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Implement aggressive loading of object references via left joins

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This commit is contained in:
hns 2003-05-28 13:33:23 +00:00
parent 8b1fed03d3
commit 469399e972
4 changed files with 311 additions and 193 deletions
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44
src/helma/objectmodel/db/DbMapping.java
View file

@ -77,6 +77,9 @@ public final class DbMapping implements Updatable {
// Map of db columns by name
HashMap columnMap;
// Array of aggressively loaded references
Relation[] joins;
// pre-rendered select statement
String selectString = null;
String insertString = null;
@ -256,6 +259,7 @@ public final class DbMapping implements Updatable {
HashMap p2d = new HashMap();
HashMap d2p = new HashMap();
ArrayList joinList = new ArrayList();
for (Enumeration e = props.keys(); e.hasMoreElements();) {
String propName = (String) e.nextElement();
@ -293,6 +297,13 @@ public final class DbMapping implements Updatable {
}
}
// check if a reference is aggressively fetched
if ((rel.reftype == Relation.REFERENCE ||
rel.reftype == Relation.COMPLEX_REFERENCE) &&
rel.aggressiveLoading) {
joinList.add(rel);
}
// app.logEvent ("Mapping "+propName+" -> "+dbField);
}
} catch (Exception x) {
@ -303,6 +314,9 @@ public final class DbMapping implements Updatable {
prop2db = p2d;
db2prop = d2p;
joins = new Relation[joinList.size()];
joins = (Relation[]) joinList.toArray(joins);
String subnodeMapping = props.getProperty("_children");
if (subnodeMapping != null) {
@ -844,9 +858,9 @@ public final class DbMapping implements Updatable {
Relation rel = columnNameToRelation(colName);
DbColumn col = new DbColumn(colName, meta.getColumnType(i + 1), rel, this);
if (col.isMapped()) {
// if (col.isMapped()) {
list.add(col);
}
// }
}
columns = new DbColumn[list.size()];
columns = (DbColumn[]) list.toArray(columns);
@ -855,6 +869,13 @@ public final class DbMapping implements Updatable {
return columns;
}
/**
* Return the array of relations that are fetched with objects of this type.
*/
public Relation[] getJoins() {
return joins;
}
/**
*
*
@ -909,7 +930,7 @@ public final class DbMapping implements Updatable {
StringBuffer s = new StringBuffer("SELECT ");
DbColumn[] cols = columns;
/* DbColumn[] cols = columns;
if (cols == null) {
cols = getColumns();
@ -922,11 +943,28 @@ public final class DbMapping implements Updatable {
}
}
for (int i = 0; i < joins.length; i++) {
} */
s.append ("*");
s.append(" FROM ");
s.append(getTableName());
s.append(" ");
for (int i = 0; i < joins.length; i++) {
if (!joins[i].otherType.isRelational()) {
continue;
}
s.append("LEFT JOIN ");
s.append(joins[i].otherType.getTableName());
s.append(" AS _HLM_");
s.append(joins[i].propName);
s.append(" ON ");
joins[i].renderJoinConstraints(s);
}
// cache rendered string for later calls.
selectString = s.toString();

