400916 in main ()

In this case the "CONNECT/DATABASE" statement triggers several calls in the
Informix LIBS and then we jump into the getuid().
You may need to go over several attempts if you can only set the breakpoint
to common functions like "open()"...

Once we find the POSIX function which is causing the sequence that causes
the delays we may have a shot of reconfigure something to solve it.
getuid() for example is necessary to get the user id under which we run....


> *******************************************************************************
> Forum Note: Use "Reply" to post a response in the discussion forum.

Fernando Nunes
My email works... but I don't check it frequently...

Messages In This Thread

[ View Thread ] [ Post Response ] [ Return to Index ] [ Read Prev Msg ] [ Read Next Msg ]

Classics Forum is maintained by Administrator with WebBBS 5.12.