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fix: StatementParser did not accept multiple query hints (#170)
Fixes #163
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olavloite committed Apr 22, 2020
1 parent f13388a commit ef41a6e503f218c00c16914aa9c1433d9b26db13
@@ -212,9 +212,9 @@ ClientSideStatement getClientSideStatement() {
}
}

private final Set<String> ddlStatements = ImmutableSet.of("CREATE", "DROP", "ALTER");
private final Set<String> selectStatements = ImmutableSet.of("SELECT", "WITH");
private final Set<String> dmlStatements = ImmutableSet.of("INSERT", "UPDATE", "DELETE");
private static final Set<String> ddlStatements = ImmutableSet.of("CREATE", "DROP", "ALTER");
private static final Set<String> selectStatements = ImmutableSet.of("SELECT", "WITH");
private static final Set<String> dmlStatements = ImmutableSet.of("INSERT", "UPDATE", "DELETE");
private final Set<ClientSideStatementImpl> statements;

/** Private constructor for singleton instance. */
@@ -445,19 +445,31 @@ public static String removeCommentsAndTrim(String sql) {

/** Removes any statement hints at the beginning of the statement. */
static String removeStatementHint(String sql) {
// Valid statement hints at the beginning of a SQL statement can only contain a fixed set of
// Valid statement hints at the beginning of a query statement can only contain a fixed set of
// possible values. Although it is possible to add a @{FORCE_INDEX=...} as a statement hint, the
// only allowed value is _BASE_TABLE. This means that we can safely assume that the statement
// hint will not contain any special characters, for example a closing curly brace, and
// that we can keep the check simple by just searching for the first occurrence of a closing
// curly brace at the end of the statement hint.
// hint will not contain any special characters, for example a closing curly brace or one of the
// keywords SELECT, UPDATE, DELETE, WITH, and that we can keep the check simple by just
// searching for the first occurrence of a keyword that should be preceded by a closing curly
// brace at the end of the statement hint.
int startStatementHintIndex = sql.indexOf('{');
int endStatementHintIndex = sql.indexOf('}');
if (startStatementHintIndex == -1 || startStatementHintIndex > endStatementHintIndex) {
// Looks like an invalid statement hint. Just ignore at this point and let the caller handle
// the invalid query.
return sql;
// Statement hints are only allowed for queries.
int startQueryIndex = -1;
String upperCaseSql = sql.toUpperCase();
for (String keyword : selectStatements) {
startQueryIndex = upperCaseSql.indexOf(keyword);
if (startQueryIndex > -1) break;
}
return removeCommentsAndTrim(sql.substring(endStatementHintIndex + 1));
if (startQueryIndex > -1) {
int endStatementHintIndex = sql.substring(0, startQueryIndex).lastIndexOf('}');
if (startStatementHintIndex == -1 || startStatementHintIndex > endStatementHintIndex) {
// Looks like an invalid statement hint. Just ignore at this point and let the caller handle
// the invalid query.
return sql;
}
return removeCommentsAndTrim(sql.substring(endStatementHintIndex + 1));
}
// Seems invalid, just return the original statement.
return sql;
}
}
@@ -339,10 +339,28 @@ public void testQueryHints() {
+ "UNION ALL\n"
+ "SELECT * FROM subQ2"));

// Multiple query hints.
assertTrue(
StatementParser.INSTANCE.isQuery(
"@{FORCE_INDEX=index_name} @{JOIN_METHOD=HASH_JOIN} SELECT * FROM tbl"));
assertTrue(
StatementParser.INSTANCE.isQuery(
"@{FORCE_INDEX=index_name} @{JOIN_METHOD=HASH_JOIN} Select * FROM tbl"));
assertTrue(
StatementParser.INSTANCE.isQuery(
"@{FORCE_INDEX=index_name}\n@{JOIN_METHOD=HASH_JOIN}\nWITH subQ1 AS (SELECT SchoolID FROM Roster),\n"
+ " subQ2 AS (SELECT OpponentID FROM PlayerStats)\n"
+ "SELECT * FROM subQ1\n"
+ "UNION ALL\n"
+ "SELECT * FROM subQ2"));

// Invalid query hints.
assertFalse(parser.isQuery("@{JOIN_METHOD=HASH_JOIN SELECT * FROM PersonsTable"));
assertFalse(parser.isQuery("@JOIN_METHOD=HASH_JOIN} SELECT * FROM PersonsTable"));
assertFalse(parser.isQuery("@JOIN_METHOD=HASH_JOIN SELECT * FROM PersonsTable"));
assertFalse(
StatementParser.INSTANCE.isQuery(
"@{FORCE_INDEX=index_name} @{JOIN_METHOD=HASH_JOIN} UPDATE tbl set FOO=1 WHERE ID=2"));
}

@Test

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