195
src/helma/objectmodel/db/Node.java
View file

@ -76,7 +76,7 @@ public final class Node implements INode, Serializable {
transient private int state;
/**
* This constructor is only used for instances of the NullNode subclass. Do not use for ordinary Nodes.
* This constructor is only used for NullNode instance. Do not use for ordinary Nodes.
*/
Node() {
created = lastmodified = System.currentTimeMillis();
@ -145,197 +145,28 @@ public final class Node implements INode, Serializable {
}
/**
* Constructor used for nodes being stored in a relational database table.
* Initializer used for nodes being stored in a relational database table.
*/
public Node(DbMapping dbm, ResultSet rs, DbColumn[] columns, WrappedNodeManager nmgr)
throws SQLException, IOException {
public void init(DbMapping dbm, String id, String name, String protoName,
Hashtable propMap, WrappedNodeManager nmgr) {
this.nmgr = nmgr;
// see what prototype/DbMapping this object should use
dbmap = dbm;
this.dbmap = dbm;
// set the prototype name
this.prototype = protoName;
created = lastmodified = System.currentTimeMillis();
for (int i = 0; i < columns.length; i++) {
// set prototype?
if (columns[i].isPrototypeField()) {
String protoName = rs.getString(i+1);
if (protoName != null) {
dbmap = nmgr.getDbMapping(protoName);
if (dbmap == null) {
// invalid prototype name!
System.err.println("Warning: Invalid prototype name: " + protoName +
" - using default");
dbmap = dbm;
}
}
}
// set id?
if (columns[i].isIdField()) {
id = rs.getString(i+1);
}
// set name?
if (columns[i].isNameField()) {
name = rs.getString(i+1);
}
Relation rel = columns[i].getRelation();
if ((rel == null) ||
((rel.reftype != Relation.PRIMITIVE) &&
(rel.reftype != Relation.REFERENCE))) {
continue;
}
Property newprop = new Property(rel.propName, this);
switch (columns[i].getType()) {
case Types.BIT:
newprop.setBooleanValue(rs.getBoolean(i+1));
break;
case Types.TINYINT:
case Types.BIGINT:
case Types.SMALLINT:
case Types.INTEGER:
newprop.setIntegerValue(rs.getLong(i+1));
break;
case Types.REAL:
case Types.FLOAT:
case Types.DOUBLE:
newprop.setFloatValue(rs.getDouble(i+1));
break;
case Types.DECIMAL:
case Types.NUMERIC:
BigDecimal num = rs.getBigDecimal(i+1);
if (num == null) {
break;
}
if (num.scale() > 0) {
newprop.setFloatValue(num.doubleValue());
} else {
newprop.setIntegerValue(num.longValue());
}
break;
case Types.VARBINARY:
case Types.BINARY:
newprop.setStringValue(rs.getString(i+1));
break;
case Types.LONGVARBINARY:
case Types.LONGVARCHAR:
try {
newprop.setStringValue(rs.getString(i+1));
} catch (SQLException x) {
Reader in = rs.getCharacterStream(i+1);
char[] buffer = new char[2048];
int read = 0;
int r = 0;
while ((r = in.read(buffer, read, buffer.length - read)) > -1) {
read += r;
if (read == buffer.length) {
// grow input buffer
char[] newBuffer = new char[buffer.length * 2];
System.arraycopy(buffer, 0, newBuffer, 0, buffer.length);
buffer = newBuffer;
}
}
newprop.setStringValue(new String(buffer, 0, read));
}
break;
case Types.CHAR:
case Types.VARCHAR:
case Types.OTHER:
newprop.setStringValue(rs.getString(i+1));
break;
case Types.DATE:
newprop.setDateValue(rs.getDate(i+1));
break;
case Types.TIME:
newprop.setDateValue(rs.getTime(i+1));
break;
case Types.TIMESTAMP:
newprop.setDateValue(rs.getTimestamp(i+1));
break;
case Types.NULL:
newprop.setStringValue(null);
break;
// continue;
default:
newprop.setStringValue(rs.getString(i+1));
break;
}
if (rs.wasNull()) {
newprop.setStringValue(null);
}
if (propMap == null) {
propMap = new Hashtable();
}
propMap.put(rel.propName.toLowerCase(), newprop);
// if the property is a pointer to another node, change the property type to NODE
if ((rel.reftype == Relation.REFERENCE) && rel.usesPrimaryKey()) {
// FIXME: References to anything other than the primary key are not supported
newprop.convertToNodeReference(rel.otherType);
// newprop.nhandle = new NodeHandle (new DbKey (rel.otherType, newprop.getStringValue ()));
// newprop.type = IProperty.NODE;
}
// mark property as clean, since it's fresh from the db
newprop.dirty = false;
}
// set the prototype from the dbmap,
// which was possibly modified while reading the resultset
setPrototype(dbmap.getTypeName());
this.id = id;
this.name = name;
// If name was not set from resultset, create a synthetical name now.
if ((name == null) || (name.length() == 0)) {
name = dbmap.getTypeName() + " " + id;
this.name = dbmap.getTypeName() + " " + id;
}
// again set created and lastmodified. This is because
// lastmodified has been been updated, and we want both values to
// be identical to show that the node hasn't been changed since
// it was first created.
this.propMap = propMap;
// set lastmodified and created timestamps and mark as clean
created = lastmodified = System.currentTimeMillis();
markAs(CLEAN);
}

