From 0573e27f7073d914132f620fd9fc1a1b373bc548 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E6=9D=A8=E5=87=AF?=
 <10183712+yangbaji@user.noreply.gitee.com>
Date: Mon, 17 Oct 2022 12:28:48 +0000
Subject: [PATCH 1/7] =?UTF-8?q?=E6=96=B0=E5=BB=BA=20yangkai?=
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diff --git a/content/zh/post/yangkai/.keep b/content/zh/post/yangkai/.keep
new file mode 100644
index 00000000..e69de29b
-- 
Gitee


From a202c6f02373d61404119f7d392106b383a86999 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E6=9D=A8=E5=87=AF?=
 <10183712+yangbaji@user.noreply.gitee.com>
Date: Mon, 17 Oct 2022 12:33:46 +0000
Subject: [PATCH 2/7] =?UTF-8?q?rename=20content/zh/post/yangkai/.keep=20to?=
 =?UTF-8?q?=20content/zh/post/yangkai/2022-10-01-openGauss=203.0=EF=BC=9A?=
 =?UTF-8?q?=E9=97=AA=E5=9B=9E=E6=81=A2=E5=A4=8D.md.?=
MIME-Version: 1.0
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Signed-off-by: 杨凯 <10183712+yangbaji@user.noreply.gitee.com>
---
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 1 file changed, 0 insertions(+), 0 deletions(-)
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diff --git a/content/zh/post/yangkai/.keep "b/content/zh/post/yangkai/2022-10-01-openGauss 3.0\357\274\232\351\227\252\345\233\236\346\201\242\345\244\215.md"
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rename from content/zh/post/yangkai/.keep
rename to "content/zh/post/yangkai/2022-10-01-openGauss 3.0\357\274\232\351\227\252\345\233\236\346\201\242\345\244\215.md"
-- 
Gitee


From 0f7838c01dee8a0fd792ec25eca9823fc570e98a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E6=9D=A8=E5=87=AF?=
 <10183712+yangbaji@user.noreply.gitee.com>
Date: Mon, 17 Oct 2022 12:35:17 +0000
Subject: [PATCH 3/7] =?UTF-8?q?update=20content/zh/post/yangkai/2022-10-01?=
 =?UTF-8?q?-openGauss=203.0=EF=BC=9A=E9=97=AA=E5=9B=9E=E6=81=A2=E5=A4=8D.m?=
 =?UTF-8?q?d.?=
MIME-Version: 1.0
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Signed-off-by: 杨凯 <10183712+yangbaji@user.noreply.gitee.com>
---
 ...52\345\233\236\346\201\242\345\244\215.md" | 393 ++++++++++++++++++
 1 file changed, 393 insertions(+)

