Cloudera Manager warning about Max Message Size for Hive MetaStore

[#1]

After upgrading from CDH 5.7.5 to 5.10.0, Cloudera Manager gives a couple of warnings about "Max Message Size for Hive Metastore":

Hive: Max Message Size for Hive MetaStore
The value of Max Message Size for Hive MetaStore (104857600) should be at least 10% of the value of Java Heap Size of Hive Metastore Server in Bytes (858993459).

Hive Metastore Server (bsl-ib-c3): Max Message Size for Hive MetaStore

The value of Max Message Size for Hive MetaStore (104857600) should be at least 10% of the value of Java Heap Size of Hive Metastore Server in Bytes (858993459).

These are just warnings, but the default 100MB is over 12% of the value of Java Heap Size..., which should satisfy the criteria of being "at least 10%". Am I missing something obvious?

[#2]

I got the same question after I upgraded CM from 5.8.3 to 5.10.

For my cluster, Java Heap Size of Hive Metastore Server is set to 8 GB, which is actually 8,598,323,200 bytes instead of what it displays in the warning. So I guess the warning is asking to increase the Max Message Size from 100MB (104,857,600 bytes) to 800MB.

Can someone verify that, as well as explain what message size actually is?

[#3]

Thanks for asking about this. The max message size for Hive Metastore should be set to 10% of the Metastore server heap size, up to a maximum of 2,147,483,647 bytes.

Unfortunately, the values used or displayed by that configuration validator may be incorrect in some cases. Until that's fixed, I recommend checking the actual HMS heap size and configuring the max message size accordingly. 

[#4]

We're just upgrading from 5.7 to 5.12 and received the same warning. In our case Hive metastore heap size is 12G so the  max message size will be set to 1.2 G . That appears bit scary to me.

What are the risks of setting the value such high ? 

How can we handle large metastore updates in case that happens ? Do we need to prepare the metastore server i.e. mysql to do somethign differently ?

What happens if we don't follow this recommandation ?

Thanks,

Sunil