java.lang.Object
- org.apache.ignite.internal.processors.cache.persistence.tree.io.PageIO
- - org.apache.ignite.internal.processors.cache.persistence.tree.io.TrackingPageIO

```
public class TrackingPageIO
extends PageIO
```
We use dedicated page for tracking pages updates. Also we divide such 'tracking' pages on two half, first is used for check that page was changed or not (during incremental snapshot), second - to accumulate changed for next snapshot. You cannot test change for not started snapshot! because it will cause of preparation for snapshot. Implementation. For each page there is own bit in both half. Tracking page is used for tracking N page after it. N depends on page size (how many bytes we can use for tracking). +-----------------------------------------+-----------------------------------------+ | left half | right half | +---------+-----------+----+------------------------------------+----+------------------------------------+ | HEADER | Last |size| |size| | | |SnapshotTag|2b. | tracking bits |2b. | tracking bits | +---------+--------- -+----+------------------------------------+----+------------------------------------+

Field Summary

Fields
Modifier and Type	Field	Description
`static int`	`BITMAP_OFFSET`	Bitmap offset.
`static long`	`CORRUPT_FLAG_FILTER_MASK`	Corrupt flag mask.
`static long`	`CORRUPT_FLAG_MASK`	Corrupt flag mask.
`static int`	`COUNT_OF_EXTRA_PAGE`	Count of extra page.
`static int`	`LAST_SNAPSHOT_TAG_OFFSET`	Last snapshot offset.
`static int`	`SIZE_FIELD_OFFSET`	Size field offset.
`static int`	`SIZE_FIELD_SIZE`	'Size' field size.
`static IOVersions<TrackingPageIO>`	`VERSIONS`

Fields inherited from class org.apache.ignite.internal.processors.cache.persistence.tree.io.PageIO
COMMON_HEADER_END, CRC_OFF, MAX_PAYLOAD_SIZE, PAGE_ID_OFF, ROTATED_ID_PART_OFF, T_BPLUS_META, T_CACHE_ID_AWARE_DATA_REF_INNER, T_CACHE_ID_AWARE_DATA_REF_LEAF, T_CACHE_ID_AWARE_PENDING_REF_INNER, T_CACHE_ID_AWARE_PENDING_REF_LEAF, T_DATA, T_DATA_METASTORAGE, T_DATA_PART, T_DATA_REF_INNER, T_DATA_REF_LEAF, T_DATA_REF_METASTORAGE_INNER, T_DATA_REF_METASTORAGE_LEAF, T_DEFRAG_LINK_MAPPING_INNER, T_DEFRAG_LINK_MAPPING_LEAF, T_H2_EX_REF_INNER_END, T_H2_EX_REF_INNER_START, T_H2_EX_REF_LEAF_END, T_H2_EX_REF_LEAF_START, T_H2_REF_INNER, T_H2_REF_LEAF, T_MARKER_PAGE, T_META, T_METASTORE_INNER, T_METASTORE_LEAF, T_PAGE_LIST_META, T_PAGE_LIST_NODE, T_PAGE_UPDATE_TRACKING, T_PART_CNTRS, T_PART_META, T_PENDING_REF_INNER, T_PENDING_REF_LEAF, TYPE_OFF, VER_OFF

Constructor Summary

Constructors
Modifier Constructor Description

protected TrackingPageIO(int ver)

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`short`	`countOfChangedPage(ByteBuffer buf, long snapshotTag, int pageSize)`
`int`	`countOfPageToTrack(int pageSize)`
`@Nullable Long`	`findNextChangedPage(ByteBuffer buf, long start, long curSnapshotTag, long lastSuccessfulSnapshotTag, int pageSize)`
`int`	`getFreeSpace(int pageSize, long pageAddr)`	Count of bytes that is currently free in this page and possibly can be used to place additional payload.
`boolean`	`isCorrupted(ByteBuffer buf)`
`long`	`markChanged(ByteBuffer buf, long pageId, long nextSnapshotTag, long lastSuccessfulSnapshotTag, int pageSize)`	Will mark pageId as changed for next (!)
`protected void`	`printPage(long addr, int pageSize, GridStringBuilder sb)`
`void`	`resetCorruptFlag(long addr)`	Reset corrupted flag to false.
`void`	`resetCorruptFlag(ByteBuffer buf)`	Reset corrupted flag to false.
`long`	`trackingPageFor(long pageId, int pageSize)`
`boolean`	`wasChanged(ByteBuffer buf, long pageId, long curSnapshotTag, long lastSuccessfulSnapshotTag, int pageSize)`

