The
DBMS_LOCK
package provides an interface to Oracle Lock Management services. - How To Install Dbms Lock Package 2017
- How To Install Dbms Lock Package In Excel
- How To Install Dbms Lock Package Without
- How To Install Dbms Lock Package System
- How To Install Dbms Lock Package In Java
- How To Install Dbms Lock Packages
You can request a lock of a specific mode, give it a unique name recognizable in another procedure in the same or another instance, change the lock mode, and release it.
This chapter contains the following topics:
The Oracle DBMSLOCK package makes the Oracle Kernel's lock management services available to user-written applications. Application locking implemented using Oracle DBMSLOCK is functionally identical to native RDBMS locking at the levels of lock modes and deadlock detection, compatibility, and visibility through V$ views. To function correctly, the IBM® OpenPages® GRC Platform Oracle packages must have access to some standard Oracle objects. In a standard Oracle deployment, database users can access the objects listed in the following tables. Some customer environments might restrict the default Oracle access model and remove public access from some of these objects. The DBMSSTATS package supports operations on user-defined statistics. When a domain index or column is associated with a statistics type (using the associate statement), operations on the index or column manipulate user-defined statistics. GRANT execute ON dbmslock TO GRANT execute ON dbmslock TO uwclass; ALLOCATEUNIQUE: Allocates a unique lock identifier (in the range of to ) given a lock name. Lock identifiers are used to enable applications to coordinate their use of locks: dbmslock.allocateunique(lockname IN VARCHAR2.
See Also:
For more information, and an example of how to use the
DBMS_LOCK
package, Oracle Database Development Guide94.1 DBMS_LOCK Overview
The
DBMS_LOCK
package has many beneficial uses. These uses include the following:
- Providing exclusive access to a device, such as a terminal
- Providing application-level enforcement of read locks
- Detecting when a lock is released and cleanup after the application
- Synchronizing applications and enforcing sequential processing
94.2 DBMS_LOCK Security Model
There might be operating system-specific limits on the maximum number of total locks available. This must be considered when using locks or making this package available to other users. Consider granting the
EXECUTE
privilege only to specific users or roles. A better alternative would be to create a cover package limiting the number of locks used and grant
EXECUTE
privilege to specific users. An example of a cover package is documented in the DBMS_LOCK.SQL
package specification file. The abbreviations for these locks as they appear in Enterprise Manager monitors are in parentheses. 94.3 DBMS_LOCK Constants
The
DBMS_LOCK
package includes several constants to use when specifying parameter values. These constants are shown in the following table.
Table 94-1 DBMS_LOCK Constants
Name | Alternate Name(s) | Type | Value | OEM Abbreviation | Description |
---|---|---|---|---|---|
NL_MODE | NuL1 | INTEGER | 1 | - | - |
SS_MODE | Sub Shared | INTEGER | 2 | ULRS | This can be used on an aggregate object to indicate that share locks are being acquired on subparts of the object. |
SX_MODE |
| INTEGER | 3 | ULRX | This can be used on an aggregate object to indicate that exclusive locks are being acquired on sub-parts of the object. |
S_MODE |
| INTEGER | 4 | ULRSX | - |
SSX_MODE |
| INTEGER | 5 | - | This indicates that the entire aggregate object has a share lock, but some of the sub-parts may additionally have exclusive locks. |
X_MODE | Exclusive | INTEGER | 6 | ULX | - |
These are the various lock modes (nl -> 'NuLl', ss -> 'Sub Shared', sx -> 'Sub eXclusive', s -> 'Shared', ssx -> 'Shared Sub eXclusive', x -> 'eXclusive').
94.4 DBMS_LOCK. Rules and Limits
When another process holds 'held', an attempt to get 'get' succeeds or fails, based on the held mode and type of get.
Table 94-2 Lock Compatibility
HELD MODE | GET NL | GET SS | GET SX | GET S | GET SSX | GET X |
---|---|---|---|---|---|---|
NL | Success | Success | Success | Success | Success | Success |
SS | Success | Success | Success | Success | Success | Fail |
SX | Success | Success | Success | Fail | Fail | Fail |
S | Success | Success | Fail | Success | Fail | Fail |
SSX | Success | Success | Fail | Fail | Fail | Fail |
X | Success | Fail | Fail | Fail | Fail | Fail |
94.5 DBMS_LOCK Operational Notes
User locks never conflict with Oracle locks because they are identified with the prefix 'UL'. You can view these locks using the Enterprise Manager lock monitor screen or the appropriate fixed views.
User locks are automatically released when a session terminates. The lock identifier is a number in the range of 0 to 1073741823.
