/// <summary>
/// Add or update a mapping in cache.
/// </summary>
/// <param name="sm">Storage mapping object.</param>
/// <param name="policy">Policy to use for preexisting cache entries during update.</param>
internal override void AddOrUpdate(IStoreMapping sm, CacheStoreMappingUpdatePolicy policy)
{
// Make key out of mapping key.
ShardKey key = ShardKey.FromRawValue(this.KeyType, sm.MinValue);
CacheMapping cm;
// We need to update TTL and update entry if:
// a) We are in update TTL mode
// b) Mapping exists and same as the one we already have
// c) Entry is beyond the TTL limit
if (policy == CacheStoreMappingUpdatePolicy.UpdateTimeToLive &&
_mappingsByKey.TryGetValue(key, out cm) &&
cm.Mapping.Id == sm.Id /*&&
* TimerUtils.ElapsedMillisecondsSince(cm.CreationTime) >= cm.TimeToLiveMilliseconds */)
{
cm = new CacheMapping(sm, CacheMapper.CalculateNewTimeToLiveMilliseconds(cm));
}
else
{
cm = new CacheMapping(sm);
}
// Remove existing entry.
this.Remove(sm);
// Add the entry to lookup table by Key.
_mappingsByKey.Add(key, cm);
}
/// <summary>
/// Converts IStoreShardMap to ShardMap.
/// </summary>
/// <param name="manager">Reference to shard map manager.</param>
/// <param name="ssm">Storage representation for ShardMap.</param>
/// <returns>ShardMap object corresponding to storange representation.</returns>
internal static ShardMap CreateShardMapFromStoreShardMap(
ShardMapManager manager,
IStoreShardMap ssm)
{
switch (ssm.MapType)
{
case ShardMapType.List:
// Create ListShardMap<TKey>
return((ShardMap)Activator.CreateInstance(
typeof(ListShardMap <>).MakeGenericType(
ShardKey.TypeFromShardKeyType(ssm.KeyType)),
BindingFlags.NonPublic | BindingFlags.Instance,
null,
new object[] { manager, ssm },
CultureInfo.InvariantCulture));
default:
Debug.Assert(ssm.MapType == ShardMapType.Range);
// Create RangeShardMap<TKey>
return((ShardMap)Activator.CreateInstance(
typeof(RangeShardMap <>).MakeGenericType(
ShardKey.TypeFromShardKeyType(ssm.KeyType)),
BindingFlags.NonPublic | BindingFlags.Instance,
null,
new object[] { manager, ssm },
CultureInfo.InvariantCulture));
}
}
/// <summary>
/// Performs binary search on the cached mappings and returns the
/// index of mapping object whose min-value is less than and closest
/// to given key value.
/// </summary>
/// <param name="key">Input key.</param>
/// <returns>Index of range in the cache which contains the given key.</returns>
private int GetIndexOfMappingWithClosestMaxGreaterThanOrEqualToMaxKey(ShardKey key)
{
IList <ShardRange> rangeKeys = _mappingsByRange.Keys;
int lb = 0;
int ub = rangeKeys.Count - 1;
while (lb <= ub)
{
int mid = lb + (ub - lb) / 2;
ShardRange current = rangeKeys[mid];
if (current.High > key)
{
if (current.Low <= key)
{
return(mid);
}
else
{
ub = mid - 1;
}
}
else
{
lb = mid + 1;
}
}
return(lb);
}
/// <summary>
/// Add or update a mapping in cache.
/// </summary>
/// <param name="sm">Storage mapping object.</param>
/// <param name="policy">Policy to use for preexisting cache entries during update.</param>
internal override void AddOrUpdate(IStoreMapping sm, CacheStoreMappingUpdatePolicy policy)
{
ShardKey min = ShardKey.FromRawValue(this.KeyType, sm.MinValue);
// Make range out of mapping key ranges.
ShardRange range = new ShardRange(
min,
ShardKey.FromRawValue(this.KeyType, sm.MaxValue));
CacheMapping cm;
ICacheStoreMapping csm;
IStoreMapping smDummy;
// We need to update TTL and update entry if:
// a) We are in update TTL mode
// b) Mapping exists and same as the one we already have
// c) Entry is beyond the TTL limit
if (policy == CacheStoreMappingUpdatePolicy.UpdateTimeToLive &&
(csm = this.LookupByKey(min, out smDummy)) != null &&
csm.Mapping.Id == sm.Id /*&&
* TimerUtils.ElapsedMillisecondsSince(csm.CreationTime) >= csm.TimeToLiveMilliseconds */)
{
cm = new CacheMapping(sm, CacheMapper.CalculateNewTimeToLiveMilliseconds(csm));
}
else
{
cm = new CacheMapping(sm);
}
this.Remove(sm);
// Add the entry to lookup table by Range.
