/// <summary>
/// Processes all storage requests.
/// </summary>
private void ProcessStorageRequests()
{
DBResults results;
bool storageUpdated = false;
// Delete all storage requests that have finished and who's arbitrator has disconnected.
m_databaseConnection.Query(@"DELETE FROM
{0}
WHERE
(success=1 OR failed=1) AND
(Select
COUNT(*)
FROM
{1} AS b
WHERE
id=recieved_arbitrator_id) = 0 ",
Settings.DB_TABLE_PENDING_STORE_REQUESTS,
Settings.DB_TABLE_ACTIVE_ARBITRATORS);
// Lock tables.
m_databaseConnection.Query("LOCK TABLES {0} WRITE, {1} WRITE",
Settings.DB_TABLE_PENDING_STORE_REQUESTS,
Settings.DB_TABLE_ACCOUNTS);
// Lets have a look at all requests and see if we find any we can commit.
results = m_databaseConnection.Query(@"SELECT *, UNIX_TIMESTAMP()-recieved_time FROM {0} WHERE
success=0 AND
failed=0",
Settings.DB_TABLE_PENDING_STORE_REQUESTS);
// Group together rows by zone id / client id.
List<int> updated_ids = new List<int>();
for (int i = 0; i < results.RowsAffected; i++)
{
DBRow row = results[i];
// Ignore this request if we have already processed it.
if (updated_ids.Contains((int)row["id"]))
{
continue;
}
// Make a list of requests to update same client/zone.
List<DBRow> sameRows = new List<DBRow>();
sameRows.Add(row);
updated_ids.Add((int)row["id"]);
// Look for other rows affecting the same zone and client.
int oldest_row_elapsed = 0;
for (int k = 0; k < results.RowsAffected; k++)
{
DBRow subrow = results[k];
// Ignore this request if we have already processed it.
if (updated_ids.Contains((int)subrow["id"]))
{
continue;
}
if ((int)row["client_id"] == (int)subrow["client_id"] &&
(int)row["zone_id"] == (int)subrow["zone_id"])
{
// Store oldest elapsed time for rows.
int subrow_elapsed = (int)(long)row["UNIX_TIMESTAMP()-recieved_time"];
if (subrow_elapsed > oldest_row_elapsed)
{
oldest_row_elapsed = subrow_elapsed;
}
sameRows.Add(subrow);
updated_ids.Add((int)subrow["id"]);
}
}
// Do we have enough rows to commit.
if (sameRows.Count >= Settings.ZoneSuperPeerCount ||
oldest_row_elapsed > Settings.STORE_REQUEST_TIMEOUT_INTERVAL / 1000)
{
Logger.Info("Found {0} matching storage requests for client #{1} in zone #{2}.",
LoggerVerboseLevel.High,
sameRows.Count,
row["client_id"],
row["zone_id"]);
// Find the request with the most number of similar requests. This
// is the row we will consider the correct row.
int mostSimilarIndex = -1;
int mostSimilarCount = 0;
int mostSimilarSuperPeerID= 0;
UserAccountPersistentState mostSimilarState = null;
for (int j = 0; j < sameRows.Count; j++)
{
UserAccountPersistentState state1 = new UserAccountPersistentState();
state1.Deserialize((byte[])sameRows[j]["state"]);
// Count number of similar row.
int similarCount = 1;
for (int l = 0; l < sameRows.Count; l++)
{
if (j == l) continue;
UserAccountPersistentState state2 = new UserAccountPersistentState();
state2.Deserialize((byte[])sameRows[l]["state"]);
if (state1.IsSimilarTo(state2))
{
similarCount++;
}
}
// Is this the most similar state so far?
if (similarCount > mostSimilarCount || (similarCount == mostSimilarCount && (int)sameRows[j]["superpeer_id"] < mostSimilarSuperPeerID))
{
mostSimilarState = state1;
mostSimilarIndex = j;
mostSimilarCount = similarCount;
mostSimilarSuperPeerID = (int)sameRows[j]["superpeer_id"];
}
}
// If we only have a maximum of 1 match, everyone fails, we can't have
// one user being authorative.
