Apache Kafka is a massively scalable message queue that is being used at more and more places connecting more and more data sources. This presentation will introduce Kafka from the perspective of a mere mortal DBA and share the experience of (and challenges with) getting events from the database to Kafka using Kafka connect including poor-man’s CDC using flashback query and traditional logical replication tools. To demonstrate how and why this is a good idea, we will build an end-to-end data processing pipeline. We will discuss how to turn changes in database state into events and stream them into Apache Kafka. We will explore the basic concepts of streaming transformations using windows and KSQL before ingesting the transformed stream in a dashboard application.

1. Streaming ETL
From rdbms to dashboard with Kafka and KSQL
Björn Rost

2. Things I am good at
•Oracle (and relational) databases
•Performance
•High-Availability
•PL/SQL and ETL
•Replication
•Exadata
•Automation/DevOps
•Linux and Solaris
•VMs and solaris containers
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3. Things I am getting good at
•Kafka and streaming
•Cloud and cloud native data processing
•Dataflow, bigquery
•Machine learning
•docker
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4. Things I am not good at
And have limited interest in
•“real” programming
•Especially java
•GUIs
•Coming up with meaningful demos
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5. ABOUT PYTHIAN
Pythian’s 400+ IT professionals help
companies adopt
and manage disruptive technologies
to better compete
© 2016 Pythian 14

6. TECHNICAL EXPERTISE
© 2016 Pythian. Confidential 15
Infrastructure: Transforming and
managing the IT infrastructure
that supports the business
DevOps: Providing critical velocity
in software deployment by adopting
DevOps practices
Cloud: Using the disruptive
nature of cloud for accelerated,
cost-effective growth
Databases: Ensuring databases
are reliable, secure, available and
continuously optimized
Big Data: Harnessing the transformative
power of data on a massive scale
Advanced Analytics: Mining data for
insights & business transformation
using data science

7. © 2016 Pythian 16
assumptions
•You know more about kafka than me
•Today you do not want to hear much
about how great Oracle is

8. AGENDA
• Motivation / what are we going to build here?
• Getting rdbms data into kafka
• streaming ETL and KSQL
• Feeding kafka into grafana
• Demo time! (or Q&A)
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9. motivation (noun)
/məʊtɪˈveɪʃ(ə)n/
AKA: how to tease you enough to pay attention through the next 42 mintues

10. overview
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11. The full(er) picture
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mysql
maxwell
kafka
ksql
elastic
clickstream

12. The 3 Vs of Big Data
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Volume
VarietyVelocity

13. StreamingRDBMS the “king of state”
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• Takes transactions and stores
consistent state
• Tell you what *is* or *was*
• One central ”system of record”
• Sucks for large volumes of logs
• Great at updates, deletes and
rollbacks
• Every DB speaks SQL
• Stores and distributes events
• Tell you what *happened*
• Has a concept of order
• Connects many different systems
• Sucks at accounting and inventories
• Append-only
• Processing = programming*

14. • I have $42 in my bank account
• The address of user xx is yyy
• Inventory
• Invoice and order data
• Spatial objects (maps)
• A transferred $42 to B
• Address change
• Add or remove an item
• Clickstreams and logs
• IoT messages
• Location movements (GPS)
• Gaming actions
Event examplesState examples
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15. Demo setup in mysql
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mysql>select * from orders order by id desc limit 5;
+-------+---------+-------+---------+
| id | product | price | user_id |
+-------+---------+-------+---------+
| 10337 | wine | 10 | 3 |
| 10336 | olives | 1 | 14 |
| 10335 | olives | 3 | 7 |
| 10334 | olives | 8 | 32 |
| 10333 | salt | 3 | 27 |
+-------+---------+-------+---------+
5 rows in set (0.00 sec)

16. rdbms -> kafka
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17. Kafka-connect-jdbc
• open source connector
• runs a query every n seconds
•Remembers offset
•Really only captures inserts
•Broken Data type mapping (oracle)
•Issues withTimezones (oracle)
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18. lumpy - @lumpyACED
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19. Simple diary example
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mysql>describe diary;
+-------+-------------+------+-----+---------+----------------+
| Field | Type | Null | Key | Default | Extra |
+-------+-------------+------+-----+---------+----------------+
| id | smallint(6) | NO | PRI | NULL | auto_increment |
| event | varchar(42) | YES | | NULL | |
+-------+-------------+------+-----+---------+----------------+
2 rows in set (0.00 sec)
mysql>select * from diary order by id desc limit 5;
+----+---------------------------------------------+
| id | event |
+----+---------------------------------------------+
| 18 | i hate the snow |
| 17 | still jealous i did not get to go to israel |
| 16 | i am jealous i did not get to go to Israel |
| 15 | i am jealous i did not get to go to india |
| 13 | i am very cold and alone |
+----+-----------------------------------_---------+
5 rows in set (0.00 sec)

20. Diary example
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mysql>insert into diary (event) values ('I would love to meet the meetup
guys');
Query OK, 1 row affected (0.00 sec)
mysql>select * from diary order by id desc limit 2;
+----+--------------------------------------+
| id | event |
+----+--------------------------------------+
| 19 | I would love to meet the meetup guys |
| 18 | i hate the snow |
+----+--------------------------------------+
2 rows in set (0.00 sec)

21. Connect-jdbc-diary.properties
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name=mysql-diary-source
connector.class=io.confluent.connect.jdbc.JdbcSourceConnector
tasks.max=1
connection.url=jdbc:mysql://localhost:3306/code_demo?user=lumpy&password=lumpy
table.whitelist=diary
mode=incrementing
incrementing.column.name=id
topic.prefix=mysql-

22. Still simple but not as easy: inventory
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SQL>describe inventory;
Name Null? Type
----------------------------------------- -------- ------------------------
ID NOT NULL NUMBER(8)
NAME VARCHAR2(42)
COUNT NUMBER(8)
SQL>select * from inventory;
ID NAME COUNT
---------- ------------ ----------
1 nametag 1
4 friends 294
5 selfies 1005

23. Still simple but not as easy: inventory
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SQL>update inventory set count=count+2 where name='friends';
1 row updated.
SQL>select * from inventory;
ID NAME COUNT
---------- ------------ ----------
1 nametag 1
4 friends 296
5 selfies 1005

24. How about one extra column to catch updates?
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alter table inventory add (last_modified timestamp);

25. How about two extra columns to catch deletes?
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alter table inventory add (valid_from timestamp,
valid_to timestamp);

26. © 2016 Pythian 35
Poor man’s CDC
• SELECT … VERSIONS BETWEEN …
• this adds pseudocolumns
• version_starttime in TS format
• version_operation
• the data is gathered from UNDO by default
• > 11.2.0.4 allow basic flashback data archives
without extra licenses
• specify retention period for as long as you want
Oracle flashback query

27. flashback query output
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ID NAME COUNT O VERSIONS_STARTTIME
---- ------------ ------- - --------------------------------
4 friends 42 I 27-JUN-17 05.10.17.000000000 AM
3 shrimp 1 I 27-JUN-17 05.10.17.000000000 AM
6 mouse ears 2 D 27-JUN-17 03.51.50.000000000 PM
4 friends 42 U 27-JUN-17 05.10.41.000000000 AM
6 mouse ears 2 I 27-JUN-17 05.23.11.000000000 AM
5 selfies 1001 U 27-JUN-17 03.56.12.000000000 PM
5 selfies 1000 U 27-JUN-17 05.10.41.000000000 AM
4 friends 42 U 27-JUN-17 03.51.22.000000000 PM
4 friends 92 U 27-JUN-17 10.14.14.000000000 PM
4 friends 117 U 27-JUN-17 10.23.17.000000000 PM
4 friends 142 U 27-JUN-17 10.28.21.000000000 PM
5 selfies 1002 U 27-JUN-17 03.56.22.000000000 PM
select id, name, count, versions_operation, versions_starttime from
inventory versions between scn minvalue and maxvalue order by
versions_starttime;

