public Interface Page

The slot number of the first slot. This is guaranteed to be zero.

Values for insertFlag.

INSERT_INITIAL - flag initializer INSERT_DEFAULT - default insert behavior, if the record does not fit on the page where the insert operation is called, an error will be returned, instead of overflowing the record. INSERT_UNDO_WITH_PURGE - if this is set, then the undo of this insert will purge the row rather than mark it as deleted, which is the default behaviro for insertAtSlot and insert. INSERT_CONDITIONAL - if this flag is set, then, the overflow is conditional. The record will be overflowed only if it exceeds the threshold specified by the properties, or the parameter. INSERT_OVERFLOW - if this flag is set, then the insert operation will overflow the record if it does not fit on the page. INSERT_FOR_SPLIT - a record is being updated that causes new portions to be inserted *and* the last new portion needs to point to an existing portion. Rules for the insert flags: 1. If INSERT_DEFAULT is set, INSERT_CONDITIONAL and INSERT_OVERFLOW will be ignored 2. INSERT_UNDO_WITH_PURGE can be set with any of the other 3 flags. 3. If INSERT_OVERFLOW is not set, INSERT_CONDITIONAL will be ignored. But, it is not necessary to set INSERT_CONDITIONAL when setting INSERT_OVERFLOW. 4. If INSERT_DEFAULT, INSERT_OVERFLOW both are not set, then, default insert action will be taken, i.e. no overflow will be allowed.

A slot number guaranteed to be invalid.

move rows from one page to another, purging in the process.

Move from this page slot[src_slot] to slot[src_slot+num_rows-1] to destPage slot[dest_slot] to slot[dest_slot + num_rows - 1], in that order. Both this page and destPage must be latched and from the same container with the same page and record format.
Slot[src_slot] to slot[src_slot+numrows-1] will be purged from this page. RecordId on the dest page will be brand new and not in any particular order or range. RecordId of the purged rows in this page is never reused. Deleted and undeleted rows are copied over just the same. Exception will be thrown if this page does not have all the rows in the moved over range.

Calls the lockRecordForWrite() method of the LockingPolicy object passed to the openContainer() call before the rows are copied over and bore the records are purged. I.e, for num_rows moved, there will be 2*num_rows calls to lockRecordForWrite.

Use with caution
As with a normal purge, no space is reserved on this page for rollback of the purge, so you must commit before inserting any rows onto this page - unless those inserts are INSERT_UNDO_WITH_PURGE.

Parameters

destPage:Page

the page to copy to

src_slot:int

start copying from this slot

num_rows:int

copy and purge this many rows from this page

dest_slot:int

copying into this slot of destPage

Exceptions

StandardException:

Standard Derby error policy

Return a time stamp that can be used to identify the page of this specific instance. For pages that don't support timestamp, returns null.

Mark the record at slot as deleted or undeleted according to delete flag.

Locking Policy

Calls the lockRecordForWrite() method of the LockingPolicy object passed to the openContainer() call before the record is deleted. If record already deleted, and an attempt is made to delete it, an exception is thrown. If record not deleted, and an attempt is made to undelete it, an exception is thrown.
MT - latched

Parameters

slot:int

is the slot number

delete:boolean

true if this record is to be deleted false if this deleted record is to be marked undeleted

undo:LogicalUndo

if logical undo may be necessary, a function pointer to the access code where the logical undo logic resides. Null if logical undo is not necessary.

Returns:RecordHandle

a Handle to the deleted/undeleted record.

Exceptions

StandardException:

if the container was not opened in update mode, or if an attempt was made to delete an already deleted record or undelete a not deleted record, or if the slot is not on the page

See Also

LockingPolicy, LogicalUndo, LogicalUndoable

See if timeStamp for this page is the same as the current instance of the page. Null timeStamp never equals the instance of the page.

Parameters

ts:PageTimeStamp

the time stamp gotten from an earlier call to this page's getTimeStamp

Returns:boolean

true if timestamp is the same

Exceptions

StandardException:

Standard Derby error policy.

