Apache
/
hbase
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

HBASE-18052 Add document for async admin

This commit is contained in:
Guanghao Zhang 2017-07-16 16:00:35 +08:00
parent a9352fe956
commit 2d5a0fbd16
1 changed files with 12 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
src/main/asciidoc/_chapters/architecture.adoc
View File

@ -265,11 +265,18 @@ For `AsyncTable`, you need to provide a thread pool when getting it. The callbac
For `RawAsyncTable`, all the callbacks are executed inside the framework thread so it is not allowed to do time consuming works in the callbacks otherwise you may block the framework thread and cause very bad performance impact. It is designed for advanced users who want to write high performance code. You can see the `org.apache.hadoop.hbase.client.example.HttpProxyExample` to see how to write fully asynchronous code with `RawAsyncTable`. And coprocessor related methods are only in `RawAsyncTable`. For `RawAsyncTable`, all the callbacks are executed inside the framework thread so it is not allowed to do time consuming works in the callbacks otherwise you may block the framework thread and cause very bad performance impact. It is designed for advanced users who want to write high performance code. You can see the `org.apache.hadoop.hbase.client.example.HttpProxyExample` to see how to write fully asynchronous code with `RawAsyncTable`. And coprocessor related methods are only in `RawAsyncTable`.
.On `AsyncAdmin` [[async.admin]]
[WARNING] === Asynchronous Admin ===
====
`AsyncAdmin` is still under development and marked as IA.Private. Use it with caution as we may change the API without any announcement. You can obtain an `AsyncConnection` from `ConnectionFactory`, and then get a `AsyncAdmin` instance from it to access HBase. Notice that there are two `getAdmin` methods to get a `AsyncAdmin` instance. One method has one extra thread pool parameter which is used to execute callbacks. It is designed for normal users. Another method doesn't need a thread pool and all the callbacks are executed inside the framework thread so it is not allowed to do time consuming works in the callbacks. It is designed for advanced users.
====
The default `getAdmin` methods will return a `AsyncAdmin` instance which use default configs. If you want to customize some configs, you can use `getAdminBuilder` methods to get a `AsyncAdminBuilder` for creating `AsyncAdmin` instance. Users are free to only set the configs they care about to create a new `AsyncAdmin` instance.
For the `AsyncAdmin` interface, most methods have the same meaning with the old `Admin` interface, expect that the return value is wrapped with a CompletableFuture usually.
For most admin operations, when the returned CompletableFuture is done, it means the admin operation has also been done. But for compact operation, it only means the compact request was sent to HBase and may need some time to finish the compact operation. For `rollWALWriter` method, it only means the rollWALWriter request was sent to the region server and may need some time to finish the `rollWALWriter` operation.
For region name, we only accept `byte[]` as the parameter type and it may be a full region name or a encoded region name. For server name, we only accept `ServerName` as the parameter type. For table name, we only accept `TableName` as the parameter type. For `list*` operations, we only accept `Pattern` as the parameter type if you want to do regex matching.
[[client.external]] [[client.external]]
=== External Clients === External Clients