Keith Turner

Call hsync(), if supported, immediately prior to closing DFS compaction files.

2

According to [this documentation](https://hadoop.apache.org/docs/stable/hadoop-project-dist/hadoop-common/filesystem/outputstream.html#HDFS_and_OutputStream.close.28.29) its best to call hsync() prior to close. This could possibly be done for files created for minor and major compaction in Accumulo. For compactions could...

Worked w/ @ddanielr on experimenting with changes for #4424 and #4425 that may not be merged into 2.1. We may eventually merge the changes into elasticity or main, not sure....

Add integration test that ensures that server process does not start against newer version of accumulo.

3

If someone with an Accumulo 2.1 cluster does the following it would be good if the last step failed. 1. Upgrades Accumulo from 2.1 to 3.1 2. Accidentally starts a...

Need a way to test UNKNOWN result for conditional mutations

2

Conditional mutations are used for metadata updates now. Conditional mutations can return a result of [UNKNOWN](https://github.com/apache/accumulo/blob/9550da7c838994f9f6e9547819566b01e4b1dc6e/core/src/main/java/org/apache/accumulo/core/client/ConditionalWriter.java#L114). The Ample code that handles conditional updates has [a method](https://github.com/apache/accumulo/blob/9550da7c838994f9f6e9547819566b01e4b1dc6e/core/src/main/java/org/apache/accumulo/core/metadata/schema/Ample.java#L631) that accepts a lambda...

Add compaction IT that verifies queues are cleared when tablets no longer need to compact.

2

This is follow on work for #3528 and #4394. Would be good to add an integration test for the changes in #4394. Unit test were added in #4394 that cover...

Improve validation in TabletManagementIteratorIT

1

TabletManagementIteratorIT has a method `int findTabletsNeedingAttention((...)` that returns the number of tablets the iterator found. The test could be improved to do more in depth validation of the data returned...

Compaction fate operation may not clean up all of its temporary metadata changes

1

When a compaction on a table is initiated via the public API a range can be specified. All tablets that overlap the range are compacted. This is driven by a...

MeterRegistryFactory lacks mechanism for configuration.

2

The MeterRegistryFactory does not have any mechanism for passing configuration. Since its likely metrics will need configuration (like a server to send metrics to) this leads to placing the configuration...

DISCUSS add resource groups to mini accumulo

5

Posting this draft PR solely for the purpose of discussion and feedback, it does not actually implement anything. The elasticity branch is heavily using the concept of servers organized into...