# DESCRIBE statement in ksqlDB for Confluent Platform ## Synopsis ```sql DESCRIBE (stream_name|table_name|STREAMS|TABLES) [EXTENDED]; ``` ## Description - DESCRIBE: List the columns in a stream or table along with their data type and other attributes, or list the relevant details for all streams and tables. - DESCRIBE EXTENDED: Display DESCRIBE information with additional runtime statistics, Kafka topic details, and the set of queries that populate the table or stream. Extended descriptions provide the following metrics for the topic backing the source being described. | ksqlDB
Metric | Description | |----------------------------------------|-------------------------------------------------------------------------------------------------------------------------| | consumer-fa
iled-messag
es | Total number of failures during message consumption on
the server. | | consumer-me
ssages-per-
sec | The number of messages consumed per second from the
topic by the server. | | consumer-to
tal-message
-bytes | Total number of bytes consumed from the topic by the
server. | | consumer-to
tal-message
s | Total number of messages consumed from the topic by
the server. | | failed-mess
ages-per-se
c | Number of failures during message consumption (for
example, deserialization failures) per second on the
server. | | last-failed | Time that the last failure occurred when a message was
consumed from the topic by the server. | | last-messag
e | Time that the last message was produced to or consumed
from the topic by the server. | | messages-pe
r-sec | Number of messages produced per second into the topic
by the server. | | total-messa
ges | Total number of messages produced into the topic by
the server. | | total-messa
ge-bytes | Total number of bytes produced into the topic by the
server. | ## Example The following statement shows how to get a description of a table. ```sql DESCRIBE ip_sum; ``` Your output should resemble: ```none Field | Type ----------------------------------------- IP | VARCHAR(STRING) (primary key) KBYTES | BIGINT ----------------------------------------- For runtime statistics and query details run: DESCRIBE EXTENDED ``` The following statement shows how to get a description of a table that has extended information. ```sql DESCRIBE ip_sum EXTENDED; ``` Your output should resemble: ```none Type : TABLE Timestamp field : Not set - using Key format : KAFKA Value format : JSON Kafka output topic : IP_SUM (partitions: 4, replication: 1) Field | Type ----------------------------------------- IP | VARCHAR(STRING) (primary key) KBYTES | BIGINT ----------------------------------------- Queries that write into this TABLE ----------------------------------- id:CTAS_IP_SUM - CREATE TABLE IP_SUM as SELECT ip, sum(bytes)/1024 as kbytes FROM CLICKSTREAM window SESSION (300 second) GROUP BY ip EMIT CHANGES; For query topology and execution plan run: EXPLAIN ; for more information Local runtime statistics ------------------------ messages-per-sec: 4.41 total-messages: 486 last-message: 12/14/17 4:32:23 PM GMT failed-messages: 0 last-failed: n/a (Statistics of the local ksqlDB server interaction with the Kafka topic IP_SUM) ``` The following statement shows how to get the descriptions for all tables. ```sql DESCRIBE TABLES; ``` Your output should resemble: ```none Name : IP_SUM Field | Type ----------------------------------------- IP | VARCHAR(STRING) (primary key) KBYTES | BIGINT ----------------------------------------- For runtime statistics and query details run: DESCRIBE EXTENDED; Name : LO_REM Field | Type ----------------------------------------- LO | VARCHAR(STRING) (primary key) KBYTES | BIGINT ----------------------------------------- For runtime statistics and query details run: DESCRIBE EXTENDED; ``` The following statement shows how to get the descriptions for all tables with extended information. ```sql DESCRIBE TABLES EXTENDED; ``` Your output should resemble: ```none Name : IP_SUM Type : TABLE Timestamp field : Not set - using Key format : KAFKA Value format : JSON Kafka output topic : IP_SUM (partitions: 4, replication: 1) Statement : CREATE TABLE IP_SUM as SELECT ip, sum(bytes)/1024 as kbytes FROM CLICKSTREAM window SESSION (300 second) GROUP BY ip EMIT CHANGES; Field | Type ----------------------------------------- IP | VARCHAR(STRING) (primary key) KBYTES | BIGINT ----------------------------------------- Queries that write into this TABLE ----------------------------------- id:CTAS_IP_SUM - CREATE TABLE IP_SUM as SELECT ip, sum(bytes)/1024 as kbytes FROM CLICKSTREAM window SESSION (300 second) GROUP BY ip EMIT CHANGES; For query topology and execution plan run: EXPLAIN ; for more information Local runtime statistics ------------------------ messages-per-sec: 4.41 total-messages: 486 last-message: 12/14/17 4:32:23 PM GMT failed-messages: 0 last-failed: n/a (Statistics of the local ksqlDB server interaction with the Kafka topic IP_SUM) Name : LO_REM Type : TABLE Timestamp field : Not set - using Key format : KAFKA Value format : JSON Kafka output topic : LO_REM (partitions: 4, replication: 1) Statement : CREATE TABLE LO_REM as SELECT lo, sum(bytes)/1024 as kbytes FROM CLICKSTREAM window SESSION (300 second) GROUP BY ip EMIT CHANGES; Field | Type ----------------------------------------- LO | VARCHAR(STRING) (primary key) KBYTES | BIGINT ----------------------------------------- Queries that write into this TABLE ----------------------------------- id:CTAS_LO_REM - CREATE TABLE LO_REM as SELECT lo, sum(bytes)/1024 as kbytes FROM CLICKSTREAM window SESSION (300 second) GROUP BY ip EMIT CHANGES; For query topology and execution plan run: EXPLAIN ; for more information Local runtime statistics ------------------------ messages-per-sec: 4.41 total-messages: 486 last-message: 12/14/17 4:32:23 PM GMT failed-messages: 0 last-failed: n/a (Statistics of the local ksqlDB server interaction with the Kafka topic LO_REM) ```