Spring Redis: Range query "greater than" on a field - spring

Question

I am using Redis to store some data and later query it and update it with latest information.
Considering an example:
I receive File data, which carries info on the file and the physical storage location of that file.
One shelf has multiple racks, and each rack can have multiple files.
Each file has a version field, and it gets updated (incremented) when an operation on file is performed.
How do I plan to store?
I need to query based on "shelfID + rack ID" -- To get all files.
I need to query based on "shelfID + rack ID + version > XX" -- To get all files with version more than specified.
Now, to get all files belonging to a shelf and rack, is achievable in Spring Data Redis.
I create a key of the combination of 2 ID's and later query based on this Key.
private <T> void save(String id, T entity) {
redisTemplate.opsForValue().set(id, entity);
}
But, how do I query for version field?
I had kept "version" field as #Indexed, but spring repository query does not work.
#RedisHash("shelves")
public class ShelfEntity {
#Indexed
#Id
private String id;
#Indexed
private String shelfId;
#Indexed
private String rackId;
#Indexed
private String fileId;
#Indexed
private Integer version;
private String fileName;
// and other updatable fields
}
Repository method:
List<ShefEntity> findAllByShelfIdAndRackIdAndVersionGreaterThan(String centerCd,
String floorCd, int version);
Above, gives error:
java.lang.IllegalArgumentException: GREATER_THAN (1): [IsGreaterThan,
GreaterThan]is not supported for redis query derivation
Q. How do I query based on Version Greater than?
Q. Is it even possible with Spring Data Redis?
Q. If possible, how should I model the data (into what data structure), in order to make such queries?
Q. If we don't use Spring, how to do this in Redis using redis-cli and data structure?
May be something like:
<key, key, value>
<shelfId+rackId, version, fileData>
I am not sure how to model this in Redis?
Update 2:
One shelf can have N racks.
One rack can have N files.
Each file object will have a version.
This version gets updated (o -> 1 -> 2....)
I want to store only the latest version of a file.
So, if we have 1 file object
shelfId - 1
rackId - 1
fileId - 1
version - 0
.... on update of version ... we should still have 1 file object.
version - 1
I tried keeping key as a MD5 hash of shelfId + rackId, in hash data structure.
But cannot query on version.
I also tried using a ZSet.
Saving it like this:
private void saveSet(List<ShelfEntity> shelfInfo) {
for (ShelfEntity item : shelfInfo) {
redisTemplate.opsForZSet()
.add(item.getId(), item, item.getVersion());
}
}
So, version becomes the score.
But the problem is we cannot update items of set.
So for one fileId, there are multiple version.
When I query, I get duplicates.
Get code:
Set<ShelfEntity> objects = (Set<ShelfEntity>) (Object) redisTemplate.opsForZSet()
.rangeByScore(generateMd5Hash("-", shelfId, rackId), startVersion,
Double.MAX_VALUE);
Now, this is an attempt to mimic version > XX

Answer 1

Create ZSET for each shelfId and rackId combination
Use two methods to save and update records in Redis
// this methods stores all shelf info in db
public void save(List<ShelfEntity> shelfInfo) {
for (ShelfEntity item : shelfInfo) {
redisTemplate.opsForZSet()
.add(item.getId(), clonedItem, item.getVersion());
}
}
Use update to remove old and insert new one, Redis does not support key update as it's a table so you need to remove the existing and add a new record
public void update(List<ShelfEntity> oldRecords, List<ShelfEntity> newRecords) {
if (oldRecords.size() != newRecords.size()){
throw new IlleagalArgumentException("old and new records must have same number of entries");
}
for (int i=0;i<oldRecords.size();i++) {
ShelfEntity oldItem = oldRecords.get(i);
ShelfEntity newItem = newRecords.get(i);
redisTemplate.opsForZSet().remove(oldItem.getId(), oldItem);
redisTemplate.opsForZSet()
.add(newItem.getId(), newItem, newItem.getVersion());
}
}
Read items from ZSET with score.
List<ShefEntity> findAllByShelfIdAndRackIdAndVersionGreaterThan(String shelfId,
String rackId, int version){
Set<TypedTuple<ShelfEntity>> objects = (Set<TypedTuple<ShelfEntity>>) redisTemplate.opsForZSet()
.rangeWithScores(generateMd5Hash("-", shelfId, rackId), new Double(version),
Double.MAX_VALUE);
List<ShelfEntity> shelfEntities = new ArrayList<>();
for (TypedTuple<ShelfEntity> entry: objects) {
shelfEntities.add(entry.getValue().setVersion( entry.getScore().intValue()));
}
return shelfEntities;
}