Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p><strong>Short answer</strong> - dev server is 32bit process.</p> <p>Long answer for "why just 256Mb?"</p> <p>First of all, let's understand how it works.</p> <p>MemoryStream has internal byte[] buffer to keep all the data. It cannot predict exact size of this buffer, so it just initializes it with some initial value. </p> <p>Position and Length properties don't reflect actual buffer size - they are logical values to reflect how many bytes is written, and easily may be smaller than actual physical buffer size.</p> <p>When this internal buffer can not fit all the data, it should be "re-sized", but in real life it means <strong>creating new buffer</strong> twice as size as previous one, and then copying data from old buffer to new buffer.</p> <p>So, if the length of your buffer is 256Mb, and you need new data to be written, this means that .Net need to find yet another 512Mb block of data - having all the rest in place, so heap should be at least 768Mb on the moment of memory allocation when you receive OutOfMemory.</p> <p>Also please notice that by default no single object, including arrays, in .Net can take more than 2Gb in size.</p> <p>Ok, so here is the sample piece which simulates what's happening:</p> <pre><code> byte[] buf = new byte[32768 - 10]; for (; ; ) { long newSize = (long)buf.Length * 2; Console.WriteLine(newSize); if (newSize &gt; int.MaxValue) { Console.WriteLine("Now we reach the max 2Gb per single object, stopping"); break; } var newbuf = new byte[newSize]; Array.Copy(buf, newbuf, buf.Length); buf = newbuf; } </code></pre> <p>If it built in x64/AnyCPU and runs from console - everything is ok. </p> <p>If it built across x86 - it fails in console. </p> <p>If you put it to say Page_Load, built in x64, and open from VS.Net web server - it fails.</p> <p>If you do the same with IIS - everything is ok.</p> <p>Hope this helps.</p>
    singulars
    1. This table or related slice is empty.
    1. POOutOfMemoryException while populating MemoryStream: 256MB allocation on 16GB system
      singulars
      1. PTQuestion
    1. PTAnswer
    1. This table or related slice is empty.
    1. USLanorkin
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POOutOfMemoryException while populating MemoryStream: 256MB allocation on 16GB system
      singulars
      1. PTQuestion
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    3. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. COMost importantly, the 512 MB being allocated must be a contiguous chunk of memory. It's not that there isn't enough address space available in 32-bit; it's just that the address space is fragmented. A Stream implementation that uses multiple smaller byte arrays could get much closer to the 2 GB limit.
      singulars
      1. PO
      1. USDaniel
    2. COThank you for the explanation. On a different subject though -- why can't OS defragment its internal RAM mapping, say, while computer is not in use? Because it's ridiculous that it can't allocate 512MB of data. What, is it Windows 95? Sometimes I wonder if Microsoft did anything special in Windows 7 since those old days...
      singulars
      1. PO
      1. USc00000fd
    3. COIt's not as bad as you may think ) Read this answer for example http://stackoverflow.com/a/5243503/2170171 In most cases 512Mb will be allocated without any issues on 16Gb RAM machine, here is such specific case http://stackoverflow.com/questions/686950/large-object-heap-fragmentation
      singulars
      1. PO
      1. USLanorkin
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload