Steve Lorello presented on Redis, dispelling common myths and demonstrating how to store and query complex objects. The key points covered included: 1. Redis can provide ACID transactions through individual commands and scripting. Data is always consistent on a single instance and eventually consistent with replication. 2. Redis ensures durability through append-only files and snapshotting databases to disk. 3. Complex objects can be stored in Redis as hashes, structured blobs, or JSON for flexible querying. 4. Secondary indexes like sorted sets or RediSearch enable finding objects by values through queries. 5. Redis OM and LINQ simplify .NET applications by providing declarative indexes and query capabilities.

2. Steve Lorello
Developer Advocate
@Redis
@slorello
github.com/slorello89
twitch.tv/redisinc

3. ● What is Redis?
● Dispelling Redis Myths
● RediSearch + JSON
● Redis OM
● Demo: FML API
Agenda

4. What is
?

5. What is Redis?
● Created by Antirez
● REmote DIctionary Server

6. What is Redis?
● Completely In Memory
● Key-Value Data Structure Store

7. What is Redis?
● Redis is Single Threaded
● Blazingly Fast NoSQL DB

8. ● Easy to Use
● Beloved by Developers
What is Redis?

9. Dispelling Redis Myths

10. Myth 1:“Redis isn’t ACIDic”

11. ACID in Redis - Atomicity
● Individual Redis commands are completely atomic
● ‘Transactions’ & Scripting for grouping commands

12. ACID in Redis - Consistency
● Depends on deployment and config
● Single instance always consistent
● Replication guarantees eventual consistency
○ Forced consistency with “WAIT” command

13. ACID in Redis - Isolation
● Single Threaded
● Isolated as there’s no concurrency

14. Myth 2: “If Redis dies I’ll
lose all my data!”

15. Redis IS Durable
● Two durability persistence models
● AOF - Append Only File
● RDB - Redis Database File

16. Durability - Append Only File (AOF)
● With each command Redis writes to AOF
● Reconstruct Redis from AOF
● AOF flush to disk is NOT necessarily synchronous

17. AOF FSYNC Policy
● FSYNC policy determines durability
● always - Synchronously flush
● everysec - Flush every second
● no - OS decides

18. Durability - Redis Database file (RDB)
● RDBs are snapshots of the database
● Taken in intervals, or by command
● More compact and faster to ingest than AOF
● Less strain on OS than AOF
● Comes at cost of higher potential data loss

19. Myth 3: Redis cannot
store complex objects

20. 3 Modes of Document Storage
● Hashes
● Structured Blobs
● JSON Data Structure

21. Hashes
● Store a set of Field-Value pairs
● Appropriate for flat objects
● Fields Names and Values are Strings

22. CRUD with Hashes
● HSET (which is variadic) to create/update
● HGET/HMGET/HGETALL to get fields in the hash
● HDEL/UNLINK to delete fields/objects

23. HSET Article:1 Source CNN Title “Florida man …” Timestamp 1654122480
Article:1
Source CNN
Title Florida man watches
Spider-Man movie
292 times, setting
new world record
Timestamp 1654122480

24. Pros:
● Native
● Performant
Cons:
● Breaks down on
more complicated
objects
● Collection storage
patterns are hard

25. Structured Blobs
● Store objects as JSON or some other type of blob string
● Simple pattern for storing objects in Redis

26. CRUD with Blobs
● SET to create
● GET to read
● GET then SET to update
● UNLINK to delete

27. SET Article:1 “{‘source’:‘cnn’,‘Title’: ‘Florida man watches. . .’,
‘Timestamp’:1654122480}”
“{‘source’:‘cnn’,‘Title’: ‘Florida man watches Spider-Man movie 292
times, setting new world record’, ‘Timestamp’:1654122480}”

28. Pros:
● Native
● Simple
Cons:
● Updates are
expensive—O(N)
● Reads are
expensive—O(N)

29. JSON Data Structure
● Store JSON objects directly
● JSON stored as trie structure within Redis
● Get/Update using JSON paths
● Requires use of Redis Stack

30. CRUD with JSON Data Structure
● JSON.SET to create/update
● JSON.GET to read
● JSON.DEL to remove fields
● UNLINK to delete

