[Redis] Cache search keywords and result

 Redis   Search caching 

▌Introduction

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This is an example of using Redis to cache the search keywords and result.

For example, we have 2 fields: “Name”(partial-match) and “From”, and we want to cache the user’s search keywords and  result in order to response the cached result for the same search keywords at the next time.

We will use the following Redis’s Data Types:

Data Type	Description	Sample
		Key	Value
Strings	Key: GUID Value: Search result	1cdda6577b644a2f918ce0daceb97bd9	[{“Name“:”Stan”, “From“: “TW“}, {“Name“:”Stanley”, “From“: “HK“}]
Sets	Key: A search’s field and keyword Value: The search result’s Redis key	Name:Stan	1cdda6577b644a2f918ce0daceb97bd9

The following search scenarios will show what will be stores in Redis.

When user search with Name: “Stan”, and the result will be cached in key X:

Data Type	Key	Value
Strings	X (X is a GUID)	[{“Name“:”Stan”, “From“: “TW“}, {“Name“:”Stanley”, “From“: “HK“}]
Sets	Name:Stan	X
Sets	From:null	X

When user search with Name: “Mary”, and the result will be cached in key Y:

Data Type	Key	Value
Strings	X	[{“Name“:”Stan”, “From“: “TW“}, {“Name“:”Stanley”, “From“: “HK“}]
Strings	Y	[{“Name“:”Mary”, “From“: “TW“}]
Sets	Name:Stan	X
Sets	Name:Mary	Y
Sets	From:null	X, Y

When user search with From: “JP”, and the result will be cached in key Z:

Data Type	Key	Value
Strings	X	[{“Name“:”Stan”, “From“: “TW“}, {“Name“:”Stanley”, “From“: “HK“}]
Strings	Y	[{“Name“:”Mary”, “From“: “TW“}]
Strings	Z	[{“Name“:”Jack”, “From“: “JP“}]
Sets	Name:Stan	X
Sets	Name:Mary	Y
Sets	Name:null	Z
Sets	From:JP	Z
Sets	From:null	X, Y

When user search with Name: “Stan” + From: “TW”, and the result will be cached in key W:

Data Type	Key	Value
Strings	X	[{“Name“:”Stan”, “From“: “TW“}, {“Name“:”Stanley”, “From“: “HK“}]
Strings	Y	[{“Name“:”Mary”, “From“: “TW“}]
Strings	Z	[{“Name“:”Jack”, “From“: “JP“}]
Strings	W	[{“Name“:”Stan”, “From“: “TW“}]
Sets	Name:Stan	X, W
Sets	Name:Mary	Y
Sets	Name:null	Z
Sets	From:JP	Z
Sets	From:TW	W
Sets	From:null	X, Y

Now next time a user searches with Name: “Stan” + From: “TW”, we will intersects the sets by the 2 keys:

l   Name:Stan

l   From:TW

That will get W, and we can return the result from key: W. The redis-cli command is as following,

$ SINTER Name:Stan From:TW

(string) W

$ MGET W

(string) [{“Name“:”Stan”, “From“: “TW“}]

Another search example with only name keyword: Name: “Mary”:

$ SINTER Name:Mary From:null

(string) Y

$ MGET Y

(string) [{“Name“:”Mary”, “From“: “TW“}]

▌Reference

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▋Redis: Data Types