2020-08-26 14:03:17 UTC - Mark Marijnissen: *Schema compatibility*
I don't understand Forward & Backward. What happen with the `?` below?

```FORWARD_TRANSITIVE:
   P1 P2 P3
C1 ?   ?  Y
C2 ?   ?  Y
C3 ?   ?  Y

BACKWARD_TRANSITIVE:

   P1 P2 P3
C1  ?  ?  ?
C2  ?  ?  ?
C3  Y  Y  Y

Where P1,P2,P3 = producer v1, v2, v3
and C1,C2,C3 = consumer v1, v2, v3```
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2020-08-26 14:03:58 UTC - Dmitri Zamysloff: @Dmitri Zamysloff has joined the 
channel
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2020-08-26 14:43:48 UTC - Alexei Grigoriev: @Alexei Grigoriev has joined the 
channel
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2020-08-26 15:04:04 UTC - Evan Furman: Hi! Is there documentation on getting 
pulsar logs into grafana via loki in non-k8s environments? We are running on 
EC2.
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2020-08-26 15:27:27 UTC - Dmitri Zamysloff: Hi All,
I am pretty new to Pulsar. Started testing 2.6.1 as possible basis for CQRS 
implementation. Have written small producer and consumer in java (two 
spring-boot applications).
1. What I cannot understand why presto does not see date (or instant) fields? I 
have tried with JSON schema and enabled JSR310 in schema definition. Messages 
are comming by consumer consistently, but in selects of presto I cannot see 
date/time fields. Also over JDBC presto driver they are not visible. 
2. Another point is that I cannot see last message over presto/presto-JDBC. Is 
there any way to see it?
3. As I red the description of Pulsar I was like WOW and I thought Pulsar can 
take over creation of Aggregates and event registry. Like I will be able to see 
somehow aggregated objects. And on other hand is event storage (i can only see 
possibility to set retention to some size) which I can then export and replay. 
But I have found, that over presto I can just see messages in topic and 
retention can be limited for namespace over admin api, which I have done.

So is pulsar only a smart messaging platform or it can do Aggregates of domain 
objects out of the box? Or I have to build the aggregated states of domain 
objects myself in some separate DB like Mongo? Shall I also take care of event 
registry myself?
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2020-08-26 15:28:13 UTC - Dmitri Zamysloff: Or maybe there any blueprint for 
cqrs implementation with pulsar?
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2020-08-26 15:28:28 UTC - Dmitri Zamysloff: Thank you in advance.
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2020-08-26 15:49:30 UTC - Addison Higham: 1. here is a mapping of how pulsar 
maps to schemas types: 
<https://pulsar.apache.org/docs/en/schema-understand/#primitive-type> but can 
you provide an example schema definition?
2. This is a known issue with a workaround, see this thread for details: 
<https://github.com/apache/pulsar/issues/4976>. Setting 
`bookkeeperExplicitLacIntervalInMills` in broker.conf to something greater than 
0 (maybe like 5-50ms) will cause this last message to be available for pulsar 
SQL
3. I am not sure I completely understand your question, but it doesn't 
automatically *create* aggregates, but it still maybe a reasonable place to 
track, send, and store aggregates

For example, suppose you have multiple different types of events and you 
transform those with a flink application or a pulsar functions window function. 
You can create a new schema representing the aggregate event, write the results 
to a topic, use compaction to keep only the most recent projection of that 
aggregation, and then use Pulsar SQL to query for aggregates for analytical use 
cases, or use a pulsar sink to a JDBC/other database for the query layer
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2020-08-26 15:52:28 UTC - Chris Hansen: I think Apache Flink can be used for 
this on top of Pulsar to keep track of the batch state. Something to look into.
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2020-08-26 18:15:10 UTC - Matt Mitchell: what would cause this producer 
problem? A slow consumer?
```org.apache.pulsar.client.api.PulsarClientException$TimeoutException: The 
producer my-producer can not send message to the topic 
<persistent://public/default/my-topic> within given timeout```
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2020-08-26 18:15:24 UTC - Matt Mitchell: Or is that an issue with the broker?
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2020-08-26 19:17:05 UTC - Erik Jansen: I have started a standalone cluster and 
produced several millions of messages to different topics. No retention set. 
After a while the topics are removed due to inactivity. When I look into the 
data directory there are however still some huge files ( 3 of them with total 
size of about 6Gbyte) with the extension: .txn. Can someone explain why these 
files still exist and what they are used for?
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2020-08-26 19:29:25 UTC - Josh Janssen: @Josh Janssen has joined the channel
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2020-08-26 23:09:18 UTC - Alexander Ursu: Hi, I recently started using the 
Postgres JDBC sink connector, and am having troubles with `ERROR: permission 
denied for table ...` , even after trying to grant all privileges to the user 
on the schema, table, etc.
For anyone that's used it before, is there some standard setup to permissions 
for the built-in sink connector that has worked for you? Also to note that this 
is on 2.6.1
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2020-08-27 03:48:29 UTC - Maksym Domarev: Is there a way to TTL topic, e.g. 
automatically delete it if it’s not in use for let’s day 2 days?
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2020-08-27 05:04:54 UTC - Raghav: Not at topic level but I think there are some 
settings at broker level for this
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2020-08-27 08:10:42 UTC - aloyszhang: TTL  can be set at namespace level using 
Admin tool. Like `bin/pulsar-admin namespaces set-message-ttl tenant/namespace 
-ttl timetInSeconds`
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2020-08-27 08:12:02 UTC - aloyszhang: see 
<https://pulsar.apache.org/docs/en/2.6.1/cookbooks-retention-expiry/#set-the-ttl-for-a-namespace|here>
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