31. JSON.SET Article:1 $ “{‘source’:‘cnn’,‘Title’: ‘Florida man watches. . .’,
‘Timestamp’:1654122480}”
“{‘source’:‘cnn’,‘Title’: ‘Florida man watches Spider-Man movie 292
times, setting new world record’, ‘Timestamp’:1654122480}”

32. Pros:
● All operations are fast
● Organized
retrieval/update of
data within object
● Works great with rich
objects
Cons:
● Needs a module

33. Myth 4: Redis can’t be used for
value searches.

34. How to Find Objects by Value in Redis
● Build Secondary Indexes
● 2 ways
○ Manually with Sets / Sorted Sets
○ Automatically with RediSearch

35. Indexing With Sorted Sets
● User Sorted Sets as indexes
● E.g.
○ Article:Source:Fox {(0, Article:1), (0, Article:2)}
○ Article:Timestamp {(1654122480, Article:1), (1654133475, Article:2)}
● Query with ZRANGE Commands
● Complex queries run with SET Combination commands

36. Indexing with RediSearch
● Three step process
● Declare how your Documents will be indexed with
FT.CREATE
● Insert your Documents as either Hashes or JSON
● Query Your Documents with FT.SEARCH

37. Build the Index FT.CREATE
● Declare Prefix of keys within Index
● Declare Storage Type(Hash or JSON)
● Declare the Schema - five types of fields
○ TAG
○ TEXT
○ NUMERIC
○ GEO
○ VECTOR

38. FT.CREATE article-idx ON JSON PREFIX 1
Article: SCHEMA $.Source as source TAG

39. Querying Within Redis
● Use RediSearch Query Language

40. FT.SEARCH article-idx “@Source:{fox}”
Command Name
Index
Query

41. Exact Match Queries
Single - @Source:{fox}
OR - @Source:{fox|cnn}

42. Full Text Search
@Title:Goat

43. Range Queries
Inclusive - @Timestamp:[1660731559 1660731559]
Exclusive - @Timestamp:[(1660731559 (1660731559]
upper/lower bounds - @Timestamp:[-inf +inf]

44. redis ōM

45. Redis OM Highlights
● Declarative syntax for creating indexes
● LINQ Based API for searching for things in Redis
● LINQ Based API for aggregating things in Redis

46. Declaring Indexes in Redis OM

47. [Document(StorageType = StorageType.Json)]
public class Article

48. Declaring an Id field
[RedisIdField]
public Ulid Id { get; set; }

49. Field Decoration - Full Text Search
[Searchable]
public string Title { get; set; }

50. Field Decoration - Numerics
[Indexed]
public long Timestamp { get; set; }

51. Field Decoration - Exact Matches
[Indexed]
public string Source { get; set; }

52. Field Decoration - Embedded Objects
[Indexed(CascadeDepth = 1)]
public MetaData MetaData { get; set; }

53. Field Decoration - Embedded Objects
[Indexed(JsonPath = "$.Source")]
public MetaData MetaData { get; set; }

54. Querying with Redis OM .NET

55. Use the RedisCollection<T> and use LINQ

56. collection.Where(x => x.Title == title);

57. Demo

58. Code PaLOUsa CoC
Code PaLOUsa is dedicated to providing a harassment-free
conference experience for everyone, regardless of gender,
sexual orientation, disability, physical appearance, body size,
race, or religion. We do not tolerate harassment of
conference participants in any form. Sexual language and
imagery is not appropriate for any conference venue,
including talks. Conference participants violating these rules
may be sanctioned or expelled from the conference without a
refund at the discretion of the conference organizers.

59. Steve Lorello
Developer Advocate
@Redis
@slorello
github.com/slorello89
slorello.com

60. Resources
Redis
https://redis.io
Redis Search Docker Image
https://hub.docker.com/r/redislabs/redisearch/
Redis OM
https://github.com/redis/redis-om-dotnet
Slides
https://www.slideshare.net/StephenLorello/indexing-searching-and-aggregation-
with-redi-search-and-net

61. Come Check Us Out!
Redis University:
https://university.redis.com
Discord:
https://discord.gg/redis