Josh Elser created CALCITE-903:
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Summary: Enable client to recover from missing server-side state
Key: CALCITE-903
URL: https://issues.apache.org/jira/browse/CALCITE-903
Project: Calcite
Issue Type: Improvement
Components: avatica
Reporter: Josh Elser
Assignee: Josh Elser
Fix For: 1.5.0-incubating
When deploying more than one instance of an avatica-server, we have the desire
to treat the collection of servers as a single server. Ideally, we want to have
the avatica-client operate in a manner that doesn't expect a server to have
specific state For example, the avatica-client should be able to know that when
a server doesn't have a statement with the ID the client thinks it should, the
client can create a new statement.
This is desirable because it allows us to use a generic load-balancer between
clients and servers without the need for clustering or sticky sessions. The
downside is that in the face of failure, operations will take longer than
normal. Even with the performance hit, as long as an avatica-server exists, the
client can still retrieve the results for some query which is ideal (tl;dr it
will take longer, but the client still gets the answer).
Two major areas that need to be addressed presently are:
1. Automatic recreation of Statements when they are not cached
2. Recreation of ResultSets to resume iteration (for fetch()). This depends on
"stable results" by the underlying JDBC driver, otherwise external
synchronization would be required. This is considered a prerequisite.
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