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Change _SqlMetaData to lazy initialize hidden column map (#521)
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@Wraith2
Wraith2 authored Aug 7, 2020
1 parent 4f04db7 commit cc9ddb5
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Showing 5 changed files with 164 additions and 55 deletions.
6 changes: 1 addition & 5 deletions ...osoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/AlwaysEncryptedHelperClasses.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -234,13 +234,9 @@ sealed internal partial class _SqlMetaDataSet
internal readonly SqlTceCipherInfoTable? cekTable; // table of "column encryption keys" used for this metadataset

internal _SqlMetaDataSet(int count, SqlTceCipherInfoTable? cipherTable)
: this(count)
{
cekTable = cipherTable;
_metaDataArray = new _SqlMetaData[count];
for (int i = 0; i < _metaDataArray.Length; ++i)
{
_metaDataArray[i] = new _SqlMetaData(i);
}
}
}

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52 changes: 18 additions & 34 deletions src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/SqlDataReader.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -276,8 +276,8 @@ internal virtual SmiExtendedMetaData[] GetInternalSmiMetaData()

if (null != metaData && 0 < metaData.Length)
{
metaDataReturn = new SmiExtendedMetaData[metaData.visibleColumns];

metaDataReturn = new SmiExtendedMetaData[metaData.VisibleColumnCount];
int returnIndex = 0;
for (int index = 0; index < metaData.Length; index++)
{
_SqlMetaData colMetaData = metaData[index];
Expand Down Expand Up @@ -316,7 +316,7 @@ internal virtual SmiExtendedMetaData[] GetInternalSmiMetaData()
length /= ADP.CharSize;
}

metaDataReturn[index] =
metaDataReturn[returnIndex] =
new SmiQueryMetaData(
colMetaData.type,
length,
Expand Down Expand Up @@ -344,6 +344,8 @@ internal virtual SmiExtendedMetaData[] GetInternalSmiMetaData()
colMetaData.IsExpression,
colMetaData.IsDifferentName,
colMetaData.IsHidden);

returnIndex += 1;
}
}
}
Expand Down Expand Up @@ -406,7 +408,7 @@ override public int VisibleFieldCount
{
return 0;
}
return (md.visibleColumns);
return md.VisibleColumnCount;
}
}

Expand Down Expand Up @@ -1141,31 +1143,6 @@ private bool TryConsumeMetaData()
Debug.Assert(!ignored, "Parser read a row token while trying to read metadata");
}

// we hide hidden columns from the user so build an internal map
// that compacts all hidden columns from the array
if (null != _metaData)
{
if (_snapshot != null && object.ReferenceEquals(_snapshot._metadata, _metaData))
{
_metaData = (_SqlMetaDataSet)_metaData.Clone();
}

_metaData.visibleColumns = 0;

Debug.Assert(null == _metaData.indexMap, "non-null metaData indexmap");
int[] indexMap = new int[_metaData.Length];
for (int i = 0; i < indexMap.Length; ++i)
{
indexMap[i] = _metaData.visibleColumns;

if (!(_metaData[i].IsHidden))
{
_metaData.visibleColumns++;
}
}
_metaData.indexMap = indexMap;
}

return true;
}

Expand Down Expand Up @@ -2621,11 +2598,11 @@ virtual public int GetSqlValues(object[] values)

SetTimeout(_defaultTimeoutMilliseconds);

int copyLen = (values.Length < _metaData.visibleColumns) ? values.Length : _metaData.visibleColumns;
int copyLen = (values.Length < _metaData.VisibleColumnCount) ? values.Length : _metaData.VisibleColumnCount;

for (int i = 0; i < copyLen; i++)
{
values[_metaData.indexMap[i]] = GetSqlValueInternal(i);
values[i] = GetSqlValueInternal(_metaData.GetVisibleColumnIndex(i));
}
return copyLen;
}
Expand Down Expand Up @@ -2964,7 +2941,7 @@ override public int GetValues(object[] values)

CheckMetaDataIsReady();

int copyLen = (values.Length < _metaData.visibleColumns) ? values.Length : _metaData.visibleColumns;
int copyLen = (values.Length < _metaData.VisibleColumnCount) ? values.Length : _metaData.VisibleColumnCount;
int maximumColumn = copyLen - 1;

