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  • Craftsmanship Tour: Day 3 &amp; 4 8th Light

    - by Liam McLennan
    Thursday morning the Illinois public transport system came through for me again. I took the Metra train north from Union Station (which was seething with inbound commuters) to Prairie Crossing (Libertyville). At Prairie Crossing I met Paul and Justin from 8th Light and then Justin drove us to the office. The 8th Light office is in an small business park, in a semi-rural area, surrounded by ponds. Upstairs there are two spacious, open areas for developers. At one end of the floor is Doug Bradbury’s walk-and-code station; a treadmill with a desk and computer so that a developer can get exercise at work. At the other end of the floor is a hammock. This irregular office furniture is indicative of the 8th Light philosophy, to pursue excellence without being limited by conventional wisdom. 8th Light have a wall covered in posters, each illustrating one person’s software craftsmanship journey. The posters are a fascinating visualisation of the similarities and differences between each of our progressions. The first thing I did Thursday morning was to create my own poster and add it to the wall. Over two days at 8th Light I did some pairing with the 8th Lighters and we shared thoughts on software development. I am not accustomed to such a progressive and enlightened environment and I found the experience inspirational. At 8th Light TDD, clean code, pairing and kaizen are deeply ingrained in the culture. Friday, during lunch, 8th Light hosted a ‘lunch and learn’ event. Paul Pagel lead us through a coding exercise using micro-pomodori. We worked in pairs, focusing on the pedagogy of pair programming and TDD. After lunch I recorded this interview with Paul Pagel and Justin Martin. We discussed 8th light, craftsmanship, apprenticeships and the limelight framework. Interview with Paul Pagel and Justin Martin My time at Didit, Obtiva and 8th Light has convinced me that I need to give up some of my independence and go back to working in a team. Craftsmen advance their skills by learning from each other, and I can’t do that working at home by myself. The challenge is finding the right team, and becoming a part of it.

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  • Back home :-)

    - by Mike Dietrich
    Wrote this entry last night in the ICE from Stuttgart to Munich but the conncetion broke: 28.5 hour journey - and close by now. Actually I would have been even closer if our TGV wouldn't have had break problems as soon as we had entered German territory. And you don't want a train which goes up to a speed of 200 mph having issues with its breaks, right? So we missed the connection in Stuttgart but I've catched the last train this night towards Munich. Distance approx 1900 km all together. Usually it takes 2.5 hours with a direct flight with Air Lingus from Munich or a bit more when you'll go through Zurich or Frankfurt. But at least you meet more people and see a bit more from the landscapes passing by :-) Except for the break problem everything worked out well so far (I'm no there finally!). I had 4 hours to change in Paris from Gare de Nord to Gare de l'Est and one thing I really have to point out: the people working for SNCF, the French National Railways, were so organized and helpful, purely amazing. I asked the man at the counter where I had to pick up my prepaid tickets for directions to Gare de l'Est - and after we had a chat about Marlene Dietrich he just grabbed his iPhone, started Google Earth and showed me the way to walk. I pretty sure it's a stupid stereotype that people in Paris or France are so unfriendly to foreigners if they don't speak French. In my past 3 stays or travels to Paris in the past 2 years I had only great experiences. And another thing I really enjoy when being in France: the food!!! The sandwich I had at the train station was packed with yummy goat cheese. And there's always Paul. You might ask yourself: Who the heck is Paul? That's Paul - or actually their website. And at Paul's they serve usually excellent fruit tartes - and this time a nice Gateau Au Chocolate. And very good Cafe Cremé as well :-) That's actually the positive part traveling this way: the food you'll get is much better than the airline food - if your airline still serves something called food ...

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  • An XEvent a Day (25 of 31) – The Twelve Days of Christmas

    - by Jonathan Kehayias
    In the spirit of today’s holiday, a couple of people have been posting SQL related renditions of holiday songs.  Tim Mitchell posted his 12 days of SQL Christmas , and Paul Randal and Kimberly Tripp went as far as to record themselves sing SQL Carols on their blog post Our Christmas Gift To You: Paul and Kimberly Singing!   For today’s post on Extended Events I give you the 12 days of Christmas, Extended Events style (all of these are based on true facts about Extended Events in SQL Server)....(read more)

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  • Chrome Apps Office Hours: Building Apps with Web Intents

