{"revision":"c10276e953456835cdbb1f3a60d58ae1980be353","document":{"id":20007,"path":"impact/root-cause-correlation.md","title":"Root cause correlation","bundle":null,"doc_type":null,"release":"australia","body":"\n# Root cause correlation\n\nRoot Cause Correlation \\(RCC\\) finds a root cause by automatically correlating metrics, logs, and event information for supported symptoms on production instances for the last 24 hours.\n\n## RCC symptom categories\n\nThe RCC feature is available for self-service alerts and Critical or Warning performance symptom categories:\n\n-   Memory\n-   Longest running sessions\n-   Slow transactions\n-   Cache flush\n-   Database locks\n-   Database impacts\n\nThe table describes the symptom categories and the corresponding alerts that the RCC engine detects.\n\n<table id=\"table_jpp_xtf_d2c\"><thead><tr><th>\n\nSymptoms​ categories\n\n</th><th>\n\nDescription\n\n</th><th>\n\nCorresponding alert\n\n</th></tr></thead><tbody><tr><td>\n\nDatabase Impact​\n\n</td><td>\n\nHelps you to identify and address extended SQL queries impacting database performance, tied to high execution time, or increased volumes. The query patterns give snapshots of 30-minute and 60-minute durations from the time that the impact is observed on query execution times.​\n\n</td><td>\n\nDatabase response time\n\n</td></tr><tr><td>\n\nCache Flush​\n\n</td><td>\n\nCache flushes and node restarts are detected, as well as high service saturation levels that may have occurred around the time a performance alert was triggered.​\n\n</td><td>\n\nDefault semaphore mean\n\n</td></tr><tr><td>\n\nLongest Running Session​\n\n</td><td>\n\n-   Searches for the top long-running sessions in mean time to recover \\(MTTR\\) logs\n-   Identifies the top transaction pattern hash with the highest processing times and then the transaction IDs.​\n\n</td><td>\n\nDefault semaphore mean\n\n</td></tr><tr><td>\n\nSlow Transactions ​\n\n</td><td>\n\n-   Identifies the top long-running transactions using the total duration, including ACL time, SQL time, CPU time, processing time, BR time, and script time.\n-   Returns the transaction IDs, the pattern hash, and these metrics to help you identify the specific causes of long-running transactions.\n\n​\n\n</td><td>\n\nDefault semaphore mean​\n\n</td></tr><tr><td>\n\nMemory​\n\n</td><td>\n\n-   Pinpoints the three nodes most impacted by garbage collection pauses, determined by the aggregate duration of the pauses.\n-   Identifies any transactions or worker threads on these nodes that exceed 200 seconds.\n\n**Note:** Users are advised to review these long-running or frequently recurring threads.​\n\n\n</td><td>\n\nNode Garbage Collection Time\n\n</td></tr><tr><td>\n\nDB locks​\n\n</td><td>\n\nThe RCC engine monitors innodb\\_row\\_lock\\_waits and threads\\_running to detect anomalous database lock events that occur when a database operation requires exclusive access.​\n\n</td><td>\n\nThreads running​\n\n</td></tr></tbody>\n</table>**Note:** As soon as any of the aforementioned alerts or Critical or Warning performance are identified, the system automatically generates an RCA report after waiting for a maximum of 10 minutes, depending on the conditions.\n\n**Parent Topic:**[Monitor instance performance with Instance Observer](https://raw.githubusercontent.com/ServiceNow/ServiceNowDocs/australia/markdown/australia/impact/io-overview.md)\n\n"}}