LGWR group commits(原)
LGWR group comments the transactions when there are more than one transactions commited while the previous commition processed.[@more@]In times of high activity, LGWR can write to the redo log file using group commits. For example, assume that a user commits a transaction. LGWR must write the transaction's redo entries to disk, and as this happens, other users issue COMMIT statements. However, LGWR cannot write to the redo log file to commit these transactions until it has completed its previous write operation. After the first transaction's entries are written to the redo log file, the entire list of redo entries of waiting transactions (not yet committed) can be written to disk in one operation, requiring less I/O than do transaction entries handled individually. Therefore, Oracle minimizes disk I/O and maximizes performance of LGWR. If requests to commit continue at a high rate, then every write (by LGWR) from the redo log buffer can contain multiple commit records.
來自 “ ITPUB部落格 ” ,連結:http://blog.itpub.net/3137/viewspace-925742/,如需轉載,請註明出處,否則將追究法律責任。
相關文章
- How to review diffs between commitsViewMIT
- Oracle LGWR程式Oracle
- 【Oracle】-【體系結構-LGWR】-LGWR的一些理解Oracle
- DBWn,CKPT,LGWR程式
- LGWR,Log Switches, and Checkpoints
- Ospaf專案-commits詞頻統計模組MIT
- 【教程】如何清空一個 Git 分支的所有 CommitsGitMIT
- LGWR writes redo log (117)
- Oracle 的Lgwr Worker的工作原理Oracle
- LGWR DBWR SMON 等程式說明
- Log Writer Process (LGWR) (115)
- Oracle DBWR,LGWR,CKPT,ARCH 觸發條件Oracle
- Oracle9i LGWR 觸發條件Oracle
- Oracle GroupOracle
- group_replication_bootstrap_group 用於什麼boot
- 資料庫的sort group by和hash group by資料庫
- DBWR,LGWR,CKPT,ARCH觸發條件總結
- CKPT、DBWn、LGWR與3S的關係
- oracle partition by group by,詳解partition by和group by對比Oracle
- MySQL Group ReplicationMySql
- Group by 優化優化
- Oracle Hash Group ByOracle
- sql用法——group bySQL
- Oracle group by使用Oracle
- Oracle DBWR,LGWR,CKPT,ARCH 觸發條件 總結Oracle
- ORA-00937: not a single-group group functionFunction
- oracle全文索引之SECTION GROUP_6_PATH_SECTION_GROUPOracle索引
- oracle全文索引之SECTION GROUP_5_AUTO_SECTION_GROUPOracle索引
- oracle全文索引之SECTION GROUP_4_XML_SECTION_GROUPOracle索引XML
- oracle全文索引之SECTION GROUP_3_HTML_SECTION_GROUPOracle索引HTML
- oracle全文索引之SECTION GROUP_2_BASIC_SECTION_GROUPOracle索引
- oracle全文索引之SECTION GROUP_1_NULL_SECTION_GROUPOracle索引Null
- PMON、SMON、DBWn、LGWR、CKPT、ARCH等後臺程式說明
- oracle 的伺服器程式(PMON, SMON,CKPT,DBWn,LGWR,ARCn)Oracle伺服器
- ORA-16198: LGWR received timedout error from KSRError
- 觸發LGWR程式寫日誌的4個條件
- LGWR寫操作會導致效能全域性卡頓案例分析
- group by 查詢原理