    Chrome Apps Office Hours: Building Apps with Web Intents Ask and vote for questions at: goo.gl Web Intents are the core mechanism for building interconnected apps on the Chrome platform. Join Paul Kinlan and Paul Lewis next week as we show you how to build client apps that send data to other web apps, and a service app that will receive input from any intent invocation. From: GoogleDevelopers Views: 0 0 ratings Time: 00:00 More in Science & Technology

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  • Booting Error while using 12.04 booting from GRUB

    - by Paul Z.
    my name is Paul. I have encountered an issue relating to GRUB booting and the booting process in general. I have been running Ubuntu 12.04 LTS on my machine for quite a while. Before that, i had (before) 10.04, 11.04, 11.10, etc. I have been running Ubuntu, in general, but more specifically 12.04 for a long time with little to no problems. The problem: Earlier today, i was using my machine and then decided to take a little break. I shut down my machine (laptop, in case anyone was wondering) and left. Later, I came back ready to start it up and continue. I started it up and it took me to the Toshiba screen (like normal) then to the GRUB screen. I guessed that nothing was truly wrong, and chose the first option (something around the lines of: Ubuntu, with linux 3.22.0-35-generic). I waited for a bit and it still displayed the same purple screen. I restarted it and now chose the option like the first but with recovery at the end. Same result. Later, I waited longer and found that my computer came up with a bunch of lines of script. I waited longer but nothing new happened. What are your suggestions as to fix this problem? I will let my computer run overnight with the recovery setting and will let you know what the result is. Until then, please help. Thank you, your time and effort is greatly appreciated!

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  • Connect a PC to MAC OSX Server

    - by Paul Sheldrake
    I'm trying to connect to a server at work which is run on a Mac but I have a PC (windows 7) at home. I have path to connect in the format of afp://server.com/files. Is there a client that I need to install on my PC that I can use to login? Thanks, Paul

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  • Connect a PC to Mac OS X Server

    - by Paul Sheldrake
    I'm trying to connect to a server at work which is run on a Mac but I have a PC (windows 7) at home. I have path to connect in the format of afp://server.com/files. Is there a client that I need to install on my PC that I can use to login? Thanks, Paul

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  • Using photos from network drive with Windows 8 photo app

    - by Paul
    I have photos on my network drive that I want to display (in live tiles preferably in the photo app). Under c:\users\paul\pictures I have made a link to them, using mklink /d: And this works fine in classic: But nothing appears in the photo.app: I am guessing that this is an issue with indexing - the photos won't appear until they are indexed, and Windows won't normally index a network drive (unless you make it "available offline, which just copies the files locally) - but this is exactly what the mklink was supposed to work around, and the properties show it is indexable: Any ideas?

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  • Automount of AFP shares on Lion clients from OS X Snow Leopard server - not working right

    - by Paul
    Recently upgraded Snow Leopard clients to Lion. AFP shares are set up as login items. The network shares on some of the machines now take a long time to come up (10 minutes). Several machines that were upgraded are acting normally, and three machines with clean installs of Lion (not upgraded) are also working normally. Is there a network file causing a conflict on some of these client machines? Thanks, Paul

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  • How to AUTOMATICALLY open all links (flash streams) in different tabs or windows IE9, Safari, or Firefox?

    - by Paul M
    Is there a way to AUTOMATICALLY open all links in a given website in different tabs or windows? I've tried "snap link plus", but it didn't work on this particular website: http://www.teledunet.com To open others streams on this website (found on the left hand side of the page), you would need to login using (cmoi123 / 12345) by clicking on "Connexion" on the top right side of the main page). Thank You In Advance! -Paul

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  • I changed the repository and now my ubuntu software center crashes