28. © 2016 Pythian 37
•aka total recall
•background job mines UNDO
•saves data to special tables
•create flashback archive per table
•define retention
•extends flashback query
flashback data archives

29. flashback query config for connect-jdbc
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connection.url=jdbc:oracle:thin:lumpy/lumpy@//localhost:1521/BRORCL
query=select id, name, count, versions_operation, versions_starttime
from inventory versions between scn minvalue and maxvalue
mode=timestamp+incrementing
timestamp.column.name=VERSIONS_STARTTIME
incrementing.column.name=ID
topic.prefix=connect-inventory

30. Using DB tx logs
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31. •DBs typically separate data (random and
async) from logs (sync and sequential)
•This increases performance and
recoverability
•Bonus: log of all changes
•Different names, same concept
•Oracle: redo and archivelogs
•Mysql: binlogs
•Postgres: Write-Ahead-Logs (WAL)
•SQL Server: transaction logs
Databases already have
”event” logs
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32. dbvisit replicate
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33. RDBMS CDC tools
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34. Maxwell for mysql
•Reads binlogs directly
•Has it’s own json format (read: not kafka-connect)
•Open, easy, awesome
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35. Maxwell setup
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maxwell --user='maxwell' --password='maxwell’
--host='127.0.0.1' --producer=kafka
--kafka.bootstrap.servers=localhost:9092
--kafka_topic=maxwell_%{database}_%{table}

36. Maxwell output
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{"database":"code",
"table":"orders",
"type":"insert",
"ts":1516802610,
"xid":42025,
"commit":true,
"data":{"id":12734,
"product":"salt",
"price":7,
"user_id":24
}
}

37. Data processing
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38. © 2016 Pythian 47
•Transform raw data from
transactional systems
•Store it again optimized for
analytics and reports
•Star-schema
•Aggregates and roll-ups
•Runs in batches, typically nighlty
ETL for traditional analytics

39. •In-memory
•Column stores
•Report in real-time
•Decision-support
•Machine learning and AI
•New data sources
•Clickstream
•IoT
•Big Data
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Hot topics in analytics

40. KSQL and Event Stream Processing
•Kafka already has kafka streams for
processing
•But you need to actually write code
▪Same problem with Apache Spark and Dataflow
(Apache Beam) etc etc
•KSQL allows stream processing with the
language you probably already know
•Currently in ”developer-preview”
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41. What’s the deal with streaming data processing?
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bounded unbounded
Finite, complete,
consistent
Infinite, uncomplete, different
inconsistent sources

42. Easy: single element transforms
•Connect SMT
•KSQL
•Kafka Streams
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43. Creating stream from topic and transforms
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create stream orders_raw (data map(varchar, varchar))
with (kafka_topic = 'maxwell_code_orders', value_format = 'JSON’);
ksql>describe orders_raw;
Field | Type
------------------------------------------------
ROWTIME | BIGINT (system)
ROWKEY | VARCHAR(STRING) (system)
DATA | MAP[VARCHAR(STRING),VARCHAR(STRING)]
------------------------------------------------

44. Creating stream from topic and transforms
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ksql>select * from orders_raw limit 5;
1516805044165 | {"database":"code","table":"orders","pk.id":546} |
{product=wine, user_id=31, price=1, id=546}
1516805044304 | {"database":"code","table":"orders","pk.id":547} |
{product=salt, user_id=17, price=2, id=547}
1516805044423 | {"database":"code","table":"orders","pk.id":548} |
{product=salt, user_id=16, price=6, id=548}
1516805044550 | {"database":"code","table":"orders","pk.id":549} |
{product=olives, user_id=11, price=8, id=549}
1516805044683 | {"database":"code","table":"orders","pk.id":550} |
{product=salt, user_id=36, price=3, id=550}
LIMIT reached for the partition.
Query terminated

45. Creating stream from topic and transforms
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create stream orders_flat as select data['id'] as id,
data['product'] as product,
data['price'] as price,
data['user_id'] as user_id
from orders_raw;
ksql>describe orders_flat;
Field | Type
-------------------------------------
ROWTIME | BIGINT (system)
ROWKEY | VARCHAR(STRING) (system)
ID | VARCHAR(STRING)
PRODUCT | VARCHAR(STRING)
PRICE | VARCHAR(STRING)
USER_ID | VARCHAR(STRING)
-------------------------------------

