578:: this allows multiple concurrent users access to the database whilst the system keeps a copy of the initial-read made by each user. When a user wants to update a record, the application determines whether another user has changed the record since it was last read. The application does this by comparing the initial-read held in memory to the database record to verify any changes made to the record. Any discrepancies between the initial-read and the database record violates concurrency rules and hence causes the system to disregard any update request. An error message is generated and the user is asked to start the update process again. It improves database performance by reducing the amount of locking required, thereby reducing the load on the database server. It works efficiently with tables that require limited updates since no users are locked out. However, some updates may fail. The downside is constant update failures due to high volumes of update requests from multiple concurrent users - it can be frustrating for users.
499:. The more coarse the lock, the higher the likelihood that the lock will stop an unrelated process from proceeding. Conversely, using a fine granularity (a larger number of locks, each protecting a fairly small amount of data) increases the overhead of the locks themselves but reduces lock contention. Granular locking where each process must hold multiple locks from a common set of locks can create subtle lock dependencies. This subtlety can increase the chance that a programmer will unknowingly introduce a
566:
occur. Pessimistic concurrency is best implemented when lock times will be short, as in programmatic processing of records. Pessimistic concurrency requires a persistent connection to the database and is not a scalable option when users are interacting with data, because records might be locked for relatively large periods of time. It is not appropriate for use in Web application development.
671:
respective locks. The first blocked lock for operation in the queue is acquired as soon as the existing blocking lock is removed from the object, and then its respective operation is executed. If a lock for operation in the queue is not blocked by any existing lock (existence of multiple compatible locks on a same object is possible concurrently), it is acquired immediately.
558:: a user who reads a record with the intention of updating it places an exclusive lock on the record to prevent other users from manipulating it. This means no one else can manipulate that record until the user releases the lock. The downside is that users can be locked out for a very long time, thereby slowing the overall system response and causing frustration.
97:, the thread simply waits ("spins") until the lock becomes available. This is efficient if threads are blocked for a short time, because it avoids the overhead of operating system process re-scheduling. It is inefficient if the lock is held for a long time, or if the progress of the thread that is holding the lock depends on preemption of the locked thread.
510:, for example, a lock could protect, in order of decreasing granularity, part of a field, a field, a record, a data page, or an entire table. Coarse granularity, such as using table locks, tends to give the best performance for a single user, whereas fine granularity, such as record locks, tends to give the best performance for multiple users.
470:: this occurs whenever one process or thread attempts to acquire a lock held by another process or thread. The more fine-grained the available locks, the less likely one process/thread will request a lock held by the other. (For example, locking a row rather than the entire table, or locking a cell rather than the entire row);
852:
has been withdrawn from the first account, but not yet deposited into the other account: money has gone missing from the system. This problem can only be fixed completely by taking locks on both account prior to changing any of the two accounts, but then the locks have to be taken according to some
776:
In most cases, proper locking depends on the CPU providing a method of atomic instruction stream synchronization (for example, the addition or deletion of an item into a pipeline requires that all contemporaneous operations needing to add or delete other items in the pipe be suspended during the
670:
indicates incompatibility, i.e, a case when a lock of the first type (in left column) on an object blocks a lock of the second type (in top row) from being acquired on the same object (by another transaction). An object typically has a queue of waiting requested (by transactions) operations with
585:
Where to use optimistic locking: this is appropriate in environments where there is low contention for data, or where read-only access to data is required. Optimistic concurrency is used extensively in .NET to address the needs of mobile and disconnected applications, where locking data rows for
565:
Where to use pessimistic locking: this is mainly used in environments where data-contention (the degree of users request to the database system at any one time) is heavy; where the cost of protecting data through locks is less than the cost of rolling back transactions, if concurrency conflicts
531:
ensures that the concurrent execution of the transaction turns out equivalent to some serial ordering of the transaction. However, deadlocks become an unfortunate side-effect of locking in databases. Deadlocks are either prevented by pre-determining the locking order between transactions or are
712:
Instability: the optimal balance between lock overhead and lock contention can be unique to the problem domain (application) and sensitive to design, implementation, and even low-level system architectural changes. These balances may change over the life cycle of an application and may entail
195:
The above example does not guarantee that the task has the lock, since more than one task can be testing the lock at the same time. Since both tasks will detect that the lock is free, both tasks will attempt to set the lock, not knowing that the other task is also setting the lock.