    - by Paul Menz
    paul@ubuntu:~$ software-center 2012-10-24 18:11:04,665 - softwarecenter.ui.gtk3.app - INFO - setting up proxy 'None' 2012-10-24 18:11:04,671 - softwarecenter.db.database - INFO - open() database: path=None use_axi=True use_agent=True 2012-10-24 18:11:05,191 - softwarecenter.backend.reviews - WARNING - Could not get usefulness from server, no username in config file 2012-10-24 18:11:05,403 - softwarecenter.ui.gtk3.app - INFO - show_available_packages: search_text is '', app is None. 2012-10-24 18:11:05,920 - softwarecenter.db.pkginfo_impl.aptcache - INFO - aptcache.open() Traceback (most recent call last): File "/usr/share/software-center/softwarecenter/db/pkginfo_impl/aptcache.py", line 243, in open self._cache = apt.Cache(GtkMainIterationProgress()) File "/usr/lib/python2.7/dist-packages/apt/cache.py", line 102, in __init__ self.open(progress) File "/usr/lib/python2.7/dist-packages/apt/cache.py", line 149, in open self._list.read_main_list() SystemError: E:Malformed line 63 in source list /etc/apt/sources.list (dist parse) 2012-10-24 18:11:07,255 - softwarecenter.db.enquire - ERROR - _get_estimate_nr_apps_and_nr_pkgs failed Traceback (most recent call last): File "/usr/share/software-center/softwarecenter/db/enquire.py", line 115, in _get_estimate_nr_apps_and_nr_pkgs tmp_matches = enquire.get_mset(0, len(self.db), None, xfilter) File "/usr/share/software-center/softwarecenter/db/appfilter.py", line 89, in __call__ if (not pkgname in self.cache and File "/usr/share/software-center/softwarecenter/db/pkginfo_impl/aptcache.py", line 263, in __contains__ return self._cache.__contains__(k) AttributeError: 'NoneType' object has no attribute '__contains__' Traceback (most recent call last): File "/usr/bin/software-center", line 176, in <module> app.run(args) File "/usr/share/software-center/softwarecenter/ui/gtk3/app.py", line 1422, in run self.show_available_packages(args) File "/usr/share/software-center/softwarecenter/ui/gtk3/app.py", line 1352, in show_available_packages self.view_manager.set_active_view(ViewPages.AVAILABLE) File "/usr/share/software-center/softwarecenter/ui/gtk3/session/viewmanager.py", line 154, in set_active_view view_widget.init_view() File "/usr/share/software-center/softwarecenter/ui/gtk3/panes/availablepane.py", line 171, in init_view self.apps_filter) File "/usr/share/software-center/softwarecenter/ui/gtk3/views/catview_gtk.py", line 238, in __init__ self.build(desktopdir) File "/usr/share/software-center/softwarecenter/ui/gtk3/views/catview_gtk.py", line 511, in build self._build_homepage_view() File "/usr/share/software-center/softwarecenter/ui/gtk3/views/catview_gtk.py", line 271, in _build_homepage_view self._append_whats_new() File "/usr/share/software-center/softwarecenter/ui/gtk3/views/catview_gtk.py", line 450, in _append_whats_new whats_new_cat = self._update_whats_new_content() File "/usr/share/software-center/softwarecenter/ui/gtk3/views/catview_gtk.py", line 439, in _update_whats_new_content docs = whats_new_cat.get_documents(self.db) File "/usr/share/software-center/softwarecenter/db/categories.py", line 124, in get_documents nonblocking_load=False) File "/usr/share/software-center/softwarecenter/db/enquire.py", line 317, in set_query self._blocking_perform_search() File "/usr/share/software-center/softwarecenter/db/enquire.py", line 212, in _blocking_perform_search matches = enquire.get_mset(0, self.limit, None, xfilter) File "/usr/share/software-center/softwarecenter/db/appfilter.py", line 89, in __call__ if (not pkgname in self.cache and File "/usr/share/software-center/softwarecenter/db/pkginfo_impl/aptcache.py", line 263, in __contains__ return self._cache.__contains__(k) AttributeError: 'NoneType' object has no attribute '__contains__'

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  • HTML5Rocks Live, Episode 1

    HTML5Rocks Live, Episode 1 In this episode of HTML5Rocks Live, Boris, Eric and Paul join us to show some great new libraries and performance tips. Please leave your comments on our plus page at goo.gl In the first chapter, Paul shows how to use some of Chrome's new developer tools to understand how things are rendering and get improved performance. In the second chapter (21:25), Boris shows off his new device.js library to help make development of mobile web applications and sites easier. Eric closes the hangout (40:00) and talks about his new file system API polyfill that uses indexed db as it's back end. 02:15 Scroll Effects Demo goo.gl 23:04 - Media Queries Site goo.gl 24:15 - WURFL goo.gl 26:40 - Boris' Device Library goo.gl 29:28 - Device.js Demo goo.gl 33:25 - Bug to add touch-enabled media query to Chrome, please star goo.gl 35:00 - Chrome's DevTools for Mobile Development 38:56 - Paul Irish's Touch Demos goo.gl 40:43 - File System API Book goo.gl 43:10 - Eric's idb.filesystem.js goo.gl 44:27 - idb.filesystem HTML5 File System Demo goo.gl 47:33 - HTML5 Filesystem Playground goo.gl From: GoogleDevelopers Views: 12239 221 ratings Time: 52:29 More in Science & Technology

