132 lines
6.1 KiB
Python
132 lines
6.1 KiB
Python
import json
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import unittest
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import xml.etree.ElementTree
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from django.db import NotSupportedError, connection, transaction
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from django.db.models import Count
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from django.test import TestCase, skipIfDBFeature, skipUnlessDBFeature
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from django.test.utils import CaptureQueriesContext
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from .models import Tag
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@skipUnlessDBFeature("supports_explaining_query_execution")
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class ExplainTests(TestCase):
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def test_basic(self):
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querysets = [
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Tag.objects.filter(name="test"),
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Tag.objects.filter(name="test").select_related("parent"),
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Tag.objects.filter(name="test").prefetch_related("children"),
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Tag.objects.filter(name="test").annotate(Count("children")),
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Tag.objects.filter(name="test").values_list("name"),
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Tag.objects.order_by().union(Tag.objects.order_by().filter(name="test")),
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Tag.objects.select_for_update().filter(name="test"),
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]
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supported_formats = connection.features.supported_explain_formats
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all_formats = (
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(None,)
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+ tuple(supported_formats)
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+ tuple(f.lower() for f in supported_formats)
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)
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for idx, queryset in enumerate(querysets):
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for format in all_formats:
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with self.subTest(format=format, queryset=idx):
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with self.assertNumQueries(1), CaptureQueriesContext(
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connection
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) as captured_queries:
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result = queryset.explain(format=format)
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self.assertTrue(
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captured_queries[0]["sql"].startswith(
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connection.ops.explain_prefix
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)
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)
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self.assertIsInstance(result, str)
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self.assertTrue(result)
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if format == "xml":
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try:
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xml.etree.ElementTree.fromstring(result)
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except xml.etree.ElementTree.ParseError as e:
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self.fail(
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f"QuerySet.explain() result is not valid XML: {e}"
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)
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elif format == "json":
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try:
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json.loads(result)
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except json.JSONDecodeError as e:
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self.fail(
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f"QuerySet.explain() result is not valid JSON: {e}"
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)
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@skipUnlessDBFeature("validates_explain_options")
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def test_unknown_options(self):
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with self.assertRaisesMessage(ValueError, "Unknown options: test, test2"):
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Tag.objects.explain(test=1, test2=1)
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def test_unknown_format(self):
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msg = "DOES NOT EXIST is not a recognized format."
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if connection.features.supported_explain_formats:
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msg += " Allowed formats: %s" % ", ".join(
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sorted(connection.features.supported_explain_formats)
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)
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with self.assertRaisesMessage(ValueError, msg):
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Tag.objects.explain(format="does not exist")
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@unittest.skipUnless(connection.vendor == "postgresql", "PostgreSQL specific")
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def test_postgres_options(self):
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qs = Tag.objects.filter(name="test")
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test_options = [
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{"COSTS": False, "BUFFERS": True, "ANALYZE": True},
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{"costs": False, "buffers": True, "analyze": True},
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{"verbose": True, "timing": True, "analyze": True},
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{"verbose": False, "timing": False, "analyze": True},
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{"summary": True},
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]
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if connection.features.is_postgresql_12:
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test_options.append({"settings": True})
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if connection.features.is_postgresql_13:
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test_options.append({"analyze": True, "wal": True})
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for options in test_options:
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with self.subTest(**options), transaction.atomic():
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with CaptureQueriesContext(connection) as captured_queries:
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qs.explain(format="text", **options)
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self.assertEqual(len(captured_queries), 1)
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for name, value in options.items():
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option = "{} {}".format(name.upper(), "true" if value else "false")
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self.assertIn(option, captured_queries[0]["sql"])
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@unittest.skipUnless(connection.vendor == "mysql", "MySQL specific")
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def test_mysql_text_to_traditional(self):
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# Ensure these cached properties are initialized to prevent queries for
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# the MariaDB or MySQL version during the QuerySet evaluation.
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connection.features.supported_explain_formats
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with CaptureQueriesContext(connection) as captured_queries:
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Tag.objects.filter(name="test").explain(format="text")
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self.assertEqual(len(captured_queries), 1)
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self.assertIn("FORMAT=TRADITIONAL", captured_queries[0]["sql"])
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@unittest.skipUnless(
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connection.vendor == "mysql", "MariaDB and MySQL >= 8.0.18 specific."
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)
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def test_mysql_analyze(self):
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qs = Tag.objects.filter(name="test")
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with CaptureQueriesContext(connection) as captured_queries:
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qs.explain(analyze=True)
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self.assertEqual(len(captured_queries), 1)
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prefix = "ANALYZE " if connection.mysql_is_mariadb else "EXPLAIN ANALYZE "
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self.assertTrue(captured_queries[0]["sql"].startswith(prefix))
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with CaptureQueriesContext(connection) as captured_queries:
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qs.explain(analyze=True, format="JSON")
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self.assertEqual(len(captured_queries), 1)
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if connection.mysql_is_mariadb:
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self.assertIn("FORMAT=JSON", captured_queries[0]["sql"])
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else:
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self.assertNotIn("FORMAT=JSON", captured_queries[0]["sql"])
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@skipIfDBFeature("supports_explaining_query_execution")
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class ExplainUnsupportedTests(TestCase):
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def test_message(self):
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msg = "This backend does not support explaining query execution."
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with self.assertRaisesMessage(NotSupportedError, msg):
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Tag.objects.filter(name="test").explain()
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