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  • Proper NSArray initialization for ivar data in a method

    - by Joost Schuur
    I'm new to Objective-C and iPhone development and have been using Apress' Beginning iPhone 3 Programming book as my main guide for a few weeks now. In a few cases as part of a viewDidLoad: method, ivars like a breadTypes NSArray are initialized like below, with an intermediate array defined and then ultimately set to the actual array like this: NSArray *breadArray = [[NSArray alloc] initWithObjects:@"White", @"Whole Weat", @"Rye", @"Sourdough", @"Seven Grain", nil]; self.breadTypes = breadArray; [breadArray release]; Why is it done this way, instead of simply like this: self.breadTypes = [[NSArray alloc] initWithObjects:@"White", @"Whole Weat", @"Rye", @"Sourdough", @"Seven Grain", nil]; Both seem to work when I compile and run it. Is the 2nd method above not doing proper memory management? I assume initWithObjects: returns an array with a retain count of 1 and I eventually release breadTypes again in the dealloc: method, so that wraps things up nicely. I'm guessing 'self.breadTypes = ...' copies the data to the new array, which is why the original array can be safely released, correct?

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  • Piping SoX in Python - subprocess alternative?

    - by Cochise Ruhulessin
    I use SoX in an application. The application uses it to apply various operations on audiofiles, such as trimming. This works fine: from subprocess import Popen, PIPE kwargs = {'stdin': PIPE, 'stdout': PIPE, 'stderr': PIPE} pipe = Popen(['sox','-t','mp3','-', 'test.mp3','trim','0','15'], **kwargs) output, errors = pipe.communicate(input=open('test.mp3','rb').read()) if errors: raise RuntimeError(errors) This will cause problems on large files hower, since read() loads the complete file to memory; which is slow and may cause the pipes' buffer to overflow. A workaround exists: from subprocess import Popen, PIPE import tempfile import uuid import shutil import os kwargs = {'stdin': PIPE, 'stdout': PIPE, 'stderr': PIPE} tmp = os.path.join(tempfile.gettempdir(), uuid.uuid1().hex + '.mp3') pipe = Popen(['sox','test.mp3', tmp,'trim','0','15'], **kwargs) output, errors = pipe.communicate() if errors: raise RuntimeError(errors) shutil.copy2(tmp, 'test.mp3') os.remove(tmp) So the question stands as follows: Are there any alternatives to this approach, aside from writing a Python extension to the Sox C API?

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  • What do I use when a cron job isn't enough? (php)

    - by mike
    I'm trying to figure out the most efficient way to running a pretty hefty PHP task thousands of times a day. It needs to make an IMAP connection to Gmail, loop over the emails, save this info to the database and save images locally. Running this task every so often using a cron isn't that big of a deal, but I need to run it every minute and I know eventually the crons will start running on top of each other and cause memory issues. What is the next step up when you need to efficiently run a task multiple times a minute? I've been reading about beanstalk & pheanstalk and I'm not entirely sure if that will do what I need. Thoughts???

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  • Recordset manipulation in SSIS

    - by JSacksteder
    In my SSIS job, I have a need to accumulate a set of rows and commit them all transitionally when processing has completed successfully. If this was pure SQL, I would use a temp table inside a transaction. In SSIS there are a number of issues complicating this. It's difficult to have multiple components share the same transaction and having temp tables that do not exist at design time is a pain. If I use Recordsets inside SSIS for this purpose, there are other issues. My understanding is that an 'Execute SQL' component will re-initialize the Recordset when it runs, so I can't use that to append an additional row. Is there a way to create an OLE DB connection that references an in-memory Recordset? Is there a better way to achieve this result?

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  • Launching Vim via Lua

    - by Keith Pimmel
    I'm writing a simple little Lua commandline app that will build a static website. I'm storing my fragments in a sqlite database. Retrieving the data from the db is straightforward as is saving it; my question comes from editing the data. Is there an elegant way to pipe the data from Lua to vim? Can vim edit a memory buffer and return it? I was planning on launching the editor via os.execute('vim') but only after grabbing a temporary file handle and dumping the database output into that. I would like to have to avoid touching the filesystem that way but that is my contingency plan.

