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  • Perf4J Logging Config Help

    - by manyxcxi
    I currently have a long running process that I am trying to analyze with Perf4J. I currently have it writing results in CSV format to its own log file using the AsyncCoalescingStatisticsAppender and a StatisticsCsvLayout on the file appender. My question is; when I try and use the --graph option from the command line (using the perf4j jar) it isn't populating the data points- it isn't populating anything. Are my appenders set incorrectly? The log file contains hundreds (sometimes thousands) of data points of about 10 different tag names. <appender name="perfAppender" class="org.apache.log4j.FileAppender"> <param name="File" value="perfStats.log"/> <layout class="org.perf4j.log4j.StatisticsCsvLayout"> </layout> </appender> <appender name="CoalescingStatistics" class="org.perf4j.log4j.AsyncCoalescingStatisticsAppender"> <!-- The TimeSlice option is used to determine the time window for which all received StopWatch logs are aggregated to create a single GroupedTimingStatistics log. Here we set it to 10 seconds, overriding the default of 30000 ms --> <param name="TimeSlice" value="10000"/> <appender-ref ref="ConsoleAppender"/> <appender-ref ref="CompositeRollingFileAppender"/> <appender-ref ref="perfAppender"/> </appender>

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  • Python Sets vs Lists

    - by mvid
    In Python, which data structure is more efficient/speedy? Assuming that order is not important to me and I would be checking for duplicates anyway, is a Python set slower than a Python list?

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  • SQL Joining Two or More from Table B with Common Data in Table A

    - by Matthew Frederick
    The real-world situation is a series of events that each have two or more participants (like sports teams, though there can be more than two in an event), only one of which is the host of the event. There is an Event db table for each unique event and a Participant db table with unique participants. They are joined together using a Matchup table. They look like this: Event EventID (PK) (other event data like the date, etc.) Participant ParticipantID (PK) Name Matchup EventID (FK to Event table) ParicipantID (FK to Participant) Host (1 or 0, only 1 host = 1 per EventID) What I'd like to get as a result is something like this: EventID ParticipantID where host = 1 Participant.Name where host = 1 ParticipantID where host = 0 Participant.Name where host = 0 ParticipantID where host = 0 Participant.Name where host = 0 ... Where one event has 2 participants and another has 3 participants, for example, the third participant column data would be null or otherwise noticeable, something like (PID = ParticipantID): EventID PID-1(host) Name-1 (host) PID-2 Name-2 PID-3 Name-3 ------- ----------- ------------- ----- ------ ----- ------ 1 7 Lions 8 Tigers 12 Bears 2 11 Dogs 9 Cats NULL NULL I suspect the answer is reasonably straightforward but for some reason I'm not wrapping my head around it. Alternately it's very difficult. :) I'm using MYSQL 5 if that affects the available SQL.

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  • High CPU usage when running several "java -version" in parallel

    - by Prateesh
    This is just out of curiosity to understand i have a small shell script for ((i = 0; i < 50; i++)) do java -version & done when i run this my CPU usage report by sar is as below 07:51:25 PM CPU %user %nice %system %iowait %steal %idle 07:51:30 PM all 6.98 0.00 1.75 1.00 0.00 90.27 07:51:31 PM all 43.00 0.00 12.00 0.00 0.00 45.00 07:51:32 PM all 86.28 0.00 13.72 0.00 0.00 0.00 07:51:33 PM all 5.25 0.00 1.75 0.50 0.00 92.50 As you can see, on the third line the CPU is at 100% My java version is 1.5.0_22-b03.

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  • Pre-generating GUIDs for use in python?

    - by rjuiaa1
    I have a python program that needs to generate several guids and hand them back with some other data to a client over the network. It may be hit with a lot of requests in a short time period and I would like the latency to be as low as reasonably possible. Ideally, rather than generating new guids on the fly as the client waits for a response, I would rather be bulk-generating a list of guids in the background that is continually replenished so that I always have pre-generated ones ready to hand out. I am using the uuid module in python on linux. I understand that this is using the uuidd daemon to get uuids. Does uuidd already take care of pre-genreating uuids so that it always has some ready? From the documentation it appears that it does not. Is there some setting in python or with uuidd to get it to do this automatically? Is there a more elegant approach then manually creating a background thread in my program that maintains a list of uuids?