_mappingsByRange.Add(range, cm);
}
/// <summary>
/// Performs binary search on the cached mappings and returns the
/// index of mapping object which contains the given key.
/// </summary>
/// <param name="key">Input key.</param>
/// <returns>Index of range in the cache which contains the given key.</returns>
private int GetIndexOfMappingContainingShardKey(ShardKey key)
{
IList <ShardRange> rangeKeys = _mappingsByRange.Keys;
int lb = 0;
int ub = rangeKeys.Count - 1;
while (lb <= ub)
{
int mid = lb + (ub - lb) / 2;
ShardRange current = rangeKeys[mid];
if (current.Contains(key))
{
return(mid);
}
else if (key < current.Low)
{
ub = mid - 1;
}
else
{
lb = mid + 1;
}
}
return(-1);
}
/// <summary>
/// Looks up a mapping by key.
/// </summary>
/// <param name="key">Key value.</param>
/// <param name="sm">Storage mapping object.</param>
/// <returns>Mapping object which has the key value.</returns>
internal override ICacheStoreMapping LookupByKey(ShardKey key, out IStoreMapping sm)
{
CacheMapping cm;
// Performs a binary search in the ranges for key value and
// then return the result.
int rangeIndex = this.GetIndexOfMappingContainingShardKey(key);
if (rangeIndex != -1)
{
ShardRange range = _mappingsByRange.Keys[rangeIndex];
cm = _mappingsByRange[range];
// DEVNOTE(wbasheer): We should clone the mapping.
sm = cm.Mapping;
}
else
{
cm = null;
sm = null;
}
return(cm);
}
/// <summary>
/// Asynchronously opens a regular <see cref="SqlConnection"/> to the shard
/// to which the specified key value is mapped.
/// </summary>
/// <typeparam name="TKey">Type of the key.</typeparam>
/// <param name="key">Input key value.</param>
/// <param name="connectionString">
/// Connection string with credential information such as SQL Server credentials or Integrated Security settings.
/// The hostname of the server and the database name for the shard are obtained from the lookup operation for key.
/// </param>
/// <param name="options">Options for validation operations to perform on opened connection.</param>
/// <returns>A Task encapsulating an opened SqlConnection.</returns>
/// <remarks>
/// Note that the <see cref="SqlConnection"/> object returned by this call is not protected against transient faults.
/// Callers should follow best practices to protect the connection against transient faults
/// in their application code, e.g., by using the transient fault handling
/// functionality in the Enterprise Library from Microsoft Patterns and Practices team.
/// This call only works if there is a single default mapping.
/// </remarks>
public Task <SqlConnection> OpenConnectionForKeyAsync <TKey>(
TKey key,
string connectionString,
ConnectionOptions options)
{
ExceptionUtils.DisallowNullArgument(connectionString, "connectionString");
Debug.Assert(this.StoreShardMap.KeyType != ShardKeyType.None);
using (ActivityIdScope activityIdScope = new ActivityIdScope(Guid.NewGuid()))
{
IShardMapper <TKey> mapper = this.GetMapper <TKey>();
if (mapper == null)
{
throw new ArgumentException(
StringUtils.FormatInvariant(
Errors._ShardMap_OpenConnectionForKey_KeyTypeNotSupported,
typeof(TKey),
this.StoreShardMap.Name,
ShardKey.TypeFromShardKeyType(this.StoreShardMap.KeyType)),
"key");
}
Debug.Assert(mapper != null);
return(mapper.OpenConnectionForKeyAsync(key, connectionString, options));
}
}
/// <summary>
/// Looks up the key value and returns the corresponding mapping.
/// </summary>
/// <typeparam name="TMapping">Mapping type.</typeparam>
/// <typeparam name="TKey">Key type.</typeparam>
/// <param name="key">Input key value.</param>
/// <param name="useCache">Whether to use cache for lookups.</param>
/// <param name="constructMapping">Delegate to construct a mapping object.</param>
/// <param name="errorCategory">Category under which errors must be thrown.</param>
/// <returns>Mapping that contains the key value.</returns>
protected TMapping Lookup <TMapping, TKey>(
TKey key,
bool useCache,
Func <ShardMapManager, ShardMap, IStoreMapping, TMapping> constructMapping,
ShardManagementErrorCategory errorCategory)
where TMapping : class, IShardProvider
{
ShardKey sk = new ShardKey(ShardKey.ShardKeyTypeFromType(typeof(TKey)), key);
if (useCache)
{
ICacheStoreMapping cachedMapping = this.Manager.Cache.LookupMappingByKey(this.ShardMap.StoreShardMap, sk);
if (cachedMapping != null)
{
return(constructMapping(this.Manager, this.ShardMap, cachedMapping.Mapping));
}
}
// Cache-miss, find mapping for given key in GSM.