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  • SDK for writing DVD's

    - by Matt Warren
    I need to add DVD writing functionality to an application I'm working on. However it needs to be able to write out files that are being grabbed "live" from a camera, over a long period of time. I can't wait until all the files are captured before I start writing them to the DVD, I need to write them out in chunks as I go along. I've looked at IMAPI v2, but the main problems seems to be that you need to point it to all the files you plan to write out to disk before you start the burning process. I know it has to concept of "sessions", which means you can write to the DVD in several parts, before you finally "close" it. But I was wondering if there were any other DVD writing SDK's that allow you to be constantly writing files to a DVD and in particular files that are only in memory. It would be more efficient if I didn't have to write the captured images out to hard before they are burned to DVD. The solution needs to work under .NET on Windows XP and vista

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  • LINQ to SQL SubmitChangess() progress

    - by Emir
    I'm using LINQ to SQLto import old DBF files into MSSQL. I'm reading all rows and adding them to database using ctx.MyTable.InsertOnSubmit(row) After reading phase is completed I have around 100 000 pending inserts. ctx.SubmitChanges() naturally is taking a long time. Is there any way to track progress of the ctx.submitchanges()? Can ctx.Log somehow be used for this purpose? Update: Is it possible to use ctx.GetChangeSet().Inserts.Count and track insert statements using the Log? Dividing ctx.SubmitChanges() into smaller chunks is not working for me, because I need transaction, all or nothing. Update 2: I've found nice class ActionTextWriter using which I will try to count inserts. http://damieng.com/blog/2008/07/30/linq-to-sql-log-to-debug-window-file-memory-or-multiple-writers

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  • Delphi - Using DeviceIoControl passing IOCTL_DISK_GET_LENGTH_INFO to get flash media physical size (Not Partition)

