Holds read and write locks until end of transaction. Obtains previous key locks to protect from phantom reads.
| Modifier and Type | Field and Description |
|---|---|
| protected ConglomerateController | base_cc
The container id of the base container for this index. |
| protected OpenBTree | open_btree
The OpenBtree to use if we have to lock anything in the btree vs. base row locking. |
| private Transaction | rawtran
The transaction to associate lock requests with. |
| Access | Constructor and Description |
|---|---|
| pack-priv | B2IRowLocking3(Transaction rawtran, int lock_level, LockingPolicy locking_policy, ConglomerateController base_cc, OpenBTree open_btree)
Constructors for This class: |
| Modifier and Type | Method and Description |
|---|---|
| protected boolean | Returns: Whether locks were acquired without releasing latch on leaf.The open_btree to associate latches with -
used if routine has to scan backward. open_btree, BTreeRowPosition The position of the row to lock. pos, boolean Whether to request the row lock, should
only be requested once per page in the scan. request_row_lock, FetchDescriptor The fetch descriptor to use to fetch the
row location for the lock request. lock_fetch_desc, DataValueDescriptor[] A scratch area to use to read in rows. lock_template, RowLocation lock_row_loc, boolean Is this a previous key lock call? previous_key_lock, boolean Is the scan for update or for read only. forUpdate, int lock_operation)Lock a row as part of doing the scan. |
| public boolean | lockNonScanPreviousRow(LeafControlRow
Latched current leaf where "current" key is. current_leaf, int The slot of row on "current_leaf" current_slot, FetchDescriptor lock_fetch_desc, DataValueDescriptor[] Empty full template row, to read row into. lock_template, RowLocation lock_row_loc, OpenBTree The open_btree to associate latches with -
used if routine has to scan backward. open_btree, int For what operation are we requesting the lock,
this should be one of the following 4 options:
LOCK_READ [read lock],
(LOCK_INS | LOCK_UPD) [ lock for insert],
(LOCK_INSERT_PREVKEY | LOCK_UPD) [lock for
previous key to insert],
(LOCK_UPD) [lock for delete or replace] lock_operation, int For what duration should the lock be held,
if INSTANT_DURATION, then the routine will
guarantee that lock was acquired while holding
the latch, but then immediately release the
lock. If COMMIT_DURATION or MANUAL_DURATION
then the lock be held when routine returns
successfully. lock_duration)Implements org. Lock the row previous to the input row. |
| public boolean | lockNonScanRow(BTree
The conglomerate we are locking. btree, LeafControlRow If non-null, this leaf is unlatched if the
routine has to wait on the lock. current_leaf, LeafControlRow If non-null, this leaf is unlatched if the
routine has to wait on the lock. aux_leaf, DataValueDescriptor[] In memory, objectified "current" row. current_row, int For what operation are we requesting the lock,
this should be one of the following 4 options:
LOCK_READ [read lock],
(LOCK_INS | LOCK_UPD) [ lock for insert],
(LOCK_INSERT_PREVKEY | LOCK_UPD) [lock for
previous key to insert],
(LOCK_UPD) [lock for delete or replace] lock_operation)Implements org. Lock the in memory row. |
| public boolean | lockNonScanRowOnPage(LeafControlRow
The control row of the current leaf to lock. current_leaf, int The slot position of the row to lock. current_slot, FetchDescriptor lock_fetch_desc, DataValueDescriptor[] A scratch area to use to read in rows. lock_template, RowLocation lock_row_loc, int For what operation are we requesting the lock,
this should be one of the following 4 options:
LOCK_READ [read lock],
(LOCK_INS | LOCK_UPD) [ lock for insert],
(LOCK_INSERT_PREVKEY | LOCK_UPD) [lock for
previous key to insert],
(LOCK_UPD) [lock for delete or replace] lock_operation)Implements org. Lock the row at the given slot. |
| private boolean | lockPreviousToFirstKey(LeafControlRow current_leaf, LeafControlRow
If non-null, this leaf is unlatched if the
routine has to wait on the lock. aux_leaf, int Whether to lock exclusive or share. lock_operation, int For what duration should the lock be held,
if INSTANT_DURATION, then the routine will
guarantee that lock was acquired while holding
the latch, but then immediately release the
lock. If COMMIT_DURATION or MANUAL_DURATION
then the lock be held when routine returns
successfully. lock_duration)Lock key previous to first key in btree. |
| private boolean | lockRowOnPage(LeafControlRow
Latched current leaf where "current" key is. current_leaf, LeafControlRow If non-null, this leaf is unlatched if the
routine has to wait on the lock. aux_leaf, int Slot of row to lock. current_slot, BTreeRowPosition The position to lock if the lock is requested
while performing a scan, null otherwise. position, FetchDescriptor Descriptor for fetching just the RowLocation,