777:
manipulation of the memory content required to add or delete the specific item). Therefore, an application can often be more robust when it recognizes the burdens it places upon an operating system and is capable of graciously recognizing the reporting of impossible demands.
716:
Composability: locks are only composable (e.g., managing multiple concurrent locks in order to atomically delete item X from table A and insert X into table B) with relatively elaborate (overhead) software support and perfect adherence by applications programming to rigorous
690:
Contention: some threads/processes have to wait until a lock (or a whole set of locks) is released. If one of the threads holding a lock dies, stalls, blocks, or enters an infinite loop, other threads waiting for the lock may wait indefinitely until the computer is
1176:
that sometimes uses the same basic implementation as the binary semaphore. However, they differ in how they are used. While a binary semaphore may be colloquially referred to as a mutex, a true mutex has a more specific use-case and definition, in that only the
461:: the extra resources for using locks, like the memory space allocated for locks, the CPU time to initialize and destroy locks, and the time for acquiring or releasing locks. The more locks a program uses, the more overhead associated with the usage;
801:
that allows multiple concurrent clients to deposit or withdraw money to an account; and give an algorithm to transfer money from one account to another. The lock-based solution to the first part of the problem is:
74:. It provides exclusive access to the locked data. Other schemes also provide shared access for reading data. Other widely implemented access modes are exclusive, intend-to-exclude and intend-to-upgrade.
491:. The granularity is a measure of the amount of data the lock is protecting. In general, choosing a coarse granularity (a small number of locks, each protecting a large segment of data) results in less
1911:
769:. However, such alternative methods often require that the actual lock mechanisms be implemented at a more fundamental level of the operating software. Therefore, they may only relieve the
219:. (The most common strategy is to standardize the lock acquisition sequences so that combinations of inter-dependent locks are always acquired in a specifically defined "cascade" order.)
586:
prolonged periods of time would be infeasible. Also, maintaining record locks requires a persistent connection to the database server, which is not possible in disconnected applications.
597:
Several variations and refinements of these major lock types exist, with respective variations of blocking behavior. If a first lock blocks another lock, the two locks are called
1188:: If the mutex knows who locked it and is supposed to unlock it, it is possible to promote the priority of that task whenever a higher-priority task starts waiting on the mutex.
1615:
1594:
1421:
A protected object provides coordinated access to shared data, through calls on its visible protected operations, which can be protected subprograms or protected entries.
1636:
789:": it is hard to combine small, correct lock-based modules into equally correct larger programs without modifying the modules or at least knowing about their internals.
698:
Overhead: the use of locks adds overhead for each access to a resource, even when the chances for collision are very rare. (However, any chance for such collisions is a
123:
1573:
495:
when a single process is accessing the protected data, but worse performance when multiple processes are running concurrently. This is because of increased
478:: the situation when each of at least two tasks is waiting for a lock that the other task holds. Unless something is done, the two tasks will wait forever.
134:
shared-memory machines. Proper support for locks in a multiprocessor environment can require quite complex hardware or software support, with substantial
1552:
1116:, which can either be empty or contain a value, typically a reference to a resource. A thread that wants to use the resource âtakesâ the value of the
527:
can be used as a means of ensuring transaction synchronicity. i.e. when making transaction processing concurrent (interleaving transactions), using
1472:
1433:
78:
482:
There is a tradeoff between decreasing lock overhead and decreasing lock contention when choosing the number of locks in synchronization.
879:
1191:
Premature task termination: Mutexes may also provide deletion safety, where the task holding the mutex cannot be accidentally deleted.
116:". These instructions allow a single process to test if the lock is free, and if free, acquire the lock in a single atomic operation.