Because a reserved user lock is the same as an Oracle lock, it has all the functionality of an Oracle lock, such as deadlock detection. Be certain that any user locks used in distributed transactions are released upon
COMMIT
, or an undetected deadlock may occur. DBMS_LOCK
is most efficient with a limit of a few hundred locks for each session. Oracle strongly recommends that you develop a standard convention for using these locks in order to avoid conflicts among procedures trying to use the same locks. For example, include your company name as part of your lock names.94.6 Summary of DBMS_LOCK Subprograms
This table lists the
DBMS_LOCK
subprograms and briefly describes them. Table 94-3 DBMS_LOCK Package Subprograms
Subprogram | Description |
---|---|
Allocates a unique lock ID to a named lock | |
Converts a lock from one mode to another | |
Releases a lock | |
Requests a lock of a specific mode. |
94.6.1 ALLOCATE_UNIQUE Procedure
This procedure allocates a unique lock identifier (in the range of 1073741824 to 1999999999) a specified lock name. Lock identifiers are used to enable applications to coordinate their use of locks. This is provided because it may be easier for applications to coordinate their use of locks based on lock names rather than lock numbers.
Parameters
Table 94-4 ALLOCATE_UNIQUE Procedure Parameters
Parameter | Description |
---|---|
lockname | Name of the lock for which you want to generate a unique ID. Do not use lock names beginning with ORA$ ; these are reserved for products supplied by Oracle. |
lockhandle | Returns the handle to the lock ID generated by ALLOCATE_UNIQUE . You can use this handle in subsequent calls to REQUEST , CONVERT , and RELEASE . A handle is returned instead of the actual lock ID to reduce the chance that a programming error accidentally creates an incorrect, but valid, lock ID. This provides better isolation between different applications that are using this package. LOCKHANDLE can be up to VARCHAR2 (128). All sessions using a lock handle returned by ALLOCATE_UNIQUE with the same lock name are referring to the same lock. Therefore, do not pass lock handles from one session to another. |
expiration_specs | Number of seconds to wait after the last ALLOCATE_UNIQUE has been performed on a specified lock, before permitting that lock to be deleted from the DBMS_LOCK_ALLOCATED table. The default waiting period is 10 days. You should not delete locks from this table. Subsequent calls to ALLOCATE_UNIQUE may delete expired locks to recover space. |
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If you choose to identify locks by name, you can use
ALLOCATE_UNIQUE
to generate a unique lock identification number for these named locks. The first session to call
ALLOCATE_UNIQUE
with a new lock name causes a unique lock ID to be generated and stored in the dbms_lock_allocated
table. Subsequent calls (usually by other sessions) return the lock ID previously generated. A lock name is associated with the returned lock ID for at least
expiration_secs
(defaults to 10 days) past the last call to ALLOCATE_UNIQUE
with the specified lock name. After this time, the row in the dbms_lock_allocated
table for this lock name may be deleted in order to recover space. ALLOCATE_UNIQUE
performs a commit. WARNING:
Named user locks may be less efficient, because Oracle uses SQL to determine the lock associated with a specified name.
Exceptions
ORA-20000
, ORU-10003:
Unable to find or insert lock <lockname
> into catalog dbms_lock_allocated
. 94.6.2 CONVERT Function
This function converts a lock from one mode to another.
CONVERT
is an overloaded function that accepts either a user-defined lock identifier, or the lock handle returned by the ALLOCATE_UNIQUE
procedure. Parameters
Table 94-5 CONVERT Function Parameters
Parameter | Description |
---|---|
id or lockhandle | User assigned lock identifier, from 0 to 1073741823, or the lock handle, returned by ALLOCATE_UNIQUE , of the lock mode you want to change |
lockmode | New mode that you want to assign to the specified lock. For the available modes and their associated integer identifiers, see Constants. |
timeout | Number of seconds to continue trying to change the lock mode. Free online janam kundli in hindi reading. If the lock cannot be converted within this time period, then the call returns a value of 1 (timeout). |
Return Values
Table 94-6 CONVERT Function Return Values
Return Value | Description |
---|---|
0 | Success |
1 | Timeout |
2 | Deadlock |
3 | Parameter error |
4 | Don't own lock specified by id or lockhandle |
5 | Illegal lock handle |
![Package Package](https://slideplayer.com/slide/7380448/24/images/6/How+do+I+configure+Oracle+to+support+geodatabases.jpg)
94.6.3 RELEASE Function
This function explicitly releases a lock previously acquired using the
REQUEST
function. Locks are automatically released at the end of a session.
RELEASE
is an overloaded function that accepts either a user-defined lock identifier, or the lock handle returned by the ALLOCATE_UNIQUE
procedure. Parameters
Table 94-7 RELEASE Function Parameter
How To Install Dbms Lock Package 2017
Parameter | Description |
---|---|
id or lockhandle | User assigned lock identifier, from 0 to 1073741823, or the lock handle, returned by ALLOCATE_UNIQUE , of the lock mode you want to change |
Return Values
Table 94-8 RELEASE Function Return Values
Return Value | Description |
---|---|
0 | Success |
3 | Parameter error |
4 | Do not own lock specified by id or lockhandle |
5 | Illegal lock handle |
94.6.4 REQUEST Function
This function requests a lock with a specified mode.
