I'm using StackExchange.Redis to store and retrieve items in redis cache using multiple databases.
However, I cannot figure out how to retrieve key/values across ALL databases. The following code retrieves keys from the default database 0, and I cannot find how to change it to retrieve keys from each database
public IEnumerable<KeyValuePair<string, object>> GetAll()
{
var result = new List<KeyValuePair<string, object>>();
var endpoints = _dataCache.Multiplexer.GetEndPoints();
var server = _dataCache.Multiplexer.GetServer(endpoints.First());
var keys = server.Keys();
foreach (var key in keys)
{
Console.WriteLine(key.ToString());
}
return result;
}
Any suggestions?
The Redis KEYS command returns all the keys in the database that match a pattern (or all the keys in the key space). Similar commands for fetching all the fields stored in a hash is HGETALL and for all fetching the members of a SMEMBERS.
Redis comes with support for multiple databases, which is very similar to the concept in SQL databases. In SQL databases, such as MySQL, PostgreSQL, and Oracle, you can define a name for your databases. However, Redis databases are represented by numbers.
Redis keyspace notifications allow you to subscribe to PubSub channels. Through the channel, clients receive published events when a Redis command or data alteration occurs. These notifications are useful when an application must respond to changes that occur to the value stored in a particular key or keys.
it seems I found the answers - need to pass the database name to the actual .Keys, as below
var keys = server.Keys(_dataCache.Database);
You need to write: var keys = server.Keys(int dbName); I added in the example how to get the values by key
public static ConnectionMultiplexer Connection
{
get
{
return ConnectionMultiplexer.Connect("serverName: port");
}
}
public Dictionary<string, string> GetDataFromDataBase(srting sPattern = "*")
{
int dbName = 2; //or 0, 1, 2
Dictionary<string, string> dicKeyValue = new Dictionary<string, string>();
var keys = Connection.GetServer("serverName: port").Keys(dbName, pattern: sPattern);
string[] keysArr = keys.Select(key =>(string)key).ToArray();
foreach(var key in keysArr)
{
dicKeyValue.Add(key, GetFromDB(dbName , key));
}
return dicKeyValue;
}
public string GetFromDB(int dbName, string key)
{
var db = Connection.GetDatabase(dbName);
return db.StringGet(key);
}
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