diff --git "a/content/zh/post/yangkai/2022-10-01-openGauss 3.0\357\274\232\351\227\252\345\233\236\346\201\242\345\244\215.md" "b/content/zh/post/yangkai/2022-10-01-openGauss 3.0\357\274\232\351\227\252\345\233\236\346\201\242\345\244\215.md"
index e69de29b..11ed3fa8 100644
--- "a/content/zh/post/yangkai/2022-10-01-openGauss 3.0\357\274\232\351\227\252\345\233\236\346\201\242\345\244\215.md"	
+++ "b/content/zh/post/yangkai/2022-10-01-openGauss 3.0\357\274\232\351\227\252\345\233\236\346\201\242\345\244\215.md"	
@@ -0,0 +1,393 @@
+     **openGauss 3.0:闪回恢复** 
+    闪回概念是Oracle最先提出来的，其本质是为了回退错误操作产生的，避免人为的“灾难”，并且要能够快速回退。
+
+    闪回恢复功能是数据库恢复技术的一环，可以有选择性的撤销一个已提交事务的影响，将数据从人为不正确的操作中进行恢复。在采用闪回技术之前，只能通过备份恢复、PITR等手段找回已提交的数据库修改，恢复时长需要数分钟甚至数小时。采用闪回技术后，恢复已提交的数据库修改前的数据，只需要秒级，而且恢复时间和数据库大小无关。
+
+openGauss的闪回分为一下两类：
+
+闪回查询
+
+闪回表
+
+ **一、闪回查询** 
+    基于MVCC多版本的数据恢复：适用于误删除、误更新、误插入数据的查询和恢复，用户通过配置旧版本保留时间，并执行相应的查询或恢复命令，查询或恢复到指定的时间点或CSN点。
+
+前提条件（下面三个缺一不可）
+
+undo_retention_time：参数用于设置undo旧版本的保留时间。
+
+undo_zone_count=16384 ---代表的时候undo log的一种资源个数
+
+enable_default_ustore_table=on --默认指定用户创建表时使用USTORE存储引擎。
+
+存储引擎:Ustore
+
+Ustore存储引擎将最新版本的“有效数据”和历史版本的“垃圾数据”分离存储。将最新版本的“有效数据”存储在数据页面上，并单独开辟一段UNDO空间，用于统一管理历史版本的“垃圾数据”，因此数据空间不会由于频繁更新而膨胀，“垃圾数据”集中回收效率更高。
+
+设置参数命令如下：
+
+gs_guc set -N all -I all -c "undo_retention_time=2000s"
+
+gs_guc set -N all -I all -c "undo_zone_count=16384"
+
+gs_guc set -N all -I all -c "enable_default_ustore_table=on"
+
+设置完重启数据库：
+
+gs_om -t restart
+
+重启后验证参数：
+
+openGauss=# show undo_retention_time;
+
+undo_retention_time
+
+---------------------
+
+2000s
+
+(1 row)
+
+openGauss=# show undo_zone_count;
+
+undo_zone_count
+
+-----------------
+
+16384
+
+(1 row)
+
+openGauss=# show enable_default_ustore_table;
+
+enable_default_ustore_table
+
+-----------------------------
+
+on
+
+(1 row)
+
+openGauss=# 
+
+下面开始演示：
+
+创建表：
+
+openGauss=# CREATE TABLE flashback_tab(
+
+id int not null,
+
+name text not null);
+
+openGauss-# 
+
+CREATE TABLE
+
+查看表存储引擎：
+
+openGauss=# \d+ flashback_tab;
+
+Table "public.flashback_tab"
+
+Column | Type | Modifiers | Storage | Stats target | Description
+
+--------+---------+-----------+----------+--------------+-------------
+
+id | integer | not null | plain | |
+
+name | text | not null | extended | |
+
+Has OIDs: no
+
+Options: orientation=row, compression=no, storage_type=USTORE, toast.storage_type=USTORE
+
+插入数据：
+
+insert into flashback_tab values (1,'ybj');
+
+查询当前日期;
+
+openGauss=# select current_timestamp;
+
+pg_systimestamp
+
+-------------------------------
+
+2022-09-29 01:13:32.691158+08
+
+(1 row)
+
+查询数据：
+
+openGauss=# select * from flashback_tab;
+
+id | name
+
+----+------
+
+1 | ybj
+
+(1 row)
+
+插入数据：
+
+openGauss=# insert into flashback_tab values (2,'yangkai');
+
+INSERT 0 1
+
+查询结果：
+
+openGauss=# select * from flashback_tab;
+
+id | name
+
+----+---------
+
+1 | ybj
+
+2 | yangkai
+
+(2 rows)
+
+---基于timestamp的闪回查询：
+
+openGauss=# SELECT * FROM flashback_tab TIMECAPSULE TIMESTAMP to_timestamp ('2022-09-29 01:13:32.691158', 'YYYY-MM-DD HH24:MI:SS.FF');
+
+id | name
+
+----+------
+
+1 | ybj
+
+(1 row)
+
+---查询timestamp对应的CSN
+
+openGauss=# select snptime,snpcsn from gs_txn_snapshot where snptime between '2022-09-29 01:13:32.691158' and ' 2022-09-29 01:15:24.921426'
+
+openGauss-# ;
+
+snptime | snpcsn
+
+-------------------------------+--------
+
+2022-09-29 01:13:32.841985+08 | 2112
+
+2022-09-29 01:13:35.87922+08 | 2114
+
+2022-09-29 01:13:38.924031+08 | 2116
+
+2022-09-29 01:13:41.966247+08 | 2118
+
+2022-09-29 01:13:45.013022+08 | 2120
+
+2022-09-29 01:13:48.04741+08 | 2122
+