2581:
1938:
773:
level from the details of implementing locks, with the problems listed above still needing to be dealt with beneath the application.
536:. An alternate to locking for database synchronicity while avoiding deadlocks involves the use of totally ordered global timestamps.
1329:
786:
1697:
145:
is required is because of concurrency, where more than one task executes the same logic. For example, consider the following
1181:
that locked the mutex is supposed to unlock it. This constraint aims to handle some potential problems of using semaphores:
100:
Locks typically require hardware support for efficient implementation. This support usually takes the form of one or more
59:, where each thread cooperates by acquiring the lock before accessing the corresponding data. Some systems also implement
705:
Debugging: bugs associated with locks are time dependent and can be very subtle and extremely hard to replicate, such as
678:
In some publications, the table entries are simply marked "compatible" or "incompatible", or respectively "yes" or "no".
47:
policies, and with a variety of possible methods there exist multiple unique implementations for different applications.
1161:
2463:
1235:
762:
741:: all other threads have to wait if a thread holding a lock is descheduled due to a time-slice interrupt or page fault.
216:
135:
1671:
2576:
2488:
1869:
1835:
1173:
915:
1304:
1124:
results in the thread blocking until the resource is available. As an alternative to locking, an implementation of
723:: a low-priority thread/process holding a common lock can prevent high-priority threads/processes from proceeding.
487:
2436:
2261:
2060:
1384:
1358:
871:
to.lock() from.lock() from.withdraw(amount) to.deposit(amount) from.unlock() to.unlock()
215:. A number of strategies can be used to avoid or recover from deadlocks or livelocks, both at design-time and at
2154:
961:
731:
can be used on uniprocessor systems to minimize the worst-case priority-inversion duration, as well as prevent
223:
1855:
1821:
2284:
2244:
1931:
1143:
1125:
1031:
993:
794:
750:
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2249:
1042:
1011:
820:
deposit(n: Integer) mutex.lock() balance â balance + n mutex.unlock()
758:
1528:
1208:
Accidental release: An error is raised on the release of the mutex if the releasing task is not its owner.
2529:
2367:
1487:
1089:
1079:
985:
938:
standard is supported by some compilers, and allows critical sections to be specified using pragmas. The
732:
706:
474:
418:
208:
2144:
1195:
900:
891:
841:
transfer(from: Account, to: Account, amount: Integer) from.withdraw(amount) to.deposit(amount)
507:
40:
1120:, leaving it empty, and puts it back when it is finished. Attempting to take a resource from an empty
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2347:
2174:
1746:
1240:
1147:
1131:
997:
919:
728:
101:
90:
36:
903:
provides protected objects that have visible protected subprograms or entries as well as rendezvous.
2392:
2357:
2324:
1974:
1924:
1014:
NSLock, NSRecursiveLock, and NSConditionLock along with the NSLocking protocol for locking as well.
907:
543:
on a databaseâthe purpose is to prevent lost updates and dirty reads. The two types of locking are
146:
1269:
2294:
2266:
2204:
2189:
2105:
1947:
1250:
454:
Before being introduced to lock granularity, one needs to understand three concepts about locks:
421:, C# can also synchronize entire methods, by using the MethodImplOptions.Synchronized attribute.
201:
71:
844:
In a concurrent program, this algorithm is incorrect because when one thread is halfway through
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2199:
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1984:
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86:
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724:
686:
Lock-based resource protection and thread/process synchronization have many disadvantages:
82:
1308:
8:
2402:
2387:
2382:
2239:
2124:
2070:
1283:
971:
746:
605:. Often, lock types blocking interactions are presented in the technical literature by a
466:
44:
1448:
1337:
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2503:
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2159:
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2004:
1966:
1861:
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64:
927:
2194:
2037:
2027:
2022:
1994:
1989:
1865:
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951:
528:
1701:
950:
attribute of methods to be synchronized, but this is specific to COM objects in the
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2179:
2100:
2090:
2080:
2075:
1532:
1245:
1220:
1178:
1135:
1083:
1035:
958:
compiler. C and C++ can easily access any native operating system locking features.
