Am trying to use spring-retry and i want to update my DB every time the spring-retry works for 5 retries.
In database a column need to be updated in order to track if the retry was made 5 times or not.
You can add a RetryListener to the RetryTemplate; the count is in the RetryContext argument passed in.
You can add more information to the context if needed, by getting a reference to it using the RetrySynchronizationManager.
Here's what I'd like to achieve:
Say you have a todo list and do the following changes:
Mark as complete task 1
Change the name of task 2
Mark as complete task 2
Change the name of task 1
At present, my system can achieve this by firing 4 http queries.
Is there a way Angular can sync the app with the server, say every 20 seconds, be able to notice when a change has been done on the same item, and group the changes into the same query.
The clever bulk update would then look like:
Update task 1, SET complete=true, name= New name
Update task 2, SET complete=true, name= New name
Has anyone ever tried this? Any idea which way I should search to find out more info about this kind of workflow?
I have the Test plan where is 10 requests. Just requests without Contant timer takes about 18 seconds. When I add one Contant timer with 1000 miliseconds delay after the third request It takes about 28 seconds.
Is It problem of the JMeter or I'm doing something wrong?
I'm running at Ubuntu - ElementaryOS with JMeter v. 2.11 r1554548.
I'm testing another server not mine laptop.
At Jmeter test plan I'm using Cache, Cookie manager and Request Defaults at the begin. One request with POST action. And Summary report, Graph results, View results in Table a Simple data writer at the end of test plan.
Everything is in one thread.
Order of timer object has no impact and does not mean it executes where it is located.
In fact it will apply to every child request of the parent of timer.
Read this:
http://jmeter.apache.org/usermanual/test_plan.html
4.10 Scoping Rules
I use NDB for my app and use iter() with limit and starting cursor to iterate through 20,000 query results in a task. A lot of time I run into timeout error.
Timeout: The datastore operation timed out, or the data was temporarily unavailable.
The way I make the call is like this:
results = query.iter(limit=20000, start_cursor=cursor, produce_cursors=True)
for item in results:
process(item)
save_cursor_for_next_time(results.cursor_after().urlsafe())
I can reduce the limit but I thought a task can run as long as 10 mins. 10 mins should be more than enough time to go through 20000 results. In fact, on a good run, the task can complete in just about a minute.
If I switched to fetch() or fetch_page(), would they be more efficient and less likely to run into the timeout error? I suspect there's a lot of overhead in iter() that causes the timeout error.
Thanks.
Fetch is not really any more efficient they all use the same mechanism, unless you know how many entities you want upfront - then fetch can be more efficient as you end up with just one round trip.
You can increase the batch size for iter, that can improve things. See https://developers.google.com/appengine/docs/python/ndb/queryclass#kwdargs_options
From the docs the default batch size is 20, which would mean for 20,000 entities a lot of batches.
Other things that can help. Consider using map and or map_async on the processing, rather than explicitly calling process(entity) Have a read https://developers.google.com/appengine/docs/python/ndb/queries#map also introducing async into your processing can mean improved concurrency.
Having said all of that you should profile so you can understand where the time is used. For instance the delays could be in your process due to things you are doing there.
There are other things to conside with ndb like context caching, you need to disable it. But I also used iter method for these. I also made an ndb version of the mapper api with the old db.
Here is my ndb mapper api that should solve timeout problems and ndb caching and easily create this kind of stuff:
http://blog.altlimit.com/2013/05/simple-mapper-class-for-ndb-on-app.html
with this mapper api you can create it like or you can just improve it too.