See Also

PageTimeStamp

Fetch a single field from a deleted or non-deleted record. Fills in the passed in Object column with the field identified by fieldid if column is not null, otherwise the record is locked but not fetched.
The fieldId of the first field is 0. If the fieldId is >= the number of fields on the record, column is restored to null

Locking Policy
No locks are obtained. It is up to the caller to obtain the correct locks.
It is guaranteed that the page latch is not released by this method

Parameters

slot:int

is the slot number

fieldId:int

is the column id

column:Object

is to be filled in with information from the record.

Returns:RecordHandle

the Handle to the record that is locked

Exceptions

StandardException:

Standard Derby error policy, a statement level exception is thrown if the slot is not on the page.

See Also

Page#fetchFromSlot, LockingPolicy

Fetch a record located in the passed in slot.

Fetch a record located in the passed in slot and fill-in the passed in StorebleRow and the Object columns contained within. If row is null then the record is locked but is not fetched.
This interface allows the caller to either return a deleted row or not. If "ignoreDelete" is set to true, fetch the record regardless of whether it is deleted or not (same as above fetchFromSlot). However, if "ignoreDelete" is set to false and the and the slot correspond to a deleted row, null is returned.
If a non-null Qualifier list is provided then the qualifier array will be applied to the row and the row will only be returned if the row qualifies, otherwise null will be returned. Values in the columns of row may or may not be altered while trying to apply the qualifiers, if null is returned the state of the columns is undefined. If a null Qualifier list is provided then no qualification is applied.
If a non-null record handle is passed in, it is assumed that the record handle corresponds to the record in the slot. If record handle is null, a record handle will be manufactured and returned if the record is not deleted or if "ignoreDelete" is true. This parameter is here for the case where the caller have already manufactured the record handle for locking or other purposes so it would make sense for the page to avoid creating a new record handle object if possible.

Parameters

rh:RecordHandle

the record handle of the row. If non-null it must refer to the same record as the slot.

slot:int

the slot number

row:Object[]

Row to be filled in with information from record.

fetchDesc:FetchDescriptor

A structure to efficiently carry a set of parameters needed to describe the fetch, these include: validColumns - A bit map of which columns in the row to be fetched. ValidColumns will not be changed by RawStore. qualifier_list - A list of Qualifiers to apply to the row to see if the row should be returned. An array of qualifiers which restrict whether or not the row should be returned by the fetch. Rows for which any one of the qualifiers returns false are not returned by the fetch. If null, no qualification is done and the requested columns of the rows are returned. Qualifiers can only reference columns which are included in the scanColumnList. The column id that a qualifier returns is the column id the table, not the column id in the partial row being returned. qualifier_scratch_space - An array of int's that matches the size of the row[] array. Used to process qualifiers, if no qualifiers are input then array need not be input. Passed in rather than allocated so that space can be allocated a single time in a scan. If not passed in then raw store will allocate and deallocate per call.

ignoreDelete:boolean

if true, return row regardless of whether it is deleted or not. If false, only return non-deleted row.

Returns:RecordHandle

A handle to the record.

Exceptions

StandardException:

Standard Derby error policy

See Also

LockingPolicy

Fetch the number of fields in a record.

Locking Policy

No locks are obtained.
MT - latched

Parameters

handle:RecordHandle

record handle to deleted or non-deleted record

Returns:int

the number of fields in the record

Exceptions

StandardException:

Standard Derby error policy, a statement level exception is thrown if the record handle does not match a record on the page.

Fetch the number of fields in a record.

Locking Policy

No locks are obtained.
It is guaranteed that the page latch is not released by this method

Parameters

slot:int

is the slot number

Returns:int

the number of fields in the record

Exceptions

StandardException:

Standard Derby error policy

Retrieve this page's aux object, returning null if there isn't one. The reference returned must only be used while the page is latched, once unlatch is called the reference to the aux object must be discarded.
MT - latched

See Also

AuxObject

Return an invalid record handle.

Returns:RecordHandle

an invalid record handle.

Find slot for record with an id greater than the passed in identifier.

