探索查询执行摘要
处理完查询返回的所有结果后，服务器通过返回执行摘要来结束事务。它是一个 ResultSummary 对象，其中包含以下信息：
检索执行摘要
当使用 Driver.execute_query() 运行查询时，执行摘要是默认返回对象的一部分，位于 summary 键下。
records, result_summary, keys = driver.execute_query("""
UNWIND ["Alice", "Bob"] AS name
MERGE (p:Person {name: name})
""", database_="neo4j",
)
# or result_summary = driver.execute_query('<QUERY>').summary如果您正在使用 事务函数，或一个 自定义转换器 结合 Driver.execute_query()，您可以使用 Result.consume() 方法检索查询执行摘要。 请注意，一旦您请求执行摘要，结果流将被耗尽。这意味着任何尚未处理的记录将不再可用。
def create_people(tx):
result = tx.run("""
UNWIND ["Alice", "Bob"] AS name
MERGE (p:Person {name: name})
""")
return result.consume()
with driver.session(database="neo4j") as session:
result_summary = session.execute_write(create_people)查询计数器
属性 ResultSummary.counters 包含查询触发的操作的计数器（作为一个 SummaryCounters 对象）。
插入一些数据并显示查询计数器
summary = driver.execute_query("""
MERGE (p:Person {name: $name})
MERGE (p)-[:KNOWS]->(:Person {name: $friend})
""", name="Mark", friend="Bob",
database_="neo4j",
).summary
print(summary.counters)
"""
{'_contains_updates': True, 'labels_added': 2, 'relationships_created': 1,
'nodes_created': 2, 'properties_set': 2}
"""还有两个额外的布尔属性，它们充当元计数器
-
contains_updates— 查询是否在其运行的数据库上触发了任何写入操作 -
contains_system_updates— 查询是否更新了system数据库
查询执行计划
如果您在查询前加上 EXPLAIN，服务器将返回它将用于运行查询的计划，但实际上不会运行它。该计划随后可在 ResultSummary.plan 属性下获取，并包含 Cypher 操作符 列表，这些操作符将用于检索结果集。您可以使用此信息来定位潜在的瓶颈或性能改进空间（例如通过创建索引）。
_, summary, _ = driver.execute_query("EXPLAIN MATCH (p {name: $name}) RETURN p", name="Alice")
print(summary.plan['args']['string-representation'])
"""
Planner COST
Runtime PIPELINED
Runtime version 5.0
Batch size 128
+-----------------+----------------+----------------+---------------------+
| Operator | Details | Estimated Rows | Pipeline |
+-----------------+----------------+----------------+---------------------+
| +ProduceResults | p | 1 | |
| | +----------------+----------------+ |
| +Filter | p.name = $name | 1 | |
| | +----------------+----------------+ |
| +AllNodesScan | p | 10 | Fused in Pipeline 0 |
+-----------------+----------------+----------------+---------------------+
Total database accesses: ?
"""如果您在查询前加上关键字 PROFILE，服务器将返回它已用于运行查询的执行计划，以及分析器统计信息。这包括所使用的操作符列表以及每个中间步骤的额外分析信息。该计划可在 ResultSummary.profile 属性下获取。请注意，查询也会被运行，因此结果对象也包含任何结果记录。
records, summary, _ = driver.execute_query("PROFILE MATCH (p {name: $name}) RETURN p", name="Alice")
print(summary.profile['args']['string-representation'])
"""
Planner COST
Runtime PIPELINED
Runtime version 5.0
Batch size 128
+-----------------+----------------+----------------+------+---------+----------------+------------------------+-----------+---------------------+
| Operator | Details | Estimated Rows | Rows | DB Hits | Memory (Bytes) | Page Cache Hits/Misses | Time (ms) | Pipeline |
+-----------------+----------------+----------------+------+---------+----------------+------------------------+-----------+---------------------+
| +ProduceResults | p | 1 | 1 | 3 | | | | |
| | +----------------+----------------+------+---------+----------------+ | | |
| +Filter | p.name = $name | 1 | 1 | 4 | | | | |
| | +----------------+----------------+------+---------+----------------+ | | |
| +AllNodesScan | p | 10 | 4 | 5 | 120 | 9160/0 | 108.923 | Fused in Pipeline 0 |
+-----------------+----------------+----------------+------+---------+----------------+------------------------+-----------+---------------------+
Total database accesses: 12, total allocated memory: 184
"""有关更多信息和示例，请参阅 基本查询调优。
通知
执行查询后，服务器可以返回 通知 以及查询结果。通知包含性能改进建议、关于使用已弃用功能的警告以及关于 Neo4j 次优使用的其他提示。
| 对于驱动程序版本 >= 5.25 和服务器版本 >= 5.23，有两种形式的通知可用（Neo4j 状态码和GQL 状态码）。对于早期版本，只有Neo4j 状态码可用。 GQL 状态码计划取代 Neo4j 状态码。 |
示例 1. 无边界最短路径引发性能通知
属性 ResultSummary.summary_notifications 包含一个 SummaryNotification 对象的列表。
records, summary, keys = driver.execute_query("""
MATCH p=shortestPath((:Person {name: 'Alice'})-[*]->(:Person {name: 'Bob'}))
RETURN p
""", database_="neo4j"
)
"""
[SummaryNotification(