237
src/helma/objectmodel/db/NodeManager.java
View file

@ -19,6 +19,7 @@ package helma.objectmodel.db;
import helma.framework.core.Application;
import helma.objectmodel.*;
import helma.util.CacheMap;
import java.math.BigDecimal;
import java.io.*;
import java.sql.*;
import java.util.*;
@ -972,6 +973,7 @@ public final class NodeManager {
public List getNodeIDs(Node home, Relation rel) throws Exception {
// Transactor tx = (Transactor) Thread.currentThread ();
// tx.timer.beginEvent ("getNodeIDs "+home);
if ((rel == null) || (rel.otherType == null) || !rel.otherType.isRelational()) {
// this should never be called for embedded nodes
throw new RuntimeException("NodeMgr.getNodeIDs called for non-relational node " +
@ -1114,7 +1116,10 @@ public final class NodeManager {
while (rs.next()) {
// create new Nodes.
Node node = new Node(rel.otherType, rs, columns, safe);
Node node = createNode(rel.otherType, rs, columns, 0);
if (node == null) {
continue;
}
Key primKey = node.getKey();
retval.add(new NodeHandle(primKey));
@ -1159,6 +1164,7 @@ public final class NodeManager {
Connection con = dbm.getConnection();
Statement stmt = con.createStatement();
DbColumn[] columns = dbm.getColumns();
Relation[] joins = dbm.getJoins();
StringBuffer q = dbm.getSelect();
try {
@ -1166,6 +1172,8 @@ public final class NodeManager {
boolean needsQuotes = dbm.needsQuotes(idfield);
q.append("WHERE ");
q.append(dbm.getTableName());
q.append(".");
q.append(idfield);
q.append(" IN (");
@ -1224,7 +1232,10 @@ public final class NodeManager {
while (rs.next()) {
// create new Nodes.
Node node = new Node(dbm, rs, columns, safe);
Node node = createNode(dbm, rs, columns, 0);
if (node == null) {
continue;
}
Key primKey = node.getKey();
// for grouped nodes, collect subnode lists for the intermediary
@ -1272,6 +1283,28 @@ public final class NodeManager {
}
}
}
int resultSetOffset = columns.length;
// create joined objects
for (int i = 0; i < joins.length; i++) {
DbMapping jdbm = joins[i].otherType;
node = createNode(jdbm, rs, jdbm.getColumns(), resultSetOffset);
if (node != null) {
primKey = node.getKey();
// register new nodes with the cache. If an up-to-date copy
// existed in the cache, use that.
synchronized (cache) {
Node oldnode = (Node) cache.put(primKey, node);
if ((oldnode != null) &&
(oldnode.getState() != INode.INVALID)) {
// found an ok version in the cache, use it.
cache.put(primKey, oldnode);
}
}
}
resultSetOffset += jdbm.getColumns().length;
}
}
// If these are grouped nodes, build the intermediary group nodes
@ -1292,6 +1325,8 @@ public final class NodeManager {
groupnode.lastSubnodeFetch = System.currentTimeMillis();
}
}
} catch (Exception x) {
System.err.println ("ERROR IN PREFETCHNODES: "+x);
} finally {
if (stmt != null) {
try {
@ -1455,6 +1490,8 @@ public final class NodeManager {
StringBuffer q = dbm.getSelect();
q.append("WHERE ");
q.append(dbm.getTableName());
q.append(".");
q.append(idfield);
q.append(" = ");
@ -1476,7 +1513,7 @@ public final class NodeManager {
return null;
}
node = new Node(dbm, rs, columns, safe);
node = createNode(dbm, rs, columns, 0);
if (rs.next()) {
throw new RuntimeException("More than one value returned by query.");
@ -1538,12 +1575,15 @@ public final class NodeManager {
if (home.getSubnodeRelation() != null && !rel.isComplexReference()) {
// combine our key with the constraints in the manually set subnode relation
q.append("WHERE ");
q.append(dbm.getTableName());
q.append(".");
q.append(rel.accessName);
q.append(" = '");
q.append(escape(kstr));
q.append("'");
q.append(" AND ");
q.append(" AND (");
q.append(home.getSubnodeRelation().trim().substring(5));
q.append(")");
} else {
q.append(rel.buildQuery(home, home.getNonVirtualParent(), kstr,
"WHERE ", false));
@ -1561,7 +1601,7 @@ public final class NodeManager {
return null;
}
node = new Node(rel.otherType, rs, columns, safe);
node = createNode(rel.otherType, rs, columns, 0);
if (rs.next()) {
throw new RuntimeException("More than one value returned by query.");
@ -1589,6 +1629,193 @@ public final class NodeManager {
return node;
}
/**
* Create a new Node from a ResultSet.
*/
public Node createNode(DbMapping dbm, ResultSet rs, DbColumn[] columns, int offset)
throws SQLException, IOException {
Hashtable propMap = new Hashtable();
String id = null;
String name = null;
String protoName = dbm.getTypeName();
DbMapping dbmap = dbm;
Node node = new Node();
for (int i = 0; i < columns.length; i++) {
// set prototype?
if (columns[i].isPrototypeField()) {
protoName = rs.getString(i+1+offset);
if (protoName != null) {
dbmap = getDbMapping(protoName);
if (dbmap == null) {
// invalid prototype name!
System.err.println("Warning: Invalid prototype name: " + protoName +
" - using default");
dbmap = dbm;
}
}
}
// set id?
if (columns[i].isIdField()) {
id = rs.getString(i+1+offset);
// if id == null, the object doesn't actually exist - return null
if (id == null) {
return null;
}
}
// set name?
if (columns[i].isNameField()) {
name = rs.getString(i+1+offset);
}
Relation rel = columns[i].getRelation();
if ((rel == null) ||
((rel.reftype != Relation.PRIMITIVE) &&
(rel.reftype != Relation.REFERENCE))) {
continue;
}
Property newprop = new Property(rel.propName, node);
switch (columns[i].getType()) {
case Types.BIT:
newprop.setBooleanValue(rs.getBoolean(i+1+offset));
break;
case Types.TINYINT:
case Types.BIGINT:
case Types.SMALLINT:
case Types.INTEGER:
newprop.setIntegerValue(rs.getLong(i+1+offset));
break;
case Types.REAL:
case Types.FLOAT:
case Types.DOUBLE:
newprop.setFloatValue(rs.getDouble(i+1+offset));
break;
case Types.DECIMAL:
case Types.NUMERIC:
BigDecimal num = rs.getBigDecimal(i+1+offset);
if (num == null) {
break;
}
if (num.scale() > 0) {
newprop.setFloatValue(num.doubleValue());
} else {
newprop.setIntegerValue(num.longValue());
}
break;
case Types.VARBINARY:
case Types.BINARY:
newprop.setStringValue(rs.getString(i+1+offset));
break;
case Types.LONGVARBINARY:
case Types.LONGVARCHAR:
try {
newprop.setStringValue(rs.getString(i+1+offset));
} catch (SQLException x) {
Reader in = rs.getCharacterStream(i+1+offset);
char[] buffer = new char[2048];
int read = 0;
int r = 0;
while ((r = in.read(buffer, read, buffer.length - read)) > -1) {
read += r;
if (read == buffer.length) {
// grow input buffer
char[] newBuffer = new char[buffer.length * 2];
System.arraycopy(buffer, 0, newBuffer, 0, buffer.length);
buffer = newBuffer;
}
}
newprop.setStringValue(new String(buffer, 0, read));
}
break;
case Types.CHAR:
case Types.VARCHAR:
case Types.OTHER:
newprop.setStringValue(rs.getString(i+1+offset));
break;
case Types.DATE:
newprop.setDateValue(rs.getDate(i+1+offset));
break;
case Types.TIME:
newprop.setDateValue(rs.getTime(i+1+offset));
break;
case Types.TIMESTAMP:
newprop.setDateValue(rs.getTimestamp(i+1+offset));
break;
case Types.NULL:
newprop.setStringValue(null);
break;
// continue;
default:
newprop.setStringValue(rs.getString(i+1+offset));
break;
}
if (rs.wasNull()) {
newprop.setStringValue(null);
}
propMap.put(rel.propName.toLowerCase(), newprop);
// if the property is a pointer to another node, change the property type to NODE
if ((rel.reftype == Relation.REFERENCE) && rel.usesPrimaryKey()) {
// FIXME: References to anything other than the primary key are not supported
newprop.convertToNodeReference(rel.otherType);
}
// mark property as clean, since it's fresh from the db
newprop.dirty = false;
}
if (id == null) {
return null;
}
node.init(dbmap, id, name, protoName, propMap, safe);
return node;
}
/**
* Get a DbMapping for a given prototype name. This is just a proxy
* method to the app's getDbMapping() method.

