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h2database
提交 dc492ea5 authored 作者: Thomas Mueller's avatar Thomas Mueller
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New experimental feature "SHUTDOWN DEFRAG".

上级 df07f1a0
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正在显示 包含 62 行增加 和 66 行删除
h2/src/main/org/h2/engine/Database.java
浏览文件 @ dc492ea5
......@@ -161,7 +161,7 @@ public class Database implements DataHandler {
private volatile boolean checkpointRunning;
private final Object reconnectSync = new Object();
private int cacheSize;
private int compactMode = -1;
private int compactMode;
private SourceCompiler compiler;
private volatile boolean metaTablesInitialized;
private boolean flushOnEachCommit;
......
h2/src/main/org/h2/store/PageStore.java
浏览文件 @ dc492ea5
......@@ -12,7 +12,6 @@ import java.util.ArrayList;
import java.util.BitSet;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.zip.CRC32;
import org.h2.command.ddl.CreateTableData;
import org.h2.command.dml.TransactionCommand;
......@@ -36,7 +35,6 @@ import org.h2.index.PageDelegateIndex;
import org.h2.index.PageIndex;
import org.h2.message.DbException;
import org.h2.message.Trace;
import org.h2.result.ResultInterface;
import org.h2.result.Row;
import org.h2.schema.Schema;
import org.h2.table.Column;
......@@ -176,7 +174,7 @@ public class PageStore implements CacheWriter {
private boolean recordPageReads;
private ArrayList<Integer> recordedPagesList;
private HashSet<Integer> recordedPagesSet;
private BitSet recordedPages;
/**
* The change count is something like a "micro-transaction-id".
......@@ -437,7 +435,7 @@ public class PageStore implements CacheWriter {
/**
* Shrink the file so there are no empty pages at the end.
*
* @param compactMode != -1 if no compacting should happen, otherwise
* @param compactMode 0 if no compacting should happen, otherwise
* TransactionCommand.SHUTDOWN_COMPACT or TransactionCommand.SHUTDOWN_DEFRAG
*/
public void compact(int compactMode) {
......@@ -469,7 +467,10 @@ public class PageStore implements CacheWriter {
long start = System.currentTimeMillis();
boolean isCompactFully = compactMode == TransactionCommand.SHUTDOWN_COMPACT;
boolean isDefrag = compactMode == TransactionCommand.SHUTDOWN_DEFRAG;
int test;
// isCompactFully = isDefrag = true;
int maxCompactTime = SysProperties.MAX_COMPACT_TIME;
int maxMove = SysProperties.MAX_COMPACT_COUNT;
......@@ -504,45 +505,42 @@ public class PageStore implements CacheWriter {
cache.clear();
ArrayList<Table> tables = database.getAllTablesAndViews(false);
recordedPagesList = New.arrayList();
recordedPagesSet = New.hashSet();
recordedPages = new BitSet();
recordPageReads = true;
for (int i = 0; i < tables.size(); i++) {
Table table = tables.get(i);
org.h2.command.Prepared pref = database.getSystemSession().prepare("select * from " +
table.getName() + " where -1=abs(rand())");
ResultInterface ri = pref.query(Integer.MAX_VALUE);
ri.close();
if (!table.isTemporary() && table.getTableType().equals(Table.TABLE)) {
// rand() < 0 is never true, but the optimizer can't know,
// therefore it's performing a table scan
database.getSystemSession().prepare(
"select * from " +
table.getSQL() +
" where rand() < zero()").query(Integer.MAX_VALUE);
int todoScanIndexesAsWell;
}
}
recordPageReads = false;
int free = getFirstFree(); // We swap, so this page is fix
if (free == -1) {