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  • Mysql Groupby and Orderby problem

    - by luvboy
    Here is my data structure when i try this sql select rec_id, customer_id, dc_number, balance from payments where customer_id='IHS050018' group by dc_number order by rec_id desc; something is wrong somewhere, idk I need rec_id customer_id dc_number balance 2 IHS050018 DC3 -1 3 IHS050018 52 600 Thanx

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  • MySQL : AVG of AVG impossible ?

    - by Tristan
    Hi, I want to do an average : the problem is for 1 item i'm calculating the AVG of each elements (working) but as soon as i want the GLOBAL average the average of the elements (something and foo) it doesn't work. I need to do that because i want to sort the result by the global average SELECT AVG(AVG(something)+AVG(foo)) /2 as moy ..... ORDER BY moy DESC Thanks,

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  • Make compiler copy characters using movsd

    - by Suma
    I would like to copy a relatively short sequence of memory (less than 1 KB, typically 2-200 bytes) in a time critical function. The best code for this on CPU side seems to be rep movsd. However I somehow cannot make my compiler to generate this code. I hoped (and I vaguely remember seeing so) using memcpy would do this using compiler built-in instrinsic, but based on disassembly and debugging it seems compiler is using call to memcpy/memmove library implementation instead. I also hoped the compiler might be smart enough to recognize following loop and use rep movsd on its own, but it seems it does not. char *dst; const char *src; // ... for (int r=size; --r>=0; ) *dst++ = *src++; Is there some way to make the Visual Studio compiler to generate rep movsd sequence other than using inline assembly?

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  • Of these 3 methods for reading linked lists from shared memory, why is the 3rd fastest?

    - by Joseph Garvin
    I have a 'server' program that updates many linked lists in shared memory in response to external events. I want client programs to notice an update on any of the lists as quickly as possible (lowest latency). The server marks a linked list's node's state_ as FILLED once its data is filled in and its next pointer has been set to a valid location. Until then, its state_ is NOT_FILLED_YET. I am using memory barriers to make sure that clients don't see the state_ as FILLED before the data within is actually ready (and it seems to work, I never see corrupt data). Also, state_ is volatile to be sure the compiler doesn't lift the client's checking of it out of loops. Keeping the server code exactly the same, I've come up with 3 different methods for the client to scan the linked lists for changes. The question is: Why is the 3rd method fastest? Method 1: Round robin over all the linked lists (called 'channels') continuously, looking to see if any nodes have changed to 'FILLED': void method_one() { std::vector<Data*> channel_cursors; for(ChannelList::iterator i = channel_list.begin(); i != channel_list.end(); ++i) { Data* current_item = static_cast<Data*>(i->get(segment)->tail_.get(segment)); channel_cursors.push_back(current_item); } while(true) { for(std::size_t i = 0; i < channel_list.size(); ++i) { Data* current_item = channel_cursors[i]; ACQUIRE_MEMORY_BARRIER; if(current_item->state_ == NOT_FILLED_YET) { continue; } log_latency(current_item->tv_sec_, current_item->tv_usec_); channel_cursors[i] = static_cast<Data*>(current_item->next_.get(segment)); } } } Method 1 gave very low latency when then number of channels was small. But when the number of channels grew (250K+) it became very slow because of looping over all the channels. So I tried... Method 2: Give each linked list an ID. Keep a separate 'update list' to the side. Every time one of the linked lists is updated, push its ID on to the update list. Now we just need to monitor the single update list, and check the IDs we get from it. void method_two() { std::vector<Data*> channel_cursors; for(ChannelList::iterator i = channel_list.begin(); i != channel_list.end(); ++i) { Data* current_item = static_cast<Data*>(i->get(segment)->tail_.get(segment)); channel_cursors.push_back(current_item); } UpdateID* update_cursor = static_cast<UpdateID*>(update_channel.tail_.get(segment)); while(true) { if(update_cursor->state_ == NOT_FILLED_YET) { continue; } ::uint32_t update_id = update_cursor->list_id_; Data* current_item = channel_cursors[update_id]; if(current_item->state_ == NOT_FILLED_YET) { std::cerr << "This should never print." << std::endl; // it doesn't continue; } log_latency(current_item->tv_sec_, current_item->tv_usec_); channel_cursors[update_id] = static_cast<Data*>(current_item->next_.get(segment)); update_cursor = static_cast<UpdateID*>(update_cursor->next_.get(segment)); } } Method 2 gave TERRIBLE latency. Whereas Method 1 might give under 10us latency, Method 2 would inexplicably often given 8ms latency! Using gettimeofday it appears that the change in update_cursor-state_ was very slow to propogate from the server's view to the client's (I'm on a multicore box, so I assume the delay is due to cache). So I tried a hybrid approach... Method 3: Keep the update list. But loop over all the channels continuously, and within each iteration check if the update list has updated. If it has, go with the number pushed onto it. If it hasn't, check the channel we've currently iterated to. void method_three() { std::vector<Data*> channel_cursors; for(ChannelList::iterator i = channel_list.begin(); i != channel_list.end(); ++i) { Data* current_item = static_cast<Data*>(i->get(segment)->tail_.get(segment)); channel_cursors.push_back(current_item); } UpdateID* update_cursor = static_cast<UpdateID*>(update_channel.tail_.get(segment)); while(true) { for(std::size_t i = 0; i < channel_list.size(); ++i) { std::size_t idx = i; ACQUIRE_MEMORY_BARRIER; if(update_cursor->state_ != NOT_FILLED_YET) { //std::cerr << "Found via update" << std::endl; i--; idx = update_cursor->list_id_; update_cursor = static_cast<UpdateID*>(update_cursor->next_.get(segment)); } Data* current_item = channel_cursors[idx]; ACQUIRE_MEMORY_BARRIER; if(current_item->state_ == NOT_FILLED_YET) { continue; } found_an_update = true; log_latency(current_item->tv_sec_, current_item->tv_usec_); channel_cursors[idx] = static_cast<Data*>(current_item->next_.get(segment)); } } } The latency of this method was as good as Method 1, but scaled to large numbers of channels. The problem is, I have no clue why. Just to throw a wrench in things: if I uncomment the 'found via update' part, it prints between EVERY LATENCY LOG MESSAGE. Which means things are only ever found on the update list! So I don't understand how this method can be faster than method 2. The full, compilable code (requires GCC and boost-1.41) that generates random strings as test data is at: http://pastebin.com/e3HuL0nr