Find the slot for the first record on the page with an id greater than the passed in identifier.
Returns the slot of the first record on the page with an id greater than the one passed in. Usefulness of this functionality depends on the client's use of the raw store interfaces. If all "new" records are always inserted at the end of the page, and the raw store continues to guarantee that all record id's will be allocated in increasing order on a given page (assuming a PAGE_REUSABLE_RECORD_ID container), then a page is always sorted in record id order. For instance current heap tables function this way. If the client ever inserts at a particular slot number, rather than at the "end" then the record id's will not be sorted.
In the case where all record id's are always sorted on a page, then this routine can be used by scan's which "lose" their position because the row they have as a position was purged. They can reposition their scan at the "next" row after the row that is now missing from the table.
This method returns the record regardless of its deleted status.
MT - latched

Parameters

handle:RecordHandle

record handle to find the next higher id.

Returns:int

record id of the first record on the page with a record id higher than the one passed in. If no such record exists, -1 is returned.

Exceptions

StandardException:

Standard exception policy.

Return the page key of this page.

MT - Latched

Returns:PageKey

The page key of this page.

See Also

ContainerHandle

Return the page number of this page.

Page numbers are unique within a container and start at ContainerHandle.FIRST_PAGE_NUMBER and increment by 1 regardless of the page size.

MT - Latched

Returns:long

The page number of this page.

See Also

ContainerHandle

Get the current version number of the page.

Returns:long

page version number

Get a record handle from a previously stored record id.

Get a record handle from a previously stored record identifier that was obtained from a RecordHandle.

MT - Latched

Parameters

recordId:int

previously stored recordId.

Returns:RecordHandle

A valid record handle or null if the record no longer exists.

See Also

RecordHandle#getId

Get the record handle of row at slot.

Get the record handle of a record on a latched page using its slot number.
MT - latched

Parameters

slot:int

the slot number

Returns:RecordHandle

the record handle.

Exceptions

StandardException:

Standard Derby error policy

Get the slot number.

Get the slot number of a record on a latched page using its record handle.

Parameters

handle:RecordHandle

the record handle

Returns:int

the slot number

Exceptions

StandardException:

Standard Derby error policy

Insert a record anywhere on the page.

Locking Policy
Calls the lockRecordForWrite() method of the LockingPolicy object passed to the openContainer() call before the record is inserted.
MT - latched

Parameters

row:Object[]

The row version of the data

validColumns:FormatableBitSet

a bit map of which columns in the row is valid. ValidColumns will not be changed by RawStore.

insertFlag:byte

see values for insertFlag below.

Returns:RecordHandle

A RecordHandle representing the new record.

Exceptions

StandardException:

if the container was not opened in update mode, or if the row cannot fit on the page, or if the row is null

Insert a record at the specified slot.

All records that occupy FIRST_SLOT_NUMBER to (slot - 1) are not moved.
All records that occupy slot to (recordCount() - 1) are moved up one slot.
The new record is inserted at the specified slot.
If slot == FIRST_SLOT_NUMBER, then the new record will be inserted at the first slot.
If slot == recordCount(), then the record is inserted in a new slot, no records are moved.
If slot is > recordCount() or if slot < FIRST_SLOT_NUMBER, an exception will be thrown.

Space Policy
If the row will not fit on a page then:

• an exception is thrown if the page has no other rows, this is an indication that the row could never fit on a page in this container.
• null is returned if there are other rows on the page, this is an indication that the row can potentially be inserted successfully onto an empty page.

Locking Policy
Calls the lockRecordForWrite() method of the LockingPolicy object passed to the openContainer() call before the record is inserted.
MT - latched

Parameters

slot:int

The specified slot

row:Object[]

The row version of the data

validColumns:FormatableBitSet

a bit map of which columns in the row is valid. ValidColumns will not be changed by RawStore.

undo:LogicalUndo

if logical undo may be necessary, a function pointer to the access code where the logical undo logic resides. Null if logical undo is not necessary.

insertFlag:byte

if INSERT_UNDO_WITH_PURGE set, then the undo of this insert will purge the row rather than mark it as deleted, which is the default bahavior for insertAtSlot and insert.

Returns:RecordHandle

A RecordHandle representing the new record, or null if the row will not fit on a non-empty page.

Exceptions

StandardException:

if the container was not opened in update mode, or if the row cannot fit on the page

See Also

LogicalUndo, LogicalUndoable

Test if a record is deleted.

Locking Policy
No locks are obtained.
It is guaranteed that the page latch is not released by this method

Parameters

slot:int

slot of record to be tested.