911:
142:
113:
32:
20:
2483:
2429:
2407:
2184:
2139:
2110:
2085:
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2012:
1979:
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540:
524:
519:
1723:
2468:
2329:
2032:
2017:
699:
533:
131:
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of instructionsâusing special instructions or instruction prefixes to disable
93:
requesting the lock until it is allowed to access the locked resource. With a
2565:
2289:
2134:
2095:
2042:
1194:
Termination deadlock: If a mutex-holding task terminates for any reason, the
939:
692:
109:
2545:
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2164:
1916:
1851:
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1230:
955:
943:
119:
105:
874:
This solution gets more complicated when more locks are involved, and the
757:
can avoid the biggest problem: deadlocks. Alternatives to locking include
63:, where attempting unauthorized access to a locked resource will force an
2498:
2473:
2458:
2377:
2209:
1003:
738:
204:
are possible substitutes if atomic locking operations are not available.
797:) gives the following example of a banking application: design a class
785:
One of lock-based programming's biggest problems is that "locks don't
16:
Synchronization mechanism for enforcing limits on access to a resource
2478:
1333:
127:
212:
94:
1198:
can release the mutex and signal waiting tasks of this condition.
1109:
1053:
968:
keyword on a thread to ensure its exclusive access to a resource.
931:
896:
Programming languages vary in their support for synchronization:
878:
function needs to know about all of the locks, so they cannot be
609:. The following is an example with the common, major lock types:
1885:
539:
There are mechanisms employed to manage the actions of multiple
39:
that prevents state from being modified or accessed by multiple
1330:"Designing Data Tier Components and Passing Data Through Tiers"
935:
749:
strategies avoid some or all of these problems. For example, a
414:
can lead to problems if the instance can be accessed publicly.
1169:
923:
222:
Some languages do support locks syntactically. An example in
827:
The second part of the problem is much more complicated. A
1793:"Shared-State Concurrency - The Rust Programming Language"
1392:
Beautiful Code: Leading
Programmers Explain How They Think
1139:
1112:
implements locking via a mutable data structure called an
1106:
prefix on certain operations to guarantee their atomicity.
859:
transfer(from: Account, to: Account, amount: Integer)
77:
Another way to classify locks is by what happens when the
1205:
multiple times as it unlocks it an equal number of times.
1017:
1000:
and libraries featuring concurrency-safe data structures.
369:// Only one thread at a time may execute this statement.
309:// Only one thread at a time may execute this statement.
81:
prevents the progress of a thread. Most locking designs
1820:(August 2013). "Basic concurrency: threads and MVars".
727:
can be used to reduce priority-inversion duration. The
1010:
to put locks on blocks of code and also provides the
1810:
1359:"Lock Based Concurrency Control Protocol in DBMS"
1142:package. It can be used for locking code blocks,
130:temporarilyâbut this technique does not work for
2563:
1854:(August 2013). "Software transactional memory".
1201:Recursion deadlock: a task is allowed to lock a
1162:Semaphore (programming) § Semaphores vs. mutexes
853:arbitrary, global ordering to prevent deadlock:
1857:Parallel and Concurrent Programming in Haskell
1823:Parallel and Concurrent Programming in Haskell
1932:
1698:"Thread Synchronization Mechanisms in Python"
1446:
1404:
1284:"ThreadPoolPriority, and MethodImplAttribute"
67:in the entity attempting to make the access.
1946:
1382:
1056:standard (ISO/IEC 1539-1:2010) provides the
1020:provides a file-based locking as well as a
824:withdraw(n: Integer) deposit(ân)
1471:: CS1 maint: numeric names: authors list (
1432:: CS1 maint: numeric names: authors list (
592:
1939:
1925:
713:tremendous changes to update (re-balance).