DbException.throwInternalError("no free page for defrag");
} else {
for (int i = 0; i < recordedPagesList.size(); i++) {
writeBack();
cache.clear();
int a = MIN_PAGE_COUNT + i;
int b = recordedPagesList.get(i);
if (a == b) {
continue;
}
boolean swapped = swap(a, b, free);
if (!swapped) {
DbException.throwInternalError("swapping not possible: " + a + " with " + b + " via " + free);
}
int index = recordedPagesList.indexOf(a);
if (index != -1) {
recordedPagesList.set(index, b);
}
recordedPagesList.set(i, a);
for (int i = 0; i < recordedPagesList.size(); i++) {
writeBack();
cache.clear();
int a = MIN_PAGE_COUNT + i;
int b = recordedPagesList.get(i);
if (a == b) {
continue;
}
int temp = getFirstFree();
if (temp == -1) {
DbException.throwInternalError("no free page for defrag");
}
swap(a, b, temp);
int index = recordedPagesList.indexOf(a);
if (index >= 0) {
recordedPagesList.set(index, b);
}
recordedPagesList.set(i, a);
}
recordedPagesList = null;
recordedPagesSet = null;
recordedPages = null;
}
// TODO can most likely be simplified
checkpoint();
......@@ -595,36 +593,32 @@ public class PageStore implements CacheWriter {
return free;
}
private boolean swap(int a, int b, int free) {
if (a < MIN_PAGE_COUNT || b < MIN_PAGE_COUNT || !isUsed(a) || !isUsed(b)) {
return false;
private void swap(int a, int b, int free) {
if (a < MIN_PAGE_COUNT || b < MIN_PAGE_COUNT) {
System.out.println(isUsed(a) + " " + isUsed(b));
DbException.throwInternalError("can't swap " + a + " and " + b);
}
Page f = (Page) cache.get(free);
if (f != null) {
DbException.throwInternalError("not free: " + f);
}
Page pageA = getPage(a);
Page pageB = getPage(b);
if (pageA == null) {
freePage(a);
} else if (pageB == null) {
freePage(b);
} else {
trace.debug("swap " + a + " with " + b + " via " + free);
try {
pageA.moveTo(systemSession, free);
free(a);
pageB = getPage(b);
pageB.moveTo(systemSession, a);
free(b);
f = getPage(free);
f.moveTo(systemSession, b);
free(free);
} finally {
changeCount++;
}
trace.debug("swap " + a + " and " + b + " via " + free);
Page pageA = null;
if (isUsed(a)) {
pageA = getPage(a);
pageA.moveTo(systemSession, free);
free(a);
}
if (isUsed(b)) {
Page pageB = getPage(b);
pageB.moveTo(systemSession, a);
free(b);
}
if (pageA != null) {
f = getPage(free);
f.moveTo(systemSession, b);
free(free);
}
return true;
}
private boolean compact(int full, int free) {
......@@ -660,7 +654,7 @@ public class PageStore implements CacheWriter {
Page p = (Page) cache.get(pageId);
if (p != null) {
return p;
}
}
Data data = createData();
readPage(pageId, data);
......@@ -691,10 +685,6 @@ public class PageStore implements CacheWriter {
statisticsIncrement(index.getTable().getName() + "." + index.getName() + " read");
}
p = PageDataLeaf.read(index, data, pageId);
if (recordPageReads && pageId >= MIN_PAGE_COUNT && !recordedPagesSet.contains(pageId)) {
recordedPagesList.add(pageId);
recordedPagesSet.add(pageId);
}
break;
}
case Page.TYPE_DATA_NODE: {
......@@ -1220,6 +1210,12 @@ public class PageStore implements CacheWriter {
* @param page the page
*/
void readPage(int pos, Data page) {
if (recordPageReads) {
if (pos >= MIN_PAGE_COUNT && !recordedPages.get(pos)) {
recordedPagesList.add(pos);
recordedPages.set(pos);
}
}
synchronized (database) {
if (pos < 0 || pos >= pageCount) {
throw DbException.get(ErrorCode.FILE_CORRUPTED_1, pos + " of " + pageCount);
......
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