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https://issues.apache.org/jira/browse/DRILL-5089?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16250402#comment-16250402
 ] 

ASF GitHub Bot commented on DRILL-5089:
---------------------------------------

Github user paul-rogers commented on a diff in the pull request:

    https://github.com/apache/drill/pull/1032#discussion_r150685113
  
    --- Diff: 
exec/java-exec/src/main/java/org/apache/drill/exec/store/dfs/FileSystemSchemaFactory.java
 ---
    @@ -73,9 +87,10 @@ public void registerSchemas(SchemaConfig schemaConfig, 
SchemaPlus parent) throws
     
         public FileSystemSchema(String name, SchemaConfig schemaConfig) throws 
IOException {
           super(ImmutableList.<String>of(), name);
    +      final DrillFileSystem fs = 
ImpersonationUtil.createFileSystem(schemaConfig.getUserName(), 
plugin.getFsConf());
           for(WorkspaceSchemaFactory f :  factories){
    -        if (f.accessible(schemaConfig.getUserName())) {
    -          WorkspaceSchema s = f.createSchema(getSchemaPath(), 
schemaConfig);
    +        WorkspaceSchema s = f.createSchema(getSchemaPath(), schemaConfig, 
fs);
    +        if ( s != null) {
    --- End diff --
    
    Here we iterate over a list of workspace schema factories. For each, we 
resolve a schemaConfig against the file system.
    
    Under what situations would we have multiple factories? Selecting from two 
distinct storage plugins?
    
    Calcite tends to resolve the same things over and over. Will this method be 
called multiple times?


> Skip initializing all enabled storage plugins for every query
> -------------------------------------------------------------
>
>                 Key: DRILL-5089
>                 URL: https://issues.apache.org/jira/browse/DRILL-5089
>             Project: Apache Drill
>          Issue Type: Improvement
>          Components: Query Planning & Optimization
>    Affects Versions: 1.9.0
>            Reporter: Abhishek Girish
>            Assignee: Chunhui Shi
>            Priority: Critical
>
> In a query's lifecycle, at attempt is made to initialize each enabled storage 
> plugin, while building the schema tree. This is done regardless of the actual 
> plugins involved within a query. 
> Sometimes, when one or more of the enabled storage plugins have issues - 
> either due to misconfiguration or the underlying datasource being slow or 
> being down, the overall query time taken increases drastically. Most likely 
> due the attempt being made to register schemas from a faulty plugin.
> For example, when a jdbc plugin is configured with SQL Server, and at one 
> point the underlying SQL Server db goes down, any Drill query starting to 
> execute at that point and beyond begin to slow down drastically. 
> We must skip registering unrelated schemas (& workspaces) for a query. 



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