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  • Can I use CAT 6a connectors with 7a cable (and get 6a performance)?

    - by Mr. Flibble
    I'm re-wiring a building and want to get the best cable possible laid - it required re-plastering to make a change to the cables and the cables will be there for the next 10 - 20 years. Currently there appears to be cat 7a cable available but not too much in the way of cat 7a connectors. Also - I won't be using 40Gig hardware in the near future. So, my question: is it possible to use cat 6a connectors / patch panels with cat 7a cable and get the same performance as I would had I used cat 6a cable? Are there any gotchas in trying to do this?

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  • Cloning single disk drive to multiple drives simultaneously

    - by mr.b
    I am looking for a way to clone single disk drive to more than one disk drive at the same time. I have prepared system images on 1TB disks, and it takes almost 2 hours to clone one disk to another, and then it goes up exponentially, in order to have say 30 disks cloned. If it was possible to clone one disk to more than single target, it would simplify whole procedure a lot. Also, is there something that prevents this kind of operation? I mean, is there some special reason why every disk cloning software that I know about supports only single target drive? Thanks!

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  • What hardware would I need (approx) to run ESXi server?

    - by mr.b
    Hi, I am considering to purchase off-the-shelf commodity hardware in order to build server that will host virtual machines using ESXi server. Intended purpose for this server is NOT mission critical tasks. It will have to run perhaps 20-50 Windows XP/Vista/7 virtual machines (in total, but closer to 20 figure). Each guest would have to have 1-2 GB of ram, and probably two-three times more disk space than guest OS needs with clean install and all updates applied (that would be around 6-8 GB for XP, and i believe closer to 10-15 for win7). Those guests will act as a test ground for a new product that is network management software, thus guests will idle most of their time once initially loaded, but if I give them some task to complete, they should be able to perform reasonably well. Now, from what I have learned... CPU is usually not much of an issue (6 cores would do it), memory should not be lacking, but doesn't have to be sum of all guests, because of overcommitment... That leads me to IO, which is, as it seems, the bottleneck. Since I have very little experience with ESXi (and ESX, too) server, I'd like to ask: How much memory could I save by overcommitment, and how does it affect performance? Is 6-core cpu enough to run above described system? Would it be possible to run entire server off two (or even one) SSD drives (to host system virtual disks, with few additional HDDs (2-3) in RAID 0 to be used as secondary storage? I read somewhere that ESXi allows having something like "master image", essentially virtual machine that is "deployed" many times, so that disk space can be saved by having only differences stored by specific guests, instead of copying around whole virtual disks. Is this true, and how can this help me? Are there any other things I need to take into consideration when building this off-the-shelf solution? I should probably mention here that I'm fully aware of issues like SPOF regarding power supply, raid 0, etc, but since it's only a testing ground and not a production system, it's not so important for me. Thanks, B.

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  • Can't install newer NVIDIA display driver on Windows 7

    - by Mr.X
    I'm using Windows 7, and the latest version of NVIDIA display driver I can install on my computer is 275.33 (or 266.58, I can't decide now, see below). When installing newer version of the driver (e.g. 275.50 and 280.26), the installer always fails at "Installing NVIDIA Control Panel", then Windows 7 reverts to 275.33 (the newest stock version?). I tried to find installation logs but couldn't find it. I tried to completely delete (in fact I renamed) c:\progra~1\nvidia~1 folder but still couldn't install. How to resolve this problem? Any help is appreciated.

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  • Upgrade manually-installed msi by assigning software through gpo

    - by Mr Happy
    In the past I rolled out software by manually installing it on a "golden" workstation, creating an (ghost)image from that and rolling that out to the other workstations. I try not to do that any more for simple/small software, and when possible (if it's an .msi) I assign the software through gpo. I'm having a problem with one of those. The software was manually installed on the image, which was rolled out, and now I have an update for that software (new msi) and I'd like to assign it through gpo. Don't know if it's relevant but it's user assigned. The new version gets installed alongside with the old version (this is possible since the program folder is different between those versions). When I install the same msi by hand, it properly removes/upgrades the old version though. Is what I am trying to do possible?

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  • MySQL - complete server migration (Ubuntu) [closed]

    - by Mr A
    Possible Duplicate: How to copy and move mysql database Dump all databases with SSH access I'm setting up a new dev machine, and I have the old one sitting right next to me. I'd like to do an exact copy of all MySQL structures and data from the old machine to the new. Nothing fancy needs to happen (it's a dev machine). No replication. I don't care about "downtimes" etc. Is there a super simple way to do this? For example, I have SSH on the old server, can I just use Nautilus, do a connect to server, and then transfer a folder over, replacing another folder with it and be done? It's the same version of MySQL on both sides. Same version of Ubuntu. Same in most respects.

