Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>You could remove the "invalid" <code>WeakReference</code> inside <code>TryGetValue</code>:</p> <p><strong>[Edit]</strong> My mistake, these solutions actually do nothing more than what you suggested, since <code>Put</code> method will swap the old object with the new one anyway. Just ignore it.</p> <pre><code>public bool TryGetValue(TKey key, out TValue value) { WeakReference weakRef; if (!this.items.TryGetValue(key, out weakRef)) { value = null; return false; } else { value = (TValue)weakRef.Target; if (value == null) this.items.Remove(key); return (value != null); } } </code></pre> <p>Or, you can immediatelly create a new instance inside your dictionary, whenever it is needed:</p> <pre><code>public TValue GetOrCreate(TKey key, Func&lt;Tkey, TValue&gt; ctor) { WeakReference weakRef; if (!this.items.TryGetValue(key, out weakRef) { Tvalue result = ctor(key); this.Put(key, result); return result; } value = (TValue)weakRef.Target; if (value == null) { Tvalue result = ctor(key); this.Put(key, result); return result; } return value; } </code></pre> <p>You would then use it like this:</p> <pre><code>static Foo CreateFoo(int id) { return cache.GetOrCreate(id, id =&gt; new Foo(id)); } </code></pre> <p><strong>[Edit]</strong> </p> <p>According to windbg, <code>WeakReference</code> instance alone occupies 16 bytes. For 100,000 collected objects, this would not be such a serious burden, so you could easily let them live.</p> <p>If this is a server app and you believe you could benefit from collecting, I would consider going for a background thread, but also implementing a simple algorithm to <strong>increase waiting time</strong> whenever you collect a relatively small number of objects.</p>
    singulars
    1. This table or related slice is empty.
    1. POCompacting a WeakReference Dictionary
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USGroo
    1. USGroo
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. COIn this case it will be re-inserted by `CreateFoo` immediately, so this is sadly no improvement.
      singulars
      1. PO
      1. USdtb
    2. COYou could do the scans to compact the dictionary when you remove a weak reference.
      singulars
      1. PO
      1. USKevin Brock
    3. COThere is not only the dead WeakReference that occupies space, but also the internal structures of the Dictionary. So even if the number of active Foo objects stays constants, the hash table needs to constantly grow to accommodate all the dead WeakReferences.
      singulars
      1. PO
      1. USdtb
 

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