if (mostSimilarCount <= 1)
{
Logger.Info("Of {0} matching storage requests for client #{1} in zone #{2}, only {3} were similar. Store request rejected.",
LoggerVerboseLevel.Normal,
sameRows.Count,
row["client_id"],
row["zone_id"],
mostSimilarCount);
m_databaseConnection.Query("UPDATE {0} SET failed=1 WHERE client_id={1} AND zone_id={2}",
Settings.DB_TABLE_PENDING_STORE_REQUESTS,
row["client_id"],
row["zone_id"]);
storageUpdated = true;
}
else
{
Logger.Info("Of {0} matching storage requests for client #{1} in zone #{2}, {3} were similar. Store request was accepted.",
LoggerVerboseLevel.High,
sameRows.Count,
row["client_id"],
row["zone_id"],
mostSimilarCount);
// Update state of storage requests.
for (int j = 0; j < sameRows.Count; j++)
{
UserAccountPersistentState state2 = new UserAccountPersistentState();
state2.Deserialize((byte[])sameRows[j]["state"]);
// If its similar to the correct state, success!
if (state2.IsSimilarTo(mostSimilarState))
{
m_databaseConnection.Query("UPDATE {0} SET success=1 WHERE id={1}",
Settings.DB_TABLE_PENDING_STORE_REQUESTS,
sameRows[j]["id"]);
Logger.Info("Storage request by SuperPeer #{0} for Client #{1} in Zone #{2} was similar to correct states and was accepted.",
LoggerVerboseLevel.High,
sameRows[j]["superpeer_id"],
sameRows[j]["client_id"],
sameRows[j]["zone_id"]);
}
// Otherwise failure :(.
else
{
m_databaseConnection.Query("UPDATE {0} SET failed=1 WHERE id={1}",
Settings.DB_TABLE_PENDING_STORE_REQUESTS,
sameRows[j]["id"]);
Logger.Info("Storage request by SuperPeer #{0} for Client #{1} in Zone #{2} was not similar to correct states, and was ignored.",
LoggerVerboseLevel.Normal,
sameRows[j]["superpeer_id"],
sameRows[j]["client_id"],
sameRows[j]["zone_id"]);
}
}
// Now actually store the data.
m_databaseConnection.QueryParameterized("UPDATE {0} SET persistent_state=@parameter_1 WHERE id={1}",
new object[] { mostSimilarState.Serialize() },
Settings.DB_TABLE_ACCOUNTS,
row["account_id"]);
storageUpdated = true;
}
}
}
// Dispose of timed out requests.
results = m_databaseConnection.Query(@"UPDATE {0} SET failed=1 WHERE
UNIX_TIMESTAMP() - recieved_time > {1}",
Settings.DB_TABLE_PENDING_STORE_REQUESTS,
Settings.STORE_REQUEST_TIMEOUT_INTERVAL / 1000);
if (results.RowsAffected > 0)
{
storageUpdated = true;
}
// Unlock tables.
m_databaseConnection.Query("UNLOCK TABLES");
}
/// <summary>
/// Checks if this persistent state is similar enough to another state that it
/// can be considered the same.
/// </summary>
/// <param name="state">Other state to check.</param>
/// <returns>True if states are similar, otherwise false.</returns>
public bool IsSimilarTo(UserAccountPersistentState state)
{
Type type = this.GetType();
foreach (FieldInfo info in type.GetFields())
{
object val1 = info.GetValue(this);
object val2 = info.GetValue(state);
SimilarityThresholdAttribute attr = info.GetCustomAttribute(typeof(SimilarityThresholdAttribute)) as SimilarityThresholdAttribute;
if (attr != null)
{
if (attr.CompareValues(val1, val2) == false)
{
return false;
}
}
}
return true;
}