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  • Musings on the launch of SQL Monitor

    - by Phil Factor
    For several years, I was responsible for the smooth running of a large number of enterprise database servers. We ran a network monitoring tool that was primitive by today’s standards but which performed the useful function of polling every system, including all the Servers in my charge. It ran a configurable script for each service that you needed to monitor that was merely required to return one of a number of integer values. These integer values represented the pain level of the service, from 10 (“hurtin’ real bad”) to 1 (“Things is great”). Not only could you program the visual appearance of each server on the network diagram according to the value of the integer, but you could even opt to run a sound file. Very soon, we had a large TFT Screen, high on the wall of the server room, with every server represented by an icon, and a speaker next to it that would give out a series of grunts, groans, snores, shrieks and funeral marches, depending on the problem. One glance at the display, and you could dive in with iSQL/QA/SSMS and check what was going on with your favourite diagnostic tools. If you saw a server icon burst into flames on the screen or droop like a jelly, you dropped your mug of coffee to do it.  It was real fun, but I remember it more for the huge difference it made to have that real-time visibility into how your servers are performing. The management soon stopped making jokes about the real reason we wanted the TFT screen. (It rendered DVDs beautifully they said; particularly flesh-tints). If you are instantly alerted when things start to go wrong, then there was a good chance you could fix it before being alerted to the problem by the users of the system.  There is a world of difference between this sort of tool, one that gives whoever is ‘on watch’ in the server room the first warning of a potential problem on one of any number of servers, and the breed of tool that attempts to provide some sort of prosthetic DBA Brain. I like to get the early warning, to get the right information to help to diagnose a problem: No auto-fix, but just the information. I prefer to leave the task of ascertaining the exact cause of a problem to my own routines, custom code, intuition and forensic instincts. A simulated aircraft cockpit doesn’t do anything for me, especially before I know where I should be flying.  Time has moved on, and that TFT screen is now, with SQL Monitor, an iPad or any other mobile or static device that can support a browser. Rather than trying to reproduce the conceptual topology of the servers, it lists them in their groups so as to give a display that scales with the increasing number of databases you monitor.  It gives the history of the major events and trends for the servers. It gives the icons and colours that you can spot out of the corner of your eye, but goes on to give you just enough information in drill-down to give you a much clearer idea of where to look with your DBA tools and routines. It doesn't swamp you with information.  Whereas a few server and database-level problems are pretty easily fixed, others depend on judgement and experience to sort out.  Although the idea of an application that automates the bulk of a DBA’s skills is attractive to many, I can’t see it happening soon. SQL Server’s complexity increases faster than the panaceas can be created. In the meantime, I believe that the best way of helping  DBAs  is to make the monitoring process as simple and effective as possible,  and provide the right sort of detail and ‘evidence’ to allow them to decide on the fix. In the end, it is still down to the skill of the DBA.

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  • Cacti: "An internal Net-Snmp error condition detected in Cacti snmp_count"

    - by Recc
    There's the odd forum topic about an error similarly obscure as this, but I haven't seen any for snmp_count in particular. Also I don't see graphing problems, though I can't simply go and eyeball all graphs. However the poller does time out and has to be stopped by its internal process preventing overruns. If I filter out the flood of this error in the log I dont get anything else except the poller timeout: 06/12/2014 12:48:00 PM - POLLER: Poller[0] Maximum runtime of 58 seconds exceeded. Exiting. 06/12/2014 12:48:00 PM - SYSTEM STATS: Time:58.8566 Method:spine Processes:1 Threads:40 Hosts:1923 HostsPerProcess:1923 DataSources:61584 RRDsProcessed:0 06/12/2014 12:48:00 PM - SPINE: Poller[0] ERROR: Spine Timed Out While Processing Hosts Internal I saw in the running processes /usr/local/spine/spine 0 2053 that's always left behind. When I kill it the flooding of the error stops. Of course it's the same on the next poll run as it goes through the devices. 2053 is apparently the DB ID for a device. I deleted it completely to see if that stops it. It doesn't, instead 2052 is seen there. I suspect It'll be the same if I keep deleting devices which I will not do. This started happening midday when I wasn't doing anything to the cacti server. I have tried reducing Maximum Threads per Process to 1 and Number of PHP Script Servers to 1. I've been running it at 10 script servers / 40 threads for months with poll cycle time of about 20 sec. I just found out Running snmpwalk on any host would begin returning the values but then timeout halfway through. This doesn't happen from different servers on the network this Cacti is suggesting still that it's a problem with it locally. Any suggestions? For one polling cycle I changed to use cmd.php instead. then I started getting errors like CMDPHP: Poller[0] Host[45] DS[541] WARNING: Result from SNMP not valid. Partial Result: U Perhaps as expected. Looking closely I see that every snmpwalk I do is interrupted at the same place as if some byte limit is hit and the connection torn down.

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  • TPROXY Not working with HAProxy, Ubuntu 14.04

    - by Nyxynyx
    I'm trying to use HAProxy as a fully transparent proxy using TPROXY in Ubuntu 14.04. HAProxy will be setup on the first server with eth1 111.111.250.250 and eth0 10.111.128.134. The single balanced server has eth1 and eth0 as well. eth1 is the public facing network interface while eth0 is for the private network which both servers are in. Problem: I'm able to connect to the balanced server's port 1234 directly (via eth1) but am not able to reach the balanced server via Haproxy port 1234 (which redirects to 1234 via eth0). Am I missing out something in this configuration? On the HAProxy server The current kernel is: Linux extremehash-lb2 3.13.0-24-generic #46-Ubuntu SMP Thu Apr 10 19:11:08 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux The kernel appears to have TPROXY support: # grep TPROXY /boot/config-3.13.0-24-generic CONFIG_NETFILTER_XT_TARGET_TPROXY=m HAProxy was compiled with TPROXY support: haproxy -vv HA-Proxy version 1.5.3 2014/07/25 Copyright 2000-2014 Willy Tarreau <[email protected]> Build options : TARGET = linux26 CPU = x86_64 CC = gcc CFLAGS = -g -fno-strict-aliasing OPTIONS = USE_LINUX_TPROXY=1 USE_LIBCRYPT=1 USE_STATIC_PCRE=1 Default settings : maxconn = 2000, bufsize = 16384, maxrewrite = 8192, maxpollevents = 200 Encrypted password support via crypt(3): yes Built without zlib support (USE_ZLIB not set) Compression algorithms supported : identity Built without OpenSSL support (USE_OPENSSL not set) Built with PCRE version : 8.31 2012-07-06 PCRE library supports JIT : no (USE_PCRE_JIT not set) Built with transparent proxy support using: IP_TRANSPARENT IPV6_TRANSPARENT IP_FREEBIND Available polling systems : epoll : pref=300, test result OK poll : pref=200, test result OK select : pref=150, test result OK Total: 3 (3 usable), will use epoll. In /etc/haproxy/haproxy.cfg, I've configured a port to have the following options: listen test1235 :1234 mode tcp option tcplog balance leastconn source 0.0.0.0 usesrc clientip server balanced1 10.111.163.76:1234 check inter 5s rise 2 fall 4 weight 4 On the balanced server In /etc/networking/interfaces I've set the gateway for eth0 to be the HAProxy box 10.111.128.134 and restarted networking. auto eth0 eth1 iface eth0 inet static address 111.111.250.250 netmask 255.255.224.0 gateway 111.131.224.1 dns-nameservers 8.8.4.4 8.8.8.8 209.244.0.3 iface eth1 inet static address 10.111.163.76 netmask 255.255.0.0 gateway 10.111.128.134 ip route gives: default via 111.111.224.1 dev eth0 10.111.0.0/16 dev eth1 proto kernel scope link src 10.111.163.76 111.111.224.0/19 dev eth0 proto kernel scope link src 111.111.250.250

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  • Snmpd update interface counters slowly or something like this