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  • How to fire server-side methods with jQuery

    - by Nasser Hajloo
    I have a large application and I'm going to enabling short-cut key for it. I'd find 2 JQuery plug-ins (demo plug-in 1 - Demo plug-in 2) that do this for me. you can find both of them in this post in StackOverFlow My application is a completed one and I'm goining to add some functionality to it so I don't want towrite code again. So as a short-cut is just catching a key combination, I'm wonder how can I call the server methods which a short-cut key should fire? So How to use either of these plug-ins, by just calling the methods I'd written before? Actually How to fire Server methods with Jquery? You can also find a good article here, by Dave Ward Update: here is the scenario. When User press CTRL+Del the GridView1_OnDeleteCommand so I have this protected void grdDocumentRows_DeleteCommand(object source, System.Web.UI.WebControls.DataGridCommandEventArgs e) { try { DeleteRow(grdDocumentRows.DataKeys[e.Item.ItemIndex].ToString()); clearControls(); cmdSaveTrans.Text = Hajloo.Portal.Common.Constants.Accounting.Documents.InsertClickText; btnDelete.Visible = false; grdDocumentRows.EditItemIndex = -1; BindGrid(); } catch (Exception ex) { Page.AddMessage(GetLocalResourceObject("AProblemAccuredTryAgain").ToString(), MessageControl.TypeEnum.Error); } } private void BindGrid() { RefreshPage(); grdDocumentRows.DataSource = ((DataSet)Session[Hajloo.Portal.Common.Constants.Accounting.Session.AccDocument]).Tables[AccDocument.TRANSACTIONS_TABLE]; grdDocumentRows.DataBind(); } private void RefreshPage() { Creditors = (decimal)((AccDocument)Session[Hajloo.Portal.Common.Constants.Accounting.Session.AccDocument]).Tables[AccDocument.ACCDOCUMENT_TABLE].Rows[0][AccDocument.ACCDOCUMENT_CREDITORS_SUM_FIELD]; Debtors = (decimal)((AccDocument)Session[Hajloo.Portal.Common.Constants.Accounting.Session.AccDocument]).Tables[AccDocument.ACCDOCUMENT_TABLE].Rows[0][AccDocument.ACCDOCUMENT_DEBTORS_SUM_FIELD]; if ((Creditors - Debtors) != 0) labBalance.InnerText = GetLocalResourceObject("Differentiate").ToString() + "?" + (Creditors - Debtors).ToString(Hajloo.Portal.Common.Constants.Common.Documents.CF) + "?"; else labBalance.InnerText = GetLocalResourceObject("Balance").ToString(); lblSumDebit.Text = Debtors.ToString(Hajloo.Portal.Common.Constants.Common.Documents.CF); lblSumCredit.Text = Creditors.ToString(Hajloo.Portal.Common.Constants.Common.Documents.CF); if (grdDocumentRows.EditItemIndex == -1) clearControls(); } Th other scenario are the same. How to enable short-cut for these kind of code (using session , NHibernate, etc)

