52bbc1065c
Requests like `col IN NULL` used to cause an error - Invalid null value for colum col. We would like to allow NULLs everywhere. When a NULL occurs on either side of a binary operator, the whole operation should just evaluate to NULL. Signed-off-by: Jan Ciolek <jan.ciolek@scylladb.com> Closes #11775
176 lines
10 KiB
Python
176 lines
10 KiB
Python
# Copyright 2020-present ScyllaDB
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#
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# SPDX-License-Identifier: AGPL-3.0-or-later
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#############################################################################
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# Tests for finer points of the meaning of "null" in various places
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#############################################################################
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import pytest
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import re
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from cassandra.protocol import InvalidRequest
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from util import unique_name, unique_key_string
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@pytest.fixture(scope="module")
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def table1(cql, test_keyspace):
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table = test_keyspace + "." + unique_name()
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cql.execute(f"CREATE TABLE {table} (p text, c text, v text, i int, s set<int>, m map<int, int>, primary key (p, c))")
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yield table
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cql.execute("DROP TABLE " + table)
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# An item cannot be inserted without a key. Verify that before we get into
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# the really interesting test below - trying to pass "null" as the value of
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# the key.
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# See also issue #3665.
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def test_insert_missing_key(cql, table1):
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s = unique_key_string()
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# A clustering key is missing. Cassandra uses the message "Some clustering
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# keys are missing: c", and Scylla: "Missing mandatory PRIMARY KEY part c"
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with pytest.raises(InvalidRequest, match=re.compile('missing', re.IGNORECASE)):
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cql.execute(f"INSERT INTO {table1} (p) VALUES ('{s}')")
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# Similarly, a missing partition key
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with pytest.raises(InvalidRequest, match=re.compile('missing', re.IGNORECASE)):
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cql.execute(f"INSERT INTO {table1} (c) VALUES ('{s}')")
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# A null key, like a missing one, is also not allowed.
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# This reproduces issue #7852.
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def test_insert_null_key(cql, table1):
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s = unique_key_string()
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with pytest.raises(InvalidRequest, match='null value'):
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cql.execute(f"INSERT INTO {table1} (p,c) VALUES ('{s}', null)")
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with pytest.raises(InvalidRequest, match='null value'):
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cql.execute(f"INSERT INTO {table1} (p,c) VALUES (null, '{s}')")
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# Try the same thing with prepared statement, where a "None" stands for
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# a null. Note that this is completely different from UNSET_VALUE - only
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# with the latter should the insertion be ignored.
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stmt = cql.prepare(f"INSERT INTO {table1} (p,c) VALUES (?, ?)")
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with pytest.raises(InvalidRequest, match='null value'):
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cql.execute(stmt, [s, None])
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with pytest.raises(InvalidRequest, match='null value'):
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cql.execute(stmt, [None, s])
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# Tests handling of "key_column in ?" where ? is bound to null.
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# Reproduces issue #8265.
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def test_primary_key_in_null(scylla_only, cql, table1):
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assert list(cql.execute(cql.prepare(f"SELECT p FROM {table1} WHERE p IN ?"), [None])) == []
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assert list(cql.execute(cql.prepare(f"SELECT p FROM {table1} WHERE p='' AND c IN ?"), [None])) == []
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assert list(cql.execute(cql.prepare(f"SELECT p FROM {table1} WHERE p='' AND (c) IN ?"), [None])) == []
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# Cassandra says "IN predicates on non-primary-key columns (v) is not yet supported".
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def test_regular_column_in_null(scylla_only, cql, table1):
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'''Tests handling of "regular_column in ?" where ? is bound to null.'''
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# Without any rows in the table, SELECT will shortcircuit before evaluating the WHERE clause.
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cql.execute(f"INSERT INTO {table1} (p,c) VALUES ('p', 'c')")
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assert list(cql.execute(cql.prepare(f"SELECT v FROM {table1} WHERE v IN ? ALLOW FILTERING"), [None])) == []
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# Though nonsensical, this operation is allowed by Cassandra. Ensure we allow it, too.