used for locking. lock_fetch_desc, DataValueDescriptor[] lock_template, RowLocation lock_row_loc, int Whether lock is for key prev to insert or not. lock_operation, int For what duration should the lock be held,
if INSTANT_DURATION, then the routine will
guarantee that lock was acquired while holding
the latch, but then immediately release the
lock. If COMMIT_DURATION or MANUAL_DURATION
then the lock be held when routine returns
successfully. lock_duration)Lock a btree row (row is at given slot in page). |
| public boolean | lockScanCommittedDeletedRow(OpenBTree
The conglomerate we are locking. open_btree, LeafControlRow The leaf page with the row to lock. leaf, DataValueDescriptor[] Empty full template row, to read row into. template, FetchDescriptor lock_fetch_desc, int The slot of row on "current_leaf" slot_no)Implements org. Lock a btree row to determine if it is a committed deleted row. |
| public boolean | Returns: Whether locks were acquired without releasing latch on leaf.The open_btree to associate latches with -
used if routine has to scan backward. open_btree, BTreeRowPosition The position of the row to lock. pos, FetchDescriptor lock_fetch_desc, DataValueDescriptor[] A scratch area to use to read in rows. lock_template, RowLocation lock_row_loc, boolean Is this a previous key lock call? previous_key_lock, boolean Is the scan for update or for read only. forUpdate, int For what operation are we requesting the lock,
this should be one of the following 4 options:
LOCK_READ [read lock],
(LOCK_INS | LOCK_UPD) [ lock for insert],
(LOCK_INSERT_PREVKEY | LOCK_UPD) [lock for
previous key to insert],
(LOCK_UPD) [lock for delete or replace] lock_operation)Implements org. Lock a row as part of doing the scan. |
| private boolean | Returns: true if previous key found without ever waiting on a latch, false if latch released in order to wait for other latch.move left in btree and lock previous key. |
| public void | unlockScanRecordAfterRead(BTreeRowPosition
Data structure that defines the current position
in the scan to be unlocked. pos, boolean Is the scan for update or for read only. forUpdate)Implements org. Release read lock on a row. |
| base_cc | back to summary |
|---|---|
| protected ConglomerateController base_cc The container id of the base container for this index. Used to build record handles to make lock calls on. | |
| open_btree | back to summary |
|---|---|
| protected OpenBTree open_btree The OpenBtree to use if we have to lock anything in the btree vs. base row locking. | |
| rawtran | back to summary |
|---|---|
| private Transaction rawtran The transaction to associate lock requests with. | |
| B2IRowLocking3 | back to summary |
|---|---|
| pack-priv B2IRowLocking3(Transaction rawtran, int lock_level, LockingPolicy locking_policy, ConglomerateController base_cc, OpenBTree open_btree) Constructors for This class: | |
| _lockScanRow | back to summary |
|---|---|
| protected boolean _lockScanRow(OpenBTree open_btree, BTreeRowPosition pos, boolean request_row_lock, FetchDescriptor lock_fetch_desc, DataValueDescriptor[] lock_template, RowLocation lock_row_loc, boolean previous_key_lock, boolean forUpdate, int lock_operation) throws StandardException Lock a row as part of doing the scan. Lock the row at the given slot (or the previous row if slot is 0). If this routine returns true all locks were acquired while maintaining the latch on leaf. If this routine returns false, locks may or may not have been acquired, and the routine should be called again after the client has researched the tree to reget the latch on the appropriate page.
| |
| lockNonScanPreviousRow | back to summary |
|---|---|
| public boolean lockNonScanPreviousRow(LeafControlRow current_leaf, int current_slot, FetchDescriptor lock_fetch_desc, DataValueDescriptor[] lock_template, RowLocation lock_row_loc, OpenBTree open_btree, int lock_operation, int lock_duration) throws StandardException Implements org. Lock the row previous to the input row. See BTreeLockingPolicy.lockNonScanPreviousRow
| |
| lockNonScanRow | back to summary |
|---|---|
| public boolean lockNonScanRow(BTree btree, LeafControlRow current_leaf, LeafControlRow aux_leaf, DataValueDescriptor[] current_row, int lock_operation) throws StandardException Implements org. Lock the in memory row. See BTree.lockRow() for more info.
| |
| lockNonScanRowOnPage | back to summary |
|---|---|
| public boolean lockNonScanRowOnPage(LeafControlRow current_leaf, int current_slot, FetchDescriptor lock_fetch_desc, DataValueDescriptor[] lock_template, RowLocation lock_row_loc, int lock_operation) throws StandardException Implements org. Doc from org. Lock the row at the given slot. If this routine returns true all locks were acquired while maintaining the latch on leaf. If this routine returns false, locks may or may not have been acquired, and the routine should be called again after the client has researched the tree to reget the latch on the appropriate page.