1747:"Programming Ruby: Threads and Processes"
1721:
1154:
1485:
1449:"Example of Tasking and Synchronization"
1305:"C# From a Java Developer's Perspective"
780:
43:at once. Locks enforce mutual exclusion
1912:Tutorial on Locks and Critical Sections
1724:"Coarrays in the next Fortran Standard"
1407:"Protected Units and Protected Objects"
485:An important property of a lock is its
122:architectures have the option of using
2564:
1850:
1816:
1390:. In Wilson, Greg; Oram, Andy (eds.).
848:, another might observe a state where
70:The simplest type of lock is a binary
1920:
1695:
1060:derived type in the intrinsic module
207:Careless use of locks can result in
885:
13:
1886:"sync package - sync - pkg.go.dev"
1236:Lock-free and wait-free algorithms
867:from.lock() to.lock()
865:// arbitrary ordering on the locks
240:// This is a monitor of an account
14:
2593:
1905:
916:application programming interface
513:
2582:Programming language comparisons
1160:This section is an excerpt from
681:
2437:Enterprise Integration Patterns
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1650:
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1608:
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1566:
1545:
1521:
1500:
1270:"lock Statement (C# Reference)"
1637:"NSLocking Protocol Reference"
1479:
1453:Ada 2005 Reference Manual
1440:
1411:Ada 2005 Reference Manual
1398:
1376:
1351:
1322:
1297:
1276:
1262:
449:
1:
1486:Marshall, Dave (March 1999).
1336:. August 2002. Archived from
1256:
1138:object in standard's library
1126:software transactional memory
910:standard provides a standard
795:software transactional memory
1696:Lundh, Fredrik (July 2007).
1383:Peyton Jones, Simon (2007).
759:non-blocking synchronization
7:
2530:Portland Pattern Repository
1616:"NSConditionLock Reference"
1595:"NSRecursiveLock Reference"
1553:"Apple Threading Reference"
1214:
942:API provides lock support.
765:programming techniques and
10:
2598:
1159:
892:Barrier (computer science)
889:
601:; otherwise the locks are
517:
508:database management system
2538:
2517:
2446:
2421:
2338:
2223:
2123:
2051:
2003:
1965:
1954:
1768:"std::sync::Mutex - Rust"
1241:Monitor (synchronization)
729:priority ceiling protocol
613:Lock compatibility table
124:uninterruptible sequences
37:synchronization primitive
2577:Software design patterns
2155:Event-based asynchronous
1948:Software design patterns
1488:"Mutual Exclusion Locks"
831:routine that is correct
607:Lock compatibility table
593:Lock compatibility table
423:
228:
151:
50:
2061:Chain of responsibility
1385:"Beautiful concurrency"
1251:Read/write lock pattern
833:for sequential programs
664:indicates compatibility
2200:Scheduled-task pattern
2150:Double-checked locking
1226:Double-checked locking
1155:Mutexes vs. semaphores
1086:object and no keyword.
922:. The current ISO/IEC
104:instructions such as "
2551:Architectural pattern
2454:Christopher Alexander
1134:provides a low-level
1100:x86 assembly language
1082:provides a low-level
1034:provides a low-level
1006:provides the keyword
992:to lock code blocks,
988:provides the keyword
812:balance: Integer
781:Lack of composability
55:Generally, locks are
2363:Dependency injection
2320:Inversion of control
2315:Data transfer object
2215:Thread-local storage
1510:. msdn.microsoft.com
928:threading facilities
767:transactional memory
725:Priority inheritance
202:Peterson's algorithm
175:// lock free, set it
41:threads of execution
2572:Concurrency control
2368:Intercepting filter
1447:ISO/IEC 8652:2007.
1405:ISO/IEC 8652:2007.
972:Visual Basic (.NET)
747:concurrency control
614:
556:Pessimistic locking
545:pessimistic locking
45:concurrency control
2525:The Hillside Group
2310:Data access object
2160:Guarded suspension
2145:Binding properties
1722:John Reid (2010).
1574:"NSLock Reference"
1286:. MSDN. p. ??