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  • SkyDrive and Consumer Cloud Services

    - by Tim Murphy
    Paul Thurrrott recently posted an article on the future of SkyDrive and I was asked what I thought about its future by @UserCommunity.  So let’s take a look. The breakdown from Microsoft that Paul described I believe is an accurate representation of users and usages. While I can’t say that I leverage SkyDrive to the extent that it was meant to be I do enjoy having OneNote hosted their and being able to consult and edit it from the desktop, web and Windows Phone. Taking that one step further is the Midwest Geeks group which started as the community of Microsoft related user groups in our region uses SkyDrive groups and shares calendars and documents.  This collaboration aspect isn’t new in itself, but having it connected with the rest of your cloud assets makes life easier. Another recent usage of this type of cloud service is storing your personal music files in order to get that same universal access.  This is a scenario that has some arguments for and against.  On the one hand own once and listen anywhere is great, but the on the other hand the bandwidth cost becomes a giant downside.  This is especially the case since most carriers are now doing away with unlimited data packages. Ultimately I see this type of resource growing an evolving at a phenomenal rate over the next few years as we continue to become more mobile.  Having multiple players such as SkyDrive and iCloud will only help to give us more options.  Only time will tell where we end up next. del.icio.us Tags: SkyDrive,Cloud Services,Paul Thurrott,UserCommunity

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  • Samba users are writing files with the same owner

    - by Alex
    I created a Samba share and 3 users (Marc, Mary and Paul), both in Ubuntu (12.04 LTS) and Samba. Then I configured 3 Win7 computers to access the share, each with different credentials. I created 3 folders, one for every user, and chown'd them to the related user, chmod'd them to 0700 and even restarted Samba. Every time that Mary or Paul create a file or a directory in the share, it ends up to be owned by Marc. They all can access the Marc folder, but none can open Mary's or Paul's. Can you help me with this problem? What am I missing?

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  • Why do we need Hash by key? [migrated]

    - by Royi Namir
    (i'm just trying to find what am I missing...) Assuming John have a clear text message , he can create a regular hash ( like md5 , or sha256) and then encrypt the message. John can now send Paul the message + its (clear text)hash and Paul can know if the message was altered. ( decrypt and then compare hashes). Even if an attacker can change the encrpyted data ( without decrypt) - - when paul will open the message - and recalc the hash - it wont generate the same hash as the one john sent him. so why do we need hash by key ?

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  • ArchBeat Link-o-Rama for 2012-10-10

    - by Bob Rhubart
    Oracle's Analytics, Engineered Systems, and Big Data Strategy | Mark Rittman Part 1 of 3 in Oracle ACE Director Mark Rittman's series on Oracle Exalytics, Oracle R Enterprise and Endeca. Series: How to Kill the Architecture Department? Part 1 | Xebia Blog Don't let the title fool you. This is not an anti-architecture post. Rather, this post, part 1 of a now four-part series, offers suggestions for preserving architecture in a form that better supports agile organizations. BPM Suite configure BAM Adapter | Peter Paul van der Beek "To have the BPM server push events to BAM – Business Activity Monitoring – we have to configure the BPM suite to use the BAM Adapter," says Peter Paul van de Beek. "The BAM Adapter is configured (like other SOA Suite and BPM Adapters) in the WebLogic Server Console." Peter Paul shows you how in this brief post. A case for not installing your own software | James Gentsch "I look selfishly forward to cloud computing and engineered systems dramatically reducing the occurrence of problems triggered by unforeseen environmental situations in the software I am responsible for," says James Gentsch. "I think this is an evolutionary game changer that will be a huge benefit to the reliability and consistent performance of the software for my customers, and may make 'well, it works here' a well forgotten phase for future software developers." Thought for the Day "I'm a strong believer in being minimalistic. Unless you actually are going to solve the general problem, don't try and put in place a framework for solving a specific one, because you don't know what that framework should look like." — Anders Hejlsberg Source: SoftwareQuotes.com`

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  • Security in Robots and Automated Systems

