941:
951:
232:
961:
39:
347:
notes that a checkpoint has been made. These are used to speed up recovery. They record information that eliminates the need to read a long way into the log's past. This varies according to checkpoint algorithm. If all dirty pages are flushed while creating the checkpoint (as in
321:(CLR) notes the rollback of a particular change to the database. Each corresponds with exactly one other Update Log Record (although the corresponding update log record is not typically stored in the Compensation Log Record). It includes this extra information:
189:
358:: This is a reference to the first log record that corresponds to a dirty page. i.e. the first update that wasn't flushed at checkpoint time. This is where redo must begin on recovery.
551:
184:(LSN): A unique ID for a log record. With LSNs, logs can be recovered in constant time. Most LSNs are assigned in monotonically increasing order, which is useful in recovery
534:
546:
364:: This is a reference to the oldest log record of the oldest in-progress transaction. This is the oldest log record needed to undo all in-progress transactions.
147:. Additionally, all transactions that are already committed but whose changes were not yet materialized in the database are re-applied. Both are done to ensure
466:
techrepublic.com, Understanding the importance of transaction logs in SQL Server, SQL Server transaction log maintenance, By Crowe, Chizek, November 11, 2004
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313:: Includes the value of the bytes of page before and after the page change. Some databases may have logs which include one or both images.
617:
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465:
284:
All log records include the general log attributes above, and also other attributes depending on their type (which is recorded in the
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132:
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327:: This field contains the LSN of the next log record that is to be undone for transaction that wrote the last Update Log.
148:
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27:
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notes that all work has been done for this particular transaction. (It has been fully committed or aborted)
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773:
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144:
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sqlshack.com, A beginner’s guide to SQL Server transaction logs, February 11, 2014 by Ivan
Stankovic
911:
804:
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135:
state or not been shut down properly, the database management system reviews the database logs for
906:
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624:
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125:
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217:
Information about the actual changes that triggered the log record to be written.
198:: A link to their last log record. This implies database logs are constructed in
685:
665:
231:
199:
829:
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349:
295:
notes an update (change) to the database. It includes this extra information:
185:
53:
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645:
515:
412:
159:
85:
49:
256: in this section. Unsourced material may be challenged and removed.
595:
208:: A reference to the database transaction generating the log record.
128:
listing changes to the database, stored in a stable storage format.
590:
650:
117:
488:
307:: Length in bytes and offset of the page are usually included.
225:
169:, a journal is the record of data altered by a given process.
32:
19:"Binary log" redirects here. For the logarithm to base 2, see
341:
notes a decision to abort and hence roll back a transaction.
158:
This term is not to be confused with other, human-readable
16:
History of actions executed by a database management system
26:"Journal (computing)" redirects here. For other uses, see
60:
162:
that a database management system usually provides.
869:
838:
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709:
638:
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301:: A reference to the Page ID of the modified page.
131:If, after a start, the database is found in an
500:
124:or hardware failures. Physically, a log is a
8:
214:: Describes the type of database log record.
444:Microsoft, The Transaction Log (SQL Server)
507:
493:
485:
335:notes a decision to commit a transaction.
272:Learn how and when to remove this message
112:) is a history of actions executed by a
436:
177:A database log record is made up of:
7:
254:adding citations to reliable sources
960:
14:
173:Anatomy of a general database log
959:
949:
940:
939:
230:
37:
950:
241:needs additional citations for
388:Error correction and detection
52:format but may read better as
1:
222:Types of database log records
986:Database management systems
516:Database management systems
167:database management systems
1012:
922:Object–relational database
403:Log-structured file system
143:the changes made by these
114:database management system
25:
18:
935:
897:Federated database system
630:Blockchain-based database
28:Journal (disambiguation)
319:Compensation Log Record
311:Before and After Images
61:converting this article
991:Transaction processing
927:Transaction processing
882:Database normalization
825:Query rewriting system
425:Federal Standard 1037C
398:Journaling file system
288:attribute, as above).
902:Referential integrity
477:neurobs.com, Logfiles
352:), it might contain:
206:Transaction ID number
892:Distributed database
250:improve this article
912:Relational calculus
790:Concurrency control
408:Write-ahead logging
182:Log Sequence Number
98:transaction journal
907:Relational algebra
851:Query optimization
656:Armstrong's axioms
116:used to guarantee
63:, if appropriate.
973:
972:
581:Wide-column store
576:Document-oriented
370:Completion Record
345:Checkpoint Record
305:Length and Offset
293:Update Log Record
282:
281:
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155:of transactions.
139:transactions and
82:
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996:Computer logging
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917:Relational model
887:Database storage
764:Stored procedure
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120:properties over
90:computer science
84:In the field of
77:
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68:
59:You can help by
41:
40:
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21:Binary logarithm
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877:Database models
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820:Query optimizer
795:Data dictionary
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749:Transaction log
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661:Codd's 12 rules
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564:Column-oriented
530:Object-oriented
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94:transaction log
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696:Surrogate key
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681:Candidate key
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393:Hash function
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333:Commit Record
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239:This section
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67:is available.
66:
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46:This article
44:
35:
34:
29:
22:
748:
472:
461:
450:
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383:Data logging
369:
361:
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344:
339:Abort Record
338:
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285:
283:
268:
259:
248:Please help
243:verification
240:
211:
205:
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181:
176:
164:
157:
145:transactions
133:inconsistent
130:
109:
105:
102:database log
101:
97:
93:
83:
70:
65:Editing help
47:
965:WikiProject
856:Replication
744:Transaction
686:Foreign key
666:CAP theorem
613:Multi-model
325:undoNextLSN
200:linked list
137:uncommitted
110:audit trail
980:Categories
830:Query plan
783:Components
701:Unique key
618:comparison
552:comparison
542:Relational
535:comparison
431:References
350:PostgreSQL
186:algorithms
153:durability
141:rolls back
106:binary log
839:Functions
774:Partition
601:In-memory
559:Key–value
262:July 2016
149:atomicity
86:databases
73:June 2015
945:Category
861:Sharding
717:Relation
691:Superkey
646:Database
639:Concepts
413:Redo log
377:See also
196:Prev LSN
955:Outline
754:Trigger
710:Objects
419:Sources
362:undoLSN
356:redoLSN
188:, like
122:crashes
769:Cursor
727:column
596:NewSQL
299:PageID
96:(also
48:is in
759:Index
722:table
625:Cloud
591:NoSQL
586:Graph
523:Types
202:form.
190:ARIES
54:prose
810:ODBC
800:JDBC
739:View
676:Null
671:CRUD
651:ACID
606:list
569:list
547:list
286:Type
212:Type
160:logs
151:and
126:file
118:ACID
92:, a
50:list
805:XQJ
732:row
252:by
165:In
108:or
88:in
982::
104:,
100:,
508:e
501:t
494:v
275:)
269:(
264:)
260:(
246:.
192:.
75:)
71:(
57:.
30:.
23:.
Text is available under the Creative Commons Attribution-ShareAlike License. Additional terms may apply.