SetTimeout(_defaultTimeoutMilliseconds);
Expand All @@ -2982,12 +2959,19 @@ override public int GetValues(object[] values)
for (int i = 0; i < copyLen; i++)
{
// Get the usable, TypeSystem-compatible value from the internal buffer
values[_metaData.indexMap[i]] = GetValueFromSqlBufferInternal(_data[i], _metaData[i]);
int fieldIndex = _metaData.GetVisibleColumnIndex(i);
values[i] = GetValueFromSqlBufferInternal(_data[fieldIndex], _metaData[fieldIndex]);

// If this is sequential access, then we need to wipe the internal buffer
if ((sequentialAccess) && (i < maximumColumn))
{
_data[i].Clear();
_data[fieldIndex].Clear();
if (fieldIndex > i && fieldIndex>0)
{
// if we jumped an index forward because of a hidden column see if the buffer before the
// current one was populated by the seek forward and clear it if it was
_data[fieldIndex - 1].Clear();
}
}
}

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6 changes: 0 additions & 6 deletions src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/TdsParser.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -4447,7 +4447,6 @@ internal bool TryProcessAltMetaData(int cColumns, TdsParserStateObject stateObj,
metaData = null;

_SqlMetaDataSet altMetaDataSet = new _SqlMetaDataSet(cColumns, null);
int[] indexMap = new int[cColumns];

if (!stateObj.TryReadUInt16(out altMetaDataSet.id))
{
Expand Down Expand Up @@ -4491,13 +4490,8 @@ internal bool TryProcessAltMetaData(int cColumns, TdsParserStateObject stateObj,
{
return false;
}

indexMap[i] = i;
}

altMetaDataSet.indexMap = indexMap;
altMetaDataSet.visibleColumns = cColumns;

metaData = altMetaDataSet;
return true;
}
Expand Down
78 changes: 68 additions & 10 deletions src/Microsoft.Data.SqlClient/netcore/src/Microsoft/Data/SqlClient/TdsParserHelperClasses.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -542,14 +542,17 @@ public object Clone()
internal sealed partial class _SqlMetaDataSet
{
internal ushort id; // for altrow-columns only
internal int[] indexMap;
internal int visibleColumns;

internal DataTable schemaTable;
private readonly _SqlMetaData[] _metaDataArray;
internal ReadOnlyCollection<DbColumn> dbColumnSchema;

private int _hiddenColumnCount;
private int[] _visibleColumnMap;

internal _SqlMetaDataSet(int count)
{
_hiddenColumnCount = -1;
_metaDataArray = new _SqlMetaData[count];
for (int i = 0; i < _metaDataArray.Length; ++i)
{
Expand All @@ -559,11 +562,10 @@ internal _SqlMetaDataSet(int count)

private _SqlMetaDataSet(_SqlMetaDataSet original)
{
this.id = original.id;
// although indexMap is not immutable, in practice it is initialized once and then passed around
this.indexMap = original.indexMap;
this.visibleColumns = original.visibleColumns;
this.dbColumnSchema = original.dbColumnSchema;
id = original.id;
_hiddenColumnCount = original._hiddenColumnCount;
_visibleColumnMap = original._visibleColumnMap;
dbColumnSchema = original.dbColumnSchema;
if (original._metaDataArray == null)
{
_metaDataArray = null;
Expand All @@ -586,6 +588,18 @@ internal int Length
}
}

internal int VisibleColumnCount
{
get
{
if (_hiddenColumnCount == -1)
{
SetupHiddenColumns();
}
return Length - _hiddenColumnCount;
}
}

internal _SqlMetaData this[int index]
{
get
Expand All @@ -599,10 +613,54 @@ internal _SqlMetaData this[int index]
}
}

public object Clone()
public int GetVisibleColumnIndex(int index)
{
if (_hiddenColumnCount == -1)
{
SetupHiddenColumns();
}
if (_visibleColumnMap is null)
{
return index;
}
else
{
return _visibleColumnMap[index];
}
}

public _SqlMetaDataSet Clone()
{
return new _SqlMetaDataSet(this);
}

private void SetupHiddenColumns()
{
int hiddenColumnCount = 0;
for (int index = 0; index < Length; index++)
{
if (_metaDataArray[index].IsHidden)
{
hiddenColumnCount += 1;
}
}