    - by Korjavin Ivan
    I update one my freebsd box to 9-stable (totally new installation) and install net-snmp for monitoring. uname -r 9.1-PRERELEASE pkg_info net-snmp-5.7.1_7 Information for net-snmp-5.7.1_7: Comment: An extendable SNMP implementation .... cat /var/db/ports/net-snmp/options # This file is auto-generated by 'make config'. # Options for net-snmp-5.7.1_7 _OPTIONS_READ=net-snmp-5.7.1_7 _FILE_COMPLETE_OPTIONS_LIST= IPV6 MFD_REWRITES PERL PERL_EMBEDDED PYTHON DUMMY TKMIB DMALLOC MYSQL AX_SOCKONLY UNPRIVILEGED OPTIONS_FILE_UNSET+=IPV6 OPTIONS_FILE_UNSET+=MFD_REWRITES OPTIONS_FILE_SET+=PERL OPTIONS_FILE_SET+=PERL_EMBEDDED OPTIONS_FILE_UNSET+=PYTHON OPTIONS_FILE_SET+=DUMMY OPTIONS_FILE_UNSET+=TKMIB OPTIONS_FILE_SET+=DMALLOC OPTIONS_FILE_UNSET+=MYSQL OPTIONS_FILE_UNSET+=AX_SOCKONLY OPTIONS_FILE_UNSET+=UNPRIVILEGED I have about 500 vlan on this machine, and collect info about interface through snmpd to 2 different software, zabbix and cacti. And both of them plot the graphs with blank fields. I tryed change polling time in zabbix, from 15, sec to 30,60,90,120,10. And anyway i have blank fields. snmpd.conf is empty - only a access controls. This configuration worked fine on freebsd 8. Where is my fault? How fix this graphs? UPD: Changing pooling time, switch off one of agent, doesnt help. I look at zabbix log (recieved data from snmpd) and see that: sorry for russian locale, just look at numbers: and thats is not true, as my "iftop" show speed was about 90Mbits, but snmpd return 2Mbits. I understand that snmpd doesnt return speed, it return just a counter. But how its possible? why 2Mbit/s ? I tryed recompile snmpd with 64-bit counters, and without it. In both variants this blank fields present. So i think its my OS (freebsd) doesnt update interface counters well. I still collect tcpdump for found this request/response. But have problem with that, to much trash. UPD2: I decrypt tcpdump-ed file, and public this as google doc at gdocfile Timediff looks strange.. Like zabbix sometimes "forget" do request, and then do twice at row, ehh UPD3: I parse log from command "while true; do netstat -bin -I vlan4008 /var/log/netstat; sleep 300; done" and load as google docs, and add formula for speed : link Looks like all counters in OS are good. Now i think problem in : 1. zabbix get request twice at row (and what about cacti) 2. snmpd use counter32

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  • 64-bit linux kernel only seeing 3 of 4GB after upgrade...

    - by Blaine
    Hey everyone. I am running Ubuntu 9.04 64-bit on my macbook. I had 2GB of ram before, and everything ran great. I just upgraded to 2x2GB (4GB), but my system only sees 3GB of it. OS X, which I am dual booting, sees all 4GB. Also, my video performance is incredibly lacking. Before the upgrade my compiz benchmark was full at 80fps, and now it is at 22fps with very choppy window dragging. Has anyone ever heard of this on a 64-bit kernel? I just don't quite understand what could be the issue. 10$ uname -a Linux macbook 2.6.28-15-generic #49-Ubuntu SMP Tue Aug 18 19:25:34 UTC 2009 x86_64 GNU/Linux $ free -m total used free shared buffers cached Mem: 2953 1031 1921 0 114 427 -/+ buffers/cache: 489 2463 Swap: 7812 0 7812 9$ lsmod Module Size Used by i915 77960 2 drm 123232 3 i915 binfmt_misc 18572 1 ppdev 16904 0 btusb 21784 2 bridge 63776 0 stp 11140 1 bridge bnep 22912 2 vboxnetadp 109356 0 vboxnetflt 116972 0 vboxdrv 1721612 1 vboxnetflt uvcvideo 69640 0 compat_ioctl32 18304 1 uvcvideo videodev 45184 2 uvcvideo,compat_ioctl32 v4l1_compat 23940 2 uvcvideo,videodev lp 19588 0 parport 49584 2 ppdev,lp snd_hda_intel 557492 3 snd_pcm_oss 52352 0 snd_mixer_oss 24960 1 snd_pcm_oss snd_pcm 99464 2 snd_hda_intel,snd_pcm_oss arc4 10240 2 snd_seq_dummy 11524 0 ecb 11392 2 snd_seq_oss 41984 0 snd_seq_midi 15744 0 snd_rawmidi 33920 1 snd_seq_midi snd_seq_midi_event 16512 2 snd_seq_oss,snd_seq_midi snd_seq 66272 6 snd_seq_dummy,snd_seq_oss,snd_seq_midi,snd_seq_midi_event ath9k 310584 0 snd_timer 34064 2 snd_pcm,snd_seq snd_seq_device 16276 5 snd_seq_dummy,snd_seq_oss,snd_seq_midi,snd_rawmidi,snd_seq mac80211 251528 1 ath9k iTCO_wdt 21712 0 iTCO_vendor_support 12420 1 iTCO_wdt joydev 20992 0 video 29204 0 snd 78920 15 snd_hda_intel,snd_pcm_oss,snd_mixer_oss,snd_pcm,snd_seq_oss,snd_rawmidi,snd_seq,snd_timer,snd_seq_device applesmc 37700 0 output 11648 1 video soundcore 16800 1 snd pcspkr 11136 0 cfg80211 43680 1 mac80211 appletouch 19972 0 isight_firmware 11520 0 input_polldev 12688 1 applesmc intel_agp 39408 1 snd_page_alloc 18704 2 snd_hda_intel,snd_pcm led_class 13064 2 ath9k,applesmc hid_apple 15872 0 usbhid 47040 0 ohci1394 42164 0 ieee1394 108288 1 ohci1394 sky2 63364 0 fbcon 49792 0 tileblit 11264 1 fbcon font 17024 1 fbcon bitblit 14464 1 fbcon softcursor 10368 1 bitblit Some information from dmesg: [ 795.820163] ACPI: EC: GPE storm detected, transactions will use polling mode [ 1762.709516] [drm:i915_getparam] *ERROR* Unknown parameter 6 [ 1763.078130] [drm:i915_getparam] *ERROR* Unknown parameter 6 [ 2362.760889] [drm:i915_getparam] *ERROR* Unknown parameter 6 [ 2416.352084] ACPI: EC: missing confirmations, switch off interrupt mode. [ 3718.721095] [drm:i915_getparam] *ERROR* Unknown parameter 6 [ 3719.108914] [drm:i915_getparam] *ERROR* Unknown parameter 6 [ 4318.773266] [drm:i915_getparam] *ERROR* Unknown parameter 6 [ 9513.813066] CE: hpet increasing min_delta_ns to 15000 nsec [ 9693.815684] npviewer.bin[6736]

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  • Linux bonded Interfaces hanging periodically

    - by David
    I've several hosts that are showing problems with connectivity. When working from the command line, for example, typing is frozen for a second or so, then recovers - then it does it again. The most egregious example host would freeze (input) for 15-30 seconds, then recover and go out 5 seconds later. Switching cables didn't do anything - but removing one of the physical cables caused everything to clear up instantly (which why I think this is a network problem). Looking at the network I couldn't see any packets floating that would explain this. These ethernet interfaces (Gigabit Dell) were working normally previously, but since we moved the systems - and put them on a new set of switches - this has been a problem on multiple theoretically identically-configured hosts. The original switches were an HP Procurve 1810-24G and an HP Procurve 1800-24G connected with LLDP; the new switches are both Cisco SG 200-26, which I understand are rebranded Linksys switches. Is this caused by a problem with the switches? Is it the switch configurations? Are the Cisco switches incapable of handling this? I don't see where the configuration is located; I searched the usual /etc/sysconfig/network/devices but there's nothing in there about options (like mii polling) and nothing about the method of balancing the two. Searching scripts, I can't find anything in /etc/init.d/network either. The hosts are almost all Red Hat Enterprise Linux 5.x systems (5.6, 5.7) but some are Ubuntu Server 10.04.3 Lucid Lynx. I need help with both if it comes to that. UPDATE: We're also seeing some problems with servers on the original switches. The HP switches and the Cisco switches are also interconnected (temporarily); there is a cable run from one switch to the next. Pings on any of these hosts show about one ICMP packet out of every 5-6 getting dropped (timed out). Could there be an interaction between the two switches? Oh, and the hosts are using bonding with Balance-RR as the method.

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  • bluetooth connection using pybluez

    - by srj0408
    I am working on bluetooth not exactly on bluetooth stack-development but to use bluetooth in one of my project. I had done all that before using some of the py-bluez commands like hciconfig, hcitool scan , then simple-agents and using serial module inside python. But that was quite random. We were able to connect only one specific device based on its bluetooth address and there was no facility of reconnection once the devices are disconnected. Now i want to try out this stuff in a sequential manner like this (i am doing that all on a RPI and for at present on ubuntu 12.04.) i) Store some names in a file along with some other information with respect to that device. ii) Run a script to find out the device in locality with those names and if any one if found, report that. For this step, i had taken a reference from BTBook , made available from MIT. Below is the script for the same, but that script only search for the single name. from bluetooth import * target_name = "XT1033" target_address = None nearby_devices = discover_devices() for address in nearby_devices: if target_name == lookup_name( address ): target_address = address break if target_address is not None: print "found target bluetooth device with address ", target_address connect_socket(target_address); else: print "could not find target bluetooth device nearby" iii) Connect the device using client sock. But i dont have any device on which i can write a simple python script. My client can be any device that will be publishing data. Now i came through a script in the same book, that actually connect to a client requesting permission to connect to server. from bluetooth import * port = 1 server_sock=BluetoothSocket( RFCOMM ) server_sock.bind(("",port)) server_sock.listen(1) client_sock, client_info = server_sock.accept() print "Accepted connection from ", client_info data = client_sock.recv(1024) print "received [%s]" % data client_sock.close() server_sock.close() here client_sock, client_info = server_sock.accept() provide the client address and port requested to be connected. Can i pass address obtained from the earlier script to this, so that it connect server to the client? iv) Then if client get disconnected, re-connect(a simple polling can be used.) All this stuff can be done using bash and py-bluez functions but i want to do that in a sequential manner.I am not a master in python but i can do some small stuff. Can any one guide me for the same or can direct me to more usefull resource through which i can continue my coding part after finding the "X", "Y" named devices.