Methods inherited from class org.apache.ignite.internal.processors.cache.persistence.tree.io.PageIO
assertPageType, assertPageType, copyPage, deriveIndexPageType, getBPlusIO, getBPlusIO, getCompactedSize, getCompactedSize, getCompressedSize, getCompressedSize, getCompressionType, getCompressionType, getCrc, getCrc, getInnerVersions, getLeafVersions, getPageId, getPageId, getPageIO, getPageIO, getPageIO, getRotatedIdPart, getType, getType, getType, getVersion, getVersion, getVersion, initNewPage, isDataPageType, isIndexPage, printPage, registerH2, registerH2ExtraInner, registerH2ExtraLeaf, registerTest, registerTest, setCompactedSize, setCompressedSize, setCompressionType, setCrc, setCrc, setPageId, setRotatedIdPart, setType, setVersion, toString

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Field Detail
  - VERSIONS
```
public static final IOVersions<TrackingPageIO> VERSIONS
```
  - CORRUPT_FLAG_MASK
```
public static final long CORRUPT_FLAG_MASK
```
    Corrupt flag mask.
    
    See Also:
    
    Constant Field Values
  - CORRUPT_FLAG_FILTER_MASK
```
public static final long CORRUPT_FLAG_FILTER_MASK
```
    Corrupt flag mask.
    
    See Also:
    
    Constant Field Values
  - LAST_SNAPSHOT_TAG_OFFSET
```
public static final int LAST_SNAPSHOT_TAG_OFFSET
```
    Last snapshot offset.
    
    See Also:
    
    Constant Field Values
  - SIZE_FIELD_OFFSET
```
public static final int SIZE_FIELD_OFFSET
```
    Size field offset.
    
    See Also:
    
    Constant Field Values
  - SIZE_FIELD_SIZE
```
public static final int SIZE_FIELD_SIZE
```
    'Size' field size.
    
    See Also:
    
    Constant Field Values
  - BITMAP_OFFSET
```
public static final int BITMAP_OFFSET
```
    Bitmap offset.
    
    See Also:
    
    Constant Field Values
  - COUNT_OF_EXTRA_PAGE
```
public static final int COUNT_OF_EXTRA_PAGE
```
    Count of extra page.
    
    See Also:
    
    Constant Field Values
- Constructor Detail
  - TrackingPageIO
```
protected TrackingPageIO(int ver)
```
    Parameters:
    
    ver - Page format version.
- Method Detail
  - markChanged
```
public long markChanged(ByteBuffer buf,
                        long pageId,
                        long nextSnapshotTag,
                        long lastSuccessfulSnapshotTag,
                        int pageSize)
```
    Will mark pageId as changed for next (!) snapshotId
    
    Parameters:
    
    buf - Buffer.
    
    pageId - Page id.
    
    nextSnapshotTag - Tag of next snapshot.
    
    pageSize - Page size.
    
    Returns:
    
    -1 if everything is ok, otherwise last saved tag.
  - isCorrupted
```
public boolean isCorrupted(ByteBuffer buf)
```
    Parameters:
    
    buf - Buffer.
    
    Returns:
    
    Was tracking page marked as corrupted or not.
  - resetCorruptFlag
```
public void resetCorruptFlag(ByteBuffer buf)
```
    Reset corrupted flag to false.
    
    Parameters:
    
    buf - Buffer.
  - resetCorruptFlag
```
public void resetCorruptFlag(long addr)
```
    Reset corrupted flag to false.
    
