/// <summary>
/// Initializes this instance.
/// </summary>
protected override void Initialize()
{
var sw = new Stopwatch();
sw.Start();
_options.Validate();
SendMessage("Setting up left and right sides of the join");
// Abstract:
//
// The current built-in join infrastructure is very naive as it uses nested
// loops. Being a O(m*n) operation, the slowdown becomes readily apparent
// as the size of the data you're working with increases. As such, the
// current infrastructure is woefully inadequate for large datasets.
//
// How can we fix this problem? We could try to implement various join
// algorithms for different scenarios, which would be a laborious exercise
// in itself.
//
// Or, we can just delegate this problem to the universal swiss army-knife of
// databases, SQLite.
//
// SQLite has many things going for it, including:
// - Support for common types of joins (important!)
// - LIGHTING FAST insert performance. The current FdoInputOperation is already optimised for SQLite
// - LIGHTING FAST read performance
// - Ability to use SQL to modify the database internals, such as creating indexes (FDO provider supports SQL commands)
//
// As such, SQLite is the perfect candidate for a temp data store to merge two
// disparate data sources. The time spent setting up this temp SQLite database (ie. Copying "left" and
// "right" side data into it) is negligible in the grand scheme of things.
//
// Process Overview:
//
// 1. Create temp SQLite database
// 2. Pump left and right sides into this database
// 3. Create indexes on join columns of both tables (IMPORTANT)
// 4. Create a view encapsulating our join
// 5. Copy this view out to our target
//
// Additional Notes:
//
// We will have to change our supported join types to line up with what SQLite supports, which
// are:
// - INNER JOIN
// - LEFT OUTER JOIN
//
// SQLite does not support RIGHT OUTER JOINs but these could be emulated by inverting the
// "left" and "right" tables for the LEFT OUTER JOIN. FULL OUTER JOIN is not supporte by
// SQLite so this will be removed from our API.
//
// Since this SQLite database is temporary, we don't bother with putting
// the right spatial context in there. Spatial contexts do not (should not) affect
// the underlying coordinates of any geometries moving to and from the data store.
//
// SQLite views by default are represented as non-Feature classes. Geometry properties
// default to BLOB data types. To "fix" this we need to add a new entry to the geometry_columns
// metadata table. This may produce an incorrect feature class (ie. Has 1-n geometry properties
// but no designated one), this is okay as we only care that the properties are there and the
// temp-target property mappings check out.
//
// Although the implementation will change, the requirements remain the same, which are:
//
// 1. The target class must not already exist (as it will be created)
// 2. If no designated geometry is specified, then the class definition will be FdoClass and not FdoFeatureClass
ClassDefinition leftCls = null;
ClassDefinition rightCls = null;
ClassDefinition mergedCls = null;
using (var leftSvc = _options.Left.Connection.CreateFeatureService())
using (var rightSvc = _options.Right.Connection.CreateFeatureService())
{
leftCls = leftSvc.GetClassByName(_options.Left.SchemaName, _options.Left.ClassName);
rightCls = rightSvc.GetClassByName(_options.Right.SchemaName, _options.Right.ClassName);
if (leftCls == null)
{
throw new FdoETLException("Left class not found " + _options.Left.SchemaName + ":" + _options.Left.ClassName);
}
if (rightCls == null)
{
throw new FdoETLException("Right class not found " + _options.Right.SchemaName + ":" + _options.Right.ClassName);
}
var leftJoinProps = new List <string>(_options.JoinPairs.AllKeys);
var rightJoinProps = new List <string>();
foreach (var p in leftJoinProps)
{
