I wonder if we should add a custom request header like
X-CouchDB-NoCache which sets all the cachebusting headers (Expires in
the paste, etc) rather than that hack.

On 11 August 2011 02:15, Filipe David Manana <fdmanana@apache.org> wrote:
> On Wed, Aug 10, 2011 at 5:58 PM, Paul Davis <paul.joseph.davis@gmail.com> wrote:
>>
>> Since no one seems to have believed me I decided to take a closer look
>
> I believe you, and in my machine, replication.js, takes about 120ms.
>
>> at replication.js tests. And as I pointed out it was just polling a
>> URL in a tight loop for 3s at a time. On my machine, this patch drops
>> replication.js from 93329ms to 41785ms
>
> That's awesome. If it doesn't make assertions fails for others, go ahead.
>
> One thing I noticed in the past is that the browser seems to cache the
> results of db.info() call. A solution (that is employed somewhere
> else, but for another request) is to add some random parameter to the
> query string, like  /db?anticache=Math.random(1000000).
>
>>. I'll point out that that's
>> more than twice as fast. And that was just an obvious optimization
>> from watching the log scroll. There are plenty more simple things that
>> could be done to speed these up.
>>
>> Also, this patch makes me think that a _replication/localid -> JSON
>> status blob might be useful. Though I dunno how possible that is. I
>> reckon if we had that these would be sped up even more.
>>
>>
>> diff --git a/share/www/script/couch.js b/share/www/script/couch.js
>> index 304c9c1..792e638 100644
>> --- a/share/www/script/couch.js
>> +++ b/share/www/script/couch.js
>> @@ -40,6 +40,8 @@ function CouchDB(name, httpHeaders) {
>>     if (this.last_req.status == 404) {
>>       return false;
>>     }
>> +    var t0 = new Date();
>> +    while(true) {if((new Date()) - t0 > 100) break;}
>>     CouchDB.maybeThrowError(this.last_req);
>>     return JSON.parse(this.last_req.responseText);
>>   };
>> diff --git a/share/www/script/test/replication.js
>> b/share/www/script/test/replication.js
>> index 65c5eaa..b82375a 100644
>> --- a/share/www/script/test/replication.js
>> +++ b/share/www/script/test/replication.js
>> @@ -149,24 +149,40 @@ couchTests.replication = function(debug) {
>>   }
>>
>>
>> -  function waitForSeq(sourceDb, targetDb) {
>> -    var targetSeq,
>> -        sourceSeq = sourceDb.info().update_seq,
>> +  function waitForSeq(sourceDb, targetDb, rep_id) {
>> +    var seq = sourceDb.info().update_seq,
>> +        ri = new RegExp(rep_id),
>> +        tasks,
>>         t0 = new Date(),
>>         t1,
>>         ms = 3000;
>>
>>     do {
>> -      targetSeq = targetDb.info().update_seq;
>> +      tasks = JSON.parse(CouchDB.request("GET",
>> "/_active_tasks").responseText);
>> +      for(var i = 0; i < tasks.length; i++) {
>> +        if(!ri.test(tasks[i].task)) continue;
>> +        var captured = /Processed (\d+)/.exec(tasks[i].status);
>> +        if(parseInt(captured[1]) >= seq) return;
>> +        break;
>> +      }
>>       t1 = new Date();
>> -    } while (((t1 - t0) <= ms) && targetSeq < sourceSeq);
>> +    } while ((t1 - t0) <= ms);
>>   }
>>
>> +  function waitForRepEnd(rep_id) {
>> +    var ri = new RegExp(rep_id),
>> +        tasks,
>> +        t0 = new Date(),
>> +        t1,
>> +        ms = 3000;
>>
>> -  function wait(ms) {
>> -    var t0 = new Date(), t1;
>>     do {
>> -      CouchDB.request("GET", "/");
>> +      tasks = JSON.parse(CouchDB.request("GET",
>> "/_active_tasks").responseText);
>> +      var found = false;
>> +      for(var i = 0; i < tasks.length; i++) {
>> +        if(!ri.test(tasks[i].task)) found = true;
>> +      }
>> +      if(!found) return;
>>       t1 = new Date();
>>     } while ((t1 - t0) <= ms);
>>   }
>> @@ -1143,7 +1159,7 @@ couchTests.replication = function(debug) {
>>
>>     var rep_id = repResult._local_id;
>>
>> -    waitForSeq(sourceDb, targetDb);
>> +    waitForSeq(sourceDb, targetDb, rep_id);
>>
>>     for (j = 0; j < docs.length; j++) {
>>       doc = docs[j];
>> @@ -1181,7 +1197,7 @@ couchTests.replication = function(debug) {
>>     var ddoc = docs[docs.length - 1]; // design doc
>>     addAtt(sourceDb, ddoc, "readme.txt", att1_data, "text/plain");
>>
>> -    waitForSeq(sourceDb, targetDb);
>> +    waitForSeq(sourceDb, targetDb, rep_id);
>>
>>     var modifDocs = docs.slice(10, 15).concat([ddoc]);
>>     for (j = 0; j < modifDocs.length; j++) {
>> @@ -1226,7 +1242,7 @@ couchTests.replication = function(debug) {
>>     // add another attachment to the ddoc on source
>>     addAtt(sourceDb, ddoc, "data.dat", att2_data, "application/binary");
>>
>> -    waitForSeq(sourceDb, targetDb);
>> +    waitForSeq(sourceDb, targetDb, rep_id);
>>
>>     copy = targetDb.open(ddoc._id);
>>     var atts = copy._attachments;
>> @@ -1263,7 +1279,7 @@ couchTests.replication = function(debug) {
>>     var newDocs = makeDocs(25, 35);
>>     populateDb(sourceDb, newDocs, true);
>>
>> -    waitForSeq(sourceDb, targetDb);
>> +    waitForSeq(sourceDb, targetDb, rep_id);
>>
>>     for (j = 0; j < newDocs.length; j++) {
>>       doc = newDocs[j];
>> @@ -1282,7 +1298,7 @@ couchTests.replication = function(debug) {
>>     TEquals(true, sourceDb.deleteDoc(newDocs[0]).ok);
>>     TEquals(true, sourceDb.deleteDoc(newDocs[6]).ok);
>>
>> -    waitForSeq(sourceDb, targetDb);
>> +    waitForSeq(sourceDb, targetDb, rep_id);
>>
>>     copy = targetDb.open(newDocs[0]._id);
>>     TEquals(null, copy);
>> @@ -1317,7 +1333,7 @@ couchTests.replication = function(debug) {
>>     };
>>     TEquals(true, sourceDb.save(doc).ok);
>>
>> -    wait(2000);
>> +    waitForRepEnd(rep_id);
>>     copy = targetDb.open(doc._id);
>>     TEquals(null, copy);
>>   }
>> @@ -1359,7 +1375,7 @@ couchTests.replication = function(debug) {
>>
>>   var tasksAfter = JSON.parse(xhr.responseText);
>>   TEquals(tasks.length, tasksAfter.length);
>> -  waitForSeq(sourceDb, targetDb);
>> +  waitForSeq(sourceDb, targetDb, rep_id);
>>   T(sourceDb.open("30") !== null);
>>
>>   // cancel replication
>>
>
>
>
> --
> Filipe David Manana,
> fdmanana@gmail.com, fdmanana@apache.org
>
> "Reasonable men adapt themselves to the world.
>  Unreasonable men adapt the world to themselves.
>  That's why all progress depends on unreasonable men."
>