Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>There are a few things you should fix.</p> <ul> <li><p>The methods on the Queue type should have pointer receivers. Otherwise, every method call will create a copy of the current queue type and any changes to queue fields will not persist beyond the method call itself.</p></li> <li><p>Waiting for all routines to finish, can be done using a <code>sync.WaitGroup</code>. This is specifically what it was designed for.</p></li> <li><p>Maintaining a thread-safe push/pop counter inside the queue type can be done by using the <code>sync/atomic</code> package.</p></li> </ul> <p>As far as speed goes, from your example, I am not quite sure what you are trying to achieve. Any optimizations might come up if you elaborate on that a little.</p> <p>Here is an example I modified from your code:</p> <pre><code>package main import ( "log" "runtime" "sync" "sync/atomic" "time" ) const SizePerThread = 10000000 type Queue struct { records string count int64 } func (q *Queue) push(record chan interface{}) { record &lt;- time.Now() newcount := atomic.AddInt64(&amp;q.count, 1) log.Printf("Push: %d", newcount) } func (q *Queue) pop(record chan interface{}) { &lt;-record newcount := atomic.AddInt64(&amp;q.count, -1) log.Printf("Pop: %d", newcount) } func main() { var wg sync.WaitGroup runtime.GOMAXPROCS(runtime.NumCPU()) record := make(chan interface{}, 1000000) queue := new(Queue) // We are launching 20 goroutines. // Let the waitgroup know it should wait for as many // of them to finish. wg.Add(20) for i := 0; i &lt; 10; i++ { go func() { defer wg.Done() for j := 0; j &lt; SizePerThread; j++ { queue.push(record) } }() go func() { defer wg.Done() for j := 0; j &lt; SizePerThread; j++ { queue.pop(record) } }() } // Wait for all goroutines to finish. wg.Wait() } </code></pre>
    singulars
    1. This table or related slice is empty.
    1. POHow to implement a counter when using golang's goroutine?
      singulars
      1. PTQuestion
    1. PTAnswer
    1. This table or related slice is empty.
    1. USjimt
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. POHow to implement a counter when using golang's goroutine?
      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. COThanks @jimt, but i'm not quite understand what you mean by **the Queue type should have pointer receivers**, could you give me a link on golang's doc? i can't find any, Thanks again.
      singulars
      1. PO
      1. USMrROY
    2. CO@MrROY: This section of Effective Go discusses the difference: http://golang.org/doc/effective_go.html#pointers_vs_values. Essentially, if the receiver is (T), your method gets a *copy* of the object it is called from and therefore cannot change it. If the receiver is (*T) it gets a pointer to it.
      singulars
      1. PO
      1. USThomas Kappler
    3. COIn cases where the number of go-routines is not strictly known at compile time, is there any reason to not call `wg.Add(1)` `defer.wg.Done()` in each created goroutine?
      singulars
      1. PO
      1. USmatthias
 

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