TMapping m = null;
IStoreResults gsmResult;
Stopwatch stopwatch = Stopwatch.StartNew();
using (IStoreOperationGlobal op = this.Manager.StoreOperationFactory.CreateFindMappingByKeyGlobalOperation(
this.Manager,
"Lookup",
this.ShardMap.StoreShardMap,
sk,
CacheStoreMappingUpdatePolicy.OverwriteExisting,
errorCategory,
true,
false))
{
gsmResult = op.Do();
}
stopwatch.Stop();
Tracer.TraceVerbose(
TraceSourceConstants.ComponentNames.BaseShardMapper,
"Lookup",
"Lookup key from GSM complete; Key type : {0}; Result: {1}; Duration: {2}",
typeof(TKey),
gsmResult.Result,
stopwatch.Elapsed);
// If we could not locate the mapping, we return null and do nothing here.
if (gsmResult.Result != StoreResult.MappingNotFoundForKey)
{
return(gsmResult.StoreMappings.Select(sm => constructMapping(this.Manager, this.ShardMap, sm)).Single());
}
return(m);
}
/// <summary>
/// Arguments used to create a point mapping.
/// </summary>
/// <param name="point">Point value being mapped.</param>
/// <param name="shard">Shard used as the mapping target.</param>
/// <param name="status">Status of the mapping.</param>
public PointMappingCreationInfo(TKey point, Shard shard, MappingStatus status)
{
ExceptionUtils.DisallowNullArgument(shard, "shard");
this.Value = point;
this.Shard = shard;
this.Status = status;
this.Key = new ShardKey(ShardKey.ShardKeyTypeFromType(typeof(TKey)), point);
}
/// <summary>
/// Calculates the hash code for the object.
/// </summary>
/// <returns>Hash code for the object.</returns>
private int CalculateHashCode()
{
int h;
h = ShardKey.QPHash(this.Protocol.GetHashCode(), this.DataSource.ToUpperInvariant().GetHashCode());
h = ShardKey.QPHash(h, this.Port.GetHashCode());
h = ShardKey.QPHash(h, this.Database.ToUpperInvariant().GetHashCode());
return(h);
}
/// <summary>
/// Constructs range based on its low and high boundary values.
/// </summary>
/// <param name="low">Low boundary value (inclusive).</param>
/// <param name="high">High boundary value (exclusive).</param>
public Range(TKey low, TKey high)
{
ShardKeyType k = ShardKey.ShardKeyTypeFromType(typeof(TKey));
_r = new ShardRange(
new ShardKey(k, low),
new ShardKey(k, high));
this.Low = low;
this.High = high;
}
/// <summary>
/// Constructs range based on its low boundary value. The low boundary value is
/// set to the one specified in <paramref name="low"/> while the
/// high boundary value is set to maximum possible value i.e. +infinity.
/// </summary>
/// <param name="low">Low boundary value (inclusive).</param>
public Range(TKey low)
{
ShardKeyType k = ShardKey.ShardKeyTypeFromType(typeof(TKey));
_r = new ShardRange(
new ShardKey(k, low),
new ShardKey(k, null));
this.Low = low;
this.HighIsMax = true;
}
/// <summary>
/// Remove a mapping object from cache.
/// </summary>
/// <param name="sm">Storage maping object.</param>
internal override void Remove(IStoreMapping sm)
{
// Make key value out of mapping key.
ShardKey key = ShardKey.FromRawValue(this.KeyType, sm.MinValue);
// Remove existing entry.
if (_mappingsByKey.ContainsKey(key))
{
_mappingsByKey.Remove(key);
}
}
public RangeMappingCreationInfo(Range <TKey> value, Shard shard, MappingStatus status)
{
ExceptionUtils.DisallowNullArgument(value, "value");
ExceptionUtils.DisallowNullArgument(shard, "shard");
this.Value = value;
this.Shard = shard;
this.Status = status;
this.Range = new ShardRange(
new ShardKey(ShardKey.ShardKeyTypeFromType(typeof(TKey)), value.Low),
new ShardKey(ShardKey.ShardKeyTypeFromType(typeof(TKey)), value.HighIsMax ? null : (object)value.High));
}
/// <summary>
/// Raise conversion exception.
/// </summary>
/// <typeparam name="TKey">Key type.</typeparam>
/// <param name="ssm">Shard map whose conversion failed.</param>
/// <param name="targetKind">Requested type of shard map.</param>
private static ShardManagementException GetConversionException <TKey>(IStoreShardMap ssm, string targetKind)
{
return(new ShardManagementException(
ShardManagementErrorCategory.ShardMapManager,
ShardManagementErrorCode.ShardMapTypeConversionError,
Errors._ShardMapExtensions_AsTypedShardMap_ConversionFailure,
ssm.Name,
targetKind,
typeof(TKey).Name,
ssm.MapType.ToString(),
ssm.KeyType == ShardKeyType.None ? string.Empty : ShardKey.TypeFromShardKeyType(ssm.KeyType).Name));
}
/// <summary>Returns the intersection of two ranges.</summary>
/// <param name="range">Range to intersect with.</param>
/// <returns>
/// The intersection of the current range and the specified range, null if ranges dont intersect.