    Parameters:
    
    addr - Buffer.
  - wasChanged
```
public boolean wasChanged(ByteBuffer buf,
                          long pageId,
                          long curSnapshotTag,
                          long lastSuccessfulSnapshotTag,
                          int pageSize)
                   throws TrackingPageIsCorruptedException
```
    Parameters:
    
    buf - Buffer.
    
    pageId - Page id.
    
    curSnapshotTag - Snapshot tag.
    
    lastSuccessfulSnapshotTag - Last successful snapshot id.
    
    pageSize - Page size.
    
    Returns:
    
    Was that pageId marked as changed between previous snapshot finish and current snapshot start or not.
    
    Throws:
    
    TrackingPageIsCorruptedException - if this tracking page was marked as corrupted.
  - countOfChangedPage
```
public short countOfChangedPage(ByteBuffer buf,
                                long snapshotTag,
                                int pageSize)
```
    Parameters:
    
    buf - Buffer.
    
    snapshotTag - Snapshot tag.
    
    pageSize - Page size.
    
    Returns:
    
    Count of pages which were marked as change for given snapshotTag.
  - trackingPageFor
```
public long trackingPageFor(long pageId,
                            int pageSize)
```
    Parameters:
    
    pageId - Page id.
    
    pageSize - Page size.
    
    Returns:
    
    Page id of tracking page which set pageId belongs to.
  - countOfPageToTrack
```
public int countOfPageToTrack(int pageSize)
```
    Parameters:
    
    pageSize - Page size.
    
    Returns:
    
    How many page we can track with 1 page.
  - findNextChangedPage
```
@Nullable
public @Nullable Long findNextChangedPage(ByteBuffer buf,
                                          long start,
                                          long curSnapshotTag,
                                          long lastSuccessfulSnapshotTag,
                                          int pageSize)
                                   throws TrackingPageIsCorruptedException
```
    Parameters:
    
    buf - Buffer.
    
    start - Start.
    
    curSnapshotTag - Snapshot id.
    
    lastSuccessfulSnapshotTag - Last successful snapshot id.
    
    pageSize - Page size.
    
    Returns:
    
    Passed pageId if it was changed or next closest one, if there is no changed page null will be returned.
    
    Throws:
    
    TrackingPageIsCorruptedException - if this tracking page was marked as corrupted.
  - printPage
```
protected void printPage(long addr,
                         int pageSize,
                         GridStringBuilder sb)
                  throws IgniteCheckedException
```
    Specified by:
    
    printPage in class PageIO
    
    Parameters:
    
    addr - Address.
    
    pageSize - Page size.
    
    sb - Sb.
    
    Throws:
    
    IgniteCheckedException
  - getFreeSpace
```
public int getFreeSpace(int pageSize,
                        long pageAddr)
```
    Count of bytes that is currently free in this page and possibly can be used to place additional payload.
    
    Specified by:
    
    getFreeSpace in class PageIO
    
    Parameters:
    
    pageSize - Page size.
    
    pageAddr - Page address.
    
    Returns:
    
    Free space.

Class TrackingPageIO

Field Summary

Fields inherited from class org.apache.ignite.internal.processors.cache.persistence.tree.io.PageIO

Constructor Summary

Method Summary

Methods inherited from class org.apache.ignite.internal.processors.cache.persistence.tree.io.PageIO

Methods inherited from class java.lang.Object

Field Detail

VERSIONS

CORRUPT_FLAG_MASK

CORRUPT_FLAG_FILTER_MASK

LAST_SNAPSHOT_TAG_OFFSET

SIZE_FIELD_OFFSET

SIZE_FIELD_SIZE

BITMAP_OFFSET

COUNT_OF_EXTRA_PAGE

Constructor Detail

TrackingPageIO

Method Detail

markChanged

isCorrupted

resetCorruptFlag

resetCorruptFlag

wasChanged

countOfChangedPage

trackingPageFor

countOfPageToTrack

findNextChangedPage

printPage

getFreeSpace