    - by SuicideClutchX2
    Alright this is the result of a couple of other questions. It appears I was doing something wrong with the suggestions and at this point have come up with an error when using the suggested API to get the media size. Those new to my problem I am working at the physical disk level, not within the confines of a partition or file system. Here is the pastebin code for the main unit (Delphi 2009) - http://clutchx2.pastebin.com/iMnq8kSx Here is the application source and executable with a form built to output the status of whats going on - http://www.mediafire.com/?js8e6ci8zrjq0de Its probably easier to use the download, unless your just looking for problems within the code. I will also paste the code here. unit Main; interface uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls; type TfrmMain = class(TForm) edtDrive: TEdit; lblDrive: TLabel; btnMethod1: TButton; btnMethod2: TButton; lblSpace: TLabel; edtSpace: TEdit; lblFail: TLabel; edtFail: TEdit; lblError: TLabel; edtError: TEdit; procedure btnMethod1Click(Sender: TObject); private { Private declarations } public { Public declarations } end; TDiskExtent = record DiskNumber: Cardinal; StartingOffset: Int64; ExtentLength: Int64; end; DISK_EXTENT = TDiskExtent; PDiskExtent = ^TDiskExtent; TVolumeDiskExtents = record NumberOfDiskExtents: Cardinal; Extents: array[0..0] of TDiskExtent; end; VOLUME_DISK_EXTENTS = TVolumeDiskExtents; PVolumeDiskExtents = ^TVolumeDiskExtents; var frmMain: TfrmMain; const FILE_DEVICE_DISK = $00000007; METHOD_BUFFERED = 0; FILE_ANY_ACCESS = 0; IOCTL_DISK_BASE = FILE_DEVICE_DISK; IOCTL_VOLUME_BASE = DWORD('V'); IOCTL_DISK_GET_LENGTH_INFO = $80070017; IOCTL_VOLUME_GET_VOLUME_DISK_EXTENTS = ((IOCTL_VOLUME_BASE shl 16) or (FILE_ANY_ACCESS shl 14) or (0 shl 2) or METHOD_BUFFERED); implementation {$R *.dfm} function GetLD(Drive: Char): Cardinal; var Buffer : String; begin Buffer := Format('\\.\%s:',[Drive]); Result := CreateFile(PChar(Buffer),GENERIC_READ Or GENERIC_WRITE,FILE_SHARE_READ,nil,OPEN_EXISTING,0,0); If Result = INVALID_HANDLE_VALUE Then begin Result := CreateFile(PChar(Buffer),GENERIC_READ,FILE_SHARE_READ,nil,OPEN_EXISTING,0,0); end; end; function GetPD(Drive: Byte): Cardinal; var Buffer : String; begin If Drive = 0 Then begin Result := INVALID_HANDLE_VALUE; Exit; end; Buffer := Format('\\.\PHYSICALDRIVE%d',[Drive]); Result := CreateFile(PChar(Buffer),GENERIC_READ Or GENERIC_WRITE,FILE_SHARE_READ,nil,OPEN_EXISTING,0,0); If Result = INVALID_HANDLE_VALUE Then begin Result := CreateFile(PChar(Buffer),GENERIC_READ,FILE_SHARE_READ,nil,OPEN_EXISTING,0,0); end; end; function GetPhysicalDiskNumber(Drive: Char): Byte; var LD : DWORD; DiskExtents : PVolumeDiskExtents; DiskExtent : TDiskExtent; BytesReturned : Cardinal; begin Result := 0; LD := GetLD(Drive); If LD = INVALID_HANDLE_VALUE Then Exit; Try DiskExtents := AllocMem(Max_Path); DeviceIOControl(LD,IOCTL_VOLUME_GET_VOLUME_DISK_EXTENTS,nil,0,DiskExtents,Max_Path,BytesReturned,nil); If DiskExtents^.NumberOfDiskExtents > 0 Then begin DiskExtent := DiskExtents^.Extents[0]; Result := DiskExtent.DiskNumber; end; Finally CloseHandle(LD); end; end; procedure TfrmMain.btnMethod1Click(Sender: TObject); var PD : DWORD; CardSize: Int64; BytesReturned: DWORD; CallSuccess: Boolean; begin PD := GetPD(GetPhysicalDiskNumber(edtDrive.Text[1])); If PD = INVALID_HANDLE_VALUE Then Begin ShowMessage('Invalid Physical Disk Handle'); Exit; End; CallSuccess := DeviceIoControl(PD, IOCTL_DISK_GET_LENGTH_INFO, nil, 0, @CardSize, SizeOf(CardSize), BytesReturned, nil); if not CallSuccess then begin edtError.Text := IntToStr(GetLastError()); edtFail.Text := 'True'; end else edtFail.Text := 'False'; CloseHandle(PD); end; end. I placed a second method button on the form so I can write a different set of code into the app if I feel like it. Only minimal error handling and safeguards are there is nothing that wasn't necessary for debugging this via source. I tried this on a Sony Memory Stick using a PSP as the reader because I cant find the adapter for using a duo in my machine. The target is an MS and half of my users use a PSP for a reader half dont. However this should work fine on SD cards and that is a secondary target for my work as well. I tried this on a usb memory card reader and several SD cards. Now that I have fixed my attempt I get an error returned. 50 ERROR_NOT_SUPPORTED The request is not supported. I have found an application that uses this API as well as alot of related functions for what I am trying todo. I am getting ready to look into it the application is called DriveImage and its source is here - http://sourceforge.net/projects/diskimage/ The only thing I have really noticed from that application is there use of TFileStream and using that to get a handle on the physical disk.

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  • Media Foundation: another way to call IMFActivate::ShutdownObject?

