Uploaded image for project: 'WiredTiger'
  1. WiredTiger
  2. WT-1396

Concurrently appending to a tree

XMLWordPrintableJSON

    • Type: Icon: Task Task
    • Resolution: Done
    • WT2.5.0
    • Affects Version/s: None
    • Component/s: None

      One reasonably common workload is for applications to append to a tree from multiple threads. For example the YCSB load phase does that.

      What generally happens is that pages grow quickly to reach the configured memory_page_max, and then forced eviction is triggered. One thread is assigned evicting the page, and all the other threads tend to end up waiting for that page to be evicted. That behavior is exhibited when profiling shows many threads waiting in

      Unable to find source-code formatter for language: __wt_page_in. Available languages are: actionscript, ada, applescript, bash, c, c#, c++, cpp, css, erlang, go, groovy, haskell, html, java, javascript, js, json, lua, none, nyan, objc, perl, php, python, r, rainbow, ruby, scala, sh, sql, swift, visualbasic, xml, yaml
      

      

      .
      


      I'm not sure if there is anything we could do to avoid having all threads waiting for reconciliation to complete. Perhaps we could switch in a new page, if operations are appends. Then proceed to reconcile (or in-memory split) the page that is now no longer the last page in the tree.
      
            
      

      

          


          

            








            
                        


            
    
            Assignee:
            
    
            
        

            
            



    
    keith.bostic@mongodb.com
            Keith Bostic (Inactive)
            
        
    
            
            

            

                            

            
    
            Reporter:
            
    
            
        

            
            



    
    alexander.gorrod@mongodb.com
            Alexander Gorrod
            
        
    
    
            

                            
            

            
                    
            
        
            Votes:
            
        
            
                                0
            
                                                Vote for this issue
                    
            
    
            
                            
            
        
            Watchers:
            
        
            
                                
                                
                            0
            
                                        Start watching this issue
                    
            
    
            
    
            

              









              
            
              
    
              
                    Created:
            
              
    
              
        
                                                                                                                                 
    
              

              
            
              
    
              
                    Updated:
            
              
    
              
        
                                                                                                                                 
    
              

              
            
              
    
              
                    Resolved: