/// <summary>
/// Finds a shard map from cache if requested and if necessary from global shard map.
/// </summary>
/// <param name="operationName">Operation name, useful for diagnostics.</param>
/// <param name="shardMapName">Name of shard map.</param>
/// <param name="lookInCacheFirst">Whether to skip first lookup in cache.</param>
/// <returns>Shard map object corresponding to one being searched.</returns>
internal ShardMap LookupShardMapByName(string operationName, string shardMapName, bool lookInCacheFirst)
{
IStoreShardMap ssm = null;
if (lookInCacheFirst)
{
// Typical scenario will result in immediate lookup succeeding.
ssm = this.Cache.LookupShardMapByName(shardMapName);
}
ShardMap shardMap;
// Cache miss. Go to store and add entry to cache.
if (ssm == null)
{
Stopwatch stopwatch = Stopwatch.StartNew();
shardMap = this.LookupShardMapByNameInStore(operationName, shardMapName);
stopwatch.Stop();
Tracer.TraceInfo(TraceSourceConstants.ComponentNames.ShardMapManager,
"LookupShardMapByName", "Lookup ShardMap: {0} in store complete; Duration: {1}",
shardMapName, stopwatch.Elapsed);
}
else
{
shardMap = ShardMapUtils.CreateShardMapFromStoreShardMap(this, ssm);
}
return(shardMap);
}
/// <summary>
/// Obtains all ShardMaps associated with the shard map manager.
/// </summary>
/// <returns>Collection of shard maps associated with the shard map manager.</returns>
private IEnumerable <ShardMap> GetShardMapsFromStore()
{
IStoreResults result;
using (IStoreOperationGlobal op = this.StoreOperationFactory.CreateGetShardMapsGlobalOperation(this, "GetShardMaps"))
{
result = op.Do();
}
return(result.StoreShardMaps
.Select(ssm => ShardMapUtils.CreateShardMapFromStoreShardMap(this, ssm)));
}
/// <summary>
/// Finds shard map with given name in global shard map.
/// </summary>
/// <param name="operationName">Operation name, useful for diagnostics.</param>
/// <param name="shardMapName">Name of shard map to search.</param>
/// <returns>Shard map corresponding to given Id.</returns>
private ShardMap LookupShardMapByNameInStore(string operationName, string shardMapName)
{
IStoreResults result;
using (IStoreOperationGlobal op = this.StoreOperationFactory.CreateFindShardMapByNameGlobalOperation(this, operationName, shardMapName))
{
result = op.Do();
}
return(result.StoreShardMaps
.Select(ssm => ShardMapUtils.CreateShardMapFromStoreShardMap(this, ssm))
.SingleOrDefault());
}