This is the voting thread for PIP-120. It will stay open for at least 48h.
https://github.com/apache/pulsar/issues/13306
--------
## Motivation
In Pulsar 2.8, we have introduced a setting to control the amount of memory
used by a client instance.
```java
interface ClientBuilder {
ClientBuilder memoryLimit(long memoryLimit, SizeUnit unit);
}
```
By default, in 2.8 and 2.9 this setting is set to 0, meaning no limit is being
enforced.
I think it's a good time for 2.10 to enable this setting by default and,
correspondingly, to disable by default the producer queue size limit.
This will simplify a lot the configuration that a producer application will
have to come up with, when publishing with many topic/partitions or
when messages
are bigger than expected.
## Proposed changes
In 2.10 release, for the `ClientBuilder`, change
* `memoryLimit`: 0 -> 64 MB
For the `ProducerBuilder`, changes
* `maxPendingMessages`: 1000 -> 0
64MB is picked because it's a small enough memory size that will guarantee
a very high producer throughput, irrespective of the individual messages size.
--
Matteo Merli
<mme...@apache.org>