rightJoinProps.Add(_options.JoinPairs[p]);
}
var leftGeom = (!string.IsNullOrEmpty(_options.GeometryProperty) && _options.Side == JoinSide.Left) ? _options.GeometryProperty : null;
var rightGeom = (!string.IsNullOrEmpty(_options.GeometryProperty) && _options.Side == JoinSide.Right) ? _options.GeometryProperty : null;
PrepareClass(leftCls, _options.LeftProperties, leftJoinProps, _options.LeftPrefix, leftGeom);
PrepareClass(rightCls, _options.RightProperties, rightJoinProps, _options.RightPrefix, rightGeom);
mergedCls = CreateMergedClass(leftCls, rightCls);
}
var dprops = new NameValueCollection();
dprops["File"] = Path.GetTempFileName();
var tempSchema = new FeatureSchema("Default", "");
var leftCopy = FdoSchemaUtil.CloneClass(leftCls);
var rightCopy = FdoSchemaUtil.CloneClass(rightCls);
string leftClassName = "LEFT_SIDE";
string rightClassName = "RIGHT_SIDE";
leftCopy.Name = leftClassName;
rightCopy.Name = rightClassName;
tempSchema.Classes.Add(leftCopy);
tempSchema.Classes.Add(rightCopy);
//Create SQLite database
Register(new FdoCreateDataStoreOperation("OSGeo.SQLite", dprops, null));
//Apply temp schema
var tempConn = new FdoConnection("OSGeo.SQLite", "File=" + dprops["File"]);
Register(new FdoApplySchemaOperation(tempConn, tempSchema));
#if DEBUG
Register(new FdoSingleActionOperation(() => { SendMessage("Temp db created in: " + dprops["File"]); }));
#endif
//Prep property mappings for bulk copy
var leftMaps = new NameValueCollection();
var rightMaps = new NameValueCollection();
var leftQuery = new FeatureQueryOptions(leftCls.Name);
var rightQuery = new FeatureQueryOptions(rightCls.Name);
foreach (var leftp in _options.LeftProperties)
{
if (string.IsNullOrEmpty(_options.LeftPrefix))
{
leftMaps.Add(leftp, leftp);
}
else
{
leftMaps.Add(leftp, _options.LeftPrefix + leftp);
}
leftQuery.AddFeatureProperty(leftp);
}
foreach (var rightp in _options.RightProperties)
{
if (string.IsNullOrEmpty(_options.RightPrefix))
{
rightMaps.Add(rightp, rightp);
}
else
{
rightMaps.Add(rightp, _options.RightPrefix + rightp);
}
rightQuery.AddFeatureProperty(rightp);
}
if (!string.IsNullOrEmpty(_options.LeftFilter))
{
leftQuery.Filter = _options.LeftFilter;
}
if (!string.IsNullOrEmpty(_options.RightFilter))
{
rightQuery.Filter = _options.RightFilter;
}
//don't forget join keys
foreach (string l in _options.JoinPairs.Keys)
{
string r = _options.JoinPairs[l];
if (!_options.LeftProperties.Contains(l))
{
leftQuery.AddFeatureProperty(l);
if (string.IsNullOrEmpty(_options.LeftPrefix))
{
leftMaps.Add(l, l);
}
else
{
leftMaps.Add(l, _options.LeftPrefix + l);
}
}
if (!_options.RightProperties.Contains(r))
{
rightQuery.AddFeatureProperty(r);
if (string.IsNullOrEmpty(_options.RightPrefix))
{
rightMaps.Add(r, r);
}
else
{
rightMaps.Add(r, _options.RightPrefix + r);
}
}
}
//don't forget geometry!
if (!string.IsNullOrEmpty(_options.GeometryProperty))
{
if (_options.Side == JoinSide.Left)
{
if (!leftQuery.PropertyList.Contains(_options.GeometryProperty))
{
leftQuery.AddFeatureProperty(_options.GeometryProperty);
if (string.IsNullOrEmpty(_options.LeftPrefix))
{
leftMaps.Add(_options.GeometryProperty, _options.GeometryProperty);
}
else
{
leftMaps.Add(_options.GeometryProperty, _options.LeftPrefix + _options.GeometryProperty);
}
}
}
else
{
if (!rightQuery.PropertyList.Contains(_options.GeometryProperty))
{
rightQuery.AddFeatureProperty(_options.GeometryProperty);
if (string.IsNullOrEmpty(_options.RightPrefix))
{
rightMaps.Add(_options.GeometryProperty, _options.GeometryProperty);
}
else
{
rightMaps.Add(_options.GeometryProperty, _options.RightPrefix + _options.GeometryProperty);
}
}
}
}
var copyLeftErrors = new List <Exception>();
var copyRightErrors = new List <Exception>();
var copyTargetErrors = new List <Exception>();
//Copy left source
ParameterlessAction copyLeft = () =>
{
SendMessage("Copying left source with filter: " + _options.LeftFilter);