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  • Sql Table Refactoring Challenge

    Ive been working a bit on cleaning up a large table to make it more efficient.  I pretty much know what I need to do at this point, but I figured Id offer up a challenge for my readers, to see if they can catch everything I have as well as to see if Ive missed anything.  So to that end, I give you my table: CREATE TABLE [dbo].[lq_ActivityLog]( [ID] [bigint] IDENTITY(1,1) NOT NULL, [PlacementID] [int] NOT NULL, [CreativeID] [int] NOT NULL, [PublisherID] [int] NOT NULL, [CountryCode] [nvarchar](10) NOT NULL, [RequestedZoneID] [int] NOT NULL, [AboveFold] [int] NOT NULL, [Period] [datetime] NOT NULL, [Clicks] [int] NOT NULL, [Impressions] [int] NOT NULL, CONSTRAINT [PK_lq_ActivityLog2] PRIMARY KEY CLUSTERED ( [Period] ASC, [PlacementID] ASC, [CreativeID] ASC, [PublisherID] ASC, [RequestedZoneID] ASC, [AboveFold] ASC, [CountryCode] ASC)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]) ON [PRIMARY] And now some assumptions and additional information: The table has 200,000,000 rows currently PlacementID ranges from 1 to 5000 and should support at least 50,000 CreativeID ranges from 1 to 5000 and should support at least 50,000 PublisherID ranges from 1 to 500 and should support at least 50,000 CountryCode is a 2-character ISO standard (e.g. US) and there is a country table with an integer ID already.  There are < 300 rows. RequestedZoneID ranges from 1 to 100 and should support at least 50,000 AboveFold has values of 1, 0, or 1 only. Period is a date (no time). Clicks range from 0 to 5000. Impressions range from 0 to 5000000. The table is currently write-mostly.  Its primary purpose is to log advertising activity as quickly as possible.  Nothing in the rest of the system reads from it except for batch jobs that pull the data into summary tables. Heres the current information on the database tables size: Design Goals This table has been in use for about 5 years and has performed very well during that time.  The only complaints we have are that it is quite large and also there are occasionally timeouts for queries that reference it, particularly when batch jobs are pulling data from it.  Any changes should be made with an eye toward keeping write performance optimal  while trying to reduce space and improve read performance / eliminate timeouts during read operations. Refactor There are, I suggest to you, some glaringly obvious optimizations that can be made to this table.  And Im sure there are some ninja tweaks known to SQL gurus that would be a big help as well.  Ill post my own suggested changes in a follow-up post for now feel free to comment with your suggestions. Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • New Java ME JSRs submitted

    - by heathervc
    Two new Java ME related JSRs were submitted to the JCP program office this week and are now available for review. JSR 360, Connected Limited Device Configuration (CLDC) 8, has been submitted by Oracle for JSR Review.  This review period is open until 15 October.  The ME EC will vote on the JSR Approval Ballot 16-29 October. JSR 361 Java ME Embedded Profile, has been submitted by Oracle for JSR Review. This review period is open until 15 October.  The ME EC will vote on the JSR Approval Ballot 16-29 October.

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  • Oracle E-Business Financials Recommended Patch Collections (RPCs) for R12.1.3 Have Been Released for August 2012

    - by Oracle_EBS
    What is a Recommended Patch Collection (RPC)? An RPC is a collection of recommended patches consolidated into a single, downloadable patch, ready to be applied. The RPCs are created with the following goals in mind: Stability: Address issues that occur often and interfere with the normal completion of crucial business processes, such as period close--as observed by Oracle Development and Global Customer Support. Root Cause Fixes: Deliver a root cause fix for data corruption issues that delay period close, normal transaction flow actions, performance, and other issues. Compact: While bundling a large number of important corrections, we have kept the file footprint as small as possible to facilitate uptake and minimize testing. Reliable: Reliable code with multiple customer downloads and comprehensive testing by QA, Support and Proactive Support. RPCs are available for the following products: Cash Management Collections E-Business Tax Financials for India Fixed Assets General Ledger Internet Expenses iReceivables Loans Payables Payments Receivables Subledger Accounting For the latest Financials Recommended Patch Collections (RPCs), please view: EBS: R12.1 Oracle Financials Recommended Patches [Doc ID 954704.1].