    - by Roger Brinkley
    Alex Dropplinger posted a Freescale blog on Securing Robotics and Automated Systems where she asks the question,“How should we secure robotics and automated systems?”.My first thought on this was duh, make sure your robot is running Java. Java's built-in services for authentication, authorization, encryption/confidentiality, and the like can be leveraged and benefit robotic or autonomous implementations. Leveraging these built-in services and pluggable encryption models of Java makes adding security to an exist bot implementation much easier. But then I thought I should ask an expert on robotics so I fired the question off to Paul Perrone of Perrone Robotics. Paul's build automated vehicles and other forms of embedded devices like auto monitoring of commercial vehicles on highways.He says that most of the works that robots do now are autonomous so it isn't a problem in the short term. But long term projects like collision avoidance technology in automobiles are going to require it.Some of the work he's doing with his Java-based MAX, set of software building blocks containing a wide range of low level and higher level software modules that developers can use to build simple to complex robot and automation applications faster and cheaper, already provide some support for JAUS compliance and because their based on Java, access to standards based security APIs.But, as Paul explained to me, "the bottom line is…it depends on the criticality level of the bot, it's network connectivity, and whether or not a standards compliance is required."

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  • TechEd 2012: MVVM In XAML

    - by Tim Murphy
    Paul Sheriff was a real character at the start of his MVVM in XAML session.  There was a lot of sarcasm and self deprecation going on prior to the .  That is never a bad way to get things rolling right after lunch.  Then things got semi-serious. The presentation itself had a number of surprises, but not all of them had to do with XAML.  When he flipped over his company’s code generation tool it took me off guard.  I am used to generator that create code for a whole project, but his tools were able to create different types of constructs on demand.  It also made it easier to follow what he was doing than some of the other demos I have seen this week where people were using code snippets. Getting to the heart of the topic I found myself thinking that I may have found my utopia for application development in MVVM.  Yes, I know there is no such thing, but this comes closer than any other pattern I have learned about.  This pattern allows the application to have better separation of concerns than I have seen before.  This is especially true since you can leverage data binding.  I’m not sure why it has taken me so long to find time for this subject. As Paul demonstrated using this pattern with XAML gives you multi-platform reusable code when you leverage common utility classes and ModelView classes.  The one drawback I see is that you have to go to the lowest common denominator between the platforms you want to support, but you always have to weigh the trade offs. And finally, the Visual Studio nuggets just keep coming.  Even though it has been available for several generations of Visual Studio I have never seen someone use linked files within a solution.  It just goes to show that I should spend more time exploring the deeper features of each dialog. del.icio.us Tags: TechEd,TechEd 2012,MVVM,Paul Sheriff,Patterns,Visual Studio 2012

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  • Error Formatting Memory Card

    - by Kirby Fromm
    I just tried to look at some of my pictures on my sony cyber-shot dsc-tx5, with a Lexar platinum II 16 GB memory stick, and it is now saying I have a formatting error every time I turn the camera on. The card and Camera are both 3 months old and have worked perfectly before. I tried to check the card on my computer and it says there is an error, so the camera is working but the card is not. Does anyone know how I can fix this to get the pictures off of the card?

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  • Securing smtp with login