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  • Adopt-a-JSR for Java EE 7 - Getting Started

    - by arungupta
    Adopt-a-JSR is an initiative started by JUG leaders to encourage JUG members to get involved in a JSR, in order to increase grass roots participation. This allows JUG members to provide early feedback to specifications before they are finalized in the JCP. The standards in turn become more complete and developer-friendly after getting feedback from a wide variety of audience. adoptajsr.org provide more details about the logistics and benefits for you and your JUG. A similar activity was conducted for OpenJDK as well. Markus Eisele also provide a great introduction to the program (in German). Java EE 7 (JSR 342) is scheduled to go final in Q2 2013. There are several new JSRs that are getting included in the platform (e.g. WebSocket, JSON, and Batch), a few existing ones are getting an overhaul (e.g. JAX-RS 2 and JMS 2), and several other getting minor updates (e.g. JPA 2.1 and Servlets 3.1). Each Java EE 7 JSR can leverage your expertise and would love your JUG to adopt a JSR. What does it mean to adopt a JSR ? Your JUG is going to identify a particular JSR, or multiple JSRs, that is of interest to the JUG members. This is mostly done by polling/discussing on your local JUG members list. Your JUG will download and review the specification(s) and javadocs for clarity and completeness. The complete set of Java EE 7 specifications, their download links, and EG archives are listed here. glassfish.org/adoptajsr provide specific areas where different specification leads are looking for feedback. Your JUG can then think of a sample application that can be built using the chosen specification(s). An existing use case (from work or a personal hobby project) may be chosen to be implemented instead. This is where your creativity and uniqueness comes into play. Most of the implementations are already integrated in GlassFish 4 and others will be integrated soon. You can also explore integration of multiple technologies and provide feedback on the simplicity and ease-of-use of the programming model. Especially look for integration with existing Java EE technologies and see if you find any discrepancies. Report any missing features that may be included in future release of the specification. The most important part is to provide feedback by filing bugs on the corresponding spec or RI project. Any thing that is not clear either in the spec or implementation should be filed as a bug. This is what will ensure that specification and implementation leads are getting the required feedback and improving the quality of the final deliverable of the JSR. How do I get started ? A simple way to get started can be achieved by following S.M.A.R.T. as explained below. Specific Identify who all will be involved ? What would you like to accomplish ? For example, even though building a sample app will provide real-world validity of the API but because of time constraints you may identify that reviewing the specification and javadocs only can be accomplished. Establish a time frame by which the activities need to be complete. Measurable Define a success for metrics. For example, this could be the number of bugs filed. Remember, quality of bugs is more important that quantity of bugs. Define your end goal, for example, reviewing 4 chapters of the specification or completing the sample application. Create a dashboard that will highlight your JUG's contribution to this effort. Attainable Make sure JUG members understand the time commitment required for providing feedback. This can vary based upon the level of involvement (any is good!) and the number of specifications picked. adoptajsr.org defines different categories of involvement. Once again, any level of involvement is good. Just reviewing a chapter, a section, or javadocs for your usecase is helpful. Relevant Pick JSRs that JUG members are willing and able to work. If the JUG members are not interested then they might loose motivation half-way through. The "able" part is tricky as you can always stretch yourself and learn a new skill ;-) Time-bound Define a time table of activities with clearly defined tasks. A tentative time table may look like: Dec 25: Discuss and agree upon the specifications with JUG Jan 1: Start Adopt-a-JSR for Java EE 7 Jan 15: Initial spec reading complete. Keep thinking through the application that will be implemented. Jan 22: Early design of the sample application is ready Jan 29: JUG members agree upon the application Next 4 weeks: Implement the application Of course, you'll need to alter this based upon your commitment. Maintaining an activity dashboard will help you monitor and track the progress. Make sure to keep filing bugs through out the process! 12 JUGs from around the world (SouJava, Campinas JUG, Chennai JUG, London Java Community, BeJUG, Morocco JUG, Peru JUG, Indonesia JUG, Congo JUG, Silicon Valley JUG, Madrid JUG, and Houston JUG) have already adopted one of the Java EE 7 JSRs. I'm already helping some JUGs bootstrap and would love to help your JUG too. What are you waiting for ?

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  • Computer Networks UNISA - Chap 15 &ndash; Network Management

    - by MarkPearl
    After reading this section you should be able to Understand network management and the importance of documentation, baseline measurements, policies, and regulations to assess and maintain a network’s health. Manage a network’s performance using SNMP-based network management software, system and event logs, and traffic-shaping techniques Identify the reasons for and elements of an asset managements system Plan and follow regular hardware and software maintenance routines Fundamentals of Network Management Network management refers to the assessment, monitoring, and maintenance of all aspects of a network including checking for hardware faults, ensuring high QoS, maintaining records of network assets, etc. Scope of network management differs depending on the size and requirements of the network. All sub topics of network management share the goals of enhancing the efficiency and performance while preventing costly downtime or loss. Documentation The way documentation is stored may vary, but to adequately manage a network one should at least record the following… Physical topology (types of LAN and WAN topologies – ring, star, hybrid) Access method (does it use Ethernet 802.3, token ring, etc.) Protocols Devices (Switches, routers, etc) Operating Systems Applications Configurations (What version of operating system and config files for serve / client software) Baseline Measurements A baseline is a report of the network’s current state of operation. Baseline measurements might include the utilization rate for your network backbone, number of users logged on per day, etc. Baseline measurements allow you to compare future performance increases or decreases caused by network changes or events with past network performance. Obtaining baseline measurements is the only way to know for certain whether a pattern of usage has changed, or whether a network upgrade has made a difference. There are various tools available for measuring baseline performance on a network. Policies, Procedures, and Regulations Following rules helps limit chaos, confusion, and possibly downtime. The following policies and procedures and regulations make for sound network management. Media installations and management (includes designing physical layout of cable, etc.) Network addressing policies (includes choosing and applying a an addressing scheme) Resource sharing and naming conventions (includes rules for logon ID’s) Security related policies Troubleshooting procedures Backup and disaster recovery procedures In addition to internal policies, a network manager must consider external regulatory rules. Fault and Performance Management After documenting every aspect of your network and following policies and best practices, you are ready to asses you networks status on an on going basis. This process includes both performance management and fault management. Network Management Software To accomplish both fault and performance management, organizations often use enterprise-wide network management software. There various software packages that do this, each collect data from multiple networked devices at regular intervals, in a process called polling. Each managed device runs a network management agent. So as not to affect the performance of a device while collecting information, agents do not demand significant processing resources. The definition of a managed devices and their data are collected in a MIB (Management Information Base). Agents communicate information about managed devices via any of several application layer protocols. On modern networks most agents use SNMP which is part of the TCP/IP suite and typically runs over UDP on port 161. Because of the flexibility and sophisticated network management applications are a challenge to configure and fine-tune. One needs to be careful to only collect relevant information and not cause performance issues (i.e. pinging a device every 5 seconds can be a problem with thousands of devices). MRTG (Multi Router Traffic Grapher) is a simple command line utility that uses SNMP to poll devices and collects data in a log file. MRTG can be used with Windows, UNIX and Linux. System and Event Logs Virtually every condition recognized by an operating system can be recorded. This is typically done using event logs. In Windows there is a GUI event log viewer. Similar information is recorded in UNIX and Linux in a system log. Much of the information collected in event logs and syslog files does not point to a problem, even if it is marked with a warning so it is important to filter your logs appropriately to reduce the noise. Traffic Shaping When a network must handle high volumes of network traffic, users benefit from performance management technique called traffic shaping. Traffic shaping involves manipulating certain characteristics of packets, data streams, or connections to manage the type and amount of traffic traversing a network or interface at any moment. Its goals are to assure timely delivery of the most important traffic while offering the best possible performance for all users. Several types of traffic prioritization exist including prioritizing traffic according to any of the following characteristics… Protocol IP address User group DiffServr VLAN tag in a Data Link layer frame Service or application Caching In addition to traffic shaping, a network or host might use caching to improve performance. Caching is the local storage of frequently needed files that would otherwise be obtained from an external source. By keeping files close to the requester, caching allows the user to access those files quickly. The most common type of caching is Web caching, in which Web pages are stored locally. To an ISP, caching is much more than just convenience. It prevents a significant volume of WAN traffic, thus improving performance and saving money. Asset Management Another key component in managing networks is identifying and tracking its hardware. This is called asset management. The first step to asset management is to take an inventory of each node on the network. You will also want to keep records of every piece of software purchased by your organization. Asset management simplifies maintaining and upgrading the network chiefly because you know what the system includes. In addition, asset management provides network administrators with information about the costs and benefits of certain types of hardware or software. Change Management Networks are always in a stage of flux with various aspects including… Software changes and patches Client Upgrades Shared Application Upgrades NOS Upgrades Hardware and Physical Plant Changes Cabling Upgrades Backbone Upgrades For a detailed explanation on each of these read the textbook (Page 750 – 761)

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  • Cloud to On-Premise Connectivity Patterns

