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Commit 7053c56f authored by unknown's avatar unknown
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Rewrite of the schema-change handling; the "see if it errors, then recalc" is,... 

Rewrite of the schema-change handling; the "see if it errors, then recalc" is, it turns out, stupid.
parent b8dedd0e
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Showing with 89 additions and 66 deletions
Dapper/SqlMapper.cs
View file @ 7053c56f
......@@ -118,13 +118,40 @@ private Link(TKey key, TValue value, Link<TKey, TValue> tail)
}
class CacheInfo
{
public Func<IDataReader, object> Deserializer { get; set; }
public DeserializerState Deserializer { get; set; }
public Func<IDataReader, object>[] OtherDeserializers { get; set; }
public Action<IDbCommand, object> ParamReader { get; set; }
private int hitCount;
public int GetHitCount() { return Interlocked.CompareExchange(ref hitCount, 0, 0); }
public void RecordHit() { Interlocked.Increment(ref hitCount); }
}
static int GetColumnHash(IDataReader reader)
{
unchecked
{
int colCount = reader.FieldCount, hash = colCount;
for (int i = 0; i < colCount; i++)
{
object tmp = reader.GetName(i);
hash = (hash * 31) + (tmp == null ? 0 : tmp.GetHashCode());
reader.GetFieldType(i);
hash = (hash * 31) + (tmp == null ? 0 : tmp.GetHashCode());
}
return hash;
}
}
struct DeserializerState
{
public readonly int Hash;
public readonly Func<IDataReader, object> Func;
public DeserializerState(int hash, Func<IDataReader, object> func)
{
Hash = hash;
Func = func;
}
}
/// <summary>
/// Called if the query cache is purged via PurgeQueryCache
......@@ -580,34 +607,19 @@ private static IEnumerable<T> QueryInternal<T>(this IDbConnection cnn, string sq
{
using (var reader = cmd.ExecuteReader())
{
Func<Func<IDataReader, object>> cacheDeserializer = () =>
var tuple = info.Deserializer;
int hash = GetColumnHash(reader);
if (tuple.Func == null || tuple.Hash != hash)
{
info.Deserializer = GetDeserializer(typeof(T), reader, 0, -1, false);
tuple = info.Deserializer = new DeserializerState(hash, GetDeserializer(typeof(T), reader, 0, -1, false));
SetQueryCache(identity, info);
return info.Deserializer;
};
if (info.Deserializer == null)
{
cacheDeserializer();
}
var deserializer = info.Deserializer;
var func = tuple.Func;
while (reader.Read())
{
object next;
try
{
next = deserializer(reader);
}
catch (DataException)
{
// give it another shot, in case the underlying schema changed
deserializer = cacheDeserializer();
next = deserializer(reader);
}
yield return (T)next;
yield return (T)func(reader);
}
}
......@@ -747,40 +759,25 @@ class DontMap { }
ownedReader = ownedCommand.ExecuteReader();
reader = ownedReader;
}
Func<IDataReader, object> deserializer = null;
DeserializerState deserializer = default(DeserializerState);
Func<IDataReader, object>[] otherDeserializers = null;
Action cacheDeserializers = () =>
int hash = GetColumnHash(reader);
if ((deserializer = cinfo.Deserializer).Func == null || (otherDeserializers = cinfo.OtherDeserializers) == null || hash != deserializer.Hash)
{
var deserializers = GenerateDeserializers(new Type[] { typeof(TFirst), typeof(TSecond), typeof(TThird), typeof(TFourth), typeof(TFifth)}, splitOn, reader);
deserializer = cinfo.Deserializer = deserializers[0];
var deserializers = GenerateDeserializers(new Type[] { typeof(TFirst), typeof(TSecond), typeof(TThird), typeof(TFourth), typeof(TFifth) }, splitOn, reader);
deserializer = cinfo.Deserializer = new DeserializerState(hash, deserializers[0]);
otherDeserializers = cinfo.OtherDeserializers = deserializers.Skip(1).ToArray();
SetQueryCache(identity, cinfo);
};
if ((deserializer = cinfo.Deserializer) == null || (otherDeserializers = cinfo.OtherDeserializers) == null)