REQUEST
is an overloaded function that accepts either a user-defined lock identifier, or the lock handle returned by the ALLOCATE_UNIQUE
procedure. Syntax
The current default values, such as
X_MODE
and MAXWAIT
, are defined in the DBMS_LOCK
package specification. Parameters
Table 94-9 REQUEST Function Parameters
Parameter | Description |
---|---|
id or lockhandle | User assigned lock identifier, from 0 to 1073741823, or the lock handle, returned by ALLOCATE_UNIQUE , of the lock mode you want to change |
lockmode | Mode that you are requesting for the lock. For the available modes and their associated integer identifiers, see Constants. |
timeout | Number of seconds to continue trying to grant the lock. If the lock cannot be granted within this time period, then the call returns a value of 1 ( timeout ). |
release_on_commit | Set this parameter to TRUE to release the lock on commit or roll-back. Otherwise, the lock is held until it is explicitly released or until the end of the session. |
Return Values
Table 94-10 REQUEST Function Return Values
Return Value | Description |
---|---|
0 | Success |
1 | Timeout |
2 | Deadlock |
3 | Parameter error |
4 | Already own lock specified by id or lockhandle |
5 | Illegal lock handle |
yarn install
is used to install all dependencies for a project. This is mostcommonly used when you have just checked out code for a project, or whenanother developer on the project has added a new dependency that you need topick up.If you are used to using npm you might be expecting to use
--save
or--save-dev
. These have been replaced by yarn add
and yarn add --dev
. Formore information, seethe yarn add
documentation.Running
yarn
with no command will run yarn install
, passing through any provided flags.If you need reproducible dependencies, which is usually the case with the continuous integration systems, you should pass
--frozen-lockfile
flag.yarn install
Install all the dependencies listed within
package.json
in the localnode_modules
folder.The
yarn.lock
file is utilized as follows:- If
yarn.lock
is present and is enough to satisfy all the dependencies listed inpackage.json
, the exact versions recorded inyarn.lock
are installed, andyarn.lock
will be unchanged. Yarn will not check for newer versions. - If
yarn.lock
is absent, or is not enough to satisfy all the dependencies listed inpackage.json
(for example, if you manually add a dependency topackage.json
), Yarn looks for the newest versions available that satisfy the constraints inpackage.json
. The results are written toyarn.lock
.
If you want to ensure
yarn.lock
is not updated, use --frozen-lockfile
.yarn install --check-files
Verifies that already installed files in
node_modules
did not get removed.yarn install --flat
Install all the dependencies, but only allow one version for each package. On the first run this will prompt you tochoose a single version for each package that is depended on at multipleversion ranges. These will be added to your
package.json
under aresolutions
field.yarn install --force
This refetches all packages, even ones that were previously installed.
yarn install --har
Outputs an HTTP archive from all thenetwork requests performed during the installation. HAR files are commonly usedto investigate network performance, and can be analyzed with tools such asGoogle’s HAR Analyzer orHAR Viewer.
yarn install --ignore-scripts
Do not execute any scripts defined in the project package.json and its dependencies.
How To Install Dbms Lock Package In Excel
yarn install --modules-folder <path>
Specifies an alternate location for the
node_modules
directory, instead of the default ./node_modules
.yarn install --no-lockfile
Don’t read or generate a
yarn.lock
lockfile.yarn install --production[=true|false]
Yarn will not install any package listed in
devDependencies
if the NODE_ENV
environment variable is set to production
. Use this flag to instruct Yarn to ignore NODE_ENV
and take its production-or-not status from this flag instead.Notes:
--production
is the same as --production=true
. --prod
is an alias of --production
.yarn install --pure-lockfile
Don’t generate a
yarn.lock
lockfile.yarn install --focus
Shallowly installs a package’s sibling workspace dependencies underneath its
node_modules
folder. This allows you to run that workspace without building the other workspaces it depends on.Must be run inside an individual workspace in a workspaces project. Can not be run in a non-workspaces project or at the root of a workspaces project.
yarn install --frozen-lockfile
Don’t generate a
yarn.lock
lockfile and fail if an update is needed.yarn install --silent
Run yarn install without printing installation log.
yarn install --ignore-engines
Ignore engines check.
yarn install --ignore-optional
Don’t install optional dependencies.
yarn install --offline
Run yarn install in offline mode.
yarn install --non-interactive
Disable interactive prompts, like when there’s an invalid version of a dependency.
yarn install --update-checksums
Update checksums in the
yarn.lock
lockfile if there’s a mismatch between them and their package’s checksum.yarn install --audit
Checks for known security issues with the installed packages. A count of found issues will be added to the output. Use the
yarn audit
command for additional details. Unlike npm, which automatically runs an audit on every install, yarn will only do so when requested. (This may change in a later update as the feature is proven to be stable.)yarn install --no-bin-links
Prevent yarn from creating symlinks for any binaries the package might contain.
![How To Install Dbms Lock Package How To Install Dbms Lock Package](https://docs.oracle.com/database/121/DBSEG/img/GUID-707E4E6C-F68B-497A-8C29-F70D9C4D0CFF-default.png)
How To Install Dbms Lock Package Without
yarn install --link-duplicates
How To Install Dbms Lock Package System
Create hardlinks to the repeated modules in node_modules.
How To Install Dbms Lock Package In Java
yarn install --verbose
How To Install Dbms Lock Packages
Show additional logs while installing dependencies