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  • Enablement 2.0 Get Specialized!

    - by mseika
    Oracle PartnerNetwork Specialized program is releasing new certifications on our latest products, and partners are invited to be the first candidates. A Certification exam goes through a rigorous review process called a beta period. Here are a few advantages of taking a Beta Exam: Certification exams during the beta period count towards your Company Specialization. Most new Certified Specialist Exams have no training requirement. Beta Exams Vouchers are available in limited quantity, so request a voucher today by contacting the Partner Enablement Team and act fast to reserve your test from the list below. For more information click here. 

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  • How to compare page views/visitors to site totals in Google Analytics?

    - by frntk
    I want to measure the effects in total traffic (views or visitors) of a single URL across a time frame. For example, let's say I published a blog post on July 2012. I want to measure what chunk of the site's total traffic is coming to this particular post on a month-by-month graph from July 2012 to date. Is there a way to do this? Edit: I should clarify that what I'd like to do is to generate a month-to-month graph, similar to the one you can see comparing a metric on a period of time against the previous equivalent period (year vs last year, for example) but comparing a particular URL traffic to the site's total traffic. In other words, I can get to the part where I can see the URL's traffic for the timeframe I selected and it shows how much of the total traffic corresponds to the current URL: But I'd like to add a second line to the graph, representing the site's total pageviews, similiar to this (but this one is showing just a different metric for the same URL): Thanks!

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  • Sensor Manager getOrientation, doesnt display text and only works in debug mode?

    - by Aidan
    Hi Guys, My code appears to crash. I'm trying to setup a SensorManager for getting the Orientation of the device. I also have a listener that should update when conditions change. But when I run this code it crashes... public void sensor(){ // Locate the SensorManager using Activity.getSystemService sm = (SensorManager) getSystemService(SENSOR_SERVICE); sm.getOrientation(mR, mOrientation); // Register your SensorListener sm.registerListener(sl, sm.getDefaultSensor(Sensor.TYPE_ORIENTATION),SensorManager.SENSOR_DELAY_NORMAL); } private final SensorEventListener sl = new SensorEventListener() { @Override public void onAccuracyChanged(Sensor sensor, int accuracy) { } @Override public void onSensorChanged(SensorEvent event) { if (event.sensor.getType()==Sensor.TYPE_ORIENTATION) { Global.Orientation = "Orientation is equal to: "+ SensorManager.getOrientation(mR, mOrientation); } } sm is defined as SensorManager sm; as a class wide variable also. I've got some other classes outputting the Orientation to a screen which I know works. The problem is somewhere in these methods. Am I doing it wrong or Is there a better way of doing this?

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  • SQL Server: SELECT rows with MAX(Column A), MAX(Column B), DISTINCT by related columns

    - by z531
    Scenario: Table A MasterID, Added Date, Added By, Updated Date, Updated By, 1, 1/1/2010, 'Fred', null, null 2, 1/2/2010, 'Barney', 'Mr. Slate', 1/7/2010 3, 1/3/2010, 'Noname', null, null Table B MasterID, Added Date, Added By, Updated Date, Updated By, 1, 1/3/2010, 'Wilma', 'The Great Kazoo', 1/5/2010 2, 1/4/2010, 'Betty', 'Dino', 1/4/2010 Table C MasterID, Added Date, Added By, Updated Date, Updated By, 1, 1/5/2010, 'Pebbles', null, null 2, 1/6/2010, 'BamBam', null, null Table D MasterID, Added Date, Added By, Updated Date, Updated By, 1, 1/2/2010, 'Noname', null, null 3, 1/4/2010, 'Wilma', null, null I need to return the max added date and corresponding user, and max updated date and corresponding user for each distinct record when tables A,B,C&D are UNION'ed, i.e.: 1, 1/5/2010, 'Pebbles', 'The Great Kazoo', 1/5/2010 2, 1/6/2010, 'BamBam', 'Mr. Slate', 1/7/2010 3, 1/4/2010, 'Wilma', null, null I know how to do this with one date/user per row, but with two is beyond me. DBMS is SQL Server 2005. T-SQL solution preferred. Thanks in advance, Dave

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  • ColdFusion structs Direct Assignment vs object literal notation.