+2022-09-29 01:13:51.078498+08 | 2124
+
+2022-09-29 01:13:54.101686+08 | 2126
+
+2022-09-29 01:13:57.123891+08 | 2128
+
+2022-09-29 01:14:00.147156+08 | 2130
+
+2022-09-29 01:14:03.169433+08 | 2132
+
+2022-09-29 01:14:06.192879+08 | 2134
+
+2022-09-29 01:14:09.216963+08 | 2136
+
+2022-09-29 01:14:12.240249+08 | 2138
+
+2022-09-29 01:14:15.26606+08 | 2140
+
+2022-09-29 01:14:18.288409+08 | 2142
+
+2022-09-29 01:14:21.309986+08 | 2144
+
+2022-09-29 01:14:24.332801+08 | 2146
+
+2022-09-29 01:14:27.378095+08 | 2148
+
+2022-09-29 01:14:30.416234+08 | 2151
+
+2022-09-29 01:14:33.460251+08 | 2153
+
+2022-09-29 01:14:36.508431+08 | 2155
+
+---基于CSN的闪回查询
+
+openGauss=# SELECT * FROM flashback_tab TIMECAPSULE CSN 2116;
+
+id | name
+
+----+------
+
+1 | ybj
+
+(1 row)
+
+ **二、闪回表** 
+    基于类似windows系统回收站的恢复：适用于误DROP、误TRUNCATE的表的恢复。用户通过配置回收站开关，并执行相应的恢复命令，可以将误DROP、误TRUNCATE的表找回。
+
+前置条件：开启回收站、设置回收站对象保留时间
+
+enable_recyclebin=on 启用回收站。 
+
+recyclebin_retention_time=30min 参数用于设置回收站对象保留时间，超过该时间的回收站对象将被自动清理。
+
+命令如下：
+
+ gs_guc set -N all -I all -c "enable_recyclebin=on"
+
+ gs_guc set -N all -I all -c "recyclebin_retention_time=30min"
+
+设置完重启数据库：
+
+gs_om -t restart
+
+[omm@huaweidb ~]$ gsql -d postgres -p 15400
+
+gsql ((openGauss 3.0.0 build 02c14696) compiled at 2022-04-01 18:12:34 commit 0 last mr )
+
+Non-SSL connection (SSL connection is recommended when requiring high-security)
+
+Type "help" for help.
+
+openGauss=# show recyclebin_retention_time;
+
+recyclebin_retention_time
+
+---------------------------
+
+30min
+
+(1 row)
+
+openGauss=# show enable_recyclebin;
+
+enable_recyclebin
+
+-------------------
+
+on
+
+(1 row)
+
+openGauss=# 
+
+下面开始操作演示：
+
+[omm@huaweidb ~]$ gsql -d postgres -p 15400
+
+gsql ((openGauss 3.0.0 build 02c14696) compiled at 2022-04-01 18:12:34 commit 0 last mr )
+
+Non-SSL connection (SSL connection is recommended when requiring high-security)
+
+Type "help" for help.
+
+--查询当前表
+
+openGauss=# select * from flashback_tab ;
+
+id | name
+
+----+---------
+
+1 | ybj
+
+2 | yangkai
+
+(2 rows)
+
+--truncate表
+
+openGauss=# truncate flashback_tab;
+
+TRUNCATE TABLE
+
+openGauss=# select * from flashback_tab ;
+
+id | name
+
+----+------
+
+(0 rows)
+
+---闪回表
+
+openGauss=# timecapsule table flashback_tab to before truncate;
+
+TimeCapsule Table
+
+--查询结果
+
+openGauss=# select * from flashback_tab ;
+
+id | name
+
+----+---------
+
+1 | ybj
+
+2 | yangkai
+
+(2 rows)
+
+--drop 表
+
+openGauss=# drop table flashback_tab;
+
+DROP TABLE
+
+openGauss=# select * from flashback_tab;
+
+ERROR: relation "flashback_tab" does not exist on dn_6001
+
+LINE 1: select * from flashback_tab;
+
+^
+
+--查看回收站：
+
+openGauss=# sELECT rcyname,rcyoriginname,rcytablespace FROM GS_RECYCLEBIN;
+
+rcyname | rcyoriginname | rcytablespace
+
+------------------------------+----------------------+---------------
+
+BIN$3C7C4EB8014$30BE34C8==$0 | pg_toast_32783_index | 0
+
+BIN$3C7C4EB8012$30BE3AA0==$0 | pg_toast_32783 | 0
+
+BIN$3C7C4EB800F$30BE40B0==$0 | flashback_tab | 0
+
+BIN$3C7C4EB800F$30BEA658==$0 | flashback_tab | 0
+
+BIN$3C7C4EB8014$30BEAF78==$0 | pg_toast_32783_index | 0
+
+BIN$3C7C4EB8012$30BEB560==$0 | pg_toast_32783 | 0
+
+(6 rows)
+
+--通过回收站闪回表并命名flashback_yangkai;
+
+openGauss=# timecapsule table flashback_tab to before drop rename to flashback_yangkai;
+
+TimeCapsule Table
+
+openGauss=# select * from flashback_yangkai;
+
+id | name
+
+----+---------
+
+1 | ybj
+
+2 | yangkai
+
+(2 rows)
+
+ **三、总结** 
+    openGauss 闪回非常强大，可以秒杀国产大部分数据库，基本可以满足日常运维需求，希望后期可以推出类似oracle数据库级别闪回、snapshot standby就完美了。
\ No newline at end of file
-- 
Gitee


