Give query case sensitive treatment in query hash (#4254)

Generating the query hash from the query text with no lowercasing of the query text
allows case-sensitive parameter values in the dashboard to have different cache entries.

Fixes #2137

migrations/versions/1038c2174f5d_make_case_insensitive_hash_of_query_text.py

@@ -0,0 +1,51 @@
+"""Make case insensitive hash of query text
+
+Revision ID: 1038c2174f5d
+Revises: fd4fc850d7ea
+Create Date: 2023-07-16 23:10:12.885949
+
+"""
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.sql import table
+
+from redash.utils import gen_query_hash
+
+# revision identifiers, used by Alembic.
+revision = '1038c2174f5d'
+down_revision = 'fd4fc850d7ea'
+branch_labels = None
+depends_on = None
+
+
+
+def change_query_hash(conn, table, query_text_to):
+    for record in conn.execute(table.select()):
+        query_text = query_text_to(record.query)
+        conn.execute(
+            table
+            .update()
+            .where(table.c.id == record.id)
+            .values(query_hash=gen_query_hash(query_text)))
+
+
+def upgrade():
+    queries = table(
+        'queries',
+        sa.Column('id', sa.Integer, primary_key=True),
+        sa.Column('query', sa.Text),
+        sa.Column('query_hash', sa.String(length=10)))
+
+    conn = op.get_bind()
+    change_query_hash(conn, queries, query_text_to=str)
+
+
+def downgrade():
+    queries = table(
+        'queries',
+        sa.Column('id', sa.Integer, primary_key=True),
+        sa.Column('query', sa.Text),
+        sa.Column('query_hash', sa.String(length=10)))
+
+    conn = op.get_bind()
+    change_query_hash(conn, queries, query_text_to=str.lower)

redash/utils/__init__.py

@@ -51,14 +51,14 @@ def slugify(s):
 
 def gen_query_hash(sql):
     """Return hash of the given query after stripping all comments, line breaks
-    and multiple spaces, and lower casing all text.
+    and multiple spaces.
 
-    TODO: possible issue - the following queries will get the same id:
+    The following queries will get different ids:
         1. SELECT 1 FROM table WHERE column='Value';
         2. SELECT 1 FROM table where column='value';
     """
     sql = COMMENTS_REGEX.sub("", sql)
-    sql = "".join(sql.split()).lower()
+    sql = "".join(sql.split())
     return hashlib.md5(sql.encode("utf-8")).hexdigest()