    - by Tom Hubbard
    The newer versions of ColdFusion (I believe CF 8 and 9) allow you to create structs with object literal notation similar to JSON. My question is, are there specific benefits (execution efficiency maybe) to using object literal notation over individual assignments for data that is essentially static? For example: With individual assignments you would do something like this: var user = {}; user.Fname = "MyFirstnam"; user.Lname = "MyLastName"; user.titles = []; ArrayAppend(user.titles,'Mr'); ArrayAppend(user.titles,'Dr.'); Whereas with object literals you would do something like. var user = {Fname = "MyFirstnam", Lname = "MyLastName", titles = ['Mr','Dr']}; Now this limited example is admittedly simple, but if titles was an array of structures (Say an array of addresses), the literal notation becomes awkward to work with.

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  • How to prevent column b containing the same value as any column a in Oracle?

    - by Janek Bogucki
    What is a good way to prevent a table with 2 columns, a and b, from having any record where column b is equal to any value in column a? This would be used for a table of corrections like this, MR -> Mr Prf. -> Prof. MRs -> Mrs I can see how it could be done with a trigger and a subquery assuming no concurrent activity but a more declarative approach would be preferable. This is an example of what should be prevented, Wing Commdr. -> Wing Cdr. Wing Cdr. -> Wing Commander Ideally the solution would work with concurrent inserts and updates.

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  • Managing string resources in a Java application - singleton?

    - by Joe Attardi
    I seek a solution to the age-old problem of managing string resources. My current implementation seems to work well, but it depends on using singletons, and I know how often singletons can be maligned. The resource manager class has a singleton instance that handles lookups in the ResourceBundle, and you use it like so: MessageResources mr = MessageResources.getMessageResources(); // returns singleton instance ... JLabel helloLabel = new JLabel(mr.getString("label.hello")); Is this an appropriate use of a singleton? Is there some better, more universally used approach that I'm not aware of? I understand that this is probably a bit subjective, but any feedback I can get would be appreciated. I'd rather find out early on that I'm doing it wrong than later on in the process. Thanks!

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  • Employing elegance in order to evade importing elephants: a case of excessive dll Imports

    - by user994179
    I am writing C# code that interfaces to a legacy (Feb 2012) C program, using DllImport. It works fine, but I need to call more than 30 different functions, turning my normally impeccable, exquisite code into something of near-elephantine proportions. Surely there must be a way around this? [Warning: those with weak stomachs may want to avert their eyes from what follows]: [DllImport("C:\\Users\\mitt\\Documents\\Visual Studio 2010\\Projects\\mrSolution\\mr\\x64\\Debug\\mrDll.dll", CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Ansi)] public static extern bool mrEngine_initialize( [In, Out, MarshalAs(UnmanagedType.LPStruct)] PLOT_SPEC PlotSpec); [DllImport("C:\\Users\\mitt\\Documents\\Visual Studio 2010\\Projects\\mrSolution\\mr\\x64\\Debug\\mrDll.dll", CallingConvention = CallingConvention.Cdecl, CharSet = CharSet.Ansi)] public static extern bool mrEngine_getDataPoint( [In, Out, MarshalAs(UnmanagedType.LPStruct)] PLOT_SPEC PlotSpec);

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  • Grouping php array items based on user and created time

    - by Jim
    This is an array of objects showing a user uploading photos: Array ( [12] => stdClass Object ( [type] => photo [created] => 2010-05-14 23:36:41 [user] => stdClass Object ( [id] => 760 [username] => mrsmith ) [photo] => stdClass Object ( [id] => 4181 ) ) [44] => stdClass Object ( [type] => photo [created] => 2010-05-14 23:37:15 [user] => stdClass Object ( [id] => 760 [username] => mrsmith ) [photo] => stdClass Object ( [id] => 4180 ) ) ) However instead of showing: mr smith uploaded one photo mr smith uploaded one photo I'd like to display: mr smith uploaded two photos by grouping similar items, grouping by user ID and them having added them within, let's say 15 minutes of each other. So I'd like to get the array in this sort of shape: Array ( [12] => stdClass Object ( [type] => photo [created] => 2010-05-14 23:36:41 [user] => stdClass Object ( [id] => 760 [username] => mrsmith ) [photos] => Array ( [0] => stdClass Object ( [id] => 4181 ) [1] => stdClass Object ( [id] => 4180 ) ) ) ) preserving the first item of the group and it's created time, and supplementing it with any other groupable photos and then unsetting any items that were grouped (so the final array doesn't have key 44 anymore as it was grouped in with 12). The array contains other actions than just photos, hence the original keys of 12 and 44. I just can't figure out a way to do this efficiently. I used to use MySQL and PHP to do this but am trying to just use pure PHP for caching reasons. Can anyone shed any insights? I thought about going through each item and seeing if I can group it with the previous one in the array but the previous one might not necessarily be relevant or even a photo. I've got total brain freeze :(

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  • Java String Replace and null characters

    - by praspa
    Testing out someone elses code (of course it was ...) , I noticed a few JSP pages printing funky non-ascii characters. Taking a dip into the source I found this tidbit. // remove any periods from first name e.g. Mr. John --> Mr John firstName = firstName.trim().replace('.','\0'); Does replacing a character in a String with a null character even work in Java? I know that '\0' will terminate a c-string. Would this be the culprit to the funky characters? Thanks PR

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  • How should I join these 3 SQL queries in Oracle?

