[jira] [Commented] (IGNITE-6173) SQL: do not start caches on client nodes

["Taras Ledkov (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/IGNITE-6173?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16634254#comment-16634254 ] 

Taras Ledkov commented on IGNITE-6173:
--------------------------------------

[~jooger], my comments:
- new test {{GridCacheDynamicLoadOnClientTest}} the try-with-resources is used for {{Statement}} objects. Why isn't used for {{Connection}}?
- please review my minor changes.

Review summary:
| Code style | OK |
| API compatibility | OK |
| Product behavior | defaults not changed |
| Documentation | not required |
| Binary compatibility | OK |
| Tests | please re-run after merge with master | 



> SQL: do not start caches on client nodes
> ----------------------------------------
>
>                 Key: IGNITE-6173
>                 URL: https://issues.apache.org/jira/browse/IGNITE-6173
>             Project: Ignite
>          Issue Type: Task
>          Components: cache, sql
>    Affects Versions: 2.1
>            Reporter: Vladimir Ozerov
>            Assignee: Yury Gerzhedovich
>            Priority: Major
>              Labels: sql-stability
>             Fix For: 2.8
>
>
> When cache is started, this even is distributed through custom discovery message. Server nodes start the cache, client nodes do nothing until cache is requested explicitly. At the same time H2 database objects are created only when cache is really started. 
> For this reason query parsing could lead to {{TABLE NOT FOUND}}, {{INDEX NOT FOUND}}, etc. errors. If such exception is observed, we force start of all known cache on a client and then retry. See {{GridCacheProcessor#createMissingQueryCaches}} method. 
> First, client node cache start leads to another custom discovery message. So query performance may suffer. Second, this is not needed! We already have all necessary cache info in discovery. 
> Let's try to find a way to use available discovery data and do not start cache on a client for SQL query execution.



--
This message was sent by Atlassian JIRA
(v7.6.3#76005)