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  • Good way to make animations with cocos2d?

    - by Johnny Oin
    Hi there, I'm making a little iphone game, and I would get some clues. Let's imagine: Two background sprites moving pretty fast from right to left, and moving up and down with accelerometer. I guess I can't use animations here, cause the movement of the background is recalculated at each frame. So I use a schedule with an interval of 0.025s and move my sprites at each clock with a : sprite.position = ccp(x, y); So here is my problem: the result is laggy, with only these two sprites. I tried both declaring sprites in the header, and getting them with CCNodes and Tags. It's quite the same. So if someone can give me a hint on what is the best way to do that, that would be so nice. I wonder if the problem can't be the fact that sprites are moving very fast, but i'm not sure. Anyway, thanks for your time. J.

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  • Javascript scope chain

    - by Geromey
    Hi, I am trying to optimize my program. I think I understand the basics of closure. I am confused about the scope chain though. I know that in general you want a low scope (to access variables quickly). Say I have the following object: var my_object = (function(){ //private variables var a_private = 0; return{ //public //public variables a_public : 1, //public methods some_public : function(){ debugger; alert(this.a_public); alert(a_private); }; }; })(); My understanding is that if I am in the some_public method I can access the private variables faster than the public ones. Is this correct? My confusion comes with the scope level of this. When the code is stopped at debugger, firebug shows the public variable inside the this keyword. The this word is not inside a scope level. How fast is accessing this? Right now I am storing any this.properties as another local variable to avoid accessing it multiple times. Thanks very much!

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  • Syntax Error in MySql StoredProc

    - by karthik
    I am using the below stored proc in mysql to generate the insert statements. I am getting the following error : Script line: 4 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '\’”\’,',’ifnull(‘,column_name,’,””)’,',\’”\’)')) INTO @S' at line 12 What would be the syntax problem in that ? DELIMITER $$ DROP PROCEDURE IF EXISTS `InsGen` $$ CREATE DEFINER=`root`@`localhost` PROCEDURE `InsGen`(in_db varchar(20),in_table varchar(20),in_file varchar(100)) BEGIN declare Whrs varchar(500); declare Sels varchar(500); declare Inserts varchar(2000); declare tablename varchar(20); set tablename=in_table; select tablename; # Comma separated column names – used for Select select group_concat(concat(‘concat(\’”\’,',’ifnull(‘,column_name,’,””)’,',\’”\’)')) INTO @Sels from information_schema.columns where table_schema=’test’ and table_name=tablename; # Comma separated column names – used for Group By select group_concat(‘`’,column_name,’`') INTO @Whrs from information_schema.columns where table_schema=’test’ and table_name=tablename; #Main Select Statement for fetching comma separated table values set @Inserts=concat(“select concat(‘insert into “, in_db,”.”,tablename,” values(‘,concat_ws(‘,’,”,@Sels,”),’);’) from “, in_db,”.”,tablename,” group by “,@Whrs, ” INTO OUTFILE ‘”, in_file ,”‘”); PREPARE Inserts FROM @Inserts; EXECUTE Inserts; END $$ DELIMITER ;

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  • Loading animation Memory leak