    - by Paul Peelen
    I have a ispconfig server, and it seems that someone is using it to send spam. I got about 130 "Mail Delivery System" email about declined send email. This spammer uses my email address as sent from adress, so I get all these email adresses to my mail. I am using Postfix and Courier. I installed my server according to this guide: http://www.howtoforge.com/perfect-server-debian-lenny-ispconfig3-p3 I did this a few months ago. My question: Can I secure my server to require login to be able to send email, and if so... how? Thanks! EDIT Some data from mail.log, these kind of error show up constantly: Jun 15 17:58:16 bolt postfix/qmgr[10712]: CC7DA1242AE: from=<paul@*****.se>, size=3782, nrcpt=1 (queue active) Jun 15 17:58:16 bolt postfix/smtp[11337]: CC7DA1242AE: to=<[email protected]>, relay=none, delay=4641, delays=4640/0.01/0.32/0, dsn=4.4.3, status=deferred (Host or domain name not found. Name service error for name=cmlisboa.pt type=MX: Host not found, try again) Jun 15 17:58:19 bolt postfix/smtpd[10836]: connect from static-200-105-220-154.acelerate.net[200.105.220.154] Jun 15 17:58:20 bolt postfix/smtpd[10836]: NOQUEUE: reject: RCPT from static-200-105-220-154.acelerate.net[200.105.220.154]: 550 5.1.1 <advertising@*****.com>: Recipient address rejected: User unknown in virtual mailbox table; from=<[email protected]> to=<advertising@*****.com> proto=ESMTP helo=<static-200-105-220-154.acelerate.net> Jun 15 17:58:20 bolt postfix/smtpd[10836]: lost connection after DATA (0 bytes) from static-200-105-220-154.acelerate.net[200.105.220.154] Jun 15 17:58:20 bolt postfix/smtpd[10836]: disconnect from static-200-105-220-154.acelerate.net[200.105.220.154] Jun 15 17:58:29 bolt postfix/smtpd[10834]: connect from unknown[62.176.172.226] Jun 15 17:58:32 bolt postfix/smtpd[10834]: 386791241F9: client=unknown[62.176.172.226] Jun 15 17:58:34 bolt postfix/cleanup[10975]: 386791241F9: message-id=<[email protected]> Jun 15 17:58:34 bolt postfix/qmgr[10712]: 386791241F9: from=<[email protected]>, size=867, nrcpt=1 (queue active) Jun 15 17:58:35 bolt postfix/smtpd[10834]: disconnect from unknown[62.176.172.226] Jun 15 17:58:35 bolt amavis[11084]: (11084-17) Blocked SPAM, [62.176.172.226] [62.176.172.226] <[email protected]> -> <*****@*****>, Message-ID: <[email protected]>, mail_id: XczovKoMBYNr, Hits: 18.471, size: 867, 833 ms Jun 15 17:58:35 bolt postfix/smtp[10732]: 386791241F9: to=<*****@*****>, relay=127.0.0.1[127.0.0.1]:10024, delay=3.5, delays=2.7/0/0/0.83, dsn=2.7.0, status=sent (250 2.7.0 Ok, discarded, id=11084-17 - SPAM) Jun 15 17:58:35 bolt postfix/qmgr[10712]: 386791241F9: removed Jun 15 17:58:43 bolt postfix/smtpd[10836]: warning: 178.121.154.194: address not listed for hostname mm-194-154-121-178.dynamic.pppoe.mgts.by Jun 15 17:58:43 bolt postfix/smtpd[10836]: connect from unknown[178.121.154.194] Jun 15 17:58:45 bolt postfix/smtpd[10727]: connect from unknown[180.134.223.86] EDIT #2 Got some more info from the logs, this is a send request: mail.info.1:Jun 15 16:41:57 bolt amavis[5399]: (05399-06) Passed CLEAN, [110.139.48.64] [110.139.48.64] <paul@*****.se> -> <[email protected]>, Message-ID: <CHILKAT-MID-7c54ebcf-5501-de9b-f0b1-4f0234290d8d@HP-IRISH>, mail_id: 35l56Ramx6Nc, Hits: -2.941, size: 3329, queued_as: 2485770086, 136 ms mail.info.1:Jun 15 16:41:57 bolt postfix/smtp[4743]: 375C570082: to=<[email protected]>, relay=127.0.0.1[127.0.0.1]:10024, delay=4.8, delays=4.7/0/0/0.14, dsn=2.0.0, status=sent (250 2.0.0 Ok, id=05399-06, from MTA([127.0.0.1]:10025): 250 2.0.0 Ok: queued as 2485770086) Which apparently got thrue. Any ideas how to restrict this?

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  • Cardinality Estimation Bug with Lookups in SQL Server 2008 onward