/// </returns>
internal ShardRange Intersect(ShardRange range)
{
ExceptionUtils.DisallowNullArgument(range, "range");
ShardKey intersectLow = ShardKey.Max(Low, range.Low);
ShardKey intersectHigh = ShardKey.Min(High, range.High);
if (intersectLow >= intersectHigh)
{
return(null);
}
return(new ShardRange(intersectLow, intersectHigh));
}
/// <summary>
/// Asynchronously finds the mapping in store for OpenConnectionForKey operation.
/// </summary>
/// <param name="sk">Key to find.</param>
/// <param name="policy">Cache update policy.</param>
/// <param name="errorCategory">Error category.</param>
/// <returns>Task with the Mapping corresponding to the given key if found as the result.</returns>
private async Task <IStoreMapping> LookupMappingForOpenConnectionForKeyAsync(
ShardKey sk,
CacheStoreMappingUpdatePolicy policy,
ShardManagementErrorCategory errorCategory)
{
IStoreResults gsmResult;
Stopwatch stopwatch = Stopwatch.StartNew();
using (IStoreOperationGlobal op = this.Manager.StoreOperationFactory.CreateFindMappingByKeyGlobalOperation(
this.Manager,
"Lookup",
this.ShardMap.StoreShardMap,
sk,
policy,
errorCategory,
true,
false))
{
gsmResult = await op.DoAsync().ConfigureAwait(false);
}
stopwatch.Stop();
Tracer.TraceVerbose(
TraceSourceConstants.ComponentNames.BaseShardMapper,
"LookupMappingForOpenConnectionForKeyAsync",
"Lookup key from GSM complete; Key type : {0}; Result: {1}; Duration: {2}",
sk.DataType,
gsmResult.Result,
stopwatch.Elapsed);
// If we could not locate the mapping, we throw.
if (gsmResult.Result == StoreResult.MappingNotFoundForKey)
{
throw new ShardManagementException(
errorCategory,
ShardManagementErrorCode.MappingNotFoundForKey,
Errors._Store_ShardMapper_MappingNotFoundForKeyGlobal,
this.ShardMap.Name,
StoreOperationRequestBuilder.SpFindShardMappingByKeyGlobal,
"LookupMappingForOpenConnectionForKeyAsync");
}
else
{
return(gsmResult.StoreMappings.Single());
}
}
/// <summary>
/// Gets all the mappings that exist within given range.
/// </summary>
/// <param name="range">Optional range value, if null, we cover everything.</param>
/// <param name="shard">Optional shard parameter, if null, we cover all shards.</param>
/// <param name="constructMapping">Delegate to construct a mapping object.</param>
/// <param name="errorCategory">Category under which errors will be posted.</param>
/// <param name="mappingType">Name of mapping type.</param>
/// <returns>Read-only collection of mappings that overlap with given range.</returns>
protected IReadOnlyList <TMapping> GetMappingsForRange <TMapping, TKey>(
Range <TKey> range,
Shard shard,
Func <ShardMapManager, ShardMap, IStoreMapping, TMapping> constructMapping,
ShardManagementErrorCategory errorCategory,
string mappingType)
where TMapping : class
{
ShardRange sr = null;
if (shard != null)
{
ExceptionUtils.EnsureShardBelongsToShardMap(
this.Manager,
this.ShardMap,
shard,
"GetMappings",
mappingType);
}
if (range != null)
{
sr = new ShardRange(
new ShardKey(ShardKey.ShardKeyTypeFromType(typeof(TKey)), range.Low),
new ShardKey(ShardKey.ShardKeyTypeFromType(typeof(TKey)), range.HighIsMax ? null : (object)range.High));
}
IStoreResults result;
using (IStoreOperationGlobal op = this.Manager.StoreOperationFactory.CreateGetMappingsByRangeGlobalOperation(
this.Manager,
"GetMappingsForRange",
this.ShardMap.StoreShardMap,
shard != null ? shard.StoreShard : null,
sr,
errorCategory,
true, // Always cache.
false))
{
result = op.Do();
}
return(result.StoreMappings
.Select(sm => constructMapping(this.Manager, this.ShardMap, sm))
.ToList()
.AsReadOnly());
}
/// <summary>
/// Looks up a mapping by key.