    - by Rajesh Raheja
    Do you have a requirement to convert an Opportunity in Salesforce.com to an Order/Quote in Oracle E-Business Suite? Or maybe you want the creation of an Oracle RightNow Incident to trigger an on-premise Oracle E-Business Suite Service Request creation for RMA and Field Scheduling? If so, read on. In a previous blog post, I discussed integrating TO cloud applications, however the use cases above are the reverse i.e. receiving data FROM cloud applications (SaaS) TO on-premise applications/databases that sit behind a firewall. Oracle SOA Suite is assumed to be on-premise with with Oracle Service Bus as the mediation and virtualization layer. The main considerations for the patterns are are security i.e. shielding enterprise resources; and scalability i.e. minimizing firewall latency. Let me use an analogy to help visualize the patterns: the on-premise system is your home - with your most valuable possessions - and the SaaS app is your favorite on-line store which regularly ships (inbound calls) various types of parcels/items (message types/service operations). You need the items at home (on-premise) but want to safe guard against misguided elements of society (internet threats) who may masquerade as postal workers and vandalize property (denial of service?). Let's look at the patterns. Pattern: Pull from Cloud The on-premise system polls from the SaaS apps and picks up the message instead of having it delivered. This may be done using Oracle RightNow Object Query Language or SOAP APIs. This is particularly suited for certain integration approaches wherein messages are trickling in, can be centralized and batched e.g. retrieving event notifications on an hourly schedule from the Oracle Messaging Service. To compare this pattern with the home analogy, you are avoiding any deliveries to your home and instead go to the post office/UPS/Fedex store to pick up your parcel. Every time. Pros: On-premise assets not exposed to the Internet, firewall issues avoided by only initiating outbound connections Cons: Polling mechanisms may affect performance, may not satisfy near real-time requirements Pattern: Open Firewall Ports The on-premise system exposes the web services that needs to be invoked by the cloud application. This requires opening up firewall ports, routing calls to the appropriate internal services behind the firewall. Fusion Applications uses this pattern, and auto-provisions the services on the various virtual hosts to secure the topology. This works well for service integration, but may not suffice for large volume data integration. Using the home analogy, you have now decided to receive parcels instead of going to the post office every time. A door mail slot cut out allows the postman can drop small parcels, but there is still concern about cutting new holes for larger packages. Pros: optimal pattern for near real-time needs, simpler administration once the service is provisioned Cons: Needs firewall ports to be opened up for new services, may not suffice for batch integration requiring direct database access Pattern: Virtual Private Networking The on-premise network is "extended" to the cloud (or an intermediary on-demand / managed service offering) using Virtual Private Networking (VPN) so that messages are delivered to the on-premise system in a trusted channel. Using the home analogy, you entrust a set of keys with a neighbor or property manager who receives the packages, and then drops it inside your home. Pros: Individual firewall ports don't need to be opened, more suited for high scalability needs, can support large volume data integration, easier management of one connection vs a multitude of open ports Cons: VPN setup, specific hardware support, requires cloud provider to support virtual private computing Pattern: Reverse Proxy / API Gateway The on-premise system uses a reverse proxy "API gateway" software on the DMZ to receive messages. The reverse proxy can be implemented using various mechanisms e.g. Oracle API Gateway provides firewall and proxy services along with comprehensive security, auditing, throttling benefits. If a firewall already exists, then Oracle Service Bus or Oracle HTTP Server virtual hosts can provide reverse proxy implementations on the DMZ. Custom built implementations are also possible if specific functionality (such as message store-n-forward) is needed. In the home analogy, this pattern sits in between cutting mail slots and handing over keys. Instead, you install (and maintain) a mailbox in your home premises outside your door. The post office delivers the parcels in your mailbox, from where you can securely retrieve it. Pros: Very secure, very flexible Cons: Introduces a new software component, needs DMZ deployment and management Pattern: On-Premise Agent (Tunneling) A light weight "agent" software sits behind the firewall and initiates the communication with the cloud, thereby avoiding firewall issues. It then maintains a bi-directional connection either with pull or push based approaches using (or abusing, depending on your viewpoint) the HTTP protocol. Programming protocols such as Comet, WebSockets, HTTP CONNECT, HTTP SSH Tunneling etc. are possible implementation options. In the home analogy, a resident receives the parcel from the postal worker by opening the door, however you still take precautions with chain locks and package inspections. Pros: Light weight software, IT doesn't need to setup anything Cons: May bypass critical firewall checks e.g. virus scans, separate software download, proliferation of non-IT managed software Conclusion The patterns above are some of the most commonly encountered ones for cloud to on-premise integration. Selecting the right pattern for your project involves looking at your scalability needs, security restrictions, sync vs asynchronous implementation, near real-time vs batch expectations, cloud provider capabilities, budget, and more. In some cases, the basic "Pull from Cloud" may be acceptable, whereas in others, an extensive VPN topology may be well justified. For more details on the Oracle cloud integration strategy, download this white paper.

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  • Cloud to On-Premise Connectivity Patterns

    - by Rajesh Raheja
    Do you have a requirement to convert an Opportunity in Salesforce.com to an Order/Quote in Oracle E-Business Suite? Or maybe you want the creation of an Oracle RightNow Incident to trigger an on-premise Oracle E-Business Suite Service Request creation for RMA and Field Scheduling? If so, read on. In a previous blog post, I discussed integrating TO cloud applications, however the use cases above are the reverse i.e. receiving data FROM cloud applications (SaaS) TO on-premise applications/databases that sit behind a firewall. Oracle SOA Suite is assumed to be on-premise with with Oracle Service Bus as the mediation and virtualization layer. The main considerations for the patterns are are security i.e. shielding enterprise resources; and scalability i.e. minimizing firewall latency. Let me use an analogy to help visualize the patterns: the on-premise system is your home - with your most valuable possessions - and the SaaS app is your favorite on-line store which regularly ships (inbound calls) various types of parcels/items (message types/service operations). You need the items at home (on-premise) but want to safe guard against misguided elements of society (internet threats) who may masquerade as postal workers and vandalize property (denial of service?). Let's look at the patterns. Pattern: Pull from Cloud The on-premise system polls from the SaaS apps and picks up the message instead of having it delivered. This may be done using Oracle RightNow Object Query Language or SOAP APIs. This is particularly suited for certain integration approaches wherein messages are trickling in, can be centralized and batched e.g. retrieving event notifications on an hourly schedule from the Oracle Messaging Service. To compare this pattern with the home analogy, you are avoiding any deliveries to your home and instead go to the post office/UPS/Fedex store to pick up your parcel. Every time. Pros: On-premise assets not exposed to the Internet, firewall issues avoided by only initiating outbound connections Cons: Polling mechanisms may affect performance, may not satisfy near real-time requirements Pattern: Open Firewall Ports The on-premise system exposes the web services that needs to be invoked by the cloud application. This requires opening up firewall ports, routing calls to the appropriate internal services behind the firewall. Fusion Applications uses this pattern, and auto-provisions the services on the various virtual hosts to secure the topology. This works well for service integration, but may not suffice for large volume data integration. Using the home analogy, you have now decided to receive parcels instead of going to the post office every time. A door mail slot cut out allows the postman can drop small parcels, but there is still concern about cutting new holes for larger packages. Pros: optimal pattern for near real-time needs, simpler administration once the service is provisioned Cons: Needs firewall ports to be opened up for new services, may not suffice for batch integration requiring direct database access Pattern: Virtual Private Networking The on-premise network is "extended" to the cloud (or an intermediary on-demand / managed service offering) using Virtual Private Networking (VPN) so that messages are delivered to the on-premise system in a trusted channel. Using the home analogy, you entrust a set of keys with a neighbor or property manager who receives the packages, and then drops it inside your home. Pros: Individual firewall ports don't need to be opened, more suited for high scalability needs, can support large volume data integration, easier management of one connection vs a multitude of open ports Cons: VPN setup, specific hardware support, requires cloud provider to support virtual private computing Pattern: Reverse Proxy / API Gateway The on-premise system uses a reverse proxy "API gateway" software on the DMZ to receive messages. The reverse proxy can be implemented using various mechanisms e.g. Oracle API Gateway provides firewall and proxy services along with comprehensive security, auditing, throttling benefits. If a firewall already exists, then Oracle Service Bus or Oracle HTTP Server virtual hosts can provide reverse proxy implementations on the DMZ. Custom built implementations are also possible if specific functionality (such as message store-n-forward) is needed. In the home analogy, this pattern sits in between cutting mail slots and handing over keys. Instead, you install (and maintain) a mailbox in your home premises outside your door. The post office delivers the parcels in your mailbox, from where you can securely retrieve it. Pros: Very secure, very flexible Cons: Introduces a new software component, needs DMZ deployment and management Pattern: On-Premise Agent (Tunneling) A light weight "agent" software sits behind the firewall and initiates the communication with the cloud, thereby avoiding firewall issues. It then maintains a bi-directional connection either with pull or push based approaches using (or abusing, depending on your viewpoint) the HTTP protocol. Programming protocols such as Comet, WebSockets, HTTP CONNECT, HTTP SSH Tunneling etc. are possible implementation options. In the home analogy, a resident receives the parcel from the postal worker by opening the door, however you still take precautions with chain locks and package inspections. Pros: Light weight software, IT doesn't need to setup anything Cons: May bypass critical firewall checks e.g. virus scans, separate software download, proliferation of non-IT managed software Conclusion The patterns above are some of the most commonly encountered ones for cloud to on-premise integration. Selecting the right pattern for your project involves looking at your scalability needs, security restrictions, sync vs asynchronous implementation, near real-time vs batch expectations, cloud provider capabilities, budget, and more. In some cases, the basic "Pull from Cloud" may be acceptable, whereas in others, an extensive VPN topology may be well justified. For more details on the Oracle cloud integration strategy, download this white paper.