From 4806b42f810fddf1ba7ae1b494e6804af1166c85 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E6=9D=A8=E5=87=AF?=
 <10183712+yangbaji@user.noreply.gitee.com>
Date: Mon, 17 Oct 2022 12:39:38 +0000
Subject: [PATCH 4/7] =?UTF-8?q?=E9=87=8D=E5=91=BD=E5=90=8D=20content/zh/po?=
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 =?UTF-8?q?ngkai/=E3=80=90=E6=88=91=E5=92=8CopenGauss=E7=9A=84=E6=95=85?=
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diff --git "a/content/zh/post/yangkai/2022-10-01-openGauss 3.0\357\274\232\351\227\252\345\233\236\346\201\242\345\244\215.md" "b/content/zh/post/yangkai/\343\200\220\346\210\221\345\222\214openGauss\347\232\204\346\225\205\344\272\213\343\200\221-openGauss 3.0\357\274\232\351\227\252\345\233\236\346\201\242\345\244\215.md"
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rename from "content/zh/post/yangkai/2022-10-01-openGauss 3.0\357\274\232\351\227\252\345\233\236\346\201\242\345\244\215.md"
rename to "content/zh/post/yangkai/\343\200\220\346\210\221\345\222\214openGauss\347\232\204\346\225\205\344\272\213\343\200\221-openGauss 3.0\357\274\232\351\227\252\345\233\236\346\201\242\345\244\215.md"
-- 
Gitee