class NameYourJob(Mapper):
def init(self):
self.KIND = YourItemModel
self.FILTERS = [YourItemModel.send_email == True]
def map(self, item):
# here is your process(item)
# process here
item.send_email = False
self.update(item)
# Then run it like this
from google.appengine.ext import deferred
deferred.defer(NameYourJob().run, 50, # <-- this is your batch
_target='backend_name_if_you_want', _name='a_name_to_avoid_dups')
For potentially long query iterations, we use a time check to ensure slow processing can be handled. Given the disparities in GAE infrastructure performance, you will likely never find an optimal processing number. The code excerpt below is from an on-line maintenance handler we use which generally runs within ten seconds. If not, we get a return code saying it needs to be run again thanks to our timer check. In your case, you would likely break the process after passing the cursor to your next queue task. Here is some sample code which is edited down to hopefully give you a good idea of our logic. One other note: you may choose to break this up into smaller bites and then fan out the smaller tasks by re-enqueueing the task until it completes. Doing 20k things at once seems very aggressive in GAE's highly variable environment. HTH -stevep
def over_dt_limit(start, milliseconds):
dt = datetime.datetime.now() - start
mt = float(dt.seconds * 1000) + (float(dt.microseconds)/float(1000))
if mt > float(milliseconds):
return True
return False
#set a start time
start = datetime.datetime.now()
# handle a timeout issue inside your query iteration
for item in query.iter():
# do your loop logic
if over_dt_limit(start, 9000):
# your specific time-out logic here
break
I am using the simple control.start_map() function of the appengine-mapreduce library to start a mapreduce job. This job successfully completes and shows ~43M mapper-calls on the resulting /mapreduce/detail?mapreduce_id=<my_id> page. However, this page makes no mention of the reduce step or any of the underlying appengine-pipeline processes that I believe are still running. Is there some way to return the pipeline ID that this calls makes so I can look at the underlying pipelines to help debug this long-running job? I would like to retrieve enough information to pull up this page: /mapreduce/pipeline/status?root=<guid>
Here is an example of the code I am using to start up my mapreduce job originally:
from third_party.mapreduce import control
mapreduce_id = control.start_map(
name="Backfill",
handler_spec="mark_tos_accepted",
reader_spec=(
"third_party.mapreduce.input_readers.DatastoreInputReader"),
mapper_parameters={
"input_reader": {
"entity_kind": "ModelX"
},
},
shard_count=64,
queue_name="backfill-mapreduce-queue",
)
Here is the mapping function:
# This is where we keep our copy of appengine-mapreduce
from third_party.mapreduce import operation as op
def mark_tos_accepted(modelx):
# Skip users who have already been marked
if (not modelx
or modelx.tos_accepted == myglobals.LAST_MATERIAL_CHANGE_TO_TOS):
return
modelx.tos_accepted = user_models.LAST_MATERIAL_CHANGE_TO_TOS
yield op.db.Put(modelx)
Here are the relevant portions of the ModelX:
class BackupModel(db.Model):
backup_timestamp = db.DateTimeProperty(indexed=True, auto_now=True)
class ModelX(BackupModel):
tos_accepted = db.IntegerProperty(indexed=False, default=0)
For more context, I am trying to debug a problem I am seeing with writes showing up in our data warehouse.
On 3/23/2013, we launched a MapReduce job (let's call it A) over a db.Model (let's call it ModelX) with ~43M entities. 7 hours later, the job "finished" and the /mapreduce/detail page showed that we had successfully mapped over all of the entities, as shown below.
mapper-calls: 43613334 (1747.47/sec avg.)
On 3/31/2013, we launched another MapReduce job (let's call it B) over ModelX. 12 hours later, the job finished with status Success and the /mapreduce/detail page showed that we had successfully mapped over all of the entities, as shown below.
mapper-calls: 43803632 (964.24/sec avg.)
I know that MR job A wrote to all ModelX entities, since we introduced a new property that none of the entities contained before. The ModelX contains an auto_add property like so.
backup_timestamp = ndb.DateTimeProperty(indexed=True, auto_now=True)
Our data warehousing process runs a query over ModelX to find those entities that changed on a certain day and then downloads those entities and stores them in a separate (AWS) database so that we can run analysis over them. An example of this query is:
db.GqlQuery('select * from ModelX where backup_timestamp >= DATETIME(2013, 4, 10, 0, 0, 0) and backup_timestamp < DATETIME(2013, 4, 11, 0, 0, 0) order by backup_timestamp')
I would expect that our data warehouse would have ~43M entities on each of the days that the MR jobs completed, but it is actually more like ~3M, with each subsequent day showing an increase, as shown in this progression:
3/16/13 230751
3/17/13 193316
3/18/13 344114
3/19/13 437790
3/20/13 443850
3/21/13 640560
3/22/13 612143
3/23/13 547817
3/24/13 2317784 // Why isn't this ~43M ?
