Improve get_used_tables_from_queries handling of table aliases

indexdigest/linters/linter_0006_not_used_columns_and_tables.py

@@ -6,39 +6,22 @@
 from collections import defaultdict, OrderedDict
 from sql_metadata import get_query_columns, get_query_tables
 
-from indexdigest.database import IndexDigestQueryError
 from indexdigest.utils import LinterEntry, is_select_query
 
 
-def get_used_tables_from_queries(database, queries):
+def get_used_tables_from_queries(queries):
     """
-    :type database  indexdigest.database.Database
     :type queries list[str]
     :rtype: list[str]
     """
-    logger = logging.getLogger(__name__)
-
     used_tables = []
     queries = filter(is_select_query, queries)
 
     for query in queries:
-        # run EXPLAIN for each query from the log
-        try:
-            for row in database.explain_query(query):
-                if row.get('table') is not None:
-                    if row['table'] not in used_tables:
-                        used_tables.append(row['table'])
-                else:
-                    # EXPLAIN may return "no matching row in const table"
-                    logger.warning('EXPLAIN %s returned no table, falling back to SQL parsing',
-                                   query)
-
-                    # fall back to SQL query parsing
-                    tables = get_query_tables(query)
-                    if tables and tables[0] not in used_tables:
-                        used_tables.append(tables[0])
-        except IndexDigestQueryError:
-            logger.error('Cannot explain the query: %s', query)
+        # parse each query from the log
+        tables = get_query_tables(query)
+        if tables and tables[0] not in used_tables:
+            used_tables.append(tables[0])
 
     return used_tables
 
@@ -55,7 +38,7 @@ def check_not_used_tables(database, queries):
     tables = database.get_tables()
 
     # analyze only SELECT queries from the log
-    used_tables = get_used_tables_from_queries(database, queries)
+    used_tables = get_used_tables_from_queries(queries)
     logger.info("These tables were used by provided queries: %s", used_tables)
 
     # now check which tables were not used
@@ -88,7 +71,7 @@ def check_not_used_columns(database, queries):
     # analyze only SELECT queries from the log
     queries = list(filter(is_select_query, queries))
 
-    used_tables = get_used_tables_from_queries(database, queries)
+    used_tables = get_used_tables_from_queries(queries)
     used_columns = defaultdict(list)
 
     logger.info("Will check these tables: %s", used_tables)

indexdigest/test/linters/test_0006_not_used_columns_and_tables.py

@@ -40,12 +40,11 @@ def test_not_used_tables(self):
 
     def test_get_used_tables_from_queries(self):
         queries = [
-            'SELECT /* a comment */ foo FROM `0006_not_used_columns` WHERE id = 1;',
+            'SELECT /* a comment */ foo FROM `0006_not_used_columns` AS r WHERE id = 1;',  # table alias
             'SELECT 1 FROM `0006_not_used_tables` WHERE id = 3;',
         ]
 
-        tables = get_used_tables_from_queries(
-            database=self.connection, queries=queries)
+        tables = get_used_tables_from_queries(queries)
 
         print(tables)
 

indexdigest/test/test_0089_handle_sql_errors.py

@@ -15,9 +15,7 @@ def queries(self):
         return read_queries_from_log('0098-handle-sql-errors-log')
 
     def test_get_used_tables_from_queries(self):
-        tables = get_used_tables_from_queries(
-            database=self.connection,
-            queries=self.queries)
+        tables = get_used_tables_from_queries(self.queries)
 
         print(tables)
 

sql/0098-handle-sql-errors-log

@@ -1,9 +1,9 @@
 -- ERROR 1140 (42000): In aggregated query without GROUP BY, expression #1 of SELECT list contains nonaggregated column 'index_digest.0020_big_table.val'; this is incompatible with sql_mode=only_full_group_by
-SELECT val, count(*) FROM 0020_big_table WHERE id BETWEEN 10 AND 20;
+SELECT val, count(*) FROM `0020_big_table` WHERE id BETWEEN 10 AND 20;
 
 -- query with aliases
-SELECT t.val as value, count(*) FROM 0020_big_table as t WHERE id BETWEEN 10 AND 20 GROUP BY val;
-SELECT val as value, count(*) FROM 0020_big_table WHERE id BETWEEN 10 AND 20 GROUP BY val;
+SELECT t.val as value, count(*) FROM `0020_big_table` as t WHERE id BETWEEN 10 AND 20 GROUP BY val;
+SELECT val as value, count(*) FROM `0020_big_table` WHERE id BETWEEN 10 AND 20 GROUP BY val;
 
 -- invalid syntax
 SELEKT foo FROM bar;