/// </summary>
/// <param name="key">Key value.</param>
/// <param name="sm">Storage mapping object.</param>
/// <returns>Mapping object which has the key value.</returns>
internal override ICacheStoreMapping LookupByKey(ShardKey key, out IStoreMapping sm)
{
CacheMapping cm;
_mappingsByKey.TryGetValue(key, out cm);
if (cm != null)
{
sm = cm.Mapping;
}
else
{
sm = null;
}
return(cm);
}
/// <summary>
/// Internal constructor used for deserialization from store representation of
/// the mapping object.
/// </summary>
/// <param name="manager">Owning ShardMapManager.</param>
/// <param name="shardMap">Owning shard map.</param>
/// <param name="mapping">Storage representation of the mapping.</param>
internal PointMapping(
ShardMapManager manager,
ShardMap shardMap,
IStoreMapping mapping)
{
Debug.Assert(manager != null);
this.Manager = manager;
Debug.Assert(mapping != null);
Debug.Assert(mapping.ShardMapId != default(Guid));
Debug.Assert(mapping.StoreShard.ShardMapId != default(Guid));
this.StoreMapping = mapping;
_shard = new Shard(this.Manager, shardMap, mapping.StoreShard);
this.Key = ShardKey.FromRawValue(ShardKey.ShardKeyTypeFromType(typeof(TKey)), mapping.MinValue);
this.Value = (TKey)this.Key.Value;
}
/// <summary>
/// Constructs request for obtaining mapping from GSM based on given key.
/// </summary>
/// <param name="shardMapManager">Shard map manager.</param>
/// <param name="operationName">Operation being executed.</param>
/// <param name="shardMap">Local shard map.</param>
/// <param name="key">Key for lookup operation.</param>
/// <param name="policy">Policy for cache update.</param>
/// <param name="errorCategory">Error category.</param>
/// <param name="cacheResults">Whether to cache the results of the operation.</param>
/// <param name="ignoreFailure">Ignore shard map not found error.</param>
protected internal FindMappingByKeyGlobalOperation(
ShardMapManager shardMapManager,
string operationName,
IStoreShardMap shardMap,
ShardKey key,
CacheStoreMappingUpdatePolicy policy,
ShardManagementErrorCategory errorCategory,
bool cacheResults,
bool ignoreFailure) :
base(shardMapManager.Credentials, shardMapManager.RetryPolicy, operationName)
{
_manager = shardMapManager;
_shardMap = shardMap;
_key = key;
_policy = policy;
_errorCategory = errorCategory;
_cacheResults = cacheResults;
_ignoreFailure = ignoreFailure;
}
/// <summary>
/// Creates a list based <see cref="ListShardMap{TKey}"/>.
/// </summary>
/// <typeparam name="TKey">Type of keys.</typeparam>
/// <param name="shardMapName">Name of shard map.</param>
/// <returns>List shard map with the specified name.</returns>
public ListShardMap <TKey> CreateListShardMap <TKey>(string shardMapName)
{
ShardMapManager.ValidateShardMapName(shardMapName);
using (ActivityIdScope activityIdScope = new ActivityIdScope(Guid.NewGuid()))
{
DefaultStoreShardMap dssm = new DefaultStoreShardMap(
Guid.NewGuid(),
shardMapName,
ShardMapType.List,
ShardKey.ShardKeyTypeFromType(typeof(TKey)));
ListShardMap <TKey> listShardMap = new ListShardMap <TKey>(this, dssm);
Tracer.TraceInfo(
TraceSourceConstants.ComponentNames.ShardMapManager,
"CreateListShardMap",
"Start; ShardMap: {0}",
shardMapName);
Stopwatch stopwatch = Stopwatch.StartNew();
this.AddShardMapToStore("CreateListShardMap", dssm);
stopwatch.Stop();
Tracer.TraceInfo(
TraceSourceConstants.ComponentNames.ShardMapManager,
"CreateListShardMap",
"Added ShardMap to Store; ShardMap: {0} Duration: {1}",
shardMapName,
stopwatch.Elapsed);
Tracer.TraceInfo(
TraceSourceConstants.ComponentNames.ShardMapManager,
"CreateListShardMap",
"Complete; ShardMap: {0} Duration: {1}",
shardMapName,
stopwatch.Elapsed);
return(listShardMap);
}
}
/// <summary>
/// Constructs request for obtaining mapping from GSM based on given key.