    - by KenC
    Hi, Here is a question about IMFActivate::ActivateObject and IMFActivate::ShutdownObject in Media Foundation. According to MSDN, the component that calls ActivateObject is responsible for calling ShutdownObject. But there are two examples not following this rule: http://msdn.microsoft.com/en-us/library/dd388503%28VS.85%29.aspx and http://msdn.microsoft.com/en-us/library/dd317912%28VS.85%29.aspx In these two examples, they call ActivateObject and then release IMFActivate interface without calling ShutdownObject method. This is going to lead to memory leaking, right? Or there is another way to release the resource occupied by the object? (Can I use IMFMediaSource::Shutdown to release the object instead of using IMFActivate::ShutdownObject) Thanks in advance.

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  • Java: Netbeans debugging session works faster than normal run

    - by Martijn Courteaux
    Hello, I'm making Braid in Netbeans 6.7.1. Computer Spec: Windows 7 Running processes: 46 Running threads: +/- 650 NVidia GeForce 9200M GS Intel Core 2 Duo CPU P8400 @ 2.26Ghz Game-spec with normal run: Memory: between 80 MB and 110 MB CPU: between 9% and 20% CPU when time rewinding: 90% The same values for the debugging session, except when I rewind the time: CPU: 20%. Is there any reason for? Is there a way to reach the same performance with a normal run. This is my repaint code: @Override public void repaint() { BufferStrategy bs = getBufferStrategy(); // numBuffers: 4 Graphics g = bs.getDrawGraphics(); g.setColor(Color.BLACK); g.fillRect(-1, -1, 2000, 2000); gamePanel.paint(g.create(x, y, gameDim.width, gameDim.height)); bs.show(); g.dispose(); Toolkit.getDefaultToolkit().sync(); update(g); } The game runs in fullscreen (undecorated + frame.size = screensize) Martijn

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  • Garbage collecting at ColdFusion CFC

    - by Sergii
    Hello. I have a CFC as singletone object in Application scope. One of the methods is used for massive data processing and periodically causes the "Java heap space" errors. EDIT All variables inside the method are VAR-scoped, so they should not be kept in the object scope when invokation ended. It can be a bit dumb question for Java people, but I'd like to know how Java garbage collector cleans up the CFC methods memory: only when whole request ends, or maybe right after each method/function invokation? Second option is interesting because it can allow me to split my large method into the few, as one of the possible optimizations.

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  • Cancel UDP recvfrom in C on Unix

    - by hora
    I'm just starting to learn how network programming in C works, and I've written a small program that sends messages to and from a UNIX terminal. I'm using pthreads in my program, one of which essentially just waits on recvfrom() to receive a message. However, I want to be able to close all threads properly if the users chooses to quit the program. The way I have it set up right now, a different thread just cancels the thread waiting on recvfrom, but I'm worried this might not be a good idea since I'm leaving sockets unclosed and I'm not freeing all the memory I allocated. Is there a way to cancel a recvfrom() call, or some way to run a certain routine upon cancelling a pthread? Thanks.

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  • Windbg pseudoregister expansion

    - by Giuseppe Guerrini
    Hi, I am trying to automate a device driver's debug session in Windows XP with Windbg. My device has an "index" register and a "data" register, both memory mapped. The index register must be filled with the internal register's index, and the value can be read from the data register. So, the followind Windbg command prints correctly the value of the internel register 0x4C: !ed [uc] 0xfa000000 0x4c; !dd [uc] 0xfa000004 L1 Now I would like to dump a range of internal registers, but it seems that the alias expansion doesn't work as expected in the !ed command. I am trying this cycle: .for (r $t0=0; @$t0<0x100; r $t0=@$t0+1) { !ed [uc] 0xfa000000 @$t0; !dd [uc] 0xfa000004 L1 } but it seems that the !ed command is ignored, as if @$t0 was expanded in an empty string. Tried "$t0", "@$t0", "${t0}" and "@${t0}", but without success. What am I doing wrong? Thank you in advance

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  • C - Malloc or calloc...and how?

    - by Pedro
    Hi...i have a txt file where the first number define the size of the array's, i know that calloc or malloc can reserve memory, but how? this code: typedef struct alpha{ int *size; char name; int tot; char line[60]; }ALPHA; fgets(line,60,fp); tot=atoi(line); size=(int*)calloc(name,sizeof(int); Imagine that in the first line of the txt is the number 10, wiht this code the size of name will be 10? like name[10]???

