Fun with Fabric in 15

© 2022 Neo4j, Inc. All rights reserved.
Fun with Fabric in 15
Eric Monk,
Principal Solutions Engineer

2
What is Fabric?

Fabric
• Enables distributing different
data across multiple Neo4j
DBMSs
• Enables searching data across
multiple Neo4j DBMSs in one
Cypher query
• Cluster = same data + replicated
• Fabric = different data + not
replicated
3
Fabric DB
DB1
DB2

Fabric
• DB1 and DB2 are sometimes
referred to as shards
• They are normal Neo4j DBMSs
◦ Can be clusters
• Fabric DB knows about the
shards
4
Fabric DB
DB1
DB2

Fabric - Why?
• Ability to scale massively for
reading and writing
• Demo from Nodes 2021
◦ 1000+ shards
◦ 900 million relationships per shard
◦ 182 millions nodes per shard
◦ Total relationships = 1 trillion
◦ Total data size = 280 TB
◦ Constant read performance
(<100ms) as scaled 2 orders of
magnitude
5
Fabric DB
DB1
DB2
Read more: https://neo4j.com/developer-
blog/behind-the-scenes-worlds-biggest-graph-
database/

Remote
Local
Fabric - Today we will keep it small
• Local Fabric DB
• Local Neo4j DB (Shard1)
• Remote AuraDB (Shard2)
6
Fabric DB
LocalDB
AuraDB
• Architecture Icon
used in upcoming
slides
• Affected area will
be colored

7
AuraDB Setup

Create AuraDB free instance
• Goto
https://console.neo4j.io/
• Sign-up or sign-in
• Click New Instance
8

9
Pick this one

10
Pick this one

11
Save
password
somewhere
safe
Click continue

12
It will take a
few minutes
to setup
Click Query
when status
goes to
Running

Connect to Aura Free Instance
13
Enter
password and
click Connect
Successful
connection
shows URL -
we'll need
that later

14
Local DB Setup

Setup Local (non-Fabric) DB
• Prerequisite
◦ Neo4j Desktop installed
◦ Local Neo4j DBMS installed with neo4j default database
• Open Neo4j Browser and connect to default database
◦ http://localhost:7474
• Run commands
◦ CREATE OR REPLACE DATABASE stackoverflow
◦ :use stackoverflow
15

16
Import Stack Overflow Data

• Launch free Neo4j Sandbox
• https://sandbox.neo4j.com/
• Select Stack Overflow
• Click Open - Goto Step 3 in
guide
(:play
https://guides.neo4j.com/sandbox/stackoverflow/index.htm
l)
17

• In Local DB
◦ Run this statement
◦ Modify tags
◦ Run once with 'neo4j' and
once with 'cypher'
• In AuraDB
◦ Run this statement
◦ Hardcode page to 20
◦ Run once with 'graphql' and
once with 'fabric'
18
Hardcode to
20 for Aura
Run 1 tag at
a time

19
Local Fabric DB Setup

Setup Fabric DB
fabric.database.name=localfabric
fabric.graph.0.uri=neo4j+s://8e4573c2.databases.neo4j.io:7687
fabric.graph.0.database=neo4j
fabric.graph.0.name=auraso
fabric.graph.1.uri=bolt://localhost:7687
fabric.graph.1.database=stackoverflow
fabric.graph.1.name=localso
fabric.graph.1.driver.ssl_enabled=false
dbms.ssl.policy.fabric.enabled=true
dbms.ssl.policy.fabric.base_directory=certificates
dbms.ssl.policy.fabric.trust_all=true
20
Modify neo4j.conf and restart
Name of fabric db
AuraDB settings
Local DB Settings -
disable SSL for local
DB
Need SSL enabled for
AuraDB

Setup Fabric DB
21
Fabric DB

22
Fabric Users Setup

Create Fabric User in AuraDB
• While in a non-system database
◦ :param password => 'graphconnect2022'
• Switch to system database
◦ CREATE USER gc_fabric SET PASSWORD $password CHANGE NOT
REQUIRED
• Not required in Aura free, may need to do this in Aura Professional or
Enterprise
◦ GRANT ROLE reader TO gc_fabric
23

Test User is Created
• In Neo4j Browser run
◦ :server disconnect
• Enter username
◦ gc_fabric
• Enter password
◦ graphconnect2022
• Switch back to neo4j
database
24

Create User in local db
• While in a non-system database
◦ :param password => 'graphconnect2022'
• Switch to system database
◦ CREATE USER gc_fabric SET PASSWORD $password CHANGE NOT
REQUIRED
• Grant reader role to gc_fabric
◦ GRANT ROLE reader TO gc_fabric
• User valid for both local db stackoverflow and localfabric
25

26
Fabric Query

Login into Local Stackoverflow DB
• In Neo4j Browser connect @
http://localhost:7474
◦ :server disconnect
• Login with gc_fabric /
graphconnect2022
• Once logged in switch to
stackoverflow db
27

Query local stackoverflow db
MATCH (q:Question)-[:TAGGED]->(t:Tag)
RETURN t.name as tag, count(q) as numQuestions
ORDER BY numQuestions DESC
28

Switch to Local Fabric DB
• Enter :use localfabric
-or-
• Click localfabric from the
dropdown
29

Query Local DB through Fabric
CALL {
USE localfabric.localso
}
RETURN tag, numQuestions
30
Same Results

Query AuraDB through Fabric
CALL {
USE localfabric.auraso
}
31
Remote Results

Query both DBs with UNION ALL
CALL {
}
UNION ALL
CALL {
}
32
Duplicate Results!
Not what we want

Collect and Merge to combine results
CALL {
}
WITH collect([tag, numQuestions]) as localResults
WITH apoc.map.fromPairs(localResults) as
localResultsMap
...
33
Collect up results so
we can combine them
with other results

...
CALL {
}
WITH localResultsMap, apoc.map.fromPairs(
collect([
tag,
numQuestions +
coalesce(localResultsMap[tag], 0)
])
) as auraCombinedWithMatchingLocalMap
...
34
Call aura
Look for matches in
localResultsMap and
add counts

...
WITH apoc.map.merge(
localResultsMap,
auraCombinedWithMatchingLocalMap
) as combinedMap
UNWIND keys(combinedMap) as tag
RETURN tag, combinedMap[tag] as numQuestions
35
Combine local map with
merged map.
Merged map entries
override matched local
entries.

Results are intelligently combined
36
Results are combined
intelligently

37
Summary

Summary
38
• Use Fabric to massively scale
• Fabric DB knows about other Neo4j DBMSs via neo4j.conf
• Need same username/password across all DBMSs
• Use CALL { USE dbname … } to access databases
• You can combine results from many databases in a single call
• How you model and shard will determine the best way to query

39
Thank you!
Contact us at
sales@neo4j.com

Fun with Fabric in 15

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