Create 20240330_03.md

Author: digoal

202403/20240330_03.md

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+## PostgreSQL 17 preview - 跟踪slot断联时间戳`pg_replication_slots.inactive_since`   
+                                                                                              
+### 作者                                                                                              
+digoal                                                                                              
+                                                                                              
+### 日期                                                                                              
+2024-03-30                                                                                    
+                                                                                              
+### 标签                                                                                              
+PostgreSQL , PolarDB , DuckDB , slot , pg_replication_slots , 无效时间 , inactive_since                         
+                                                                                              
+----                                                                                              
+                                                                                              
+## 背景     
+跟踪PostgreSQL slot断连时的时间戳.    
+  
+https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=a11f330b5584f2430371d68871e00f5c63735299  
+```  
+Track last_inactive_time in pg_replication_slots.  
+  
+author	Amit Kapila <[email protected]>	  
+Mon, 25 Mar 2024 11:04:33 +0000 (16:34 +0530)  
+committer	Amit Kapila <[email protected]>	  
+Mon, 25 Mar 2024 11:04:33 +0000 (16:34 +0530)  
+commit	a11f330b5584f2430371d68871e00f5c63735299  
+tree	b53cafab5f97bb5440db906e20ca0f38e46a0fd9	tree  
+parent	0f7863afef67e462574fe5af6317e26a2f2d47fb	commit | diff  
+Track last_inactive_time in pg_replication_slots.  
+  
+This commit adds a new property called last_inactive_time for slots. It is  
+set to 0 whenever a slot is made active/acquired and set to the current  
+timestamp whenever the slot is inactive/released or restored from the disk.  
+Note that we don't set the last_inactive_time for the slots currently being  
+synced from the primary to the standby because such slots are typically  
+inactive as decoding is not allowed on those.  
+  
+The 'last_inactive_time' will be useful on production servers to debug and  
+analyze inactive replication slots. It will also help to know the lifetime  
+of a replication slot - one can know how long a streaming standby, logical  
+subscriber, or replication slot consumer is down.  
+  
+The 'last_inactive_time' will also be useful to implement inactive  
+timeout-based replication slot invalidation in a future commit.  
+  
+Author: Bharath Rupireddy  
+Reviewed-by: Bertrand Drouvot, Amit Kapila, Shveta Malik  
+Discussion: https://www.postgresql.org/message-id/CALj2ACW4aUe-_uFQOjdWCEN-xXoLGhmvRFnL8SNw_TZ5nJe+aw@mail.gmail.com  
+```  
+  
+https://git.postgresql.org/gitweb/?p=postgresql.git;a=commit;h=6d49c8d4b4f4a20eb5b4c501d78cf894fa13c0ea  
+```  
+Change last_inactive_time to inactive_since in pg_replication_slots.  
+author	Amit Kapila <[email protected]>	  
+Wed, 27 Mar 2024 03:57:44 +0000 (09:27 +0530)  
+committer	Amit Kapila <[email protected]>	  
+Wed, 27 Mar 2024 03:57:44 +0000 (09:27 +0530)  
+commit	6d49c8d4b4f4a20eb5b4c501d78cf894fa13c0ea  
+tree	67eaaf5d79dea7aede098b19222897923894be78	tree  
+parent	bb952c8c8b13279eca039499249cb5dc60991603	commit | diff  
+Change last_inactive_time to inactive_since in pg_replication_slots.  
+  
+Commit a11f330b55 added last_inactive_time to show the last time the slot  
+was inactive. But, it tells the last time that a currently-inactive slot  
+previously *WAS* active. This could be unclear, so we changed the name to  
+inactive_since.  
+  
+Reported-by: Robert Haas  
+Author: Bharath Rupireddy  
+Reviewed-by: Bertrand Drouvot, Shveta Malik, Amit Kapila  
+Discussion: https://postgr.es/m/CA+Tgmob_Ta-t2ty8QrKHBGnNLrf4ZYcwhGHGFsuUoFrAEDw4sA@mail.gmail.com  
+Discussion: https://postgr.es/m/CALj2ACUXS0SfbHzsX8bqo+7CZhocsV52Kiu7OWGb5HVPAmJqnA@mail.gmail.com  
+```   
+