1. Narmal C*

2. Another Email App
● Email “broken” / “sucks”
● iOS / Scala / C* / AWS

3. Concept

4. Concept
Conversation
Topic Topic
Email Email Email Email

5. Data Model - Conversations
CREATE TABLE conversations (
user_id uuid,
ts big_int,
recipients_hash text,
PRIMARY KEY(user_id, ts);

6. Data Model - Conversations
INSERT INTO.conversations (user_id, ts, rec_hash) VALUES (1,
‘141...x‘, pr135t’);
INSERT INTO.conversations (user_id, ts, subject) VALUES (1,
‘141...y‘, ‘ra881’);
INSERT INTO.conversations (user_id, ts, subject) VALUES (1,
‘141...z‘, ‘pr135t!’);
1
141y:rec_hash
ra881
141x:rec_hash
pr135t
141z:rec_hash
pr135t

7. Data Model - Edge Case
141y:rec_hash
ra881
141x:rec_hash
pr135t
141z:rec_hash
pr135t
2x recipients_hash => ‘pr135t
def mostRecent[T](models: List[T])(implicit tc: MostRecentItems[T]): Seq[T] = {
models.groupBy(model => tc.member(model))
.map(_._2.headOption)
.filter(_.isDefined)
.map(_.get).toSeq
.sortBy(model => tc.ts(model)).reverse
}

8. Data Model - Topics
CREATE TABLE topics (
user_id uuid,
rec_hash text,
ts bigint,
thread_id,
PRIMARY KEY((user_id, rec_hash), ts);

9. INSERT INTO topics (user_id, rec_hash, ts, thread_id) VALUES
(1, ‘pr135t’, ‘141...x‘, ‘d97’);
INSERT INTO topics (user_id, rec_hash, ts, thread_id) VALUES
(1, ‘ra881’, ‘141...y‘, c24);
INSERT INTO topics (user_id, rec_hash, ts, thread_id) VALUES
(1, ‘pr135t!’, ‘141...z‘, ‘d97’);
1 | pr135t
141x:thread_id
d97
141y:thread_id
c24
141z:thread_id
d97
1 | ra881

10. Data Model - Emails
CREATE TABLE emails_by_topic (
user_id uuid,
thread_id text,
ts big_int,
id text,
body text,
PRIMARY KEY(user_id, thread_id), ts, id);

11. INSERT INTO emails (user_id, thread_id, ts, id, body) VALUES
(1, ‘d97’, ‘141...x‘, ‘32’, “GO”);
INSERT INTO emails (user_id, thread_id, ts, id, body) VALUES
(1, ‘c24’, ‘141...y‘, 99, “YEAH”);
INSERT INTO topics (user_id, thread_id, ts, id, body) VALUES (1,
‘d97’, ‘141...z‘, 33, ‘ROYALS’);
1 | d97
141x:32:body
GO
141y:99:body
YEAH
141z:33:body
ROYALS
1 | c24

12. Concept 2

13. Concept 2
Conversation
Email Email Email Email

14. Data Model - Emails 2
CREATE TABLE emails_by_conversation (
user_id uuid,
rec_hash text,
ts big_int,
id text,
thread_id
body text,
PRIMARY KEY(user_id, rec_hash), ts, id);

15. INSERT INTO emails (user_id, rec_hash, ts, id, body) VALUES (1,
‘pr135t’, ‘141...x‘, ‘32’, “YEAH!”);
INSERT INTO emails (user_id, rec_hash, ts, id, body) VALUES (1,
‘ra881’, ‘141...y‘, 99, “GO”);
INSERT INTO topics (user_id, rec_hash, ts, id, body) VALUES (1,
‘pr135t’, ‘141...z‘, 33, ‘ROYALS’);
1 | pr135t
141x:32:body
YEAH
141y:99:body
GO
141z:33:body
ROYALS
1 | ra881

16. Other
● EC2
● Multiple data centers
● Spark