    - by Paul White
    Cost-based optimization stands or falls on the quality of cardinality estimates (expected row counts).  If the optimizer has incorrect information to start with, it is quite unlikely to produce good quality execution plans except by chance.  There are many ways we can provide good starting information to the optimizer, and even more ways for cardinality estimation to go wrong.  Good database people know this, and work hard to write optimizer-friendly queries with a schema and metadata (e.g. statistics) that reduce the chances of poor cardinality estimation producing a sub-optimal plan.  Today, I am going to look at a case where poor cardinality estimation is Microsoft’s fault, and not yours. SQL Server 2005 SELECT th.ProductID, th.TransactionID, th.TransactionDate FROM Production.TransactionHistory AS th WHERE th.ProductID = 1 AND th.TransactionDate BETWEEN '20030901' AND '20031231'; The query plan on SQL Server 2005 is as follows (if you are using a more recent version of AdventureWorks, you will need to change the year on the date range from 2003 to 2007): There is an Index Seek on ProductID = 1, followed by a Key Lookup to find the Transaction Date for each row, and finally a Filter to restrict the results to only those rows where Transaction Date falls in the range specified.  The cardinality estimate of 45 rows at the Index Seek is exactly correct.  The table is not very large, there are up-to-date statistics associated with the index, so this is as expected. The estimate for the Key Lookup is also exactly right.  Each lookup into the Clustered Index to find the Transaction Date is guaranteed to return exactly one row.  The plan shows that the Key Lookup is expected to be executed 45 times.  The estimate for the Inner Join output is also correct – 45 rows from the seek joining to one row each time, gives 45 rows as output. The Filter estimate is also very good: the optimizer estimates 16.9951 rows will match the specified range of transaction dates.  Eleven rows are produced by this query, but that small difference is quite normal and certainly nothing to worry about here.  All good so far. SQL Server 2008 onward The same query executed against an identical copy of AdventureWorks on SQL Server 2008 produces a different execution plan: The optimizer has pushed the Filter conditions seen in the 2005 plan down to the Key Lookup.  This is a good optimization – it makes sense to filter rows out as early as possible.  Unfortunately, it has made a bit of a mess of the cardinality estimates. The post-Filter estimate of 16.9951 rows seen in the 2005 plan has moved with the predicate on Transaction Date.  Instead of estimating one row, the plan now suggests that 16.9951 rows will be produced by each clustered index lookup – clearly not right!  This misinformation also confuses SQL Sentry Plan Explorer: Plan Explorer shows 765 rows expected from the Key Lookup (it multiplies a rounded estimate of 17 rows by 45 expected executions to give 765 rows total). Workarounds One workaround is to provide a covering non-clustered index (avoiding the lookup avoids the problem of course): CREATE INDEX nc1 ON Production.TransactionHistory (ProductID) INCLUDE (TransactionDate); With the Transaction Date filter applied as a residual predicate in the same operator as the seek, the estimate is again as expected: We could also force the use of the ultimate covering index (the clustered one): SELECT th.ProductID, th.TransactionID, th.TransactionDate FROM Production.TransactionHistory AS th WITH (INDEX(1)) WHERE th.ProductID = 1 AND th.TransactionDate BETWEEN '20030901' AND '20031231'; Summary Providing a covering non-clustered index for all possible queries is not always practical, and scanning the clustered index will rarely be optimal.  Nevertheless, these are the best workarounds we have today. In the meantime, watch out for poor cardinality estimates when a predicate is applied as part of a lookup. The worst thing is that the estimate after the lookup join in the 2008+ plans is wrong.  It’s not hopelessly wrong in this particular case (45 versus 16.9951 is not the end of the world) but it easily can be much worse, and there’s not much you can do about it.  Any decisions made by the optimizer after such a lookup could be based on very wrong information – which can only be bad news. If you think this situation should be improved, please vote for this Connect item. © 2012 Paul White – All Rights Reserved twitter: @SQL_Kiwi email: [email protected]

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  • BIOS flash XP, 1 long beep, 2 short beeps, over&over

    - by Paul
    BIOS issue on HP dv9233cl laptop, wiped drive of Vista, loaded XP, not all the drives loaded. Went to the HP website, downloaded all drivers for this laptop. Started loading them. Loaded WIN Flash HP Network System BIOS Window SP42187. After a minute a low resolution screen appeared stating "It is now safe to turn off the computer" I waited a minute and half. Turned it off. Let it set 10 seconds try to start and No screen images at all and a nasty loud long beep 2 short beeps, 2 seconds of silence and it happens over & over again. I have unplugged/removed battery, still same problem, Any sugg.... Thx.. Paul

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  • LTO 3 tape drive needing repaired

    - by DO it all Paul
    We have an IBM LTO 3 tape drive that needs repaired and with the £400 price tag i'm having to shop around for quotes. My question is has anyone actually repaired one before and how was in done? The first error LED was showing a 6, then i cleared the mangled tape only for it to start flashing alternate 'o' on the 7 segment display, simliar to a half 8, flashing top to bottom and it would just flash away like that coupled with a flashing amber light. I tried a reset holding the eject button for it to show an 'r' the go back to flashing again as before. I checked the IBM solutions for the codes but this flashing isn't documented at all. Would be great if anyone had any experience in this area. Thank you, Paul

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