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def test_delete_impossible_clustering_range(cql, table1):
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cql.execute(f"DELETE FROM {table1} WHERE p='p' and c<'a' and c>'a'")
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def test_delete_null_key(cql, table1):
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with pytest.raises(InvalidRequest, match='null value'):
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cql.execute(f"DELETE FROM {table1} WHERE p=null")
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with pytest.raises(InvalidRequest, match='null value'):
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cql.execute(cql.prepare(f"DELETE FROM {table1} WHERE p=?"), [None])
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with pytest.raises(InvalidRequest, match='null value'):
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cql.execute(f"DELETE FROM {table1} WHERE p='p' AND c=null")
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with pytest.raises(InvalidRequest, match='null value'):
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cql.execute(cql.prepare(f"DELETE FROM {table1} WHERE p='p' AND c=?"), [None])
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# Test what SELECT does with the restriction "WHERE v=NULL".
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# In SQL, "WHERE v=NULL" doesn't match anything - because nothing is equal
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# to null - not even null. SQL also provides a more useful restriction
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# "WHERE v IS NULL" which matches all rows where v is unset.
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# Scylla and Cassandra do *not* support the "IS NULL" syntax yet (they do
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# have "IS NOT NULL" but only in a definition of a materialized view),
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# so it is commonly requested that "WHERE v=NULL" should do what "IS NULL"
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# is supposed to do - see issues #4776 and #8489 for Scylla and
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# CASSANDRA-10715 for Cassandra, where this feature was requested.
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# Nevertheless, in Scylla we decided to follow SQL: "WHERE v=NULL" should
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# matche nothing, not even rows where v is unset. This is what the following
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# test verifies.
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# This test fails on Cassandra (hence cassandra_bug) because Cassandra
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# refuses the "WHERE v=NULL" relation, rather than matching nothing.
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# We consider this a mistake, and not something we want to emulate in Scylla.
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def test_filtering_eq_null(cassandra_bug, cql, table1):
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p = unique_key_string()
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cql.execute(f"INSERT INTO {table1} (p,c,v) VALUES ('{p}', '1', 'hello')")
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cql.execute(f"INSERT INTO {table1} (p,c,v) VALUES ('{p}', '2', '')")
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cql.execute(f"INSERT INTO {table1} (p,c) VALUES ('{p}', '3')")
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# As explained above, none of the above-inserted rows should match -
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# not even the one with an unset v:
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assert list(cql.execute(f"SELECT c FROM {table1} WHERE p='{p}' AND v=NULL ALLOW FILTERING")) == []
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# Similarly, inequality restrictions with NULL, like > NULL, also match
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# nothing.
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def test_filtering_inequality_null(cassandra_bug, cql, table1):
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p = unique_key_string()
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cql.execute(f"INSERT INTO {table1} (p,c,i) VALUES ('{p}', '1', 7)")
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cql.execute(f"INSERT INTO {table1} (p,c,i) VALUES ('{p}', '2', -3)")
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cql.execute(f"INSERT INTO {table1} (p,c) VALUES ('{p}', '3')")
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assert list(cql.execute(f"SELECT c FROM {table1} WHERE p='{p}' AND i>NULL ALLOW FILTERING")) == []
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assert list(cql.execute(f"SELECT c FROM {table1} WHERE p='{p}' AND i>=NULL ALLOW FILTERING")) == []
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assert list(cql.execute(f"SELECT c FROM {table1} WHERE p='{p}' AND i<NULL ALLOW FILTERING")) == []
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assert list(cql.execute(f"SELECT c FROM {table1} WHERE p='{p}' AND i<=NULL ALLOW FILTERING")) == []
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# Similarly, CONTAINS restriction with NULL should also match nothing.
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# Reproduces #10359.
