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* [PATCH 6/6] 0003 review
@ 2021-02-15 15:36 Tomas Vondra <[email protected]>
0 siblings, 0 replies; 2+ messages in thread
From: Tomas Vondra @ 2021-02-15 15:36 UTC (permalink / raw)
---
src/test/regress/input/copy.source | 4 ++--
src/test/regress/output/copy.source | 4 ++--
2 files changed, 4 insertions(+), 4 deletions(-)
diff --git a/src/test/regress/input/copy.source b/src/test/regress/input/copy.source
index ddde33e7cc..4ee1b26326 100644
--- a/src/test/regress/input/copy.source
+++ b/src/test/regress/input/copy.source
@@ -204,7 +204,7 @@ drop table parted_copytest;
--
-- progress reporting
---
+--
-- setup
-- reuse employer datatype, that has a small sized data set
@@ -221,7 +221,7 @@ create function notice_after_progress_reporting() returns trigger AS
$$
declare report record;
begin
- -- We cannot expect 'pid' nor 'relid' to be consistent over runs due to
+ -- We cannot expect 'pid' nor 'relid' to be consistent over runs due to
-- variance in system process ids, and concurrency in runs of tests.
-- Additionally, due to the usage of this test in pg_regress, the 'datid'
-- also is not consistent between runs.
diff --git a/src/test/regress/output/copy.source b/src/test/regress/output/copy.source
index 60f4206aa1..8ebfb7ae81 100644
--- a/src/test/regress/output/copy.source
+++ b/src/test/regress/output/copy.source
@@ -167,7 +167,7 @@ select * from parted_copytest where b = 2;
drop table parted_copytest;
--
-- progress reporting
---
+--
-- setup
-- reuse employer datatype, that has a small sized data set
create table progress_reporting (
@@ -181,7 +181,7 @@ create function notice_after_progress_reporting() returns trigger AS
$$
declare report record;
begin
- -- We cannot expect 'pid' nor 'relid' to be consistent over runs due to
+ -- We cannot expect 'pid' nor 'relid' to be consistent over runs due to
-- variance in system process ids, and concurrency in runs of tests.
-- Additionally, due to the usage of this test in pg_regress, the 'datid'
-- also is not consistent between runs.
--
2.26.2
--------------DA8D60BF026F7ACE69A9AEE5--
^ permalink raw reply [nested|flat] 2+ messages in thread
* Re: Can we change pg_rewind used without wal_log_hints and data_checksums
@ 2026-01-15 06:14 [email protected]
0 siblings, 0 replies; 2+ messages in thread
From: [email protected] @ 2026-01-15 06:14 UTC (permalink / raw)
To: Laurenz Albe <[email protected]>; pgsql-hackers <[email protected]>
>See https://postgr.es/m/CA%2BTgmoY4j%2Bp7JY69ry8GpOSMMdZNYqU6dtiONPrcxaVG%2BSPByg%40mail.gmail.com
>In more detail:
>1. there is a transaction open on the primary server (server A)
>2. the transaction inserts a row
>3. a checkpoint happens
>4. the transaction commits
>5. the session reads the row it just inserted, which sets hint bits on the row
>that mark it as generally visible
>Now the standby (server B) promoted between steps 3 and 4, which means that on server B
>(the new primary), the transaction didn't commit and the row is invisible.
>Now if we run pg_rewind on server A, it examines the local WAL to find all the blocks
>that were modified after the last common checkpoint (which happened in step 3 above).
>If neither wal_log_hints = on nor checksums are enabled (which effectively forces
>WAL-logging hint bit changes), there is no track of step 5 in the WAL, and pg_rewind
>fails to copy that block from server B. The consequence is that after pg_rewind, the
>row is *still* visible on server A because of the hint bits. That is data corruption.
>Therefore, the requirement cannot be relaxed.
Yes I known the step and I have check the mail link. As described in the top mail we can find some way to solve the problem so that pg_rewind can run without wal_log_hints and data_checksums.
Currently pg_rewind search wal start at checkpoint lsn or redo lsn, I mean to search more wal to cover whole releated transactions so any releated pages with copyed, and we never warried about hint bits issue.
Anyway, I wish my mail in right format. Because my last mail reply to Michael out of order and miss from this thread.
---Movead Li
^ permalink raw reply [nested|flat] 2+ messages in thread
end of thread, other threads:[~2026-01-15 06:14 UTC | newest]
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2021-02-15 15:36 [PATCH 6/6] 0003 review Tomas Vondra <[email protected]>
2026-01-15 06:14 Re: Can we change pg_rewind used without wal_log_hints and data_checksums [email protected]
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