1186:Priority inversion
978:keyword like C#'s
926:standard supports
791:Simon Peyton Jones
755:serializing tokens
721:Priority inversion
612:
575:Optimistic locking
549:optimistic locking
2559:
2558:
2353:Business delegate
2285:Publishâsubscribe
2119:
2118:
1797:doc.rust-lang.org
1772:doc.rust-lang.org
1672:"The Mutex class"
1529:"Synchronization"
1174:locking mechanism
1072:statements since
1038:mechanism with a
954:architecture and
658:
657:
2589:
2358:Composite entity
2235:Front controller
1975:Abstract factory
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1700:. Archived from
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1674:. Archived from
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1307:. Archived from
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1246:Mutual exclusion
1221:Critical section
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912:mutual exclusion
886:Language support
877:
863:from < to
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830:
816:mutex: Lock
800:
793:(an advocate of
615:
611:
541:concurrent users
534:waits-for graphs
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143:atomic operation
114:compare-and-swap
33:mutual exclusion
21:computer science
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1862:OâReilly Media
1843:
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1828:OâReilly Media
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529:2-phased locks
525:Database locks
518:Main article:
515:
514:Database locks
512:
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229:
152:
141:The reason an
132:multiprocessor
57:advisory locks
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2489:Martin Fowler
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1852:Marlow, Simon
1847:
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1837:9781449335946
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1818:Marlow, Simon
1813:
1798:
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1773:
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1718:
1704:on 2020-11-01
1703:
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1678:on 2017-07-04
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1508:"Synchronize"
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1363:GeeksforGeeks
1360:
1354:
1340:on 2008-05-08
1339:
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1311:on 2013-01-02
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1024:class in the
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940:POSIX pthread
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682:Disadvantages
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493:lock overhead
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110:fetch-and-add
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84:
80:
79:lock strategy
75:
73:
68:
66:
62:
58:
48:
46:
42:
38:
34:
30:
26:
22:
2546:Anti-pattern
2509:Linda Rising
2435:
2428:
2373:Lazy loading
2305:Identity map
2272:
2169:
1956:Gang of Four
1893:. Retrieved
1889:
1880:
1856:
1846:
1822:
1812:
1800:. Retrieved
1796:
1787:
1775:. Retrieved
1771:
1762:
1751:. Retrieved
1741:
1730:. Retrieved
1717:
1706:. Retrieved
1702:the original
1691:
1680:. Retrieved
1676:the original
1666:
1652:
1641:. Retrieved
1639:. Apple, inc
1631:
1620:. Retrieved
1618:. Apple, inc
1610:
1599:. Retrieved
1597:. Apple, inc
1589:
1578:. Retrieved
1576:. Apple, inc
1568:
1557:. Retrieved
1555:. Apple, inc
1547:
1536:. Retrieved
1523:
1512:. Retrieved
1502:
1491:. Retrieved
1481:
1456:. Retrieved
1452:
1442:
1420:
1414:. Retrieved
1410:
1400:
1391:
1378:
1367:. Retrieved
1365:. 2018-03-07
1362:
1353:
1342:. Retrieved
1338:the original
1324:
1313:. Retrieved
1309:the original
1299:
1288:. Retrieved
1278:
1264:
1231:File locking
1167:
1128:also exists.
1074:Fortran 2008
1052:The ISO/IEC
990:synchronized
918:(API) since
906:The ISO/IEC
895:
873:
868:
864:
860:
856:
843:
838:
832:
826:
821:
817:
813:
809:
805:
784:
775:
770:
744:
717:conventions.
693:power cycled
685:
675:
674:
667:
661:
652:
647:
637:
632:
606:
602:
599:incompatible
598:
596:
573:
555:
548:
544:
538:
523:
505:
500:
496:
492:
486:
484:
481:
473:
464:
458:
453:
416:
409:
378:_balanceLock
318:_balanceLock
270:_balanceLock
221:
206:
194:
140:
120:Uniprocessor
118:
106:test-and-set
99:
76:
69:
60:
56:
54:
28:
24:
18:
2518:Communities
2499:Jim Coplien
2474:Grady Booch
2459:Erich Gamma
2403:Type tunnel
2388:Object pool
2383:Null object
2378:Mock object
2240:Interceptor
2210:Thread pool
2125:Concurrency
2071:Interpreter
1394:. O'Reilly.
