I agree with Yong, we should back-support the existing configuration,
otherwise, the pulsar helm chart also need to be changed when upgrade
BookKeeper 4.14.x to 4.15.x

Thanks,
Hang

Enrico Olivelli <eolive...@gmail.com> 于2022年10月10日周一 16:07写道:
>
> Il Lun 10 Ott 2022, 07:44 Yong Zhang <zhangyong1025...@gmail.com> ha
> scritto:
>
> > We shouldn't remove any existing configuration or feature in a so short
> > time. I think at least we need to back-support the existing configuration.
> > If we must do the break, we should make the existing things in a
> > deprecation
> > state for a while.
> >
> > Breaking existing configurations would make a huge impact.
> > Maybe we can add back the previous configurations in the next minor
> > release for 4.15. So user can upgrade their cluster to 4.15.3 without
> > changing any configuration.
> >
> > WDYT?
> >
>
> Great idea
>
> Enrico
>
>
> > Yong
> >
> >
> >
> >
> > On Sun, 9 Oct 2022 at 23:20, Enrico Olivelli <eolive...@gmail.com> wrote:
> >
> > > Il Dom 9 Ott 2022, 17:03 Hang Chen <chenh...@apache.org> ha scritto:
> > >
> > > > I found the PR https://github.com/apache/bookkeeper/pull/3056 has
> > > > changed the rocksDB default cache size from 10% of direct memory to
> > > > 206150041(196MB), which will lead to entry read performance decrease
> > > > when there are huge number of entries stored in the ledger directory.
> > > > It will have a huge impact on the read performance when the BookKeeper
> > > > cluster upgrades from 4.14.x to 4.15.x.
> > > >
> > >
> > >
> > > I think that that patch shoud had passed from the BP process.
> > > It is a huge breaking change.
> > > Personally I missed it.
> > >
> > > BTW now it is there, we should have talked about it in the release notes,
> > > and we now must add some guidance to users upgrading to this version of
> > BK.
> > >
> > > It is a pity that we cannot keep the automatic value.
> > >  BTW in all the Pulsar cluster I know I think that they are overriding
> > that
> > > value because the default value is not big enough.
> > >
> > > I think that at this point we only have to document on the website the
> > > breaking change and add a page about BK and RocksDB
> > >
> > > Enrico
> > >
> > >
> > > > The motivation of PR 3056 is to change RocksDB configuration to a
> > > > single configuration file, and it introduces the following drawbacks.
> > > > 1. Most users, especially those unfamiliar with RocksDB, will be
> > > > confused about tuning RocksDB performance due to lack of guidance on
> > > > some important key parameters.
> > > > 2. The RocksDB blockCacheSize configuration can only be set to a fixed
> > > > value, not a percentage of direct memory.
> > > >
> > > > In order to simplify the RocksDB configuration and make it easy to
> > > > tune the performance of the RocksDB, I prefer to separate the RocksDB
> > > > configuration into two parts.
> > > > 1. The most important configurations, which is usually changed to tune
> > > > RocksDB performance, will be located in conf/bk_server.conf
> > > > 2. Other advanced configuration will be in a separate RocksDB
> > > > configuration file
> > > >
> > > > For the default RocksDB blockCacheSize change, Do you need to trigger
> > > > a new release to change it back? Current Pulsar master branch uses
> > > > BookKeeper 4.14.x, and we can change the default value back to 10% of
> > > > direct memory to avoid the entry read performance degradation caused
> > > > by upgrading Pulsar's BookKeeper dependency to 4.15.x.
> > > >
> > > > Do you guys have any suggestions?
> > > >
> > > > Thanks,
> > > > Hang
> > > >
> > >
> >

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