title='The provided pattern is unbounded, consider adding an upper limit to the number of node hops.',
code='Neo.ClientNotification.Statement.UnboundedVariableLengthPattern',
description='Using shortest path with an unbounded pattern will likely result in long execution times. It is recommended to use an upper limit to the number of node hops in your pattern.',
severity_level=<NotificationSeverity.INFORMATION: 'INFORMATION'>,
category=<NotificationCategory.PERFORMANCE: 'PERFORMANCE'>,
raw_severity_level='INFORMATION',
raw_category='PERFORMANCE',
position=SummaryNotificationPosition(line=1, column=22, offset=21)
)]
"""对于版本 >= 5.25，属性 ResultSummary.gql_status_objects 包含一个 GqlStatusObject 序列。这些是符合 GQL 规范的状态对象。
某些（但并非所有）GqlStatusObjects 是通知，而另一些则报告结果状态：00000 表示“成功”，02000 表示“无数据”，00001 表示“省略结果”。ResultSummary.gql_status_objects 始终包含至少一个条目，其中包含结果状态。
records, summary, keys = driver.execute_query("""
MATCH p=shortestPath((:Person {name: 'Alice'})-[*]->(:Person {name: 'Bob'}))
RETURN p
""", database_="neo4j"
)
for status in summary.gql_status_objects:
print("GQLSTATUS:", status.gql_status)
print("Description:", status.status_description)
# Not all statuses are notifications.
print("Is notification:", status.is_notification)
# Notification and thus vendor-specific fields.
# These fields are only meaningful for notifications.
if status.is_notification:
# The position in the query that caused the notification.
print("Position:", status.position)
# The notification's classification is counterpart to `neo4j.NotificationCategory`.
# However, the term `category` has a different meaning in the context of GQL.
print("Classification:", status.classification)
print("Unparsed classification:", status.raw_classification)
print("Severity:", status.severity)
print("Unparsed severity:", status.raw_severity)
# Any raw extra information provided by the DBMS:
print("Diagnostic record:", status.diagnostic_record)
print("=" * 80)
"""
GQLSTATUS: 02000
Description: note: no data
Is notification: False
Diagnostic record: {'OPERATION': '', 'OPERATION_CODE': '0', 'CURRENT_SCHEMA': '/'}
================================================================================
GQLSTATUS: 03N91
Description: info: unbounded variable length pattern. The provided pattern `(:Person {name: 'Alice'})-[*]->(:Person {name: 'Bob'})` is unbounded. Shortest path with an unbounded pattern may result in long execution times. Use an upper limit (e.g. `[*..5]`) on the number of node hops in your pattern.
Is notification: True
Position: line: 1, column: 22, offset: 21
Classification: NotificationClassification.PERFORMANCE
Unparsed classification: PERFORMANCE
Severity: NotificationSeverity.INFORMATION
Unparsed severity: INFORMATION
Diagnostic record: {'_classification': 'PERFORMANCE', '_status_parameters': {'pat': "(:Person {name: 'Alice'})-[*]->(:Person {name: 'Bob'})"}, '_severity': 'INFORMATION', '_position': {'offset': 21, 'line': 1, 'column': 22}, 'OPERATION': '', 'OPERATION_CODE': '0', 'CURRENT_SCHEMA': '/'}
================================================================================
"""过滤通知
默认情况下，服务器会分析每个查询的所有类别和严重程度的通知。从版本 5.7 开始，您可以使用参数 notifications_min_severity 和/或 notifications_disabled_categories/notifications_disabled_classifications 来限制您感兴趣的通知的严重程度和/或类别/分类。限制服务器允许发出的通知数量会带来轻微的性能提升。
严重性过滤器适用于 Neo4j 和 GQL 通知。类别和分类过滤器仅因 GQL 和 Neo4j 词汇之间的差异而独立存在；然而，这两种过滤器都会影响任一形式的通知，因此您应该只使用其中一个。如果您同时提供类别和分类过滤器，它们的内容将被合并。您可以在创建 Driver 实例或创建会话时使用这些参数中的任何一个。
通过将最小严重程度设置为 'OFF'，您可以完全禁用通知。
只允许
WARNING 通知，不允许 HINT 或 GENERIC 类别# at driver level
driver = neo4j.GraphDatabase.driver(
URI, auth=AUTH,
notifications_min_severity='WARNING', # or 'OFF' to disable entirely
notifications_disabled_classifications=['HINT', 'GENERIC'], # filters categories as well
)
# at session level
session = driver.session(
database="neo4j",
notifications_min_severity='INFORMATION', # or 'OFF' to disable entirely
notifications_disabled_classifications=['HINT'] # filters categories as well
)