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  • Running a Java daemon with a GWT front-end served by embedded Jetty

    - by BinaryMuse
    Greetings, coders, Background Info and Code I am trying to create a daemon-type program (e.g., it runs constantly, polling for things to do) that is managed by a GWT application (servlets in a WAR) which is in turn served by an embedded Jetty server (using a WebAppContext). I'm having problems making the GWT application aware of the daemon object. For testing things, I currently have two projects: The daemon and embedded Jetty server in one (EmbJetTest), and the GWT application in another (DefaultApp). This is the current state of the code: First, EmbJetTest creates an embedded Jetty server like so, using a ServletContextListener to inject the daemon object into the web application context: EmbJetTest.server = new Server(8080); // Create and start the daemon Daemon daemon = new Daemon(); Thread thread = new Thread(daemon); thread.start(); // war handler WebAppContext waContext = new WebAppContext(); waContext.setContextPath("/webapp"); waContext.setWar("./apps/DefaultApp.war"); waContext.addEventListener(new DaemonLoader(daemon)); // Add it to the server EmbJetTest.server.setHandler(waContext); EmbJetTest.server.setThreadPool(new QueuedThreadPool(10)); // Start the server; join() blocks until we shut down EmbJetTest.server.start(); EmbJetTest.server.join(); // Stop the daemon thread daemon.stopLoop(); Daemon is a very simple object with a couple properties, at the moment. DaemonLoader is the following ServletContextListener implementation: private Daemon daemon; public DaemonLoader(Daemon daemon) { this.daemon = daemon; } @Override public void contextDestroyed(ServletContextEvent arg0) { } @Override public void contextInitialized(ServletContextEvent arg0) { arg0.getServletContext().setAttribute("daemon", this.daemon); } Then, in one of my servlets in the GWT application, I have the following code: Daemon daemon = (Daemon) this.getServletContext().getAttribute("daemon"); However, when I visit localhost:8080/webapp/* and invoke the servlet, this code throws a ClassCastException, even though the classes are of the same type. This StackOverflow answer indicates that this is because the two classes are loaded with different classloaders. Question My question is twofold. Am I even on the right track here? Am I going about this completely the wrong way? Something tells me I am, but I can't think of another way to make the daemon available to both applications. Is there a better way to communicate with the daemon from the GWT application? Should the GWT app own the daemon and somehow start the daemon itself? The daemon needs to run even if no one visits the one of the GWT app's servlets--how could I do this? If I am on the right track, how can I get around the classloader issue? Thanks in advance.

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  • ASP.NET MVC ajax chat

    - by nccsbim071
    I built an ajax chat in one of my mvc website. everything is working fine. I am using polling. At certain interval i am using $.post to get the messages from the db. But there is a problem. The message retrieved using $.post keeps on repeating. here is my javascript code and controller method. var t; function GetMessages() { var LastMsgRec = $("#hdnLastMsgRec").val(); var RoomId = $("#hdnRoomId").val(); //Get all the messages associated with this roomId $.post("/Chat/GetMessages", { roomId: RoomId, lastRecMsg: LastMsgRec }, function(Data) { if (Data.Messages.length != 0) { $("#messagesCont").append(Data.Messages); if (Data.newUser.length != 0) $("#usersUl").append(Data.newUser); $("#messagesCont").attr({ scrollTop: $("#messagesCont").attr("scrollHeight") - $('#messagesCont').height() }); $("#userListCont").attr({ scrollTop: $("#userListCont").attr("scrollHeight") - $('#userListCont').height() }); } else { } $("#hdnLastMsgRec").val(Data.LastMsgRec); }, "json"); t = setTimeout("GetMessages()", 3000); } and here is my controller method to get the data: public JsonResult GetMessages(int roomId,DateTime lastRecMsg) { StringBuilder messagesSb = new StringBuilder(); StringBuilder newUserSb = new StringBuilder(); List<Message> msgs = (dc.Messages).Where(m => m.RoomID == roomId && m.TimeStamp > lastRecMsg).ToList(); if (msgs.Count == 0) { return Json(new { Messages = "", LastMsgRec = System.DateTime.Now.ToString() }); } foreach (Message item in msgs) { messagesSb.Append(string.Format(messageTemplate,item.User.Username,item.Text)); if (item.Text == "Just logged in!") newUserSb.Append(string.Format(newUserTemplate,item.User.Username)); } return Json(new {Messages = messagesSb.ToString(),LastMsgRec = System.DateTime.Now.ToString(),newUser = newUserSb.ToString().Length == 0 ?"":newUserSb.ToString()}); } Everything is working absloutely perfect. But i some messages getting repeated. The first time page loads i am retrieving the data and call GetMessages() function. I am loading the value of field hdnLastMsgRec the first time page loads and after the value for this field are set by the javascript. I think the message keeps on repeating because of asynchronous calls. I don't know, may be you guys can help me solve this. or you can suggest better way to implement this.

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  • Problems related to showing MessageBox from non-GUI threads

    - by Hans Løken
    I'm working on a heavily data-bound Win.Forms application where I've found some strange behavior. The app has separate I/O threads receiving updates through asynchronous web-requests which it then sends to the main/GUI thread for processing and updating of application-wide data-stores (which in turn may be data-bound to various GUI-elements, etc.). The server at the other end of the web-requests requires periodic requests or the session times out. I've gone through several attempted solutions of dealing with thread-issues etc. and I've observed the following behavior: If I use Control.Invoke for sending updates from I/O-thread(s) to main-thread and this update causes a MessageBox to be shown the main form's message pump stops until the user clicks the ok-button. This also blocks the I/O-thread from continuing eventually leading to timeouts on the server. If I use Control.BeginInvoke for sending updates from I/O-thread(s) to main-thread the main form's message pump does not stop, but if the processing of an update leads to a messagebox being shown, the processing of the rest of that update is halted until the user clicks ok. Since the I/O-threads keep running and the message pump keeps processing messages several BeginInvoke's for updates may be called before the one with the message box is finished. This leads to out-of-sequence updates which is unacceptable. I/O-threads add updates to a blocking queue (very similar to http://stackoverflow.com/questions/530211/creating-a-blocking-queuet-in-net/530228#530228). GUI-thread uses a Forms.Timer that periodically applies all updates in the blocking queue. This solution solves both the problem of blocking I/O threads and sequentiality of updates i.e. next update will be never be started until previous is finished. However, there is a small performance cost as well as introducing a latency in showing updates that is unacceptable in the long run. I would like update-processing in the main-thread to be event-driven rather than polling. So to my question. How should I do this to: avoid blocking the I/O-threads guarantee that updates are finished in-sequence keep the main message pump running while showing a message box as a result of an update.

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  • HTTP request, strange socket behavoir

    - by hoodoos
    I expirience strange behavior when doing HTTP requests through sockets, here the request: POST https://test.com:443/service/XMLSelect HTTP/1.1 Content-Length: 10926 Host: test.com User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; .NET CLR 1.1.4322; .NET CLR 1.0.3705) Authorization: Basic XXX SOAPAction: http://test.com/SubmitXml Later on there goes body of my request with given content length. After that I recive something like: HTTP/1.1 200 OK Server: Apache-Coyote/1.1 Content-Type: text/xml;charset=utf-8 Transfer-Encoding: chunked Date: Tue, 30 Mar 2010 06:13:52 GMT So everything seem to be fine here. I read all contents from network stream and successfuly recieve response. But my socket which I'm doing polling on switches it's modes like that: write ( i write headers and request here ) read ( after headers sent i begin to recieve response ) write ( STRANGE BEHAVIOUR HERE. WHY? here i send nothing really ) read ( here it switches to read back again ) last two steps can repeat several times. So I want to ask what leads for socket's mode change? And in this case it's not a big problem, but when I use gzip compression in my request ( no idea how it's related ) and ask server to send gzipped response to me like this: POST https://test.com:443/service/XMLSelect HTTP/1.1 Content-Length: 1076 Accept-Encoding: gzip Content-Encoding: gzip Host: test.com User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; .NET CLR 1.1.4322; .NET CLR 1.0.3705) Authorization: Basic XXX SOAPAction: http://test.com/SubmitXml I recieve response like that: HTTP/1.1 200 OK Server: Apache-Coyote/1.1 Content-Encoding: gzip Content-Type: text/xml;charset=utf-8 Transfer-Encoding: chunked Date: Tue, 30 Mar 2010 07:26:33 GMT 2000 ? I recieve a chunk size and GZIP header, it's all okay. And here's what is happening with my poor little socket meanwhile: write ( i write headers and request here ) read ( after headers sent i begin to recieve response ) write ( STRANGE BEHAVIOUR HERE. And it finally sits here forever waiting for me to send something! But if i refer to HTTP I don't have to send anything more! ) What can it be related to? What it wants me to send? Is it remote web server's problem or do I miss something? PS All actual service references and login/passwords replaced with fake ones :)

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  • What Causes Boost Asio to Crash Like This?