Exceptions

StandardException:

Standard Derby error policy, a statement level exception is thrown if the slot is not on the page.

Check if this page has been changed in such a way that scans that are positioned on it will have to reposition. Only called on B-tree pages.

Parameters

version:long

the version number of the page when the scan positioned on it (after which version the page should not have changed in a way that requires repositioning)

Returns:boolean

true if a scan that was positioned on the page at page version version needs to reposition; false otherwise

Return a record handle for the given constant record id.

Return a record handle that doesn't represent a record but rather has a special meaning. Used for special cases like creating a key specific to the page, but not specific to a row on the page.

See RecordHandle interface for a list of "special record handles."

Parameters

recordHandleConstant:int

the special recordId

Returns:RecordHandle

The created record handle.

Exceptions

StandardException:

if input is not a special record identifier.

See Also

RecordHandle

Move record to a page toward the beginning of the file.

As part of compressing the table records need to be moved from the end of the file toward the beginning of the file. Only the contiguous set of free pages at the very end of the file can be given back to the OS. This call is used to purge the row from the current page, insert it into a previous page, and return the new row location Mark the record identified by position as deleted. The record may be undeleted sometime later using undelete() by any transaction that sees the record.

The interface is optimized to work on a number of rows at a time, optimally processing all rows on the page at once. The call will process either all rows on the page, or the number of slots in the input arrays - whichever is smaller. Locking Policy

MUST be called with table locked, not locks are requested. Because it is called with table locks the call will go ahead and purge any row which is marked deleted. It will also use purge rather than delete to remove the old row after it moves it to a new page. This is ok since the table lock insures that no other transaction will use space on the table before this transaction commits.
A page latch on the new page will be requested and released.

Parameters

slot:int

Slot of row to move.

row:Object[]

A template to read the current row into as part of moving it.

old_handle:RecordHandle[]

An array to be filled in by the call with the old handles of all rows moved.

new_handle:RecordHandle[]

An array to be filled in by the call with the new handles of all rows moved.

Returns:int

the number of rows processed.

Exceptions

StandardException:

Standard Derby error policy

See Also

LockingPolicy

Return the number of records on this page that are not marked as deleted.
MT - latched

Exceptions

StandardException:

Standard Derby error policy

Purge the row(s) from page.

Purge the row(s) from page, get rid of the row(s) and slot(s) - USE WITH CAUTION, please see entire description of this operation before attempting to use this. Starting from the specified slot, n rows will be purged. That is, rows that occupies from slot to slot+n-1 will be purged from the page.

Locking Policy

Calls the lockRecordForWrite() method of the LockingPolicy object passed to the openContainer() call before the records are purged.

NOTE : CAVEAT
This operation will physically get rid of the row from the page, so if a subsequent operation on this page uses a slot that has been purged, then the undo of this operation will fail. It is only safe to use this operation if the caller knows that it has exclusive access to the page for the duration of the transaction, i.e, effectively holding a page lock on the page

Parameters

slot:int

the starting slot number

numpurges:int

number of slots to purge. If <= 0, just returns as a no-op.

needDataLogged:boolean

if set to true data is logged for purges else only headers.

Exceptions

StandardException:

Standard Derby error policy

See Also

LockingPolicy

Return the number of records on the page. The returned count includes rows that are deleted, i.e. it is the same as the number of slots on the page.
MT - latched

Exceptions

StandardException:

Standard Derby error policy

does the record still exist on the page?

If "ignoreDelete" is true and the record handle represents a record on the page (either marked deleted or not) return true. If "ignoreDelete" is false return true if the record handle represents a record on the page and the record is not marked as deleted. Return false otherwise.
MT - Latched

Parameters

handle:RecordHandle

handle of the record to look for.

ignoreDelete:boolean

if true, then routine will return true even if the row is marked deleted.

Returns:boolean

boolean indicating if the record still exists on the page.

Exceptions

StandardException:

Standard exception policy.

Set the aux object for this page. To clear the auxObject in the page, pass in a null AuxObject. If the AuxObject has already been set, this method will call auxObjectInvalidated() on the old aux objkect and replace it with aux.
MT - latched

See Also

AuxObject

Set a hint in the page object to indicate that scans positioned on it need to reposition. Only called on B-tree pages.

