The
DBMS_LOCK
package provides an interface to Oracle Lock Management services. 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.- How To Install Dbms Lock Package Without
- How To Install Dbms Lock Package 2017
- How To Install Dbm Classic
- How To Install Dbms Lock Package In Nigeria
I am trying to write a small bit of PL/SQL that has a non-CPU burning sleep in it. The following works in sqldeveloper begin dbmslock.sleep(5); end; BUT (as the same user), I can't do the fol. I think i need to install the package again but i am not sure which script to use for the same. I'm not sure which script does that either. But if I were in this position, I'd go to another database of the same exact version that does have this package and see if I could get the DDL to recreate it. Installing with poetry.lock This brings us to the second scenario. If there is already a poetry.lock file as well as a pyproject.toml file when you run poetry install, it means either you ran the install command before, or someone else on the project ran the install command and committed the poetry.lock file to the project (which is good). DBMSLOB package The DBMSLOB package provides the capability to operate on large objects. In the following sections describing the individual procedures and functions, lengths and offsets are measured in bytes if the large objects are BLOBs.
See Also:
For more information, and an example of how to use the DBMS_LOCK
package, see 'About User Locks' in Oracle Database Application Developer's Guide - FundamentalsThis chapter contains the following topics:
- Overview
- Security Model
- Constants
- Rules and Limits
- Operational Notes
Using DBMS_LOCK
Overview
Some uses of user locks:
- 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
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.Constants
The
DBMS_LOCK
package uses the constants shown in Table 53-1.Table 53-1 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 | - | |
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').
Rules and Limits
When another process holds 'held', an attempt to get 'get' does the following:
Table 53-2 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 |
The constant
maxwait
waits forever.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.Summary of DBMS_LOCK Subprograms
Table 53-3 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. | |
Puts a procedure to sleep for a specific time. |
ALLOCATE_UNIQUE Procedure
This procedure allocates a unique lock identifier (in the range of 1073741824 to 1999999999) given a 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.
Syntax
Parameters
Table 53-4 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 given 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. |
Usage Notes
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 given 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.Note:
Named user locks may be less efficient, because Oracle uses SQL to determine the lock associated with a given name.
Exceptions Arcgis 10.1 keygen download.
ORA-20000
, ORU-10003:
Unable to find or insert lock <lockname
> into catalog dbms_lock_allocated
.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.Syntax
Parameters
Table 53-5 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 given lock. For the available modes and their associated integer identifiers, see Constants. |
timeout | Number of seconds to continue trying to change the lock mode. If the lock cannot be converted within this time period, then the call returns a value of 1 (timeout). |
Return Values
Table 53-6 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 |
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.Syntax
Parameters
Table 53-7 RELEASE Function Parameter
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 53-8 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 |
REQUEST Function
This function requests a lock with a given 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 53-9 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 53-10 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 |
SLEEP Procedure
This procedure suspends the session for a given period of time.
Syntax
Parameters
Table 53-11 SLEEP Procedure Parameters
Parameter | Description |
---|---|
seconds | Amount of time, in seconds, to suspend the session. The smallest increment can be entered in hundredths of a second; for example, 1.95 is a legal time value. |
Package Manager is software which allows a user in case of installation of new software, up-gradation of system, or updating any specific software and such sorts of things. In case of Linux based systems wherein one software has lots of dependencies which are required to be present on system for a complete installation of that software, such software’s like package manager become a much needed tool on every system.
Each Linux Distribution ships with its default package manager for above stated functionalities, but of all these most found ones are: yum on RHEL and Fedora systems (where it is being currently replaced with DNF from Fedora 22+ onwards) and apt from Debian.
If you’re looking for APT tool to block or disable certain specific package updates, then you should read this article.
Dnf or Danified yum is replacing yum on Fedora systems which is another one in our list. If explored properly, these Package Managers can be used for following functionalities:
- Installing new software from the repository.
- Resolve dependencies of the software by installing those dependencies before installing the software.
- Maintaining database of dependencies of each software.
- Downgrade version of any existing software.
- Upgrading the kernel version.
- Listing packages available for installation.
We’ve already covered detailed articles separately on each individual package managers with practical examples, you should must read them to control and manager package management in your respective Linux distributions.
Read Also:
In the article, we will see how to lock/disable certain package updates using Yum package manager in RHEL/CentOS and Fedora systems (applicable till Fedora 21, later newer Fedora version ships with dnf as default package manager).
Disable/Lock Package Updates using Yum
Yellow dog Updater, Modified (yum) is package management tool in RedHat based distributions such as CentOS and Fedora. Various strategies used to Lock/Disable Package Updates using Yum are discussed below:
1. Permanently Disable Package for Install or Update
1. Open and edit the
yum.conf
file, which is located in /etc/yum.conf or in /etc/yum/yum.conf.It looks like below:
Here, to exclude certain package from installation or up-gradation, you just need to add exclude variable along with name of package you wish to exclude. For example, if I want to exclude all the
python-3
packages from getting updated, then I will just append following line to yum.conf
:For more than one package to exclude just separate their names by space.
Note: to include these packages, ignoring entries in
yum.conf
, use “-disableexcludes” and set it to all|main|repoid, where ‘main’ are those entered in yum.conf and ‘repoid’ are those whose exclusion is specified in repos.d directory, as explained later on.Now let’s try to install or update the specified packages and see the yum command will disable them installing or updating.
2. Temporarily Disable Package for Install or Update
2. Above was a permanent solution to exclude a package as unless file is edited, that package won’t get updated. Here is a temporary solution for this also. Just at the time when you go for any update, use
-x
switch in yum command to exclude package which you do not want to update, like:The above command will update all the packages whose updates are available, excluding
python-3
on your system.How To Install Dbms Lock Package Without
Here, for excluding multiple packages, use
-x
multiple times, or separate package names with ','
in a single switch.3. Using
--exclude
switch works same as -x, just need to replace -x with –exclude and pass ','
separated list of package names to it.3. Disable Package Updates using Repository
4. For any package installed from any external source via adding a repository, there is another way to stop its up-gradation in future. This can be done by editing its
.repo
file which is created in /etc/yum/repos.d/ or /etc/yum.repos.d directory.How To Install Dbms Lock Package 2017
Add the exclude option with the package name in the repo. Like: to exclude any package say wine from epel repo, add the following line in
epel.repo
file:Now try to update the wine package, you will get error like shown below:
4. Disable Package Update Using versionlock Option
How To Install Dbm Classic
5. Another way in yum to mask the version of any package thus making it unavailable for up-gradation, is to use
versionlock
option of yum, but to do this, you must yum-plugin-versionlock package installed on the system.For example, to lock the version of package say httpd to 2.4.6 only, just write following command as root.
Sample Output
To view locked packages, use the following command will list the packages which have been version locked.
Sample Output
Conclusion
How To Install Dbms Lock Package In Nigeria
These are a few tips which will help you Disable/Lock Package updates using yum package manager. If you have any other tricks to do the same things, you can comment them with us.