    - by Scott Lawson
    My program appears to run just fine most of the time, but occasionally I get a segmentation fault. boost version = 1.41.0 running on RHEL 4 compiled with GCC 3.4.6 Backtrace: #0 0x08138546 in boost::asio::detail::posix_fd_set_adapter::is_set (this=0xb74ed020, descriptor=-1) at /home/scottl/boost_1_41_0/boost/asio/detail/posix_fd_set_adapter.hpp:57 __result = -1 'ÿ' #1 0x0813e1b0 in boost::asio::detail::reactor_op_queue::perform_operations_for_descriptors (this=0x97f3b6c, descriptors=@0xb74ed020, result=@0xb74ecec8) at /home/scottl/boost_1_41_0/boost/asio/detail/reactor_op_queue.hpp:204 op_iter = {_M_node = 0xb4169aa0} i = {_M_node = 0x97f3b74} #2 0x081382ca in boost::asio::detail::select_reactor::run (this=0x97f3b08, block=true) at /home/scottl/boost_1_41_0/boost/asio/detail/select_reactor.hpp:388 read_fds = {fd_set_ = {fds_bits = {16, 0 }}, max_descriptor_ = 65} write_fds = {fd_set_ = {fds_bits = {0 }}, max_descriptor_ = -1} retval = 1 lock = { = {}, mutex_ = @0x97f3b1c, locked_ = true} except_fds = {fd_set_ = {fds_bits = {0 }}, max_descriptor_ = -1} max_fd = 65 tv_buf = {tv_sec = 0, tv_usec = 710000} tv = (timeval *) 0xb74ecf88 ec = {m_val = 0, m_cat = 0x81f2c24} sb = { = {}, blocked_ = true, old_mask_ = {__val = {0, 0, 134590223, 3075395548, 3075395548, 3075395464, 134729792, 3075395360, 135890240, 3075395368, 134593920, 3075395544, 135890240, 3075395384, 134599542, 3020998404, 135890240, 3075395400, 134614095, 3075395544, 4, 3075395416, 134548135, 3021172996, 4294967295, 3075395432, 134692921, 3075395504, 0, 3075395448, 134548107, 3021172992}}} #3 0x0812eb45 in boost::asio::detail::task_io_service ::do_one (this=0x97f3a70, lock=@0xb74ed230, this_idle_thread=0xb74ed240, ec=@0xb74ed2c0) at /home/scottl/boost_1_41_0/boost/asio/detail/task_io_service.hpp:260 more_handlers = false c = {lock_ = @0xb74ed230, task_io_service_ = @0x97f3a70} h = (boost::asio::detail::handler_queue::handler *) 0x97f3aa0 polling = false task_has_run = true #4 0x0812765f in boost::asio::detail::task_io_service ::run (this=0x97f3a70, ec=@0xb74ed2c0) at /home/scottl/boost_1_41_0/boost/asio/detail/task_io_service.hpp:103 ctx = { = {}, owner_ = 0x97f3a70, next_ = 0x0} this_idle_thread = {wakeup_event = { = {}, cond_ = {__c_lock = { __status = 0, __spinlock = 22446}, __c_waiting = 0x2bd7, __padding = "\000\000\000\000×+\000\000\000\000\000\000×+\000\000\000\000\000\000\204:\177\t\000\000\000", __align = 0}, signalled_ = true}, next = 0x0} lock = { = {}, mutex_ = @0x97f3a84, locked_ = false} n = 11420 #5 0x08125e99 in boost::asio::io_service::run (this=0x97ebbcc) at /home/scottl/boost_1_41_0/boost/asio/impl/io_service.ipp:58 ec = {m_val = 0, m_cat = 0x81f2c24} s = 8 #6 0x08154424 in boost::_mfi::mf0::operator() (this=0x9800870, p=0x97ebbcc) at /home/scottl/boost_1_41_0/boost/bind/mem_fn_template.hpp:49 No locals. #7 0x08154331 in boost::_bi::list1 ::operator(), boost::_bi::list0 (this=0x9800878, f=@0x9800870, a=@0xb74ed337) at /home/scottl/boost_1_41_0/boost/bind/bind.hpp:236 No locals. #8 0x081541e5 in boost::_bi::bind_t, boost::_bi::list1 ::operator() (this=0x9800870) at /home/scottl/boost_1_41_0/boost/bind/bind_template.hpp:20 a = {} #9 0x08154075 in boost::detail::thread_data, boost::_bi::list1 ::run (this=0x98007a0) at /home/scottl/boost_1_41_0/boost/thread/detail/thread.hpp:56 No locals. #10 0x0816fefd in thread_proxy () at /usr/lib/gcc/i386-redhat-linux/3.4.6/../../../../include/c++/3.4.6/bits/locale_facets.tcc:2443 __ioinit = {static _S_refcount = , static _S_synced_with_stdio = } ---Type to continue, or q to quit--- typeinfo for common::RuntimeException = {} typeinfo name for common::RuntimeException = "N6common16RuntimeExceptionE" #11 0x00af23cc in start_thread () from /lib/tls/libpthread.so.0 No symbol table info available. #12 0x00a5c96e in __init_misc () from /lib/tls/libc.so.6 No symbol table info available.

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  • Loading external pngs into an AS2 swf that is loaded into an AS3 swf wrapper

    - by James Fassett
    I have a Wrapper SWF that loads a series of AS2 movies. Each AS2 movie loads a series of .png files. AS3_wrapper.swf |-> AS2_1.swf |-> image_1.png |-> image_2.png |-> AS2_2.swf |-> image_1.png |-> image_2.png Inside of the AS2 I listen for the load of the pngs using onLoadInit and update my UI. This works fine for the first AS2 swf. But when I load the second AS2 swf the onLoadInit isn't triggered for the pngs. My guess is that the images are in a cache or something like that. I put a random string on the end of the request to try and avoid the cache but that doesn't seem to work. The code in the as2 looks roughly like this: var flagLoader:MovieClipLoader = new MovieClipLoader(); var listener:Object = new Object(); listener.onLoadInit = Delegate.create(this, handleImageLoad); flagLoader.addListener(listener); var row:MovieClip = frame1["row" + (numLoaded + 1)]; flagLoader.loadClip(predictionData[numLoaded].flag + "?r="+Math.random(), row.flag); I'm making sure to load only one image at a time (I've read anecdotal evidence loading more than one thing at a time can confuse the MovieClipLoader). For the first as2 file everything works great. When I load the second as2 file the handleImageLoad never gets called. Update: Even more perplexing is if I reload the first AS2 movie (after the second AS2 movie fails to load the images) the first AS2 movie loads the images again fine. Update 2: After trying to change from using a MovieClipLoader to polling (as was helpfully suggested) I have found some more evidence that is relevant. When I load the first AS2 files and trace from the top level clip it prints out _root. The second AS2 file when loaded traces the same _root. This lead me to check if they were clashing on names and they are. Both have a child called frame. The first one, when I trace it comes out as _root.frame as expected. The second AS2 file traces _level0.instance3.instance118.instance111.frame. I'm guessing this is related to the problem. Flash is keeping the _root of the two files the same but it is changing the locations of their children (for subsequently loaded files that have children with the same names). So either the onLoad is going to the wrong clip or the events about it loading are.

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  • Java EE javax.xml.bind.MarshalException

    - by sandeep
    Hi, I am getting javax.xml.bind.MarshalException error. I am sending List from my webservice to the backingbean and I have this error. WARNING: invocation error on ejb endpoint Login_webservice at /Login_webserviceService/Login_webservice : javax.xml.bind.MarshalException - with linked exception: [javax.xml.bind.JAXBException: class JPA.Cantable nor any of its super class is known to this context.] javax.xml.ws.WebServiceException: javax.xml.bind.MarshalException - with linked exception: [javax.xml.bind.JAXBException: class JPA.Cantable nor any of its super class is known to this context.] at com.sun.xml.ws.message.jaxb.JAXBMessage.writePayloadTo(JAXBMessage.java:325) at com.sun.xml.ws.message.AbstractMessageImpl.writeTo(AbstractMessageImpl.java:142) at com.sun.xml.ws.encoding.StreamSOAPCodec.encode(StreamSOAPCodec.java:109) at com.sun.xml.ws.encoding.SOAPBindingCodec.encode(SOAPBindingCodec.java:278) at com.sun.xml.ws.transport.http.HttpAdapter.encodePacket(HttpAdapter.java:380) at com.sun.xml.ws.transport.http.HttpAdapter.access$100(HttpAdapter.java:92) at com.sun.xml.ws.transport.http.HttpAdapter$HttpToolkit.handle(HttpAdapter.java:525) at com.sun.xml.ws.transport.http.HttpAdapter.handle(HttpAdapter.java:285) at com.sun.xml.ws.transport.http.servlet.ServletAdapter.handle(ServletAdapter.java:143) at org.glassfish.webservices.Ejb3MessageDispatcher.handlePost(Ejb3MessageDispatcher.java:116) at org.glassfish.webservices.Ejb3MessageDispatcher.invoke(Ejb3MessageDispatcher.java:87) at org.glassfish.webservices.EjbWebServiceServlet.dispatchToEjbEndpoint(EjbWebServiceServlet.java:196) at org.glassfish.webservices.EjbWebServiceServlet.service(EjbWebServiceServlet.java:127) at javax.servlet.http.HttpServlet.service(HttpServlet.java:847) Here is my code: Backing bean @WebServiceRef(wsdlLocation = "http://localhost:26565/Login_webserviceService/Login_webservice?WSDL") public String login() { System.out.println("Login Phase entered"); int result = 0; List list; List finalList = null; try { Weblogin.LoginWebserviceService service = new Weblogin.LoginWebserviceService(); Weblogin.LoginWebservice port = service.getLoginWebservicePort(); result = port.login(voterID, password); Weblogin.LoginWebservice port1 = service.getLoginWebservicePort(); list = port1.candDetails(1); finalList = list; this.setList(finalList); } catch (Exception e) { e.printStackTrace(); } if (result == 1) return "polling"; else return "login"; } Webservice public List candDetails(int pollEvent) { List resultList = null; List finalList = null; try { if (pollEvent == 1) { resultList = em.createNamedQuery("Cantable.findAll").getResultList(); finalList = resultList; } } catch (Exception e) { e.printStackTrace(); } return resultList; }