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  • Connecting to multiple firebird Databases via Delphi

    - by Branden
    I am integrating a system with 2 other applications, 1 using a Firebird database whilst the other BIS (using ADO). My delphi application uses Firebird. I need to read data from my database, insert it into both the BIS database and the other application firebird database. I have created seperate data modules for each. Sending data to the ADO works fine, but when writing to the other Firebird DB (my db still open) I get strange errors. I have managed to isolate the problem to the second firebird DB. Small data writes seems fine. The data structures are completly different, so un able to use a synch tool. is there a way to overcome this by using multi threading or seperate memory space each Firebird instance uses?

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  • Optimize code performance when odd/even threads are doing different things in CUDA

    - by Orion Nebula
    Hi all! I have two large vectors, I am trying to do some sort of element multiplication, where an even-numbered element in the first vector is multiplied by the next odd-numbered element in the second vector .... and where the odd-numbered element in the first vector is multiplied by the preceding even-numbered element in the second vector Ex. vector 1 is V1(1) V1(2) V1(3) V1(4) vector 2 is V2(1) V2(2) V2(3) V2(4) V1(1) * V2(2) V1(3) * V2(4) V1(2) * V2(1) V1(4) * V2(3) I have written a Cuda code to do this: (Pds has the elements of the first vector in shared memory, Nds the second Vector) //instead of using %2 .. i check for the first bit to decide if number is odd/even -- faster if ((tx & 0x0001) == 0x0000) Nds[tx+1] = Pds[tx] * Nds[tx+1]; else Nds[tx-1] = Pds[tx] * Nds[tx-1]; __syncthreads(); Is there anyway to further accelerate this code or avoid divergence ? Thanks

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  • Problem with HSQLDB & SequenceGenerator

    - by Srirangan
    Hi, I have an entity which has an ID field: @Id @Column(name = "`U##ID_VOIE`") @GeneratedValue(generator = "VOIE_SEQ") private String id; The class has the sequence generator defined as well: @SequenceGenerator(name = "VOIE_SEQ", sequenceName = "VOIE_SEQ") and the Oracle schema has the requisite sequence present. Everything works okay. We also have tests, which uses an in-memory HSQLDB. Before running the tests, all the tables are created based on the Hibernate entity classes. However the table for this particular class is not being created. And error pops up, because ID is a String and the SequenceGenerator in HSQLDB returns an INT / LONG / Numeric value. The application is using a legacy Oracle database and ID_VOIE column must remain a String / Varchar. Any solutions?

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  • How do sprites work?

    - by Alan
    How do sprites work? I've seen sprites from old school games like Super Mario Brothers, and wondered how they're animated to make a game. They're always presented as one big image map, so how are they used? For Mario (as an example) are there precalculated image co-ordinates that outline mario, and are swapped between various mario sprites to produce animation? Or are sprites pre "cut" during game initialization using precalculated images co-ordinates and stored in memory somewhere? Obviously I know nothing about game development.

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  • Linq To Sql: Compiled Queries and Extension Methods

    - by Beni
    Hi community, I'm interessted, how does Linq2Sql handles a compiled query, that returns IQueryable. If I call an extension method based on a compiled query like "GetEntitiesCompiled().Count()" or "GetEntitiesCompiled().Take(x)". What does Linq2Sql do in the background? This would be very bad, so in this situation I should write a compiled query like "CountEntitiesCompiled". Does he load the result (in this case "GetEntitiesCompiled()") into the memory (mapped to the entity class like "ToList()")? So what situations make sense, when the compiled queries return IQueryable, that query is not able to modify, before request to the Sql-Server. So in my opinion I can just as good return List. Thanks for answers!

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  • When is a C++ terminate handler the Right Thing(TM)?