if (hiddenColumnCount > 0)
{
int[] visibleColumnMap = new int[Length - hiddenColumnCount];
int mapIndex = 0;
for (int metaDataIndex = 0; metaDataIndex < Length; metaDataIndex++)
{
if (!_metaDataArray[metaDataIndex].IsHidden)
{
visibleColumnMap[mapIndex] = metaDataIndex;
mapIndex += 1;
}
}
_visibleColumnMap = visibleColumnMap;
}
_hiddenColumnCount = hiddenColumnCount;
}
}

internal sealed class _SqlMetaDataSetCollection
Expand Down Expand Up @@ -649,10 +707,10 @@ internal _SqlMetaDataSet GetAltMetaData(int id)
public object Clone()
{
_SqlMetaDataSetCollection result = new _SqlMetaDataSetCollection();
result.metaDataSet = metaDataSet == null ? null : (_SqlMetaDataSet)metaDataSet.Clone();
result.metaDataSet = metaDataSet == null ? null : metaDataSet.Clone();
foreach (_SqlMetaDataSet set in _altMetaDataSetArray)
{
result._altMetaDataSetArray.Add((_SqlMetaDataSet)set.Clone());
result._altMetaDataSetArray.Add(set.Clone());
}
return result;
}
Expand Down
77 changes: 77 additions & 0 deletions src/Microsoft.Data.SqlClient/tests/ManualTests/SQL/DataReaderTest/DataReaderTest.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -2,6 +2,7 @@
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

using System;
using System.Collections.Generic;
using System.Data;
using System.Text;
Expand Down Expand Up @@ -225,5 +226,81 @@ private static bool IsColumnBitSet(SqlConnection con, string selectQuery, int in
}
return columnSetPresent;
}

[ConditionalFact(typeof(DataTestUtility), nameof(DataTestUtility.AreConnStringsSetup))]
public static void CheckHiddenColumns()
{
// hidden columns can be found by using CommandBehavior.KeyInfo or at the sql level
// by using the FOR BROWSE option. These features return the column information requested and
// also include any key information required to be able to find the row containing the data
// requested. The additional key information is provided as hidden columns and can be seen using
// the difference between VisibleFieldCount and FieldCount on the reader

string tempTableName = DataTestUtility.GenerateObjectName();

string createQuery = $@"
create table [{tempTableName}] (
user_id int not null identity(1,1),
first_name varchar(100) null,
last_name varchar(100) null);
alter table [{tempTableName}] add constraint pk_{tempTableName}_user_id primary key (user_id);
insert into [{tempTableName}] (first_name,last_name) values ('Joe','Smith')
";

string dataQuery = $@"select first_name, last_name from [{tempTableName}]";


int fieldCount = 0;
int visibleFieldCount = 0;
Type[] types = null;
string[] names = null;

using (SqlConnection connection = new SqlConnection(DataTestUtility.TCPConnectionString))
{
connection.Open();

try
{
using (SqlCommand createCommand = new SqlCommand(createQuery, connection))
{
createCommand.ExecuteNonQuery();
}

using (SqlCommand queryCommand = new SqlCommand(dataQuery, connection))
{
using (SqlDataReader reader = queryCommand.ExecuteReader(CommandBehavior.KeyInfo))
{
fieldCount = reader.FieldCount;
visibleFieldCount = reader.VisibleFieldCount;
types = new Type[fieldCount];
names = new string[fieldCount];
for (int index = 0; index < fieldCount; index++)
{
types[index] = reader.GetFieldType(index);
names[index] = reader.GetName(index);
}
}
}
}
finally
{
DataTestUtility.DropTable(connection, tempTableName);
}
}

Assert.Equal(3, fieldCount);
Assert.Equal(2, visibleFieldCount);
Assert.NotNull(types);
Assert.NotNull(names);

// requested fields
Assert.Contains("first_name", names, StringComparer.Ordinal);
Assert.Contains("last_name", names, StringComparer.Ordinal);

// hidden field
Assert.Contains("user_id", names, StringComparer.Ordinal);
}
}
}

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