| |
| lockPreviousToFirstKey | back to summary |
|---|---|
| private boolean lockPreviousToFirstKey(LeafControlRow current_leaf, LeafControlRow aux_leaf, int lock_operation, int lock_duration) throws StandardException Lock key previous to first key in btree. In the previous key locking protocol repeatable read and phantom protection is guaranteed by locking a range of keys in the btree. The range is defined by the key previous to the first key you look at and all subsequent keys you look at. The first key in the index is a special case, as there are no keys previous to it. In that case a special key is declared the "previous key" to the first key in the btree and is locked instead. In this implementation that first key is defined to be in the base container, page ContainerHandle.FIRST_PAGE_NUMBER, record id PREVIOUS_KEY_HANDLE. Note that the previous key is the same for all indexes on a given conglomerate. It seemed better for all locks on a base table to have the same containerid, rather than having some locks generated from a btree have a containerid from base table and some having a containerid from the btree. If this turns out to be a problem we could either have 2 different containerid's, be more creative with the record id, or even add more to the lock key.
| |
| lockRowOnPage | back to summary |
|---|---|
| private boolean lockRowOnPage(LeafControlRow current_leaf, LeafControlRow aux_leaf, int current_slot, BTreeRowPosition position, FetchDescriptor lock_fetch_desc, DataValueDescriptor[] lock_template, RowLocation lock_row_loc, int lock_operation, int lock_duration) throws StandardException Lock a btree row (row is at given slot in page). Lock the row at the given slot in the page. Meant to be used if caller only has the slot on the page to be locked, and has not read the row yet. This routine fetches the row location field from the page, and then locks that rowlocation in the base container. Lock a btree row, enforcing the standard lock/latch protocol. On return the row is locked. Return status indicates if the lock was waited for, which will mean a latch was dropped while waiting. In general a false status means that the caller will either have to research the tree unless some protocol has been implemented that insures that the row will not have moved while the latch was dropped. This routine request a row lock NOWAIT on the in-memory row "current_row.". If the lock is granted the routine will return true. If the lock cannot be granted NOWAIT, then the routine will release the latch on "current_leaf" and "aux_leaf" (if aux_leaf is non-null), and then it will request a WAIT lock on the row.
| |
| lockScanRow | back to summary |
|---|---|
| public boolean lockScanRow(OpenBTree open_btree, BTreeRowPosition pos, FetchDescriptor lock_fetch_desc, DataValueDescriptor[] lock_template, RowLocation lock_row_loc, boolean previous_key_lock, boolean forUpdate, int lock_operation) throws StandardException Implements org. Lock a row as part of doing the scan. Lock the row at the given slot (or the previous row if slot is 0). If this routine returns true all locks were acquired while maintaining the latch on leaf. If this routine returns false, locks may or may not have been acquired, and the routine should be called again after the client has researched the tree to reget the latch on the appropriate page.
| |
| searchLeftAndLockPreviousKey | back to summary |
|---|---|
| private boolean searchLeftAndLockPreviousKey(LeafControlRow current_leaf, FetchDescriptor lock_fetch_desc, DataValueDescriptor[] lock_template, RowLocation lock_row_loc, OpenBTree open_btree, int lock_operation, int lock_duration) throws StandardException move left in btree and lock previous key. Enter routine with "current_leaf" latched. This routine implements the left travel ladder locking protocol to search the leaf pages from right to left for the previous key to 1st key on current_leaf. There are 2 cases: 1) the previous page has keys, in which case the last key on that page is locked, other wise search continues on the next page to the left. 2) there are no keys on the current page and there is no page to the left. In this case the special "leftmost key" lock is gotten by calling lockPreviousToFirstKey(). Left laddar locking is used if all latches can be obtained immediately with NOWAIT. This means that current latch is held while asking for left latch NOWAIT, and if left latch is granted then subsequently current latch can be released. If this protocol is followed and all latches are granted then caller is guaranteed that the correct previous key has been locked and current_page latch remains. The NOWAIT protocol is used to avoid latch/latch deadlocks. The overall protocol is that one never holds a latch while waiting on another unless the direction of travel is down and to the right. If along the search a latch has to be waited on then latches are released and a wait is performed, and "false" status is returned to caller. In this case the routine can no longer be sure of it's current position and may have to retry the whole operation.
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| unlockScanRecordAfterRead | back to summary |
|---|---|
| public void unlockScanRecordAfterRead(BTreeRowPosition pos, boolean forUpdate) throws StandardException Implements org. Release read lock on a row. For serializable, there is no work to do.
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