[
https://issues.apache.org/jira/browse/ARROW-11549?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Sikan Chen updated ARROW-11549:
-------------------------------
Description:
Gandiva's caching mechanism for filters relies on {{FilterCacheKey}} to return
the correct cached filter. {{FilterCacheKey}}'s hash function factors in the
string representation of a given expression, however {{Expression::ToString()}}
doesn't really distinguish null and string literal 'null'. As a result,
incorrect filters may be returned from the cache.
In our case, we are building a SQL parser on top of gandiva, but, for instance,
both of
{code:java}
WHERE null = null
{code}
and
{code:java}
WHERE 'null' = 'null'
{code}
result in the same string representation of gandiva expression:
{code:java}
bool equal((const string) null, (const string) null)
{code}
A simple test to demonstrate the issue:
{code:java}
auto f = field("foo", utf8());
auto schema = arrow::schema({f});
auto node_a = TreeExprBuilder::MakeStringLiteral("null");
auto node_b = TreeExprBuilder::MakeStringLiteral("null");
auto equal_func =
TreeExprBuilder::MakeFunction("equal", {node_a, node_b},
arrow::boolean());
auto condition = TreeExprBuilder::MakeCondition(equal_func);
std::shared_ptr<Filter> filter1;
auto status = Filter::Make(schema, condition, &filter1);
EXPECT_TRUE(status.ok());
auto string_type = std::make_shared<arrow::StringType>();
node_a = TreeExprBuilder::MakeNull(string_type);
node_b = TreeExprBuilder::MakeNull(string_type);
equal_func =
TreeExprBuilder::MakeFunction("equal", {node_a, node_b},
arrow::boolean());
condition = TreeExprBuilder::MakeCondition(equal_func);
std::shared_ptr<Filter> filter2;
status = Filter::Make(schema, condition, &filter2);
EXPECT_TRUE(status.ok());
EXPECT_TRUE(filter1.get() != filter2.get());
{code}
Making {{LiteralToStream}} add quotes around the literal seems like a
quick-and-dirty fix.
was:
Gandiva's caching mechanism for filters relies on {{FilterCacheKey}} to return
the correct cached filter. {{FilterCacheKey}}'s hash function factors in the
string representation of a given expression, however {{Expression::ToString()}}
doesn't really distinguish null and string literal 'null'. As a result,
incorrect filters may be returned from the cache.
In our case, we are building a SQL parser on top of gandiva, but, for instance,
both of
{code:java}
WHERE null = null
{code}
and
{code:java}
WHERE 'null' = 'null'
{code}
result in the same string representation of gandiva expression:
{code:java}
bool equal((const string) null, (const string) null)
{code}
A simple test to demonstrate the issue:
{code:java}
auto f = field("foo", utf8());
auto schema = arrow::schema({f});
auto node_a = TreeExprBuilder::MakeStringLiteral("null");
auto node_b = TreeExprBuilder::MakeStringLiteral("null");
auto equal_func =
TreeExprBuilder::MakeFunction("equal", {node_a, node_b},
arrow::boolean());
auto condition = TreeExprBuilder::MakeCondition(equal_func);
std::shared_ptr<Filter> filter1;
auto status = Filter::Make(schema, condition, &filter1);
EXPECT_TRUE(status.ok());
auto string_type = std::make_shared<arrow::StringType>();
node_a = TreeExprBuilder::MakeNull(string_type);
node_b = TreeExprBuilder::MakeNull(string_type);
equal_func =
TreeExprBuilder::MakeFunction("equal", {node_a, node_b},
arrow::boolean());
condition = TreeExprBuilder::MakeCondition(equal_func);
std::shared_ptr<Filter> filter2;
status = Filter::Make(schema, condition, &filter2);
EXPECT_TRUE(status.ok());
EXPECT_TRUE(filter1.get() != filter2.get());
{code}
Making {{LiteralToStream}} adding quotes around the literal seems like a
quick-and-dirty fix.
> Expression::ToString() doesn't distinguish null and string literal 'null',
> causing issues with FilterCacheKey
> -------------------------------------------------------------------------------------------------------------
>
> Key: ARROW-11549
> URL: https://issues.apache.org/jira/browse/ARROW-11549
> Project: Apache Arrow
> Issue Type: Bug
> Components: C++, C++ - Gandiva
> Reporter: Sikan Chen
> Priority: Critical
>
> Gandiva's caching mechanism for filters relies on {{FilterCacheKey}} to
> return the correct cached filter. {{FilterCacheKey}}'s hash function factors
> in the string representation of a given expression, however
> {{Expression::ToString()}} doesn't really distinguish null and string literal
> 'null'. As a result, incorrect filters may be returned from the cache.
> In our case, we are building a SQL parser on top of gandiva, but, for
> instance, both of
> {code:java}
> WHERE null = null
> {code}
> and
> {code:java}
> WHERE 'null' = 'null'
> {code}
> result in the same string representation of gandiva expression:
> {code:java}
> bool equal((const string) null, (const string) null)
> {code}
> A simple test to demonstrate the issue:
> {code:java}
> auto f = field("foo", utf8());
> auto schema = arrow::schema({f});
> auto node_a = TreeExprBuilder::MakeStringLiteral("null");
> auto node_b = TreeExprBuilder::MakeStringLiteral("null");
> auto equal_func =
> TreeExprBuilder::MakeFunction("equal", {node_a, node_b},
> arrow::boolean());
> auto condition = TreeExprBuilder::MakeCondition(equal_func);
> std::shared_ptr<Filter> filter1;
> auto status = Filter::Make(schema, condition, &filter1);
> EXPECT_TRUE(status.ok());
> auto string_type = std::make_shared<arrow::StringType>();
> node_a = TreeExprBuilder::MakeNull(string_type);
> node_b = TreeExprBuilder::MakeNull(string_type);
> equal_func =
> TreeExprBuilder::MakeFunction("equal", {node_a, node_b},
> arrow::boolean());
> condition = TreeExprBuilder::MakeCondition(equal_func);
> std::shared_ptr<Filter> filter2;
> status = Filter::Make(schema, condition, &filter2);
> EXPECT_TRUE(status.ok());
> EXPECT_TRUE(filter1.get() != filter2.get());
> {code}
>
> Making {{LiteralToStream}} add quotes around the literal seems like a
> quick-and-dirty fix.
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