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  • javaEE javax.xml.bind.MarshalException

    - by sandeep
    Hi, I am getting javax.xml.bind.MarshalException error. I am sending List from my webservice to the backingbean and I have this error. Here is my code: Errors WARNING: invocation error on ejb endpoint Login_webservice at /Login_webserviceService/Login_webservice : javax.xml.bind.MarshalException - with linked exception: [javax.xml.bind.JAXBException: class JPA.Cantable nor any of its super class is known to this context.] javax.xml.ws.WebServiceException: javax.xml.bind.MarshalException - with linked exception: [javax.xml.bind.JAXBException: class JPA.Cantable nor any of its super class is known to this context.] at com.sun.xml.ws.message.jaxb.JAXBMessage.writePayloadTo(JAXBMessage.java:325) at com.sun.xml.ws.message.AbstractMessageImpl.writeTo(AbstractMessageImpl.java:142) at com.sun.xml.ws.encoding.StreamSOAPCodec.encode(StreamSOAPCodec.java:109) at com.sun.xml.ws.encoding.SOAPBindingCodec.encode(SOAPBindingCodec.java:278) at com.sun.xml.ws.transport.http.HttpAdapter.encodePacket(HttpAdapter.java:380) at com.sun.xml.ws.transport.http.HttpAdapter.access$100(HttpAdapter.java:92) at com.sun.xml.ws.transport.http.HttpAdapter$HttpToolkit.handle(HttpAdapter.java:525) at com.sun.xml.ws.transport.http.HttpAdapter.handle(HttpAdapter.java:285) at com.sun.xml.ws.transport.http.servlet.ServletAdapter.handle(ServletAdapter.java:143) at org.glassfish.webservices.Ejb3MessageDispatcher.handlePost(Ejb3MessageDispatcher.java:116) at org.glassfish.webservices.Ejb3MessageDispatcher.invoke(Ejb3MessageDispatcher.java:87) at org.glassfish.webservices.EjbWebServiceServlet.dispatchToEjbEndpoint(EjbWebServiceServlet.java:196) at org.glassfish.webservices.EjbWebServiceServlet.service(EjbWebServiceServlet.java:127) at javax.servlet.http.HttpServlet.service(HttpServlet.java:847) Backing bean @WebServiceRef(wsdlLocation = "http://localhost:26565/Login_webserviceService/Login_webservice?WSDL") public String login() { System.out.println("Login Phase entered"); int result = 0; List list; List finalList = null; try { Weblogin.LoginWebserviceService service = new Weblogin.LoginWebserviceService(); Weblogin.LoginWebservice port = service.getLoginWebservicePort(); result = port.login(voterID, password); Weblogin.LoginWebservice port1 = service.getLoginWebservicePort(); list = port1.candDetails(1); finalList = list; this.setList(finalList); } catch (Exception e) { e.printStackTrace(); } if (result == 1) return "polling"; else return "login"; } Webservice public List candDetails(int pollEvent) { List resultList = null; List finalList = null; try { if (pollEvent == 1) { resultList = em.createNamedQuery("Cantable.findAll").getResultList(); finalList = resultList; } } catch (Exception e) { e.printStackTrace(); } return resultList; }

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  • What's the best Scala build system?

    - by gatoatigrado
    I've seen questions about IDE's here -- Which is the best IDE for Scala development? and What is the current state of tooling for Scala?, but I've had mixed experiences with IDEs. Right now, I'm using the Eclipse IDE with the automatic workspace refresh option, and KDE 4's Kate as my text editor. Here are some of the problems I'd like to solve: use my own editor IDEs are really geared at everyone using their components. I like Kate better, but the refresh system is very annoying (it doesn't use inotify, rather, maybe a 10s polling interval). The reason I don't use the built-in text editor is because broken auto-complete functionalities cause the IDE to hang for maybe 10s. rebuild only modified files The Eclipse build system is broken. It doesn't know when to rebuild classes. I find myself almost half of the time going to project-clean. Worse, it seems even after it has finished building my project, a few minutes later it will pop up with some bizarre error (edit - these errors appear to be things that were previously solved with a project clean, but then come back up...). Finally, setting "Preferences / Continue launch if project contains errors" to "prompt" seems to have no effect for Scala projects (i.e. it always launches even if there are errors). build customization I can use the "nightly" release, but I'll want to modify and use my own Scala builds, not the compiler that's built into the IDE's plugin. It would also be nice to pass [e.g.] -Xprint:jvm to the compiler (to print out lowered code). fast compiling Though Eclipse doesn't always build right, it does seem snappy -- even more so than fsc. I looked at Ant and Maven, though haven't employed either yet (I'll also need to spend time solving #3 and #4). I wanted to see if anyone has other suggestions before I spend time getting a suboptimal build system working. Thanks in advance! UPDATE - I'm now using Maven, passing a project as a compiler plugin to it. It seems fast enough; I'm not sure what kind of jar caching Maven does. A current repository for Scala 2.8.0 is available [link]. The archetypes are very cool, and cross-platform support seems very good. However, about compile issues, I'm not sure if fsc is actually fixed, or my project is stable enough (e.g. class names aren't changing) -- running it manually doesn't bother me as much. If you'd like to see an example, feel free to browse the pom.xml files I'm using [github]. UPDATE 2 - from benchmarks I've seen, Daniel Spiewak is right that buildr's faster than Maven (and, if one is doing incremental changes, Maven's 10 second latency gets annoying), so if one can craft a compatible build file, then it's probably worth it...

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  • how to implement a "soft barrier" in multithreaded c++

    - by Jason
    I have some multithreaded c++ code with the following structure: do_thread_specific_work(); update_shared_variables(); //checkpoint A do_thread_specific_work_not_modifying_shared_variables(); //checkpoint B do_thread_specific_work_requiring_all_threads_have_updated_shared_variables(); What follows checkpoint B is work that could have started if all threads have reached only checkpoint A, hence my notion of a "soft barrier". Typically multithreading libraries only provide "hard barriers" in which all threads must reach some point before any can continue. Obviously a hard barrier could be used at checkpoint B. Using a soft barrier can lead to better execution time, especially since the work between checkpoints A and B may not be load-balanced between the threads (i.e. 1 slow thread who has reached checkpoint A but not B could be causing all the others to wait at the barrier just before checkpoint B). I've tried using atomics to synchronize things and I know with 100% certainty that is it NOT guaranteed to work. For example using openmp syntax, before the parallel section start with: shared_thread_counter = num_threads; //known at compile time #pragma omp flush Then at checkpoint A: #pragma omp atomic shared_thread_counter--; Then at checkpoint B (using polling): #pragma omp flush while (shared_thread_counter > 0) { usleep(1); //can be removed, but better to limit memory bandwidth #pragma omp flush } I've designed some experiments in which I use an atomic to indicate that some operation before it is finished. The experiment would work with 2 threads most of the time but consistently fail when I have lots of threads (like 20 or 30). I suspect this is because of the caching structure of modern CPUs. Even if one thread updates some other value before doing the atomic decrement, it is not guaranteed to be read by another thread in that order. Consider the case when the other value is a cache miss and the atomic decrement is a cache hit. So back to my question, how to CORRECTLY implement this "soft barrier"? Is there any built-in feature that guarantees such functionality? I'd prefer openmp but I'm familiar with most of the other common multithreading libraries. As a workaround right now, I'm using a hard barrier at checkpoint B and I've restructured my code to make the work between checkpoint A and B automatically load-balancing between the threads (which has been rather difficult at times). Thanks for any advice/insight :)

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  • Writing to a comet stream using tomcat 6.0

