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new ac34f28 Documentation update of virtual table system_views.clients
ac34f28 is described below
commit ac34f28e31bbc294db80e2b5d06f8904a7f41a46
Author: Bereng <[email protected]>
AuthorDate: Tue Mar 8 11:26:44 2022 +0100
Documentation update of virtual table system_views.clients
patch by Tibor Repasi; reviewed by Berenguer Blasi, Ekaterina Dimitrova for
CASSANDRA-17344
---
doc/modules/cassandra/pages/new/virtualtables.adoc | 117 ++++++++++++++++-----
1 file changed, 93 insertions(+), 24 deletions(-)
diff --git a/doc/modules/cassandra/pages/new/virtualtables.adoc
b/doc/modules/cassandra/pages/new/virtualtables.adoc
index 914bc27..69035ae 100644
--- a/doc/modules/cassandra/pages/new/virtualtables.adoc
+++ b/doc/modules/cassandra/pages/new/virtualtables.adoc
@@ -109,18 +109,80 @@ We shall discuss some of the virtual tables in more
detail next.
=== Clients Virtual Table
The `clients` virtual table lists all active connections (connected
-clients) including their ip address, port, connection stage, driver
+clients) including their ip address, port, client_options, connection stage,
driver
name, driver version, hostname, protocol version, request count, ssl
enabled, ssl protocol and user name:
....
-cqlsh:system_views> select * from system_views.clients;
- address | port | connection_stage | driver_name | driver_version |
hostname | protocol_version | request_count | ssl_cipher_suite | ssl_enabled |
ssl_protocol | username
------------+-------+------------------+-------------+----------------+-----------+------------------+---------------+------------------+-------------+--------------+-----------
- 127.0.0.1 | 50628 | ready | null | null |
localhost | 4 | 55 | null | False |
null | anonymous
- 127.0.0.1 | 50630 | ready | null | null |
localhost | 4 | 70 | null | False |
null | anonymous
+cqlsh> EXPAND ON ;
+Now Expanded output is enabled
+cqlsh> SELECT * FROM system_views.clients;
+
+@ Row 1
+------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ address | 127.0.0.1
+ port | 50687
+ client_options | {'CQL_VERSION': '3.4.5', 'DRIVER_NAME': 'DataStax Python
Driver', 'DRIVER_VERSION': '3.25.0'}
+ connection_stage | ready
+ driver_name | DataStax Python Driver
+ driver_version | 3.25.0
+ hostname | localhost
+ protocol_version | 5
+ request_count | 16
+ ssl_cipher_suite | null
+ ssl_enabled | False
+ ssl_protocol | null
+ username | anonymous
+
+@ Row 2
+------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ address | 127.0.0.1
+ port | 50688
+ client_options | {'CQL_VERSION': '3.4.5', 'DRIVER_NAME': 'DataStax Python
Driver', 'DRIVER_VERSION': '3.25.0'}
+ connection_stage | ready
+ driver_name | DataStax Python Driver
+ driver_version | 3.25.0
+ hostname | localhost
+ protocol_version | 5
+ request_count | 4
+ ssl_cipher_suite | null
+ ssl_enabled | False
+ ssl_protocol | null
+ username | anonymous
+
+@ Row 3
+------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ address | 127.0.0.1
+ port | 50753
+ client_options | {'APPLICATION_NAME': 'TestApp', 'APPLICATION_VERSION':
'1.0.0', 'CLIENT_ID': '55b3efbd-c56b-469d-8cca-016b860b2f03', 'CQL_VERSION':
'3.0.0', 'DRIVER_NAME': 'DataStax Java driver for Apache Cassandra(R)',
'DRIVER_VERSION': '4.13.0'}
+ connection_stage | ready
+ driver_name | DataStax Java driver for Apache Cassandra(R)
+ driver_version | 4.13.0
+ hostname | localhost
+ protocol_version | 5
+ request_count | 18
+ ssl_cipher_suite | null
+ ssl_enabled | False
+ ssl_protocol | null
+ username | anonymous
+
+@ Row 4
+------------------+-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ address | 127.0.0.1
+ port | 50755
+ client_options | {'APPLICATION_NAME': 'TestApp', 'APPLICATION_VERSION':
'1.0.0', 'CLIENT_ID': '55b3efbd-c56b-469d-8cca-016b860b2f03', 'CQL_VERSION':
'3.0.0', 'DRIVER_NAME': 'DataStax Java driver for Apache Cassandra(R)',
'DRIVER_VERSION': '4.13.0'}
+ connection_stage | ready
+ driver_name | DataStax Java driver for Apache Cassandra(R)
+ driver_version | 4.13.0
+ hostname | localhost
+ protocol_version | 5
+ request_count | 7
+ ssl_cipher_suite | null
+ ssl_enabled | False
+ ssl_protocol | null
+ username | anonymous
-(2 rows)
+(4 rows)
....
Some examples of how `clients` can be used are:
@@ -130,29 +192,36 @@ upgrading and with `nodetool enableoldprotocolversions`
and
`nodetool disableoldprotocolversions` during upgrades.
* To identify clients sending too many requests.
* To find if SSL is enabled during the migration to and from ssl.
+* To identify all options the client is sending, e.g. APPLICATION_NAME and
APPLICATION_VERSION
The virtual tables may be described with `DESCRIBE` statement. The DDL
listed however cannot be run to create a virtual table. As an example
describe the `system_views.clients` virtual table:
....
-cqlsh:system_views> DESC TABLE system_views.clients;
-CREATE TABLE system_views.clients (
- address inet,
- connection_stage text,
- driver_name text,
- driver_version text,
- hostname text,
- port int,
- protocol_version int,
- request_count bigint,
- ssl_cipher_suite text,
- ssl_enabled boolean,
- ssl_protocol text,
- username text,
- PRIMARY KEY (address, port)) WITH CLUSTERING ORDER BY (port ASC)
- AND compaction = {'class': 'None'}
- AND compression = {};
+cqlsh> DESCRIBE TABLE system_views.clients;
+
+/*
+Warning: Table system_views.clients is a virtual table and cannot be recreated
with CQL.
+Structure, for reference:
+VIRTUAL TABLE system_views.clients (
+ address inet,
+ port int,
+ client_options frozen<map<text, text>>,
+ connection_stage text,
+ driver_name text,
+ driver_version text,
+ hostname text,
+ protocol_version int,
+ request_count bigint,
+ ssl_cipher_suite text,
+ ssl_enabled boolean,
+ ssl_protocol text,
+ username text,
+ PRIMARY KEY (address, port)
+) WITH CLUSTERING ORDER BY (port ASC)
+ AND comment = 'currently connected clients';
+*/
....
=== Caches Virtual Table
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