    - by Joseph Garvin
    The C++ standard provides the std::set_terminate function which lets you specify what function std::terminate should actually call. std::terminate should only get called in dire circumstances, and sure enough the situations the standard describes for when it's called are dire (e.g. an uncaught exception). When std::terminate does get called the situation seems analagous to being out of memory -- there's not really much you can sensically do. I've read that it can be used to make sure resources are freed -- but for the majority of resources this should be handled automatically by the OS when the process exits (e.g. file handles). Theoretically I can see a case for if say, you needed to send a server a specific message when exiting due to a crash. But the majority of the time the OS handling should be sufficient. When is using a terminate handler the Right Thing(TM)? Update: People interested in what can be done with custom terminate handlers might find this non-portable trick useful.

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  • Read entire file in Scala?

    - by Brendan OConnor
    What's a simple and canonical way to read an entire file into memory in Scala? (Ideally, with control over character encoding.) The best I can come up with is: scala.io.Source.fromPath("file.txt").getLines.reduceLeft(_+_) or am I supposed to use one of Java's god-awful idioms, the best of which (without using an external library) seems to be: import java.util.Scanner import java.io.File new Scanner(new File("file.txt")).useDelimiter("\\Z").next() From reading mailing list discussions, it's not clear to me that scala.io.Source is even supposed to be the canonical I/O library. I don't understand what its intended purpose is, exactly. ... I'd like something dead-simple and easy to remember. For example, in these languages it's very hard to forget the idiom ... Ruby open("file.txt").read Ruby File.read("file.txt") Python open("file.txt").read()

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  • Writing out BMP files with DataBuffer.TYPE_FLOAT or DataBuffer.TYPE_DOUBLE in java

    - by Basil Dsouza
    Hi Guys, I had a problem working with the image classes in java. I am creating a buffered image with DataBuffer.TYPE_DOUBLE. This all works fine in memory (I think). But the problem starts when I try to write it using ImageIO.write. Initially I was getting no exception at all and instead was only getting an empty output file for my troubles.. After a bit of poking around in the code, i found out that the bmp writer doesnt support writing type_double type of files. From: BMPImageWriterSpi.canEncodeImage: if (dataType < DataBuffer.TYPE_BYTE || dataType > DataBuffer.TYPE_INT) return false; So my question is, does anyone have a way of writing out those kind of images to disk? any documentation or tutorial, or link would be helpful. Thanks, Basil Dsouza

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  • Discover the environment and relative path of the running application

    - by Shyam
    Hi, While playing with RubyCocoa, I keep progressing with my idea for my application. Because my application will be going to use configuration files, I would like to know how I discover the relative path to store these inside my application structure (or if a better idea emerges, please elaborate also the "why"). Also good for me to know is to discover environment variables, such as operating system version, the amount of memory that is available and such. Hyperlinks would be awesome too. Please notice I use RubyCocoa and thank you for your feedback, comments and answers!

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  • What's the best way to count unique visitors with Hadoop?

    - by beagleguy
    hey all, just getting started on hadoop and curious what the best way in mapreduce would be to count unique visitors if your logfiles looked like this... DATE siteID action username 05-05-2010 siteA pageview jim 05-05-2010 siteB pageview tom 05-05-2010 siteA pageview jim 05-05-2010 siteB pageview bob 05-05-2010 siteA pageview mike and for each site you wanted to find out the unique visitors for each site? I was thinking the mapper would emit siteID \t username and the reducer would keep a set() of the unique usersnames per key and then emit the length of that set. However that would be potentially storing millions of usernames in memory which doesn't seem right. Anyone have a better way? I'm using python streaming by the way thanks

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  • Do Blob properties on entities affect query performance?

    - by Jaroslav Záruba
    Hello I'm trying to make my mind on whether to store a binary representation of an entity as its Blob property, or whether I better keep the blobs in some separate 'wrapping' class. Possible impact on memory heap and/or a query execution time are my concerns in the first case, complexity votes against the other one. I know Blobs are not indexed, i.e. index size is not what I'm worrying about. Also I assume for blobs Datastore puts defaultFetchGroup to false, but does it mean that blobs don't make a difference in queries? Regards J. Záruba

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