{
cacheDeserializers();
}
Func<IDataReader, TReturn> mapIt = GenerateMapper<TFirst, TSecond, TThird, TFourth, TFifth, TReturn>(deserializer, otherDeserializers, map);
Func<IDataReader, TReturn> mapIt = GenerateMapper<TFirst, TSecond, TThird, TFourth, TFifth, TReturn>(deserializer.Func, otherDeserializers, map);
if (mapIt != null)
{
while (reader.Read())
{
TReturn next;
try
{
next = mapIt(reader);
}
catch (DataException)
{
cacheDeserializers();
mapIt = GenerateMapper<TFirst, TSecond, TThird, TFourth, TFifth, TReturn>(deserializer, otherDeserializers, map);
next = mapIt(reader);
}
yield return next;
yield return mapIt(reader);
}
}
}
......@@ -1773,19 +1770,14 @@ public IEnumerable<T> Read<T>()
CacheInfo cache = GetCacheInfo(typedIdentity);
var deserializer = cache.Deserializer;
Func<Func<IDataReader, object>> deserializerGenerator = () =>
int hash = GetColumnHash(reader);
if (deserializer.Func == null || deserializer.Hash != hash)
{
deserializer = GetDeserializer(typeof(T), reader, 0, -1, false);
deserializer = new DeserializerState(hash, GetDeserializer(typeof(T), reader, 0, -1, false));
cache.Deserializer = deserializer;
return deserializer;
};
if (deserializer == null)
{
deserializer = deserializerGenerator();
}
consumed = true;
return ReadDeferred<T>(gridIndex, deserializer, typedIdentity, deserializerGenerator);
return ReadDeferred<T>(gridIndex, deserializer.Func, typedIdentity);
}
private IEnumerable<TReturn> MultiReadInternal<TFirst, TSecond, TThird, TFourth, TFifth, TReturn>(object func, string splitOn)
......@@ -1888,23 +1880,13 @@ public IEnumerable<T> Read<T>()
}
#endif
private IEnumerable<T> ReadDeferred<T>(int index, Func<IDataReader, object> deserializer, Identity typedIdentity, Func<Func<IDataReader, object>> deserializerGenerator)
private IEnumerable<T> ReadDeferred<T>(int index, Func<IDataReader, object> deserializer, Identity typedIdentity)
{
try
{
while (index == gridIndex && reader.Read())
{
object next;
try
{
next = deserializer(reader);
}
catch (DataException)
{
deserializer = deserializerGenerator();
next = deserializer(reader);
}
yield return (T)next;
yield return (T)deserializer(reader);
}
}
finally // finally so that First etc progresses things even when multiple rows
......
Tests/Tests.cs
View file @ 7053c56f
......@@ -1517,6 +1517,47 @@ public void TestCommandWithInheritedTransaction()
}
}
public void TestReaderWhenResultsChange()
{
try
{
connection.Execute("create table #ResultsChange (X int);create table #ResultsChange2 (Y int);insert #ResultsChange (X) values(1);insert #ResultsChange2 (Y) values(1);");
var obj1 = connection.Query<ResultsChangeType>("select * from #ResultsChange").Single();
obj1.X.IsEqualTo(1);
obj1.Y.IsEqualTo(0);
obj1.Z.IsEqualTo(0);
var obj2 = connection.Query<ResultsChangeType>("select * from #ResultsChange rc inner join #ResultsChange2 rc2 on rc2.Y=rc.X").Single();
obj2.X.IsEqualTo(1);
obj2.Y.IsEqualTo(1);
obj2.Z.IsEqualTo(0);
connection.Execute("alter table #ResultsChange add Z int null");
connection.Execute("update #ResultsChange set Z = 2");
var obj3 = connection.Query<ResultsChangeType>("select * from #ResultsChange").Single();
obj3.X.IsEqualTo(1);
obj3.Y.IsEqualTo(0);
obj3.Z.IsEqualTo(2);
var obj4 = connection.Query<ResultsChangeType>("select * from #ResultsChange rc inner join #ResultsChange2 rc2 on rc2.Y=rc.X").Single();
obj4.X.IsEqualTo(1);
obj4.Y.IsEqualTo(1);
obj4.Z.IsEqualTo(2);
} finally
{
connection.Execute("drop table #ResultsChange;drop table #ResultsChange2;");
}
}
class ResultsChangeType
{
public int X { get; set; }
public int Y { get; set; }
public int Z { get; set; }
}
class TransactedConnection : IDbConnection
{
IDbConnection _conn;
......
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