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https://issues.apache.org/jira/browse/DRILL-5963?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Arina Ielchiieva updated DRILL-5963:
------------------------------------
Description:
Canceling the below query that is hung in planning state, leaves the query in
ENQUEUED state for ever.
Here is the query that is hung in planning state
{noformat}
0: jdbc:drill:schema=dfs.tmp> select 1 || ',' || 2 || ',' || 3 || ',' || 4 ||
',' || 5 || ',' || 6 || ',' || 7 || ',' || 8 || ',' || 9 || ',' || 0 || ',' AS
CSV_DATA from (values(1));
+--+
| |
+--+
+--+
No rows selected (304.291 seconds)
{noformat}
Explain plan for that query also just hangs.
{noformat}
explain plan for select 1 || ',' || 2 || ',' || 3 || ',' || 4 || ',' || 5 ||
',' || 6 || ',' || 7 || ',' || 8 || ',' || 9 || ',' || 0 || ',' AS CSV_DATA
from (values(1));
...
{noformat}
The above issues show the following problems:
*1. Simple query with reasonable number of concat functions hangs.*
In reality query does not hang it just take lots of time to execute. The root
cause is that during planning time DrillFuncHolderExpr return type is
extensively used to determine matching function, matching type etc. Though this
type is retrieved via
[getter|https://github.com/apache/drill/blob/master/exec/java-exec/src/main/java/org/apache/drill/exec/expr/DrillFuncHolderExpr.java#L41]
in reality complex logic is executed beaneath it. For example for [concat
function|https://github.com/apache/drill/blob/master/exec/java-exec/src/main/java/org/apache/drill/exec/expr/fn/output/ConcatReturnTypeInference.java#L47].
Since function return type can not be changes during DrillFuncHolderExpr life
time, it is safe to cache it.
*2. No mechanism to cancel query during ENQUEUED state.*
Currently Drill does not have mechanism to cancel query before STARTING /
RUNNING states. Plus ENQUEUED state includes two PLANNING and ENQUEUED.
Also submitting mechanism for submitting query to the queue is blocking, making
foreman wait till enqueueing is done Making it non-blocking will prevent
consuming threads that just sit idle in a busy system and also is important
when we move to a real admission control solution.
The following changes were made to address above issues:
a. two new states were added: PREPARING (when foreman is initialized) and
PLANNING (includes logical and / or physical planning).
b. process of query enqueuing was made non-blocking. Once query was enqueued,
fragments runner is called to submit fragments locally and remotely.
c. ability to cancel query during planning and enqueued states was added.
was:
Canceling the below query that is hung in planning state, leaves the query in
ENQUEUED state for ever.
Here is the query that is hung in planning state
{noformat}
0: jdbc:drill:schema=dfs.tmp> select 1 || ',' || 2 || ',' || 3 || ',' || 4 ||
',' || 5 || ',' || 6 || ',' || 7 || ',' || 8 || ',' || 9 || ',' || 0 || ',' AS
CSV_DATA from (values(1));
+--+
| |
+--+
+--+
No rows selected (304.291 seconds)
{noformat}
Explain plan for that query also just hangs.
{noformat}
explain plan for select 1 || ',' || 2 || ',' || 3 || ',' || 4 || ',' || 5 ||
',' || 6 || ',' || 7 || ',' || 8 || ',' || 9 || ',' || 0 || ',' AS CSV_DATA
from (values(1));
...
{noformat}
> Canceling a query hung in planning state, leaves the query in ENQUEUED state
> for ever.
> --------------------------------------------------------------------------------------
>
> Key: DRILL-5963
> URL: https://issues.apache.org/jira/browse/DRILL-5963
> Project: Apache Drill
> Issue Type: Bug
> Components: Execution - Flow
> Affects Versions: 1.12.0
> Environment: Drill 1.12.0-SNAPSHOT, commit:
> 4a718a0bd728ae02b502ac93620d132f0f6e1b6c
> Reporter: Khurram Faraaz
> Assignee: Arina Ielchiieva
> Priority: Critical
> Attachments: enqueued-2.png
>
>
> Canceling the below query that is hung in planning state, leaves the query in
> ENQUEUED state for ever.
> Here is the query that is hung in planning state
> {noformat}
> 0: jdbc:drill:schema=dfs.tmp> select 1 || ',' || 2 || ',' || 3 || ',' || 4 ||
> ',' || 5 || ',' || 6 || ',' || 7 || ',' || 8 || ',' || 9 || ',' || 0 || ','
> AS CSV_DATA from (values(1));
> +--+
> | |
> +--+
> +--+
> No rows selected (304.291 seconds)
> {noformat}
> Explain plan for that query also just hangs.
> {noformat}
> explain plan for select 1 || ',' || 2 || ',' || 3 || ',' || 4 || ',' || 5 ||
> ',' || 6 || ',' || 7 || ',' || 8 || ',' || 9 || ',' || 0 || ',' AS CSV_DATA
> from (values(1));
> ...
> {noformat}
> The above issues show the following problems:
> *1. Simple query with reasonable number of concat functions hangs.*
> In reality query does not hang it just take lots of time to execute. The root
> cause is that during planning time DrillFuncHolderExpr return type is
> extensively used to determine matching function, matching type etc. Though
> this type is retrieved via
> [getter|https://github.com/apache/drill/blob/master/exec/java-exec/src/main/java/org/apache/drill/exec/expr/DrillFuncHolderExpr.java#L41]
> in reality complex logic is executed beaneath it. For example for [concat
> function|https://github.com/apache/drill/blob/master/exec/java-exec/src/main/java/org/apache/drill/exec/expr/fn/output/ConcatReturnTypeInference.java#L47].
> Since function return type can not be changes during DrillFuncHolderExpr
> life time, it is safe to cache it.
> *2. No mechanism to cancel query during ENQUEUED state.*
> Currently Drill does not have mechanism to cancel query before STARTING /
> RUNNING states. Plus ENQUEUED state includes two PLANNING and ENQUEUED.
> Also submitting mechanism for submitting query to the queue is blocking,
> making foreman wait till enqueueing is done Making it non-blocking will
> prevent consuming threads that just sit idle in a busy system and also is
> important when we move to a real admission control solution.
> The following changes were made to address above issues:
> a. two new states were added: PREPARING (when foreman is initialized) and
> PLANNING (includes logical and / or physical planning).
> b. process of query enqueuing was made non-blocking. Once query was enqueued,
> fragments runner is called to submit fragments locally and remotely.
> c. ability to cancel query during planning and enqueued states was added.
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