    - by Nazgulled
    I have these 3 queries: SELECT title, year, MovieGenres(m.mid) genres, MovieDirectors(m.mid) directors, MovieWriters(m.mid) writers, synopsis, poster_url FROM movies m WHERE m.mid = 1; SELECT AVG(rating) FROM movie_ratings WHERE mid = 1; SELECT COUNT(rating) FROM movie_ratings WHERE mid = 1; And I need to join them into a single query. I was able to do it like this: SELECT title, year, MovieGenres(m.mid) genres, MovieDirectors(m.mid) directors, MovieWriters(m.mid) writers, synopsis, poster_url, AVG(rating) average, COUNT(rating) count FROM movies m INNER JOIN movie_ratings mr ON m.mid = mr.mid WHERE m.mid = 1 GROUP BY title, year, MovieGenres(m.mid), MovieDirectors(m.mid), MovieWriters(m.mid), synopsis, poster_url; But I don't really like that "huge" GROUP BY, is there a simpler way to do it?

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  • NFS v4, HA Migration, and stale handles on clients

    - by Karl Katzke
    I'm managing a server running NFS v4 with Pacemaker/OpenAIS. NFS is configured to use TCP. When I migrate the NFS server to another node in the Pacemaker cluster, even though the metadata is persisted, connections from the clients 'hang' and eventually time out after 90 seconds. After that 90 seconds, the old mountpoint becomes 'stale' and the mounted files can no longer be accessed. The 90 second grace period seems to be part of the server configuration and not the client configuration. I see this message on the server: kernel: NFSD: starting 90-second grace period If I restart the NFS client on the client nodes after I migrate (unmounting and then remounting the share), then I don't experience the problem, but connections and file transfers still interrupted. Three questions: What is the 90 second grace period? What's it there for? How can I keep the files from going stale on the clients without restarting them after I migrate the NFS server to another node? Is it actually possible to migrate the NFS server without having large file uploads drop?

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  • virtualbox snapshot size

    - by intuited
    I've started using Windows 7 under VirtualBox on an Ubuntu 10.10 host. I took about 6 snapshots over the course of setting up the VM from the Windows restore image that came with the computer. My installations were more or less limited to windows updates, antivirus, and the VB Guest Additions. I uninstalled much more than I installed. The VM was running for about 24 hours total. The snapshots increased in size at a worrisome rate, even when the machine was idle: the snapshot .vdi file for the period between 11:22 PM and 9:02 AM is 6 gigs in size; during that time very little happened. The other .vdi files are between 0.5 and 3 GB, most between 1 and 2 GB. The corresponding .sav files are between 0.5 and 1 GB. The Internet connection where I was doing this is limited to 30KB/s download, which, constantly saturated, works out to less than 3 GB per 24 hour period. Is this normal? Is there something that can be done to make snapshots more practical? update On starting up the VM again, I've noticed that mscorsvw is using significant processing time. Apparently this process [precompiles .NET assemblies]. This may have been going on during the period when I was taking snapshots, which might explain some of the snapshot size increase. I would be somewhat surprised to learn that this could be responsible for over 10 GB of additional disk usage, or that it would run for roughly 24 hours. Is this possible?

