Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>Most likely you are partially misled in your interpretation of the profilers results. Profilers are notoriously overinflating the performance impact of small, frequently called methods. In your case, the profiling overhead for the get()-method is probably larger than the actual processing spent in the method itself. The situation is worsened further, since the instrumentation also interferes with the JIT's capability to inline methods.</p> <p>As a rule of thumb for this situation - if the total processing time for a piece of work of known length increases more then two- to threefold when running under the profiler, the profiling overhead will give you skewed results.</p> <p>To verify your changes actually do have impact, always measure performance improvements <b>without the profiler</b>, too. The profiler can hint you about bottlenecks, but it can also deceive you to look at places where nothing is wrong.</p> <p>Array bounds checking can have a surprisingly large impact on performance (if you do comparably little else), but it can also be hard to clearly separate from general memory access penalties. In some trivial cases, the JIT might be able to eliminate them (there have been efforts towards bounds check elimination in Java 6), but this is AFAIK mostly limited to simple loop constructs like for(x=0; x&lt;array.length; x++). Under some circumstances you may be able to replace array access by simple member access, completely avoiding the bound checks, but its limited to the rare cases where you access you array exclusively by constant indices. I see no way to apply it to your problem.</p> <p>The change suggested by Mark Peters is most likely not solely faster because it eliminates a bounds check, but also because it alters the locality properties of your data structures in a more cache friendly way.</p>
    singulars
    1. This table or related slice is empty.
    1. POcan array access be optimized?
      singulars
      1. PTQuestion
    1. PTAnswer
    1. This table or related slice is empty.
    1. USDurandal
    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. COA lot of the codebase is little more than array manipulations; I've been wondering if I was getting bitten by the overhead of the array bounds checks, but you make a good point about the locality of the properties.
      singulars
      1. PO
      1. USMichael
 

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