    - by Ayaz Alavi
    Hi, I have written network class that is managing all network calls for my application. There are two methods showLoadingAnimationView and hideLoadingAnimationView that will show UIActivityIndicatorView in a view over my current viewcontroller with fade background. I am getting memory leaks somewhere on these two methods. Here is the code -(void)showLoadingAnimationView { textmeAppDelegate *textme = (textmeAppDelegate *)[[UIApplication sharedApplication] delegate]; [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:YES]; if(wrapperLoading != nil) { [wrapperLoading release]; } wrapperLoading = [[UIView alloc] initWithFrame:CGRectMake(0.0, 0.0, 320.0, 480.0)]; wrapperLoading.backgroundColor = [UIColor clearColor]; wrapperLoading.alpha = 0.8; UIView *_loadingBG = [[UIView alloc] initWithFrame:CGRectMake(0.0, 0.0, 320.0, 480.0)]; _loadingBG.backgroundColor = [UIColor blackColor]; _loadingBG.alpha = 0.4; circlingWheel = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleWhiteLarge]; CGRect wheelFrame = circlingWheel.frame; circlingWheel.frame = CGRectMake(((320.0 - wheelFrame.size.width) / 2.0), ((480.0 - wheelFrame.size.height) / 2.0), wheelFrame.size.width, wheelFrame.size.height); [wrapperLoading addSubview:_loadingBG]; [wrapperLoading addSubview:circlingWheel]; [circlingWheel startAnimating]; [textme.window addSubview:wrapperLoading]; [_loadingBG release]; [circlingWheel release]; } -(void)hideLoadingAnimationView { [[UIApplication sharedApplication] setNetworkActivityIndicatorVisible:NO]; wrapperLoading.alpha = 0.0; [self.wrapperLoading removeFromSuperview]; //[NSTimer scheduledTimerWithTimeInterval:0.8 target:wrapperLoading selector:@selector(removeFromSuperview) userInfo:nil repeats:NO]; } Here is how I am calling these two methods [NSThread detachNewThreadSelector:@selector(showLoadingAnimationView) toTarget:self withObject:nil]; and then somewhere later in the code i am using following function call to hide animation. [self hideLoadingAnimationView]; I am getting memory leaks when I call showLoadingAnimationView function. Anything wrong in the code or is there any better technique to show loading animation when we do network calls?

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  • create new db in mysql with php syntax

    - by Jacksta
    I am trying to create a new db called testDB2, below is my code. Once running the script all I am getting an error on line 7 Fatal error: Call to undefined function mysqlquery() in /home/admin/domains/domain.com.au/public_html/db_createdb.php on line 7 This is my code <? $sql = "CREATE database testDB2"; $connection = mysql_connect("localhost", "admin_user", "pass") or die(mysql_error()); $result = mysqlquery($sql, $connection) or die(mysql_error()); if ($result) { $msg = "<p>Databse has been created!</p>"; } ?> <HTML> <head> <title>Create MySQL database</title> </head> <body> <? echo "$msg"; ?> </body> </HTML>

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  • SQL: Speed Improvement - Cluttered union query

    - by vol7ron
    SELECT * FROM ( SELECT a.user_id, a.f_name, a.l_name, b.user_id, b.f_name, b.l_name FROM current_tbl a INNER JOIN import_tbl b ON ( a.user_id = b.user_id ) UNION SELECT a.user_id, a.f_name, a.l_name, b.user_id, b.f_name, b.l_name FROM current_tbl a INNER JOIN import_tbl b ON ( lower(a.f_name)=lower(b.f_name) AND lower(a.l_name)=lower(b.l_name) ) ) foo -- UNION -- SELECT a.user_id , a.f_name , a.l_name , '' , '' , '' FROM current_tbl a WHERE a.user_id NOT IN ( select user_id from( SELECT a.user_id, a.f_name, a.l_name, b.user_id, b.f_name, b.l_name FROM current_tbl a INNER JOIN import_tbl b ON ( a.user_id = b.user_id ) UNION SELECT a.user_id, a.f_name, a.l_name, b.user_id, b.f_name, b.l_name FROM current_tbl a INNER JOIN import_tbl b ON ( lower(a.f_name)=lower(b.f_name) AND lower(a.l_name)=lower(b.l_name) ) ) bar ) ORDER BY user_id Example of table population: current_tbl: ------------------------------- user_id | f_name | l_name ---------+----------+---------- A1 | Adam | Acorn A2 | Beth | Berry A3 | Calv | Chard | | import_tbl: ------------------------------- user_id | f_name | l_name ---------+----------+---------- A1 | Adam | Acorn A2 | Beth | Butcher <- last_name different | | Expected Output: ----------------------------------------------------------------------- user_id1 | f_name1 | l_name1 | user_id2 | f_name2 | l_name2 ----------+-----------+-----------+------------+-----------+----------- A1 | Adam | Acorn | A1 | Adam | Acorn A2 | Beth | Berry | A2 | Beth | Butcher A3 | Calv | Chard | | | Doing this method gets rid of conditions where the row would be: A2 | Beth | Berry | A2 | Beth | Butcher But it keeps the A3 row I hope this makes sense and I haven't overly simplified it. This is a continuation question from my other question. The succession of these improvements has dropped the query down from ~32000ms to where it's at now ~1200ms - quite an improvement. I supect I can optimize by using UNION ALL in the subquery and of course the usual index optimizations, but I'm looking for the best SQL optimization. FYI this particular case is for PostgreSQL.