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def test_filtering_contains_null(cassandra_bug, cql, table1):
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p = unique_key_string()
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cql.execute(f"INSERT INTO {table1} (p,c,s) VALUES ('{p}', '1', {{1, 2}})")
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cql.execute(f"INSERT INTO {table1} (p,c,s) VALUES ('{p}', '2', {{3, 4}})")
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cql.execute(f"INSERT INTO {table1} (p,c) VALUES ('{p}', '3')")
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assert list(cql.execute(f"SELECT c FROM {table1} WHERE p='{p}' AND s CONTAINS NULL ALLOW FILTERING")) == []
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# Similarly, CONTAINS KEY restriction with NULL should also match nothing.
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# Reproduces #10359.
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def test_filtering_contains_key_null(cassandra_bug, cql, table1):
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p = unique_key_string()
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cql.execute(f"INSERT INTO {table1} (p,c,m) VALUES ('{p}', '1', {{1: 2}})")
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cql.execute(f"INSERT INTO {table1} (p,c,m) VALUES ('{p}', '2', {{3: 4}})")
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cql.execute(f"INSERT INTO {table1} (p,c) VALUES ('{p}', '3')")
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assert list(cql.execute(f"SELECT c FROM {table1} WHERE p='{p}' AND m CONTAINS KEY NULL ALLOW FILTERING")) == []
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# The above tests test_filtering_eq_null and test_filtering_inequality_null
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# have WHERE x=NULL or x>NULL where "x" is a regular column. Such a
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# comparison requires ALLOW FILTERING for non-NULL parameters, so we also
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# require it for NULL. Unlike the previous tests, this one also passed on
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# Cassandra.
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def test_filtering_null_comparison_no_filtering(cql, table1):
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with pytest.raises(InvalidRequest, match='ALLOW FILTERING'):
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cql.execute(f"SELECT c FROM {table1} WHERE p='x' AND i=NULL")
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with pytest.raises(InvalidRequest, match='ALLOW FILTERING'):
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cql.execute(f"SELECT c FROM {table1} WHERE p='x' AND i>NULL")
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with pytest.raises(InvalidRequest, match='ALLOW FILTERING'):
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cql.execute(f"SELECT c FROM {table1} WHERE p='x' AND i>=NULL")
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with pytest.raises(InvalidRequest, match='ALLOW FILTERING'):
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cql.execute(f"SELECT c FROM {table1} WHERE p='x' AND i<NULL")
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with pytest.raises(InvalidRequest, match='ALLOW FILTERING'):
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cql.execute(f"SELECT c FROM {table1} WHERE p='x' AND i<=NULL")
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with pytest.raises(InvalidRequest, match='ALLOW FILTERING'):
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cql.execute(f"SELECT c FROM {table1} WHERE p='x' AND s CONTAINS NULL")
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with pytest.raises(InvalidRequest, match='ALLOW FILTERING'):
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cql.execute(f"SELECT c FROM {table1} WHERE p='x' AND m CONTAINS KEY NULL")
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# Cassandra considers the null subscript 'm[null]' to be an invalid request.
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# In Scylla we decided to it differently (we think better): m[null] is simply
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# a null, so the filter 'WHERE m[null] = 3' is not an error - it just doesn't
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# match anything. This is more consistent with our usual null handling (null[2]
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# and null < 2 are both defined as returning null), and will also allow us
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# in the future to support non-constant subscript - for example m[a] where
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# the column a can be null for some rows and non-null for other rows.
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# Before we implemented the above decision, we had multiple bugs in this case,
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# resulting in bizarre errors and even crashes (see #10361, #10399 and #10417).
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#
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# Because this test uses a shared table (table1), then depending on how it's
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# run, it sometimes sees an empty table and sometimes a table with data
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# (and null values for the map m...), so this test mixes several different
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# concerns and problems. The same problems are better covered separately
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# by test_filtering.py::test_filtering_with_subscript and
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# test_filtering.py::test_filtering_null_map_with_subscript so this test
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# should eventually be deleted.
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def test_map_subscript_null(cql, table1, cassandra_bug):
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assert list(cql.execute(f"SELECT p FROM {table1} WHERE m[null] = 3 ALLOW FILTERING")) == []
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assert list(cql.execute(cql.prepare(f"SELECT p FROM {table1} WHERE m[?] = 3 ALLOW FILTERING"), [None])) == []
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