From 52e9d30c5cd46505d3ace92731b0fd5f93b1ac04 Mon Sep 17 00:00:00 2001
From: Itai Shirav <itais@infinidat.com>
Date: Sun, 10 Jul 2016 16:40:47 +0300
Subject: [PATCH 1/2] stream only SELECTs, to prevent "connection reset by
 peer" errors

---
 src/infi/clickhouse_orm/database.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/infi/clickhouse_orm/database.py b/src/infi/clickhouse_orm/database.py
index 1761469..342c870 100644
--- a/src/infi/clickhouse_orm/database.py
+++ b/src/infi/clickhouse_orm/database.py
@@ -58,7 +58,7 @@ class Database(object):
 
     def select(self, query, model_class=None, settings=None):
         query += ' FORMAT TabSeparatedWithNamesAndTypes'
-        r = self._send(query, settings)
+        r = self._send(query, settings, True)
         lines = r.iter_lines()
         field_names = parse_tsv(next(lines))
         field_types = parse_tsv(next(lines))
@@ -103,9 +103,9 @@ class Database(object):
         query = "SELECT module_name from `%s`.`%s` WHERE package_name = '%s'" % (self.db_name, MigrationHistory.table_name(), migrations_package_name)
         return set(obj.module_name for obj in self.select(query))
 
-    def _send(self, data, settings=None):
+    def _send(self, data, settings=None, stream=False):
         params = self._build_params(settings)
-        r = requests.post(self.db_url, params=params, data=data, stream=True)
+        r = requests.post(self.db_url, params=params, data=data, stream=stream)
         if r.status_code != 200:
             raise DatabaseException(r.text)
         return r

From 5906d90b1fcdb24c85b2cdb35b298665c1f0e273 Mon Sep 17 00:00:00 2001
From: Itai Shirav <itais@infinidat.com>
Date: Mon, 11 Jul 2016 13:04:48 +0300
Subject: [PATCH 2/2] migrations support - documentation

---
 MIGRATIONS.rst | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++
 README.rst     |  9 +++++++
 2 files changed, 74 insertions(+)
 create mode 100644 MIGRATIONS.rst

diff --git a/MIGRATIONS.rst b/MIGRATIONS.rst
new file mode 100644
index 0000000..0f0d5e2
--- /dev/null
+++ b/MIGRATIONS.rst
@@ -0,0 +1,65 @@
+Migrations
+==========
+
+Over time, the ORM models in your application may change. Migrations provide a way to modify the database
+tables according to the changes in your models, without writing raw SQL.
+
+The migrations that were applied to the database are recorded in the ``infi_clickhouse_orm_migrations`` table,
+so migrating the database will only apply any missing migrations.
+
+Writing Migrations
+------------------
+
+To write migrations, create a Python package. Then create a python file for the initial migration. The migration
+files must begin with a four-digit number, and will be applied in sequence. For example::
+
+    analytics
+       |
+       +-- analytics_migrations
+              |
+              +-- __init__.py
+              |
+              +-- 0001_initial.py
+              |
+              +-- 0002_add_user_agents_table.py
+
+Each migration file is expected to contain a list of ``operations``, for example::
+
+    from infi.clickhouse_orm import migrations
+    from analytics import models
+
+    operations = [
+        migrations.CreateTable(models.Visits),
+        migrations.CreateTable(models.Visitors)
+    ]
+
+The following operations are supported:
+
+**CreateTable**
+
+A migration operation that creates a table for a given model class.
+
+**DropTable**
+
+A migration operation that drops the table of a given model class.
+
+**AlterTable**
+
+A migration operation that compares the table of a given model class to
+the model's fields, and alters the table to match the model. The operation can:
+
+- add new columns
+- drop obsolete columns
+- modify column types
+
+Default values are not altered by this operation.
+
+Running Migrations
+------------------
+
+To migrate a database, create a ``Database`` instance and call its ``migrate`` method with the package
+name containing your migrations::
+
+    Database('analytics_db').migrate('analytics.analytics_migrations')
+
+Note that you may have more than one migrations package.
\ No newline at end of file
diff --git a/README.rst b/README.rst
index 7070323..e70e585 100644
--- a/README.rst
+++ b/README.rst
@@ -142,6 +142,15 @@ You can optionally pass conditions to the query::
 Note that ``order_by`` must be chosen so that the ordering is unique, otherwise there might be
 inconsistencies in the pagination (such as an instance that appears on two different pages).
 
+Schema Migrations
+-----------------
+
+Over time, your models may change and the database will have to be modified accordingly.
+Migrations allow you to describe these changes succinctly using Python, and to apply them
+to the database. A migrations table automatically keeps track of which migrations were already applied.
+
+For details please refer to the MIGRATIONS.rst document.
+
 Field Types
 -----------