From f6a6bba8bdd13d322352ba7f97d36fa7aff3eaff Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E6=9D=A8=E5=87=AF?=
 <10183712+yangbaji@user.noreply.gitee.com>
Date: Mon, 17 Oct 2022 12:40:53 +0000
Subject: [PATCH 5/7] =?UTF-8?q?=E9=87=8D=E5=91=BD=E5=90=8D=20content/zh/po?=
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 =?UTF-8?q?=E5=9B=9E=E6=81=A2=E5=A4=8D.md=20=E4=B8=BA=20content/zh/post/ya?=
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diff --git "a/content/zh/post/yangkai/\343\200\220\346\210\221\345\222\214openGauss\347\232\204\346\225\205\344\272\213\343\200\221-openGauss 3.0\357\274\232\351\227\252\345\233\236\346\201\242\345\244\215.md" "b/content/zh/post/yangkai/\343\200\220openGauss\346\212\200\346\234\257\346\226\207\347\253\240\345\276\201\351\233\206\343\200\221-openGauss 3.0\357\274\232\351\227\252\345\233\236\346\201\242\345\244\215.md"
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Gitee


From 09611ebb5dba8895d4f9ecb816248912c9f8dfff Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E6=9D=A8=E5=87=AF?=
 <10183712+yangbaji@user.noreply.gitee.com>
Date: Mon, 17 Oct 2022 13:06:55 +0000
Subject: [PATCH 6/7] =?UTF-8?q?=E6=96=B0=E5=BB=BA=20=E6=9D=A8=E5=87=AF?=
MIME-Version: 1.0
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Content-Transfer-Encoding: 8bit

---
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diff --git "a/content/zh/post/\346\235\250\345\207\257/.keep" "b/content/zh/post/\346\235\250\345\207\257/.keep"
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index 00000000..e69de29b
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Gitee


From 69c68f4f49aaf4d913d67c2a4bfaef3cf0ada9ef Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E6=9D=A8=E5=87=AF?=
 <10183712+yangbaji@user.noreply.gitee.com>
Date: Mon, 17 Oct 2022 13:07:48 +0000
Subject: [PATCH 7/7] =?UTF-8?q?rename=20content/zh/post/=E6=9D=A8=E5=87=AF?=
 =?UTF-8?q?/.keep=20to=20content/zh/post/=E6=9D=A8=E5=87=AF/=E3=80=90openG?=
 =?UTF-8?q?auss=E6=8A=80=E6=9C=AF=E6=96=87=E7=AB=A0=E5=BE=81=E9=9B=86?=
 =?UTF-8?q?=E3=80=91-openGauss=203.0=EF=BC=9A=E9=97=AA=E5=9B=9E=E6=81=A2?=
 =?UTF-8?q?=E5=A4=8D.md.?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Signed-off-by: 杨凯 <10183712+yangbaji@user.noreply.gitee.com>
---
 ...57\274\232\351\227\252\345\233\236\346\201\242\345\244\215.md" | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 rename "content/zh/post/\346\235\250\345\207\257/.keep" => "content/zh/post/\346\235\250\345\207\257/\343\200\220openGauss\346\212\200\346\234\257\346\226\207\347\253\240\345\276\201\351\233\206\343\200\221-openGauss 3.0\357\274\232\351\227\252\345\233\236\346\201\242\345\244\215.md" (100%)

diff --git "a/content/zh/post/\346\235\250\345\207\257/.keep" "b/content/zh/post/\346\235\250\345\207\257/\343\200\220openGauss\346\212\200\346\234\257\346\226\207\347\253\240\345\276\201\351\233\206\343\200\221-openGauss 3.0\357\274\232\351\227\252\345\233\236\346\201\242\345\244\215.md"
similarity index 100%
rename from "content/zh/post/\346\235\250\345\207\257/.keep"
rename to "content/zh/post/\346\235\250\345\207\257/\343\200\220openGauss\346\212\200\346\234\257\346\226\207\347\253\240\345\276\201\351\233\206\343\200\221-openGauss 3.0\357\274\232\351\227\252\345\233\236\346\201\242\345\244\215.md"
-- 
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