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  • Android sending lots of SMS messages

    - by Robert Parker
    I have a app, which sends a lot of SMS messages to a central server. Each user will probably send ~300 txts/day. SMS messages are being used as a networking layer, because SMS is almost everywhere and mobile internet is not. The app is intended for use in a lot of 3rd world countries where mobile internet is not ubiquitous. When I hit a limit of 100 messages, I get a prompt for each message sent. The prompt says "A large number of SMS messages are being sent". This is not ok for the user to get prompted each time to ask if the app can send a text message. The user doesn't want to get 30 consecutive prompts. I found this android source file with google. It could be out of date, I can't tell. It looks like there is a limit of 100 sms messages every 3600000ms(1 day) for each application. http://www.netmite.com/android/mydroid/frameworks/base/telephony/java/com/android/internal/telephony/gsm/SMSDispatcher.java /** Default checking period for SMS sent without uesr permit */ private static final int DEFAULT_SMS_CHECK_PERIOD = 3600000; /** Default number of SMS sent in checking period without uesr permit */ private static final int DEFAULT_SMS_MAX_ALLOWED = 100; and /** * Implement the per-application based SMS control, which only allows * a limit on the number of SMS/MMS messages an app can send in checking * period. */ private class SmsCounter { private int mCheckPeriod; private int mMaxAllowed; private HashMap<String, ArrayList<Long>> mSmsStamp; /** * Create SmsCounter * @param mMax is the number of SMS allowed without user permit * @param mPeriod is the checking period */ SmsCounter(int mMax, int mPeriod) { mMaxAllowed = mMax; mCheckPeriod = mPeriod; mSmsStamp = new HashMap<String, ArrayList<Long>> (); } boolean check(String appName) { if (!mSmsStamp.containsKey(appName)) { mSmsStamp.put(appName, new ArrayList<Long>()); } return isUnderLimit(mSmsStamp.get(appName)); } private boolean isUnderLimit(ArrayList<Long> sent) { Long ct = System.currentTimeMillis(); Log.d(TAG, "SMS send size=" + sent.size() + "time=" + ct); while (sent.size() > 0 && (ct - sent.get(0)) > mCheckPeriod ) { sent.remove(0); } if (sent.size() < mMaxAllowed) { sent.add(ct); return true; } return false; } } Is this even the real android code? It looks like it is in the package "com.android.internal.telephony.gsm", I can't find this package on the android website. How can I disable/modify this limit? I've been googling for solutions, but I haven't found anything.

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  • In MySQL, what is the most effective query design for joining large tables with many to many relatio

    - by lighthouse65
    In our application, we collect data on automotive engine performance -- basically source data on engine performance based on the engine type, the vehicle running it and the engine design. Currently, the basis for new row inserts is an engine on-off period; we monitor performance variables based on a change in engine state from active to inactive and vice versa. The related engineState table looks like this: +---------+-----------+---------------+---------------------+---------------------+-----------------+ | vehicle | engine | engine_state | state_start_time | state_end_time | engine_variable | +---------+-----------+---------------+---------------------+---------------------+-----------------+ | 080025 | E01 | active | 2008-01-24 16:19:15 | 2008-01-24 16:24:45 | 720 | | 080028 | E02 | inactive | 2008-01-24 16:19:25 | 2008-01-24 16:22:17 | 304 | +---------+-----------+---------------+---------------------+---------------------+-----------------+ For a specific analysis, we would like to analyze table content based on a row granularity of minutes, rather than the current basis of active / inactive engine state. For this, we are thinking of creating a simple productionMinute table with a row for each minute in the period we are analyzing and joining the productionMinute and engineEvent tables on the date-time columns in each table. So if our period of analysis is from 2009-12-01 to 2010-02-28, we would create a new table with 129,600 rows, one for each minute of each day for that three-month period. The first few rows of the productionMinute table: +---------------------+ | production_minute | +---------------------+ | 2009-12-01 00:00 | | 2009-12-01 00:01 | | 2009-12-01 00:02 | | 2009-12-01 00:03 | +---------------------+ The join between the tables would be engineState AS es LEFT JOIN productionMinute AS pm ON es.state_start_time <= pm.production_minute AND pm.production_minute <= es.event_end_time. This join, however, brings up multiple environmental issues: The engineState table has 5 million rows and the productionMinute table has 130,000 rows When an engineState row spans more than one minute (i.e. the difference between es.state_start_time and es.state_end_time is greater than one minute), as is the case in the example above, there are multiple productionMinute table rows that join to a single engineState table row When there is more than one engine in operation during any given minute, also as per the example above, multiple engineState table rows join to a single productionMinute row In testing our logic and using only a small table extract (one day rather than 3 months, for the productionMinute table) the query takes over an hour to generate. In researching this item in order to improve performance so that it would be feasible to query three months of data, our thoughts were to create a temporary table from the engineEvent one, eliminating any table data that is not critical for the analysis, and joining the temporary table to the productionMinute table. We are also planning on experimenting with different joins -- specifically an inner join -- to see if that would improve performance. What is the best query design for joining tables with the many:many relationship between the join predicates as outlined above? What is the best join type (left / right, inner)?

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