Doug Rohrer created CASSANDRA-17623:
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Summary: Frozen maps may be serialized unsorted, causing inability
to query later
Key: CASSANDRA-17623
URL: https://issues.apache.org/jira/browse/CASSANDRA-17623
Project: Cassandra
Issue Type: Bug
Reporter: Doug Rohrer
CASSANDRA-7859 introduced the ability to use frozen collections as parts of
primary keys. This +requires+ all frozen maps to be persisted with their
entries sorted by the map keys. If the map is +not+ sorted correctly, it
becomes impossible to project all of the map values out of the map using the
map projection/selection syntax. For example, the select below would fail if
the map was not sorted correctly and the higher-valued key was persisted first:
{code:sql}
CREATE TABLE test.test (k text, c frozen<map<text, text>>, PRIMARY KEY (k, c));
INSERT INTO test.test (k, c) VALUES ('key', {'z':'second_value',
'a':'first_value'});
SELECT k, c['a'] from test.test where k='key' -- c['a'] would return NULL here
{code}
Additionally, if you attempted to select just that row by using the complete
map value in a WHERE clause, which is also supported, it would return no rows
unless the map provided by the query processor just happened to be sorted the
same way as the persisted value.
However, there is a bug in Maps.java where we don't actually use a SortedMap in
{{Maps.Value#fromSerialized}}, which manifests if a client sends an unsorted
map as a bound parameter to a query on insert or select. In either case, the
map may not be sorted correctly, leading to either invalid data being persisted
to disk (in the INSERT case) or the query not being able to be
executed/returning 0 rows even though a row _should_ exist (SELECT).
This bug affects any usage of parameterized queries (tested with the DataStax
driver, and was originally discovered when using the CQLSSTableWriter code to
write data locally).
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