28
src/helma/objectmodel/db/Relation.java
View file

@ -626,6 +626,8 @@ public final class Relation {
String accessColumn = (accessName == null) ? otherType.getIDField() : accessName;
q.append(otherType.getTableName());
q.append(".");
q.append(accessColumn);
q.append(" = ");
@ -678,21 +680,39 @@ public final class Relation {
public String renderConstraints(INode home, INode nonvirtual)
throws SQLException {
StringBuffer q = new StringBuffer();
String suffix = " AND ";
String prefix = " AND ";
for (int i = 0; i < constraints.length; i++) {
q.append(prefix);
constraints[i].addToQuery(q, home, nonvirtual);
q.append(suffix);
}
if (filter != null) {
q.append(prefix);
q.append(filter);
q.append(suffix);
}
return q.toString();
}
public void renderJoinConstraints(StringBuffer select) {
for (int i = 0; i < constraints.length; i++) {
select.append(ownType.getTableName());
select.append(".");
select.append(constraints[i].localName);
select.append(" = _HLM_");
select.append(propName);
select.append(".");
select.append(constraints[i].foreignName);
if (i == constraints.length-1) {
select.append(" ");
} else {
select.append(" AND ");
}
}
}
/**
* Get the order section to use for this relation
*/
@ -966,6 +986,8 @@ public final class Relation {
local = ref.getString(homeprop);
}
q.append(otherType.getTableName());
q.append(".");
q.append(foreignName);
q.append(" = ");