var copy = ExpressUtility.CreateBulkCopy(
_options.Left.Connection,
tempConn,
_options.Left.SchemaName,
leftQuery,
tempSchema.Name, //temp sqlite schema name
leftClassName, //sqlite "left" class name
leftMaps);
copy.ProcessMessage += delegate(object sender, MessageEventArgs e)
{
SendMessage(e.Message);
};
copy.Execute();
copyLeftErrors.AddRange(copy.GetAllErrors());
};
Register(new FdoSingleActionOperation(copyLeft));
//Register(new FdoInputOperation(_options.Left.Connection, leftQuery));
//Register(new FdoOutputOperation(tempConn, leftClassName, leftMaps));
//Copy right source
ParameterlessAction copyRight = () =>
{
SendMessage("Copying right source with filter: " + _options.RightFilter);
var copy = ExpressUtility.CreateBulkCopy(
_options.Right.Connection,
tempConn,
_options.Right.SchemaName,
rightQuery,
tempSchema.Name, //temp sqlite schema name
rightClassName, //sqlite "right" class name
rightMaps);
copy.ProcessMessage += delegate(object sender, MessageEventArgs e)
{
SendMessage(e.Message);
};
copy.Execute();
copyRightErrors.AddRange(copy.GetAllErrors());
};
Register(new FdoSingleActionOperation(copyRight));
//Register(new FdoInputOperation(_options.Right.Connection, rightQuery));
//Register(new FdoOutputOperation(tempConn, rightClassName, rightMaps));
string srcClass = "VIEW_INPUT";
//Create indexes on left and right sides to optimize read performance
ParameterlessAction indexLeft = () =>
{
using (var svc = tempConn.CreateFeatureService())
{
SendMessage("Creating left side index in temp db");
string sql = "CREATE INDEX IDX_LEFT_ID ON " + leftClassName + "(";
var tokens = new List <string>();
foreach (string p in _options.JoinPairs.Keys)
{
if (!string.IsNullOrEmpty(_options.LeftPrefix))
{
tokens.Add(_options.LeftPrefix + p);
}
else
{
tokens.Add(p);
}
}
sql = sql + string.Join(", ", tokens.ToArray()) + ")";
SendMessage("Executing SQL: " + sql);
svc.ExecuteSQLNonQuery(sql);
}
};
ParameterlessAction indexRight = () =>
{
using (var svc = tempConn.CreateFeatureService())
{
SendMessage("Creating right side index in temp db");
string sql = "CREATE INDEX IDX_RIGHT_ID ON " + rightClassName + "(";
var tokens = new List <string>();
foreach (string p in _options.JoinPairs.Keys)
{
string prop = _options.JoinPairs[p];
if (!string.IsNullOrEmpty(_options.RightPrefix))
{
tokens.Add(_options.RightPrefix + prop);
}
else
{
tokens.Add(prop);
}
}
sql = sql + string.Join(", ", tokens.ToArray()) + ")";
SendMessage("Executing SQL: " + sql);
svc.ExecuteSQLNonQuery(sql);
}
};
Register(new FdoSingleActionOperation(indexLeft));
Register(new FdoSingleActionOperation(indexRight));
//Create view
ParameterlessAction createView = () =>
{
using (var svc = tempConn.CreateFeatureService())
{
SendMessage("Creating view in temp db");
StringBuilder sql = new StringBuilder("CREATE VIEW ");
sql.Append(srcClass + " AS SELECT ");
foreach (var p in _options.LeftProperties)
{
if (!string.IsNullOrEmpty(_options.LeftPrefix))
{
sql.Append("l." + _options.LeftPrefix + p + ", ");
}
else
{
sql.Append("l." + p + ", ");
}
}
if (!string.IsNullOrEmpty(_options.GeometryProperty))
{
if (_options.Side == JoinSide.Left)
{
if (!_options.LeftProperties.Contains(_options.GeometryProperty))
{
if (!string.IsNullOrEmpty(_options.LeftPrefix))
{
sql.Append("l." + _options.LeftPrefix + _options.GeometryProperty + ", ");
}
else
{
sql.Append("l." + _options.GeometryProperty + ", ");
}
}
}
else
{
if (!_options.RightProperties.Contains(_options.GeometryProperty))
{
if (!string.IsNullOrEmpty(_options.RightPrefix))
{
sql.Append("r." + _options.RightPrefix + _options.GeometryProperty + ", ");
}
else
{
sql.Append("r." + _options.GeometryProperty + ", ");
}
}
}
}
int rc = _options.RightProperties.Count;
int i = 0;
foreach (var p in _options.RightProperties)
{
string pn = p;
if (!string.IsNullOrEmpty(_options.RightPrefix))