/// </summary>
/// <param name="shardMapManager">Shard map manager.</param>
/// <param name="operationName">Operation being executed.</param>
/// <param name="shardMap">Local shard map.</param>
/// <param name="key">Key for lookup operation.</param>
/// <param name="policy">Policy for cache update.</param>
/// <param name="errorCategory">Error category.</param>
/// <param name="cacheResults">Whether to cache the results of the operation.</param>
/// <param name="ignoreFailure">Ignore shard map not found error.</param>
/// <returns>The store operation.</returns>
public virtual IStoreOperationGlobal CreateFindMappingByKeyGlobalOperation(
ShardMapManager shardMapManager,
string operationName,
IStoreShardMap shardMap,
ShardKey key,
CacheStoreMappingUpdatePolicy policy,
ShardManagementErrorCategory errorCategory,
bool cacheResults,
bool ignoreFailure)
{
return(new FindMappingByKeyGlobalOperation(
shardMapManager,
operationName,
shardMap,
key,
policy,
errorCategory,
cacheResults,
ignoreFailure));
}
/// <summary>Constructs a shard range from low boundary (inclusive) to high high boundary (exclusive)</summary>
/// <param name="low">Low boundary (inclusive)</param>
/// <param name="high">High boundary (exclusive)</param>
public ShardRange(ShardKey low, ShardKey high)
{
ExceptionUtils.DisallowNullArgument(low, "low");
ExceptionUtils.DisallowNullArgument(high, "high");
if (low >= high)
{
throw new ArgumentOutOfRangeException(
"low",
low,
string.Format(
Errors._ShardRange_LowGreaterThanOrEqualToHigh,
low,
high));
}
this.Low = low;
this.High = high;
this.KeyType = Low.KeyType;
_hashCode = this.CalculateHashCode();
}
/// <summary>
/// Internal constructor used for deserialization from store representation of
/// the mapping object.
/// </summary>
/// <param name="manager">Owning ShardMapManager.</param>
/// <param name="shardMap">Owning shard map.</param>
/// <param name="mapping">Storage representation of the mapping.</param>
internal RangeMapping(
ShardMapManager manager,
ShardMap shardMap,
IStoreMapping mapping)
{
Debug.Assert(manager != null);
this.Manager = manager;
Debug.Assert(mapping != null);
Debug.Assert(mapping.ShardMapId != default(Guid));
Debug.Assert(mapping.StoreShard.ShardMapId != default(Guid));
this.StoreMapping = mapping;
_shard = new Shard(this.Manager, shardMap, mapping.StoreShard);
this.Range = new ShardRange(
ShardKey.FromRawValue(ShardKey.ShardKeyTypeFromType(typeof(TKey)), mapping.MinValue),
ShardKey.FromRawValue(ShardKey.ShardKeyTypeFromType(typeof(TKey)), mapping.MaxValue));
this.Value = this.Range.High.IsMax ?
new Range <TKey>(this.Range.Low.GetValue <TKey>()) :
new Range <TKey>(this.Range.Low.GetValue <TKey>(), this.Range.High.GetValue <TKey>());
}
/// <summary>
/// Calculates the hash code for the object.
/// </summary>
/// <returns>Hash code for the object.</returns>
private int CalculateHashCode()
{
return(ShardKey.QPHash(this.Low.GetHashCode(), this.High.GetHashCode()));
}
/// <summary>Checks whether the specified key is inside the range.</summary>
/// <param name="key">The key to check</param>
/// <returns>True if inside, false otherwise</returns>
public bool Contains(ShardKey key)
{
ExceptionUtils.DisallowNullArgument(key, "key");
return((key >= Low) && (key < High));
}
/// <summary>
/// Splits the given mapping into 2 at the given key. The new mappings point to the same shard
/// as the existing mapping.
/// </summary>
/// <param name="existingMapping">Given existing mapping.</param>
/// <param name="splitAt">Split point.</param>
/// <param name="lockOwnerId">Lock owner id of this mapping</param>
/// <returns>Read-only collection of 2 new mappings thus created.</returns>
internal IReadOnlyList <RangeMapping <TKey> > Split(RangeMapping <TKey> existingMapping, TKey splitAt, Guid lockOwnerId)
{
this.EnsureMappingBelongsToShardMap <RangeMapping <TKey> >(
existingMapping,
"Split",
"existingMapping");
ShardKey shardKey = new ShardKey(ShardKey.ShardKeyTypeFromType(typeof(TKey)), splitAt);
if (!existingMapping.Range.Contains(shardKey) ||
existingMapping.Range.Low == shardKey ||
existingMapping.Range.High == shardKey)
{
throw new ArgumentOutOfRangeException(
"splitAt",
Errors._ShardMapping_SplitPointOutOfRange);
}
IStoreShard newShard = new DefaultStoreShard(
existingMapping.Shard.StoreShard.Id,
Guid.NewGuid(),
existingMapping.ShardMapId,
existingMapping.Shard.StoreShard.Location,
existingMapping.Shard.StoreShard.Status);
IStoreMapping mappingToRemove = new DefaultStoreMapping(
existingMapping.StoreMapping.Id,
existingMapping.StoreMapping.ShardMapId,
newShard,
existingMapping.StoreMapping.MinValue,
existingMapping.StoreMapping.MaxValue,
existingMapping.StoreMapping.Status,
existingMapping.StoreMapping.LockOwnerId);
IStoreMapping[] mappingsToAdd = new IStoreMapping[2]
{
new DefaultStoreMapping(
Guid.NewGuid(),
newShard.ShardMapId,
newShard,
existingMapping.Range.Low.RawValue,
shardKey.RawValue,
(int)existingMapping.Status,
lockOwnerId),
new DefaultStoreMapping(
Guid.NewGuid(),
newShard.ShardMapId,
newShard,
shardKey.RawValue,
existingMapping.Range.High.RawValue,
(int)existingMapping.Status,
lockOwnerId)
};
using (IStoreOperation op = this.Manager.StoreOperationFactory.CreateReplaceMappingsOperation(
this.Manager,
StoreOperationCode.SplitMapping,
this.ShardMap.StoreShardMap,
new[] { new Tuple <IStoreMapping, Guid>(mappingToRemove, lockOwnerId) },
mappingsToAdd.Select(mappingToAdd => new Tuple <IStoreMapping, Guid>(mappingToAdd, lockOwnerId)).ToArray()))
{
op.Do();
}
return(mappingsToAdd
.Select(m => new RangeMapping <TKey>(this.Manager, this.ShardMap, m))
.ToList()
.AsReadOnly());
}
/// <summary>
/// Finds all mappings to be purged based on the given input ranges.
