HIVE-27023: Add setting to prevent tez session from being opened duri…

[maswin]

What changes were proposed in this pull request?

A setting to disable tez session being preemptively opened during startup of hive cli.

Why are the changes needed?

DML only operations won't need a tez session to be opened. Oozie action that launches hive cli for DML only operations need this setting. Sometimes before the tez session thread could complete, the oozie hive action completes its DML operations and clears the scratch folders causing the tez session to fail with following exception:

Application application_1667416881396_24229473 failed 3 times due to AM Container for appattempt_1667416881396_24229473_000003 exited with exitCode: -1000
Failing this attempt.Diagnostics: [2023-02-02 19:02:12.139]File does not exist: hdfs://<name_node>/tmp/<db>/_tez_session_dir/4050c4b0-b7af-4eda-832b-399c954eb576/.tez/application_1667416881396_24229473/tez.session.local-resources.pbjava.io.FileNotFoundException: File does not exist: hdfs://<name_node>/tmp/<db>/_tez_session_dir/4050c4b0-b7af-4eda-832b-399c954eb576/.tez/application_1667416881396_24229473/tez.session.local-resources.pbat org.apache.hadoop.hdfs.DistributedFileSystem$29.doCall(DistributedFileSystem.java:1529)at org.apache.hadoop.hdfs.DistributedFileSystem$29.doCall(DistributedFileSystem.java:1522)at org.apache.hadoop.fs.FileSystemLinkResolver.resolve(FileSystemLinkResolver.java:81)at org.apache.hadoop.hdfs.DistributedFileSystem.getFileStatus(DistributedFileSystem.java:1537)at

Does this PR introduce any user-facing change?

New config value, otherwise no.

How was this patch tested?

Manually tested

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
No Duplication information

[aturoczy]

@abstractdog @ramesh0201 So in this case with this config you can avoid to have a tez session? Is this safe? I can imagine a use case for it. What do you think?

[abstractdog]

I don't get when this exactly happens: in the supported infrastructure (beeline + hiveserver2) if we don't configure an initial session pool in hiveserver2 (hive.server2.tez.initialize.default.sessions=false), there shouldn't be any tez session
how does this happen? hive cli is not supported any more

[maswin]

I don't get when this exactly happens: in the supported infrastructure (beeline + hiveserver2) if we don't configure an initial session pool in hiveserver2 (hive.server2.tez.initialize.default.sessions=false), there shouldn't be any tez session how does this happen? hive cli is not supported any more

@abstractdog - The issue can happen when Hive action is used in Oozie - https://github.com/apache/oozie/blob/d4e36739d798589567ac331b348e8786c876aefa/sharelib/hive/src/main/java/org/apache/oozie/action/hadoop/HiveMain.java#L312
It directly calls the CliDriver class which spawns a tez session.

[abstractdog]

thanks for clarifying @maswin
even if HiveCLI is not supported, oozie is still using that, so it makes sense to fix this, but introducing a new property doesn't seem to address the root cause, which is:

Sometimes before the tez session thread could complete, the oozie hive action completes its DML operations and clears the scratch folders causing the tez session to fail with following exception

this makes me think that in case there are operations using the tez session and then oozie does some DML operations, this can still happen, right? so the root cause looks independent of the fact that you reproduced it with DML-only scenario, so this fix is more likely hiding the problem, which is cleaning up scratch directories before tez sessions are closed, which is unexpected and needs to be fixed

[maswin]

this makes me think that in case there are operations using the tez session and then oozie does some DML operations, this can still happen, right? so the root cause looks independent of the fact that you reproduced it with DML-only scenario, so this fix is more likely hiding the problem, which is cleaning up scratch directories before tez sessions are closed, which is unexpected and needs to be fixed

Ahh, true.

This happens because the tez session is opened in a separate thread in async mode via beginStart() -

hive/cli/src/java/org/apache/hadoop/hive/cli/CliDriver.java

Line 785 in f78ca5d

if (HiveConf.getBoolVar(conf, ConfVars.HIVE_CLI_TEZ_SESSION_ASYNC)) {

And before closing the session we don't wait for the tez session to close.
I have add a call for endStart() in the finally block now. That should probably fix the root cause.

But it might also be beneficial to provide the setting to disable opening tez session everytime due to resource wastage.

[abstractdog]

@maswin : basically it makes sense to prevent tez sessions to be opened at all

1. we already have HIVE_CLI_TEZ_SESSION_ASYNC, let's have HIVE_CLI_TEZ_SESSION_LAZY_START for better naming
2. clarify in HiveConf what that means, I mean having both "async" and "lazy" could be very confusing at first sight: "async" is about starting SessionState and not waiting for tez session to be started, and "lazy" is about not starting tez session at all while starting SessionState

[abstractdog]

@maswin: I just reopened this, I think it looks good, let me merge if the tests pass

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
No Duplication information

The version of Java (11.0.8) you have used to run this analysis is deprecated and we will stop accepting it soon. Please update to at least Java 17.
Read more here

[github-actions]

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs.
Feel free to reach out on the dev@hive.apache.org list if the patch is in need of reviews.

[abstractdog]

reopened again as I forgot about this :)

[abstractdog]

@maswin can you please rebase this PR on top of master?

[maswin]

@maswin can you please rebase this PR on top of master?

@abstractdog : Done

[sonarcloud]

Quality Gate passed

Kudos, no new issues were introduced!

0 New issues
0 Security Hotspots
No data about Coverage
No data about Duplication

See analysis details on SonarCloud