LLAP troubleshooting and debugging

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This is the central page that links to other LLAP debugging articles. You can find articles dealing with specific problems below; to provide some background and to help resolve other issues, there are also some helpful general-purpose articles:

A one-page overview of LLAP architecture: https://community.hortonworks.com/articles/149894/llap-a-one-page-architecture-overview.html

On the general debugging - where to find logs, UIs, metrics, etc.: https://community.hortonworks.com/articles/149896/llap-debugging-overview-logs-uis-etc.html

You might also find this non-debugging LLAP sizing and setup guide interesting: https://community.hortonworks.com/articles/149486/llap-sizing-and-setup.html

Before getting to specific issues, there are some limitations with LLAP that you should be aware of; the following significant features are not supported:

• HA (work in progress).
• doAs=true (no current plans to support it).
• Temporary functions (will not be supported; use permanent functions).
• CLI access (use beeline).

Then, there are some articles about specific issues:

• LLAP doesn't start - https://community.hortonworks.com/articles/149899/investigating-when-llap-doesnt-start.html
• Queries are slow or stuck on LLAP - https://community.hortonworks.com/articles/149900/investigating-when-the-queries-on-llap-are-slow-or...
• Investigating cache usage - https://community.hortonworks.com/articles/149901/investigating-llap-cache-hit-rate.html

This list will be expanded in future with the issues that people are facing with LLAP.