/// </summary>
/// <param name="ts">LSM transaction scope.</param>
/// <returns>Mappings which are to be removed.</returns>
private IEnumerable <IStoreMapping> GetMappingsToPurge(IStoreTransactionScope ts)
{
IEnumerable <IStoreMapping> lsmMappings = null;
IStoreResults result;
if (_rangesToRemove == null)
{
// If no ranges are specified, get all the mappings for the shard.
result = ts.ExecuteOperation(
StoreOperationRequestBuilder.SpGetAllShardMappingsLocal,
StoreOperationRequestBuilder.GetAllShardMappingsLocal(_shardMap, _shard, null));
if (result.Result != StoreResult.Success)
{
// Possible errors are:
// StoreResult.ShardMapDoesNotExist
// StoreResult.StoreVersionMismatch
// StoreResult.MissingParametersForStoredProcedure
throw StoreOperationErrorHandler.OnRecoveryErrorLocal(
result,
_shardMap,
this.Location,
ShardManagementErrorCategory.Recovery,
this.OperationName,
StoreOperationRequestBuilder.SpGetAllShardMappingsLocal);
}
lsmMappings = result.StoreMappings;
}
else
{
// If any ranges are specified, only delete intersected ranges.
IDictionary <ShardRange, IStoreMapping> mappingsToPurge = new Dictionary <ShardRange, IStoreMapping>();
foreach (ShardRange range in _rangesToRemove)
{
switch (_shardMap.MapType)
{
case ShardMapType.Range:
result = ts.ExecuteOperation(
StoreOperationRequestBuilder.SpGetAllShardMappingsLocal,
StoreOperationRequestBuilder.GetAllShardMappingsLocal(
_shardMap,
_shard,
range));
break;
default:
Debug.Assert(_shardMap.MapType == ShardMapType.List);
result = ts.ExecuteOperation(
StoreOperationRequestBuilder.SpFindShardMappingByKeyLocal,
StoreOperationRequestBuilder.FindShardMappingByKeyLocal(
_shardMap,
ShardKey.FromRawValue(_shardMap.KeyType, range.Low.RawValue)));
break;
}
if (result.Result != StoreResult.Success)
{
if (result.Result != StoreResult.MappingNotFoundForKey)
{
// Possible errors are:
// StoreResult.ShardMapDoesNotExist
// StoreResult.StoreVersionMismatch
// StoreResult.MissingParametersForStoredProcedure
throw StoreOperationErrorHandler.OnRecoveryErrorLocal(
result,
_shardMap,
this.Location,
ShardManagementErrorCategory.Recovery,
this.OperationName,
_shardMap.MapType == ShardMapType.Range ?
StoreOperationRequestBuilder.SpGetAllShardMappingsLocal :
StoreOperationRequestBuilder.SpFindShardMappingByKeyLocal);
}
else
{
// No intersections being found is fine. Skip to the next mapping.
Debug.Assert(_shardMap.MapType == ShardMapType.List);
}
}
else
{
foreach (IStoreMapping mapping in result.StoreMappings)
{
ShardRange intersectedRange = new ShardRange(
ShardKey.FromRawValue(_shardMap.KeyType, mapping.MinValue),
ShardKey.FromRawValue(_shardMap.KeyType, mapping.MaxValue));
mappingsToPurge[intersectedRange] = mapping;
}
}
}
lsmMappings = mappingsToPurge.Values;
}
return(lsmMappings);
}
/// <summary>
/// Given a key value, asynchronously obtains a SqlConnection to the shard in the mapping
/// that contains the key value.
