Hi, On Mon, Mar 18, 2024 at 08:49:34AM -0700, Noah Misch wrote: > On Mon, Mar 18, 2024 at 09:04:44AM +0000, Bertrand Drouvot wrote: > > --- a/src/backend/utils/activity/wait_event_names.txt > > +++ b/src/backend/utils/activity/wait_event_names.txt > > @@ -24,7 +24,12 @@ > > # SGML tables of wait events for inclusion in the documentation. > > # > > # When adding a new wait event, make sure it is placed in the appropriate > > -# ClassName section. > > +# ClassName section. If the wait event is backpatched to a version < 17 > > then > > +# put it under a "Backpatch" delimiter at the end of the related ClassName > > +# section. > > Back-patch from v17 to pre-v17 won't use this, because v16 has hand-maintained > enums. It's back-patch v18->v17 or v22->v17 where this will come up.
Thanks for looking at it! Oh right, the comment is wrong, re-worded in v2 attached. Regards, -- Bertrand Drouvot PostgreSQL Contributors Team RDS Open Source Databases Amazon Web Services: https://aws.amazon.com
>From 868d97a853c45639685198c9090cedd77dc4b9af Mon Sep 17 00:00:00 2001 From: Bertrand Drouvot <bertranddrouvot...@gmail.com> Date: Mon, 18 Mar 2024 08:34:19 +0000 Subject: [PATCH v2] Add "Backpatch" regions in wait_event_names.txt When backpatching, adding an event will renumber others, which can make an extension report the wrong event until recompiled. This is due to the fact that generate-wait_event_types.pl sorts events to position them. The "Backpatch" region added here ensures no ordering is done for the wait events found after this delimiter. --- .../activity/generate-wait_event_types.pl | 26 ++++++++++++++++++- .../utils/activity/wait_event_names.txt | 19 +++++++++++++- 2 files changed, 43 insertions(+), 2 deletions(-) 100.0% src/backend/utils/activity/ diff --git a/src/backend/utils/activity/generate-wait_event_types.pl b/src/backend/utils/activity/generate-wait_event_types.pl index f1adf0e8e7..d129d94889 100644 --- a/src/backend/utils/activity/generate-wait_event_types.pl +++ b/src/backend/utils/activity/generate-wait_event_types.pl @@ -38,7 +38,9 @@ die "Not possible to specify --docs and --code simultaneously" open my $wait_event_names, '<', $ARGV[0] or die; +my @backpatch_lines; my @lines; +my $backpatch = 0; my $section_name; my $note; my $note_name; @@ -59,10 +61,26 @@ while (<$wait_event_names>) { $section_name = $_; $section_name =~ s/^.*- //; + $backpatch = 0; next; } - push(@lines, $section_name . "\t" . $_); + # Are we dealing with backpatch wait events? + if (/^Backpatch:$/) + { + $backpatch = 1; + next; + } + + # Backpatch wait events won't be sorted during code generation + if ($gen_code && $backpatch) + { + push(@backpatch_lines, $section_name . "\t" . $_); + } + else + { + push(@lines, $section_name . "\t" . $_); + } } # Sort the lines based on the second column. @@ -70,6 +88,12 @@ while (<$wait_event_names>) my @lines_sorted = sort { uc((split(/\t/, $a))[1]) cmp uc((split(/\t/, $b))[1]) } @lines; +# If we are generating code then concat @lines_sorted and @backpatch_lines. +if ($gen_code) +{ + push(@lines_sorted, @backpatch_lines); +} + # Read the sorted lines and populate the hash table foreach my $line (@lines_sorted) { diff --git a/src/backend/utils/activity/wait_event_names.txt b/src/backend/utils/activity/wait_event_names.txt index c08e00d1d6..b6303a0fdb 100644 --- a/src/backend/utils/activity/wait_event_names.txt +++ b/src/backend/utils/activity/wait_event_names.txt @@ -24,7 +24,11 @@ # SGML tables of wait events for inclusion in the documentation. # # When adding a new wait event, make sure it is placed in the appropriate -# ClassName section. +# ClassName section. If the wait event is backpatched from master to a version +# >= 17 then put it under a "Backpatch:" delimiter at the end of the related +# ClassName section (on the non master branches) or at its natural position on +# the master branch. +# Ensure that the backpatch regions are always empty on the master branch. # # WaitEventLWLock and WaitEventLock have their own C code for their wait event # enums and function names. Hence, for these, only the SGML documentation is @@ -61,6 +65,7 @@ WAL_SENDER_MAIN "Waiting in main loop of WAL sender process." WAL_SUMMARIZER_WAL "Waiting in WAL summarizer for more WAL to be generated." WAL_WRITER_MAIN "Waiting in main loop of WAL writer process." +Backpatch: # # Wait Events - Client @@ -82,6 +87,7 @@ WAIT_FOR_STANDBY_CONFIRMATION "Waiting for WAL to be received and flushed by the WAL_SENDER_WAIT_FOR_WAL "Waiting for WAL to be flushed in WAL sender process." WAL_SENDER_WRITE_DATA "Waiting for any activity when processing replies from WAL receiver in WAL sender process." +Backpatch: # # Wait Events - IPC @@ -149,6 +155,7 @@ WAL_RECEIVER_WAIT_START "Waiting for startup process to send initial data for st WAL_SUMMARY_READY "Waiting for a new WAL summary to be generated." XACT_GROUP_UPDATE "Waiting for the group leader to update transaction status at end of a parallel operation." +Backpatch: # # Wait Events - Timeout @@ -169,6 +176,7 @@ VACUUM_DELAY "Waiting in a cost-based vacuum delay point." VACUUM_TRUNCATE "Waiting to acquire an exclusive lock to truncate off any empty pages at the end of a table vacuumed." WAL_SUMMARIZER_ERROR "Waiting after a WAL summarizer error." +Backpatch: # # Wait Events - IO @@ -256,6 +264,7 @@ WAL_SYNC "Waiting for a WAL file to reach durable storage." WAL_SYNC_METHOD_ASSIGN "Waiting for data to reach durable storage while assigning a new WAL sync method." WAL_WRITE "Waiting for a write to a WAL file." +Backpatch: # # Wait Events - Buffer Pin @@ -265,6 +274,7 @@ Section: ClassName - WaitEventBufferPin BUFFER_PIN "Waiting to acquire an exclusive pin on a buffer." +Backpatch: # # Wait Events - Extension @@ -274,6 +284,8 @@ Section: ClassName - WaitEventExtension Extension "Waiting in an extension." +Backpatch: + # # Wait Events - LWLock # @@ -330,6 +342,8 @@ DSMRegistry "Waiting to read or update the dynamic shared memory registry." InjectionPoint "Waiting to read or update information related to injection points." SerialControl "Waiting to read or update shared <filename>pg_serial</filename> state." +# Don't create a Backpatch region here. + # # END OF PREDEFINED LWLOCKS (DO NOT CHANGE THIS LINE) # @@ -377,6 +391,7 @@ SerialSLRU "Waiting to access the serializable transaction conflict SLRU cache." SubtransSLRU "Waiting to access the sub-transaction SLRU cache." XactSLRU "Waiting to access the transaction status SLRU cache." +# Don't create a Backpatch region here. # # Wait Events - Lock @@ -399,3 +414,5 @@ object "Waiting to acquire a lock on a non-relation database object." userlock "Waiting to acquire a user lock." advisory "Waiting to acquire an advisory user lock." applytransaction "Waiting to acquire a lock on a remote transaction being applied by a logical replication subscriber." + +Backpatch: -- 2.34.1