Set the time stamp to what is on page at this instance. No op if this page does not support time stamp.

Exceptions

StandardException:

Standard Derby error policy.

Is this page/deleted row a candidate for immediate reclaim space.

Used by access methods after executing a delete on "slot_just_deleted" to ask whether a post commit should be queued to try to reclaim space after the delete commits.

Will return true if the number of non-deleted rows on the page is <= "num_non_deleted_rows". For instance 0 means schedule reclaim only if all rows are deleted, 1 if all rows but one are deleted.

Will return true if the row just deleted is either a long row or long column. In this case doing a reclaim space on the single row may reclaim multiple pages of free space, so better to do it now rather than wait for all rows on page to be deleted. This case is to address the worst case scenario of all rows with long columns, but very short rows otherwise. In this case there could be 1000's of rows on the main page with many gigabytes of data on overflow pages in deleted space that would not be reclaimed until all rows on the page were deleted.

Parameters

num_non_deleted_rows:int

threshold number of non-deleted rows to schedule reclaim space.

slot_just_deleted:int

row on page to check for long row/long column

Returns:boolean

true if a reclaim space should be scheduled post commit on this page, false otherwise.

Exceptions

StandardException:

Standard exception policy.

Is it likely that an insert will fit on this page?

Return true if there is a good chance an insert will fit on this page, false otherwise. If this returns true then an insert may still fail by throwing an exception or by returning null, see insertAtSlot for details. It is very probable that this call is much faster than the version that takes a row. In situations where it is expected that the majority of times a row will fit on a page this method should be used and the null return handled from insert/insertAtSlot.
MT - latched

Returns:boolean

true if it is likely an insert will fit on the page.

Exceptions

StandardException:

Standard exception policy.

will insert of this row fit on this page?

Return true if this record is guaranteed to be inserted successfully using insert() or insertAtSlot(). This guarantee is only valid if the following conditions are fulfilled before an insert is called with t his row.

• The page is not unlatched
• The page is not modified in any way, ie. no updates or other inserts
• The row is not modified in such a way that would change its storage size

Parameters

row:Object[]

The row to check for insert.

validColumns:FormatableBitSet

bit map to interpret valid columns in row.

overflowThreshold:int

The percentage of the page to use for the insert. 100 means use 100% of the page, 50 means use 50% of page (ie. make sure 2 rows fit per page).

Returns:boolean

true if insert of this row will fit on this page.

Exceptions

StandardException:

Standard exception policy.

Unlatch me, the page is exclusivly latched by its current user until this method call is made.
After using this method the caller must throw away the reference to the Page object, e.g.

	ref.unlatch();
	ref = null;

Update the complete record identified by the slot.

Locking Policy

Calls the lockRecordForWrite() method of the LockingPolicy object passed to the openContainer() call before the record is undeleted. If record already deleted, an exception is thrown.
It is guaranteed that the page latch is not released by this method

Parameters

slot:int

is the slot number

validColumns:FormatableBitSet

a bit map of which columns in the row is valid. ValidColumns will not be changed by RawStore.

Returns:RecordHandle

a Handle to the updated record.

Exceptions

StandardException:

the container was not opened in update mode, or the slot is not on the page

Update a field within the record, replacing its current value with the stored representation of newValue. Record is identified by slot. If the field does not exist then it is added to the record, but only if (fieldId - 1) exists

Locking Policy

Calls the lockRecordForWrite() method of the LockingPolicy object passed to the openContainer() call before the record is updated.
It is guaranteed that the page latch is not released by this method

Parameters

slot:int

is the slot number

fieldId:int

is the column id

newValue:Object

has the new colum value to be stored in the record

undo:LogicalUndo

if logical undo may be necessary, a function pointer to the access code where the logical undo logic resides. Null if logical undo is not necessary.

Returns:RecordHandle

a Handle to the updated record.

Exceptions

StandardException:

Standard Derby error policy, a statement level exception is thrown if the slot is not on the page, or if the record is deleted, or if the fieldId is not on the record and (fieldId - 1) does not exist, or if the container was not opened in update mode.

See Also

LockingPolicy, LogicalUndo, LogicalUndoable