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  • WPF Dragging causes renderer to stop

    - by Cameron MacFarland
    I'm having a problem with my WPF app, where any sort of drag operation stops the UI from updating. The issue seems periodic, as in, the item drags, stops, drags again, stops, etc. in 2 second intervals. It's affecting all controls, including scroll bars. If checked this question as well as this one, and it doesn't seem to be caused by window transparencies. I'm running Win7 x64 with .NET 3.5sp1. Does anyone know what might be causing this, or a way of figuring out what might be causing this?

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  • Problem with SQL, ResultSet in java

    - by aphex
    How can I iterate ResultSet ? I've tried with the following code, but i get the error java.sql.SQLException: Illegal operation on empty result set. while ( !rs.isLast()) { rs.next(); int id = rs.getInt("person_id"); SQL.getInstance().getSt().execute("INSERT ref_person_pub(person_id) VALUES(" + id + ")"); }

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  • MySQL table data transformation -- how can I dis-aggregate MySQL time data?

    - by lighthouse65
    We are coding for a MySQL data warehousing application that stores descriptive data (User ID, Work ID, Machine ID, Start and End Time columns in the first table below) associated with time and production quantity data (Output and Time columns in the first table below) upon which aggregate (SUM, COUNT, AVG) functions are applied. We now wish to dis-aggregate time data for another type of analysis. Our current data table design: +---------+---------+------------+---------------------+---------------------+--------+------+ | User ID | Work ID | Machine ID | Event Start Time | Event End Time | Output | Time | +---------+---------+------------+---------------------+---------------------+--------+------+ | 080025 | ABC123 | M01 | 2008-01-24 16:19:15 | 2008-01-24 16:34:45 | 2120 | 930 | +---------+---------+------------+---------------------+---------------------+--------+------+ Reprocessing dis-aggregation that we would like to do would be to transform table content based on a granularity of minutes, rather than the current production event ("Event Start Time" and "Event End Time") granularity. The resulting reprocessing of existing table rows would look like: +---------+---------+------------+---------------------+--------+ | User ID | Work ID | Machine ID | Production Minute | Output | +---------+---------+------------+---------------------+--------+ | 080025 | ABC123 | M01 | 2010-01-24 16:19 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:20 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:21 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:22 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:23 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:24 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:25 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:26 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:27 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:28 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:29 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:30 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:31 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:22 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:33 | 133 | | 080025 | ABC123 | M01 | 2010-01-24 16:34 | 133 | +---------+---------+------------+---------------------+--------+ So the reprocessing would take an existing row of data created at the granularity of production event and modify the granularity to minutes, eliminating redundant (Event End Time, Time) columns while doing so. It assumes a constant rate of production and divides output by the difference in minutes plus one to populate the new table's Output column. I know this can be done in code...but can it be done entirely in a MySQL insert statement (or otherwise entirely in MySQL)? I am thinking of a INSERT ... INTO construction but keep getting stuck. An additional complexity is that there are hundreds of machines to include in the operation so there will be multiple rows (one for each machine) for each minute of the day. Any ideas would be much appreciated. Thanks.

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  • has anyone used simile timeline with large amounts of data

    - by oo
    i am using this simile timeline with large amounts of data and i keep getting firefox popping up saying "a script has appeared to no longer be running, do you want to kill it"? is there a limit to the amount of json you can send back to it. I have about 1000 different timeline points with dates, descriptions, etc.

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  • How well do zippers perform in practice, and when should they be used?

    - by Rob
    I think that the zipper is a beautiful idea; it elegantly provides a way to walk a list or tree and make what appear to be local updates in a functional way. Asymptotically, the costs appear to be reasonable. But traversing the data structure requires memory allocation at each iteration, where a normal list or tree traversal is just pointer chasing. This seems expensive (please correct me if I am wrong). Are the costs prohibitive? And what under what circumstances would it be reasonable to use a zipper?

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