    - by user301247
    Hey I'm new to java servlets and I am trying to write one that uses comet so that I can create a long polling Ajax request. I can successfully start the stream and perform operations but I can't write anything out. Here is my code: public class CometTestServlet extends HttpServlet implements CometProcessor { /** * */ private static final long serialVersionUID = 1070949541963627977L; private MessageSender messageSender = null; protected ArrayList<HttpServletResponse> connections = new ArrayList<HttpServletResponse>(); public void event(CometEvent cometEvent) throws IOException, ServletException { HttpServletRequest request = cometEvent.getHttpServletRequest(); HttpServletResponse response = cometEvent.getHttpServletResponse(); //final PrintWriter out = response.getWriter(); if (cometEvent.getEventType() == CometEvent.EventType.BEGIN) { PrintWriter writer = response.getWriter(); writer.println("<!doctype html public \"-//w3c//dtd html 4.0 transitional//en\">"); writer.println("<head><title>JSP Chat</title></head><body bgcolor=\"#FFFFFF\">"); writer.println("</body></html>"); writer.flush(); cometEvent.setTimeout(10 * 1000); //cometEvent.close(); } else if (cometEvent.getEventType() == CometEvent.EventType.ERROR) { log("Error for session: " + request.getSession(true).getId()); synchronized(connections) { connections.remove(response); } cometEvent.close(); } else if (cometEvent.getEventType() == CometEvent.EventType.END) { log("End for session: " + request.getSession(true).getId()); synchronized(connections) { connections.remove(response); } PrintWriter writer = response.getWriter(); writer.println("</body></html>"); cometEvent.close(); } else if (cometEvent.getEventType() == CometEvent.EventType.READ) { //handleReadEvent(cometEvent); InputStream is = request.getInputStream(); byte[] buf = new byte[512]; do { int n = is.read(buf); //can throw an IOException if (n > 0) { log("Read " + n + " bytes: " + new String(buf, 0, n) + " for session: " + request.getSession(true).getId()); } else if (n < 0) { //error(cometEvent, request, response); return; } } while (is.available() > 0); } } Any help would be appreciated.

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  • XmlHttpRequest bug?

    - by valdo
    Hello all. I'm writing a program that among other things needs to download a file given its URL. I'm too lazy to implement the Http/Https protocols manually, so that I needed some library/object/function that'll do the job. Critical requirement: The download must be asynchronous. That is, the thread that issued the download must be able to do something else "while" downloading the file, plus the download must be able to be aborted anytime without any barbaric side effects (such as internal call to TerminateThread). Nice-to-have requirements: Should be able to download the file "into memory". Means - read the contents of the file as they arrive, not necessarily save it into some "file system" file. It'd be nice to have some convenient Win32 progress notification mechanism (waitable event, semahpore, completion port, etc.), rather than just periodically polling the download status. I've chosen the XmlHttpRequest COM object to do the work. It seemed to work fine enough, plus it supported asynchronous mode. However I noticed that after some period it just stops working. That is, after several successful file downloads it stops downloading anything. I periodically poll it to get its status, it reports "in-progress", but nothing actually happens, and there's no network activity. Moreover, when the same process creates another instance of XmlHttpRequest object to perform new downloads - the effect is the same. The object reports "in progress", whereas it doesn't even try to connect to the server (according to network sniffers and system TCP state). The only way to make this object work back is to restart the process. This makes me suspect that there's a sort of a bug (sorry, I meant undocumented feature) in the object. Also it's not a bug at the level of an individual object, since the problem persists when the object is destroyed and another one is created. It's probably some global state of the DLL that implements this object. Does anyone know something about this? Is this a known bug? I'm pretty sure there's no chance that I have another bug in my code, because of which it seems to me to be the bug is in the XmlHttpRequest. I've done enoughtests and spent time with the debugger to conclude without reasonable doubt that it's just the object stops working. BTW, while the object should work, I do all the waiting via MsgWaitXXXX API calls. So that if this object needs the message loop to work properly (for instance, it may create a hidden notification window and bind it to a socket via WSAAsyncSelect) - I give it the opportunity.

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  • What is causing this SQL 2005 Primary Key Deadlock between two real-time bulk upserts?

    - by skimania
    Here's the scenario: I've got a table called MarketDataCurrent (MDC) that has live updating stock prices. I've got one process called 'LiveFeed' which reads prices streaming from the wire, queues up inserts, and uses a 'bulk upload to temp table then insert/update to MDC table.' (BulkUpsert) I've got another process which then reads this data, computes other data, and then saves the results back into the same table, using a similar BulkUpsert stored proc. Thirdly, there are a multitude of users running a C# Gui polling the MDC table and reading updates from it. Now, during the day when the data is changing rapidly, things run pretty smoothly, but then, after market hours, we've recently started seeing an increasing number of Deadlock exceptions coming out of the database, nowadays we see 10-20 a day. The imporant thing to note here is that these happen when the values are NOT changing. Here's all the relevant info: Table Def: CREATE TABLE [dbo].[MarketDataCurrent]( [MDID] [int] NOT NULL, [LastUpdate] [datetime] NOT NULL, [Value] [float] NOT NULL, [Source] [varchar](20) NULL, CONSTRAINT [PK_MarketDataCurrent] PRIMARY KEY CLUSTERED ( [MDID] ASC )WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] ) ON [PRIMARY] - stackoverflow wont let me post images until my reputation goes up to 10, so i'll add them as soon as you bump me up, hopefully as a result of this question. ![alt text][1] [1]: http://farm5.static.flickr.com/4049/4690759452_6b94ff7b34.jpg I've got a Sql Profiler Trace Running, catching the deadlocks, and here's what all the graphs look like. stackoverflow wont let me post images until my reputation goes up to 10, so i'll add them as soon as you bump me up, hopefully as a result of this question. ![alt text][2] [2]: http://farm5.static.flickr.com/4035/4690125231_78d84c9e15_b.jpg Process 258 is called the following 'BulkUpsert' stored proc, repeatedly, while 73 is calling the next one: ALTER proc [dbo].[MarketDataCurrent_BulkUpload] @updateTime datetime, @source varchar(10) as begin transaction update c with (rowlock) set LastUpdate = getdate(), Value = t.Value, Source = @source from MarketDataCurrent c INNER JOIN #MDTUP t ON c.MDID = t.mdid where c.lastUpdate < @updateTime and c.mdid not in (select mdid from MarketData where LiveFeedTicker is not null and PriceSource like 'LiveFeed.%') and c.value <> t.value insert into MarketDataCurrent with (rowlock) select MDID, getdate(), Value, @source from #MDTUP where mdid not in (select mdid from MarketDataCurrent with (nolock)) and mdid not in (select mdid from MarketData where LiveFeedTicker is not null and PriceSource like 'LiveFeed.%') commit And the other one: ALTER PROCEDURE [dbo].[MarketDataCurrent_LiveFeedUpload] AS begin transaction -- Update existing mdid UPDATE c WITH (ROWLOCK) SET LastUpdate = t.LastUpdate, Value = t.Value, Source = t.Source FROM MarketDataCurrent c INNER JOIN #TEMPTABLE2 t ON c.MDID = t.mdid; -- Insert new MDID INSERT INTO MarketDataCurrent with (ROWLOCK) SELECT * FROM #TEMPTABLE2 WHERE MDID NOT IN (SELECT MDID FROM MarketDataCurrent with (NOLOCK)) -- Clean up the temp table DELETE #TEMPTABLE2 commit To clarify, those Temp Tables are being created by the C# code on the same connection and are populated using the C# SqlBulkCopy class. To me it looks like it's deadlocking on the PK of the table, so I tried removing that PK and switching to a Unique Constraint instead but that increased the number of deadlocks 10-fold. I'm totally lost as to what to do about this situation and am open to just about any suggestion. HELP!!

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  • DataGridView live display of datatable using virtual mode

    - by Chris
    I have a DataGridView that will display records (log entries) from a database. The amount of records that can exist at a time is very large. I would like to use the virtual mode feature of the DataGridView to display a page of data, and to minimize the amount of data that has to be transferred across a network at a given time. Polling for data is out of the question. There will be several clients running at a time, all of which are on the same network and viewing the records. If they all poll for data, the network will run very slowly. The data is read-only to the user; they won't be able to edit any of it, just view it. I need to know when updates occur in the database, and I need to update the screen with those updates accordingly using virtual mode. If a page of data a user is viewing contains data that has change, he/she will see those updates on that page. If updates were made to data in the database, but not in the data the user is viewing, then not much really changes on the user screen (Maybe just the scroll bar if records were added or removed). My current approach is using SQL server change tracking with the sync framework. Each client has a local SQL Server CE instance and database file that is kept in sync with the main database server. I use the information from the synchronization event to see if any changes were made to the main database and were sync'ed to the client. I need to use the DataGridView virtual mode here because I can't have thousands of records loaded into the DataGridView at once, otherwise memory usage goes through the roof. The main challenge right now is knowing how to use virtual mode to provide a seamless experience to the user by allowing them to scroll up and down through the records, and also have records update on the fly without interfering with the user inappropriately. Has anybody dealt with this issue before, and if so, where I can see how they did it? I've gone through some of the MSDN documentation and examples on virtual mode. So far, I haven't found documentation and/or examples on their site that explains how to do what I am trying to accomplish.

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