Files
scylladb/cql3/single_column_relation.cc
Nadav Har'El 92d5f61ba5 cql: support single-value IN restriction wherever EQ restriction is supported
There are several places were IN restrictions are not currently supported,
especially in queries involving a secondary index. However, when the IN
restriction has just a single value, it is nothing more than an equality
restriction and can be converted into one and be supported. So this patch
does exactly this.

Note that Cassandra does this conversion since August 2016, and therefore
supports the special case of single-value IN even where general IN is not
supported. So it's important for Cassandra compatibility that we do this
conversion too.

This patch also includes a test with two queries involving a secondary
index that were previously disallowed because of the "IN" on the primary
key or the indexed column - and are now allowed when the IN restriction
has just a single value. A third query tested is not related to secondary
indexes, but confirms we don't break multi-column single-value IN queries.

Fixes #4455.

Signed-off-by: Nadav Har'El <nyh@scylladb.com>
Message-Id: <20190428160317.23328-1-nyh@scylladb.com>
2019-04-30 12:13:06 +01:00

147 lines
6.5 KiB
C++

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/*
* Copyright (C) 2015 ScyllaDB
*
* Modified by ScyllaDB
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#include "cql3/single_column_relation.hh"
#include "cql3/restrictions/single_column_restriction.hh"
#include "cql3/statements/request_validations.hh"
#include "cql3/cql3_type.hh"
#include "cql3/lists.hh"
#include "unimplemented.hh"
#include "types/map.hh"
#include "types/list.hh"
using namespace cql3::restrictions;
namespace cql3 {
::shared_ptr<term>
single_column_relation::to_term(const std::vector<::shared_ptr<column_specification>>& receivers,
::shared_ptr<term::raw> raw,
database& db,
const sstring& keyspace,
::shared_ptr<variable_specifications> bound_names) {
// TODO: optimize vector away, accept single column_specification
assert(receivers.size() == 1);
auto term = raw->prepare(db, keyspace, receivers[0]);
term->collect_marker_specification(bound_names);
return term;
}
::shared_ptr<restrictions::restriction>
single_column_relation::new_EQ_restriction(database& db, schema_ptr schema, ::shared_ptr<variable_specifications> bound_names) {
const column_definition& column_def = to_column_definition(schema, _entity);
if (!_map_key) {
auto term = to_term(to_receivers(schema, column_def), _value, db, schema->ks_name(), bound_names);
return ::make_shared<single_column_restriction::EQ>(column_def, std::move(term));
}
auto&& receivers = to_receivers(schema, column_def);
auto&& entry_key = to_term({receivers[0]}, _map_key, db, schema->ks_name(), bound_names);
auto&& entry_value = to_term({receivers[1]}, _value, db, schema->ks_name(), bound_names);
return make_shared<single_column_restriction::contains>(column_def, std::move(entry_key), std::move(entry_value));
}
::shared_ptr<restrictions::restriction>
single_column_relation::new_IN_restriction(database& db, schema_ptr schema, ::shared_ptr<variable_specifications> bound_names) {
const column_definition& column_def = to_column_definition(schema, _entity);
auto receivers = to_receivers(schema, column_def);
assert(_in_values.empty() || !_value);
if (_value) {
auto term = to_term(receivers, _value, db, schema->ks_name(), bound_names);
return make_shared<single_column_restriction::IN_with_marker>(column_def, dynamic_pointer_cast<lists::marker>(term));
}
auto terms = to_terms(receivers, _in_values, db, schema->ks_name(), bound_names);
// Convert a single-item IN restriction to an EQ restriction
if (terms.size() == 1) {
return ::make_shared<single_column_restriction::EQ>(column_def, std::move(terms[0]));
}
return ::make_shared<single_column_restriction::IN_with_values>(column_def, std::move(terms));
}
std::vector<::shared_ptr<column_specification>>
single_column_relation::to_receivers(schema_ptr schema, const column_definition& column_def)
{
using namespace statements::request_validations;
auto receiver = column_def.column_specification;
if (schema->is_dense() && column_def.is_regular()) {
throw exceptions::invalid_request_exception(format("Predicates on the non-primary-key column ({}) of a COMPACT table are not yet supported", column_def.name_as_text()));
}
if (is_contains() && !receiver->type->is_collection()) {
throw exceptions::invalid_request_exception(format("Cannot use CONTAINS on non-collection column \"{}\"", receiver->name));
}
if (is_contains_key()) {
if (!dynamic_cast<const map_type_impl*>(receiver->type.get())) {
throw exceptions::invalid_request_exception(format("Cannot use CONTAINS KEY on non-map column {}", receiver->name));
}
}
if (_map_key) {
check_false(dynamic_cast<const list_type_impl*>(receiver->type.get()), "Indexes on list entries (%s[index] = value) are not currently supported.", receiver->name);
check_true(dynamic_cast<const map_type_impl*>(receiver->type.get()), "Column %s cannot be used as a map", receiver->name);
check_true(receiver->type->is_multi_cell(), "Map-entry equality predicates on frozen map column %s are not supported", receiver->name);
check_true(is_EQ(), "Only EQ relations are supported on map entries");
}
if (receiver->type->is_collection()) {
// We don't support relations against entire collections (unless they're frozen), like "numbers = {1, 2, 3}"
check_false(receiver->type->is_multi_cell() && !is_legal_relation_for_non_frozen_collection(),
"Collection column '%s' (%s) cannot be restricted by a '%s' relation",
receiver->name,
receiver->type->as_cql3_type(),
get_operator());
if (is_contains_key() || is_contains()) {
receiver = make_collection_receiver(receiver, is_contains_key());
} else if (receiver->type->is_multi_cell() && _map_key && is_EQ()) {
return {
make_collection_receiver(receiver, true),
make_collection_receiver(receiver, false),
};
}
}
return {std::move(receiver)};
}
}