/// </summary>
/// <typeparam name="TMapping">Mapping type.</typeparam>
/// <typeparam name="TKey">Key type.</typeparam>
/// <param name="key">Input key value.</param>
/// <param name="constructMapping">Delegate to construct a mapping object.</param>
/// <param name="errorCategory">Error category.</param>
/// <param name="connectionString">
/// Connection string with credential information, the DataSource and Database are
/// obtained from the results of the lookup operation for key.
/// </param>
/// <param name="secureCredential">Secure SQL Credential.</param>
/// <param name="options">Options for validation operations to perform on opened connection.</param>
/// <returns>A task encapsulating an opened SqlConnection as the result.</returns>
protected async Task <SqlConnection> OpenConnectionForKeyAsync <TMapping, TKey>(
TKey key,
Func <ShardMapManager, ShardMap, IStoreMapping, TMapping> constructMapping,
ShardManagementErrorCategory errorCategory,
string connectionString,
SqlCredential secureCredential,
ConnectionOptions options = ConnectionOptions.Validate) where TMapping : class, IShardProvider
{
ShardKey sk = new ShardKey(ShardKey.ShardKeyTypeFromType(typeof(TKey)), key);
// Try to find the mapping within the cache.
ICacheStoreMapping csm = this.Manager.Cache.LookupMappingByKey(this.ShardMap.StoreShardMap, sk);
IStoreMapping sm;
if (csm != null)
{
sm = csm.Mapping;
}
else
{
sm = await this.LookupMappingForOpenConnectionForKeyAsync(
sk,
CacheStoreMappingUpdatePolicy.OverwriteExisting,
errorCategory).ConfigureAwait(false);
}
SqlConnection result;
bool lookupMappingOnEx = false;
CacheStoreMappingUpdatePolicy cacheUpdatePolicyOnEx = CacheStoreMappingUpdatePolicy.OverwriteExisting;
try
{
// Initially attempt to connect based on lookup results from either cache or GSM.
result = await this.ShardMap.OpenConnectionAsync(
constructMapping(this.Manager, this.ShardMap, sm),
connectionString,
secureCredential,
options).ConfigureAwait(false);
csm.ResetTimeToLiveIfNecessary();
return(result);
}
catch (ShardManagementException smme)
{
// If we hit a validation failure due to stale version of mapping, we will perform one more attempt.
if (((options & ConnectionOptions.Validate) == ConnectionOptions.Validate) &&
smme.ErrorCategory == ShardManagementErrorCategory.Validation &&
smme.ErrorCode == ShardManagementErrorCode.MappingDoesNotExist)
{
// Assumption here is that this time the attempt should succeed since the cache entry
// has already been either evicted, or updated based on latest data from the server.
lookupMappingOnEx = true;
cacheUpdatePolicyOnEx = CacheStoreMappingUpdatePolicy.OverwriteExisting;
}
else
{
// The error was not due to validation but something else e.g.
// 1) Shard map does not exist
// 2) Mapping could not be found.
throw;
}
}
catch (SqlException)
{
// We failed to connect. If we were trying to connect from an entry in cache and mapping expired in cache.
if (csm != null && csm.HasTimeToLiveExpired())
{
using (IdLock _idLock = new IdLock(csm.Mapping.StoreShard.Id))
{
// Similar to DCL pattern, we need to refresh the mapping again to see if we still need to go to the store
// to lookup the mapping after acquiring the shard lock. It might be the case that a fresh version has already
// been obtained by some other thread.
csm = this.Manager.Cache.LookupMappingByKey(this.ShardMap.StoreShardMap, sk);
// Only go to store if the mapping is stale even after refresh.
if (csm == null || csm.HasTimeToLiveExpired())
{
// Refresh the mapping in cache. And try to open the connection after refresh.
lookupMappingOnEx = true;
cacheUpdatePolicyOnEx = CacheStoreMappingUpdatePolicy.UpdateTimeToLive;
}
else
{
sm = csm.Mapping;
}
}
}
else
{
// Either:
// 1) The mapping is still within the TTL. No refresh.
// 2) Mapping was not in cache, we originally did a lookup for mapping in GSM and even then could not connect.
throw;
}
}
if (lookupMappingOnEx)
{
sm = await this.LookupMappingForOpenConnectionForKeyAsync(
sk,
cacheUpdatePolicyOnEx,
errorCategory).ConfigureAwait(false);
}
// One last attempt to open the connection after a cache refresh
result = await this.ShardMap.OpenConnectionAsync(
constructMapping(this.Manager, this.ShardMap, sm),
connectionString,
secureCredential,
options).ConfigureAwait(false);
// Reset TTL on successful connection.
csm.ResetTimeToLiveIfNecessary();
return(result);
}
