We're using Cassandra 2.2.
This document lists a number of CQL limits. I'm particularly interested in the
Collection limits for Set and List. If I've interpreted it correctly, the
document states that values in Sets are limited to 65535 bytes.
This limit, as far as I know, exists because the set identity is implemented
with a composite value in the column name of the storage engine's cell (similar
to the clustering column value limit), which CQL restricts to that many bytes.
(Is this correct?)
Consider a table like
CREATE TABLE test.bounds ( someid text, someorder text, words
set<text>,
PRIMARY KEY (guid, deviceid))
with
PreparedStatement ps = session.prepare("INSERT INTO bounds (someid, someorder,
epset) VALUES (?, ?, ?)");BoundStatement bs = ps.bind("id", "order",
ImmutableSet.of(StringUtils.repeat('a', 66000)));session.execute(bs);
This will throw the expected exception
Caused by: com.datastax.driver.core.exceptions.InvalidQueryException: The sum
of all clustering columns is too long (66024 > 65535)
Now if I change the table to use a List instead of a Set
CREATE TABLE test.bounds ( someid text, someorder text, words
Set<text>,
PRIMARY KEY (guid, deviceid))
and use
BoundStatement bs = ps.bind("id", "order",
ImmutableList.of(StringUtils.repeat('a', 66000)));
I do not receive an exception. The document, however, states that List value
sizes are also limited to 65535 bytes. Is the document incorrect or am I
misinterpreting?
I assumed List values are implemented as simple column values in the underlying
storage and the order is maintained through their timestamps.