46. Creating stream from topic and transforms
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create stream orders as select cast(id as integer) as id,
product,
cast(price as bigint) as price,
cast(user_id as integer) as user_id
from orders_flat;
ksql>describe orders;
Field | Type
-------------------------------------
ROWTIME | BIGINT (system)
ROWKEY | VARCHAR(STRING) (system)
ID | INTEGER
PRODUCT | VARCHAR(STRING)
PRICE | BIGINT
USER_ID | INTEGER
-------------------------------------

47. Creating stream from topic and transforms
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ksql>select * from orders limit 5;
1516805228829 | {"database":"code","table":"orders","pk.id":2031} | 2031 |
olives | 1 | 21
1516805228964 | {"database":"code","table":"orders","pk.id":2032} | 2032 |
salt | 2 | 28
1516805229114 | {"database":"code","table":"orders","pk.id":2033} | 2033 |
wine | 1 | 26
1516805229254 | {"database":"code","table":"orders","pk.id":2034} | 2034 |
wine | 5 | 2
1516805229377 | {"database":"code","table":"orders","pk.id":2035} | 2035 |
salt | 5 | 1
LIMIT reached for the partition.
Query terminated

48. Aggregates are a lot harder
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4 3 2

49. And then there are joins
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4 3 2

50. © 2016 Pythian 59

51. Slicing a stream into windows
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08:00 08:05 08:10 08:15 08:20

52. Late arrivals make this more complicated…
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08:00 08:05 08:10 08:15 08:20
event_ts=8:02

53. Tumbling windows: fixed-size, gap-less
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08:00 08:05 08:10 08:15 08:20

54. Hopping windows: fixed-size, overlapping
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08:00 08:05 08:10 08:15 08:20

55. session windows: variable-size, timeout per key
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08:00 08:05 08:10 08:15 08:20

56. Create a windowed aggregate in ksql
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create table orders_per_min as select product,
sum(price) amount
from orders
window hopping (size 60 seconds,
advance by 15 seconds)
group by product;
CREATE TABLE orders_per_min_ts as select rowTime as event_ts, *
from orders_per_min;

57. Create a windowed aggregate in ksql
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ksql>select event_ts, product, amount from
orders_per_min_ts limit 20;
1516805280000 | olives | 444
1516805295000 | olives | 436
1516805310000 | olives | 307
1516805325000 | olives | 125
1516805280000 | salt | 921
1516805295000 | salt | 906
1516805310000 | salt | 528
1516805325000 | salt | 229
1516805280000 | wine | 470
1516805295000 | wine | 470
1516805310000 | wine | 305
1516805325000 | wine | 103

58. Aggregate functions
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Function Example Description
COUNT COUNT(col1) Count the number of rows
MAX MAX(col1)
Return the maximum value for a
given column and window
MIN MIN(col1)
Return the minimum value for a
given column and window
SUM SUM(col1) Sums the column values
TOPK TOPK(col1, k)
Return the TopK values for the
given column and window
TOPKDISTINCT TOPKDISTINCT(col1, k)
Return the distinct TopK values
for the given column and window

59. Demo time!
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mysql
maxwell
kafka
ksql
elastic
clickstream
Huge credit to github clickstream demo

60. •https://www.confluent.io/blog/turnin
g-the-database-inside-out-with-
apache-samza/
•https://www.confluent.io/blog/ksql-
open-source-streaming-sql-for-apache-
kafka/
•https://www.rittmanmead.com/blog/
2017/10/ksql-streaming-sql-for-
apache-kafka/
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More resources

61. •RDBMS also want to speak “stream”
•Stream processing is coming fast and
is here to stay
•KSQL is something to be excited
about
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Summary
https://github.com/bjoernrost/mysql-ksql-etl-demo

62. THANK YOU
Paragraph
72© 2016 Pythian