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js-scripts/many_collections.js

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+// benchmark many collections vs. 1
+//
+
+// you want to do this, but be careful so commented out!:
+//  db.dropDatabase();
+
+t = db.abc;
+
+function time(f) { 
+	var s = new Date();
+	f();
+	print("time: " + ((new Date())-s));
+}
+
+function a() {
+	for( var i = 0; i < 2000000; i++ ) {
+        /* // this version changes collections every 1000 docs.  as the shell is the bottleneck
+		   // we are trying here to limit calls to getCollection() and the string build.
+		   // time: 199
+		   if( i % 1000 == 0 ) { 
+			t = db.getCollection("tst." + (i/1000)%1000);
+        }*/
+
+		/* this version switches collection every record. time: 135 */
+		t = db.getCollection("tst." + i%1000);
+
+		/* to use one colleciton, comment out both of the above. time:128 */
+
+		t.insert({i:i});
+        if( i % 100000 == 0 ) {
+            print(i);
+            print(new Date());
+		}
+	}
+	printjson( db.getLastErrorObj() );
+}
+
+time(a);
+