3/25/13 3701792 // Why didn't this go down to ~500K again?
3/26/13 4166678
3/27/13 3513732
3/28/13 3652571
This makes me think that although the op.db.Put() calls issued by the mapreduce job are still running in some pipeline or queue and causing this trickle effect.
Furthermore, if I query for entities with an old backup_timestamp, I can go back pretty far and still get plenty of entities, but I would expect all of these queries to return 0:
In [4]: ModelX.all().filter('backup_timestamp <', 'DATETIME(2013,2,23,1,1,1)').count()
Out[4]: 1000L
In [5]: ModelX.all().filter('backup_timestamp <', 'DATETIME(2013,1,23,1,1,1)').count()
Out[5]: 1000L
In [6]: ModelX.all().filter('backup_timestamp <', 'DATETIME(2012,1,23,1,1,1)').count()
Out[6]: 1000L
However, there is this strange behavior where the query returns entities that it should not:
In [8]: old = ModelX.all().filter('backup_timestamp <', 'DATETIME(2012,1,1,1,1,1)')
In [9]: paste
for o in old[1:100]:
print o.backup_timestamp
## -- End pasted text --
2013-03-22 22:56:03.877840
2013-03-22 22:56:18.149020
2013-03-22 22:56:19.288400
2013-03-22 22:56:31.412290
2013-03-22 22:58:37.710790
2013-03-22 22:59:14.144200
2013-03-22 22:59:41.396550
2013-03-22 22:59:46.482890
2013-03-22 22:59:46.703210
2013-03-22 22:59:57.525220
2013-03-22 23:00:03.864200
2013-03-22 23:00:18.040840
2013-03-22 23:00:39.636020
Which makes me think that the index is just taking a long time to be updated.
I have also graphed the number of entities that our data warehousing downloads and am noticing some cliff-like drops that makes me think that there is some behind-the-scenes throttling going on somewhere that I cannot see with any of the diagnostic tools exposed on the appengine dashboard. For example, this graph shows a fairly large spike on 3/23, when we started the mapreduce job, but then a dramatic fall shortly thereafter.
This graph shows the count of entities returned by the BackupTimestamp GqlQuery for each 10-minute interval for each day. Note that the purple line shows a huge spike as the MapReduce job spins up, and then a dramatic fall ~1hr later as the throttling kicks in. This graph also shows that there seems to be some time-based throttling going on.
I don't think you'll have any reducer functions there, because all you've done is start a mapper. To do a complete mapreduce, you have to explicitly instantiate a MapReducePipeline and call start on it. As a bonus, that answers your question, as it returns the pipeline ID which you can then use in the status URL.
Just trying to understand the specific problem. Is it that you are expecting a bigger number of entities in your AWS database? I would suspect that the problem lies with the process that downloads your old ModelX entities into an AWS database, that it's somehow not catching all the updated entities.
Is the AWS-downloading process modifying ModelX in any way? If not, then why would you be surprised at finding entities with an old modified time stamp? modified would only be updated on writes, not on read operations.
Kind of unrelated - with respect to throttling I've usually found a throttled task queue to be the problem, so maybe check how old your tasks in there are or if your app is being throttled due to a large amount of errors incurred somewhere else.
control.start_map doesn't use pipeline and has no shuffle/reduce step. When the mapreduce status page shows its finished, all mapreduce related taskqueue tasks should have finished. You can examine your queue or even pause it.
I suspect there are problems related to old indexes for the old Model or to eventual consistency. To debug MR, it is useful to filter your warnings/errors log and search by the mr id. To help with your particular case, it might be useful to see your Map handler.