1028:extension.
1004:Objective-C
974:provides a
948:synchronize
771:application
644:write-lock
624:write-lock
488:granularity
450:Granularity
441:// do stuff
417:Similar to
2566:Categories
2413:Delegation
2348:Blackboard
2053:Behavioral
2005:Structural
1967:Creational
1895:2021-11-23
1890:pkg.go.dev
1802:3 November
1777:3 November
1753:2008-05-30
1732:2020-02-17
1708:2008-05-30
1682:2016-12-29
1643:2009-10-17
1622:2009-10-17
1601:2009-10-17
1580:2009-10-17
1559:2009-10-17
1538:2008-05-30
1514:2008-05-30
1493:2008-05-30
1458:2010-02-27
1416:2010-02-27
1369:2023-12-28
1344:2008-05-30
1315:2011-11-22
1290:2011-11-22
1257:References
956:Visual C++
944:Visual C++
890:See also:
629:read-lock
603:compatible
467:contention
432:SomeMethod
412:lock(this)
128:interrupts
2479:Kent Beck
2205:Semaphore
2195:Scheduler
2038:Flyweight
2028:Decorator
2023:Composite
1995:Singleton
1990:Prototype
1467:cite book
1428:cite book
1334:Microsoft
1058:lock_type
1047:threading
1045:from the
835:would be
763:lock-free
739:Convoying
707:deadlocks
621:read-lock
618:Lock type
410:The code
226:follows:
87:execution
72:semaphore
65:exception
2539:See also
2341:patterns
2227:patterns
2180:Proactor
2127:patterns
2101:Strategy
2091:Observer
2081:Mediator
2076:Iterator
1958:patterns
1215:See also
1064:and the
1026:pthreads
982:keyword.
976:SyncLock
914:(locks)
876:transfer
857:function
846:transfer
839:function
829:transfer
733:deadlock
676:Comment:
501:deadlock
475:deadlock
387:_balance
351:Withdraw
327:_balance
252:_balance
217:run-time
213:livelock
209:deadlock
198:Dekker's
138:issues.
95:spinlock
2393:Servant
2325:Model 2
2185:Reactor
2175:Monitor
2140:Balking
2111:Visitor
2086:Memento
2066:Command
2013:Adapter
1980:Builder
1658:"flock"
1148:objects
1144:methods
1110:Haskell
1096:struct.
1054:Fortran
1049:module.
1012:classes
998:objects
994:methods
952:Windows
799:Account
787:compose
357:decimal
297:decimal
291:Deposit
264:private
249:decimal
246:private
237:Account
89:of the
35:) is a
2447:People
2330:Broker
2033:Facade
2018:Bridge
1868:
1834:
1749:. 2001
1070:unlock
1032:Python
936:OpenMP
934:. The
930:since
880:hidden
850:amount
822:method
818:method
814:member
810:member
751:funnel
426:public
393:amount
360:amount
345:public
333:amount
300:amount
285:public
279:object
267:object
231:public
149:code:
112:" or "
102:atomic
91:thread
31:(from
2422:Books
2339:Other
2275:-tier
2096:State
2043:Proxy
1727:(PDF)
1388:(PDF)
1172:is a
1170:mutex
1136:Mutex
1084:mutex
1043:class
1036:mutex
1022:Mutex
932:C++11
806:class
745:Some
506:In a
465:lock
234:class
184:myPID
83:block
51:Types
29:mutex
2398:Twin
2255:MVVM
2170:Lock
2165:Join
1866:ISBN
1832:ISBN
1804:2020
1779:2020
1473:link
1434:link
1179:task
1140:sync
1122:MVar
1118:MVar
1114:MVar
1104:LOCK
1090:Rust
1080:Ruby
1066:lock
1040:Lock
986:Java
980:lock
966:lock
869:else
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