{
pn = _options.RightPrefix + pn;
}
if (i == rc - 1)
{
sql.Append("r." + pn + " FROM ");
}
else
{
sql.Append("r." + pn + ", ");
}
i++;
}
sql.Append(leftClassName + " l ");
switch (_options.JoinType)
{
case FdoJoinType.Inner:
sql.Append("INNER JOIN " + rightClassName + " r ON ");
break;
case FdoJoinType.Left:
sql.Append("LEFT OUTER JOIN " + rightClassName + " r ON ");
break;
default:
throw new FdoETLException("Unsupported join type: " + _options.JoinType);
}
rc = _options.JoinPairs.Count;
i = 0;
foreach (string l in _options.JoinPairs.Keys)
{
string r = _options.JoinPairs[l];
string left = l;
string right = r;
if (!string.IsNullOrEmpty(_options.LeftPrefix))
{
left = _options.LeftPrefix + left;
}
if (!string.IsNullOrEmpty(_options.RightPrefix))
{
right = _options.RightPrefix + right;
}
if (i == rc - 1)
{
sql.Append("l." + left + " = r." + right);
}
else
{
sql.Append("l." + left + " = r." + right + " AND ");
}
i++;
}
SendMessage("Executing SQL: " + sql.ToString());
svc.ExecuteSQLNonQuery(sql.ToString());
}
};
Register(new FdoSingleActionOperation(createView));
//Hack FDO metadata to make this a feature class
if (!string.IsNullOrEmpty(_options.GeometryProperty))
{
ParameterlessAction reg = () =>
{
using (var svc = tempConn.CreateFeatureService())
{
SendMessage("Exposing view as a FDO feature class");
string sql = "INSERT INTO geometry_columns(f_table_name, f_geometry_column, geometry_type, geometry_dettype, coord_dimension, srid, geometry_format) VALUES('" + srcClass + "','" + _options.GeometryProperty + "',15,7743,0,0,'FGF')";
SendMessage("Executing SQL: " + sql.ToString());
svc.ExecuteSQLNonQuery(sql);
}
};
Register(new FdoSingleActionOperation(reg));
}
//Copy view to target
ParameterlessAction applyTarget = () =>
{
using (var svc = _options.Target.Connection.CreateFeatureService())
{
SendMessage("Fetching target schema");
var schema = svc.GetSchemaByName(_options.Target.SchemaName);
IncompatibleClass cls;
if (!svc.CanApplyClass(mergedCls, out cls))
{
SendMessage("Fixing incompatibilities in merged class");
mergedCls = svc.AlterClassDefinition(mergedCls, cls);
}
SendMessage("Adding merged class to target schema");
schema.Classes.Add(mergedCls);
SendMessage("Applying modified target schema");
svc.ApplySchema(schema);
}
};
Register(new FdoSingleActionOperation(applyTarget));
var tempQuery = new FeatureQueryOptions("VIEW_INPUT");
var targetMapping = new NameValueCollection();
foreach (PropertyDefinition p in mergedCls.Properties)
{
tempQuery.AddFeatureProperty(p.Name);
//Target class is a replica of the temp one, so all properties
//have the same name in both source and target
targetMapping[p.Name] = p.Name;
}
ParameterlessAction copyToTarget = () =>
{
var copy = ExpressUtility.CreateBulkCopy(
tempConn,
_options.Target.Connection,
tempSchema.Name,
tempQuery,
_options.Target.SchemaName,
_options.Target.ClassName,
targetMapping);
copy.ProcessMessage += delegate(object sender, MessageEventArgs e)
{
SendMessage(e.Message);
};
copy.Execute();
copyTargetErrors.AddRange(copy.GetAllErrors());
sw.Stop();
};
Register(new FdoSingleActionOperation(copyToTarget));
//Log all errors
ParameterlessAction logErrors = () =>
{
SendMessage(copyLeftErrors.Count + " errors encountered copying left source to temp db");
_allErrors.AddRange(copyLeftErrors);
SendMessage(copyRightErrors.Count + " errors encountered copying right source to temp db");
_allErrors.AddRange(copyRightErrors);
SendMessage(copyTargetErrors.Count + " errors encountered copying merged source to target");
_allErrors.AddRange(copyTargetErrors);
SendMessage("Join Operation completed in " + sw.Elapsed.ToString());
};
Register(new FdoSingleActionOperation(logErrors));
}
public FdoSingleActionOperation(ParameterlessAction action)
{
_action = action;
}
public FdoSingleActionOperation(ParameterlessAction action)
{
_action = action;
}