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Cross-check lists of predefined LWLocks.
Both lwlocknames.txt and wait_event_names.txt contain a list of all the predefined LWLocks, i.e., those with predefined positions within MainLWLockArray. It is easy to miss one or the other, especially since the list in wait_event_names.txt omits the "Lock" suffix from all the LWLock wait events. This commit adds a cross- check of these lists to the script that generates lwlocknames.h. If the lists do not match exactly, building will fail. Suggested-by: Robert Haas Reviewed-by: Robert Haas, Michael Paquier, Bertrand Drouvot Discussion: https://postgr.es/m/20240102173120.GA1061678%40nathanxps13
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lines changed

5 files changed

+67
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‎src/backend/Makefile

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -130,7 +130,7 @@ $(top_builddir)/src/port/libpgport_srv.a: | submake-libpgport
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parser/gram.h: parser/gram.y
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$(MAKE) -C parser gram.h
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133-
storage/lmgr/lwlocknames.h: storage/lmgr/generate-lwlocknames.pl storage/lmgr/lwlocknames.txt
133+
storage/lmgr/lwlocknames.h: storage/lmgr/generate-lwlocknames.pl storage/lmgr/lwlocknames.txt utils/activity/wait_event_names.txt
134134
$(MAKE) -C storage/lmgr lwlocknames.h lwlocknames.c
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136136
utils/activity/wait_event_types.h: utils/activity/generate-wait_event_types.pl utils/activity/wait_event_names.txt

‎src/backend/storage/lmgr/Makefile

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -39,8 +39,8 @@ s_lock_test: s_lock.c $(top_builddir)/src/common/libpgcommon.a $(top_builddir)/s
3939
lwlocknames.c: lwlocknames.h
4040
touch $@
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42-
lwlocknames.h: $(top_srcdir)/src/backend/storage/lmgr/lwlocknames.txt generate-lwlocknames.pl
43-
$(PERL) $(srcdir)/generate-lwlocknames.pl $<
42+
lwlocknames.h: $(top_srcdir)/src/backend/storage/lmgr/lwlocknames.txt $(top_srcdir)/src/backend/utils/activity/wait_event_names.txt generate-lwlocknames.pl
43+
$(PERL) $(srcdir)/generate-lwlocknames.pl $^
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4545
check: s_lock_test
4646
./s_lock_test

‎src/backend/storage/lmgr/generate-lwlocknames.pl

Lines changed: 49 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -15,6 +15,7 @@
1515
GetOptions('outdir:s' => \$output_path);
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1717
open my $lwlocknames, '<', $ARGV[0] or die;
18+
open my $wait_event_names, '<', $ARGV[1] or die;
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1920
# Include PID in suffix in case parallel make runs this multiple times.
2021
my $htmp = "$output_path/lwlocknames.h.tmp$$";
@@ -30,6 +31,40 @@
3031

3132
print $c "const char *const IndividualLWLockNames[] = {";
3233

34+
#
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# First, record the predefined LWLocks listed in wait_event_names.txt. We'll
36+
# cross-check those with the ones in lwlocknames.txt.
37+
#
38+
my @wait_event_lwlocks;
39+
my $record_lwlocks = 0;
40+
41+
while (<$wait_event_names>)
42+
{
43+
chomp;
44+
45+
# Check for end marker.
46+
last if /^# END OF PREDEFINED LWLOCKS/;
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48+
# Skip comments and empty lines.
49+
next if /^#/;
50+
next if /^\s*$/;
51+
52+
# Start recording LWLocks when we find the WaitEventLWLock section.
53+
if (/^Section: ClassName - WaitEventLWLock$/)
54+
{
55+
$record_lwlocks = 1;
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next;
57+
}
58+
59+
# Go to the next line if we are not yet recording LWLocks.
60+
next if not $record_lwlocks;
61+
62+
# Record the LWLock.
63+
(my $waiteventname, my $waitevendocsentence) = split(/\t/, $_);
64+
push(@wait_event_lwlocks, $waiteventname . "Lock");
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}
66+
67+
my $i = 0;
3368
while (<$lwlocknames>)
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{
3570
chomp;
@@ -50,6 +85,15 @@
5085
die "lwlocknames.txt not in order" if $lockidx < $lastlockidx;
5186
die "lwlocknames.txt has duplicates" if $lockidx == $lastlockidx;
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88+
die "$lockname defined in lwlocknames.txt but missing from "
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. "wait_event_names.txt"
90+
if $i >= scalar @wait_event_lwlocks;
91+
die "lists of predefined LWLocks do not match (first mismatch at "
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. "$wait_event_lwlocks[$i] in wait_event_names.txt and $lockname in "
93+
. "lwlocknames.txt)"
94+
if $wait_event_lwlocks[$i] ne $lockname;
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$i++;
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5397
while ($lastlockidx < $lockidx - 1)
5498
{
5599
++$lastlockidx;
@@ -63,6 +107,11 @@
63107
print $h "#define $lockname (&MainLWLockArray[$lockidx].lock)\n";
64108
}
65109

110+
die
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"$wait_event_lwlocks[$i] defined in wait_event_names.txt but missing from "
112+
. "lwlocknames.txt"
113+
if $i < scalar @wait_event_lwlocks;
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66115
printf $c "\n};\n";
67116
print $h "\n";
68117
printf $h "#define NUM_INDIVIDUAL_LWLOCKS %s\n", $lastlockidx + 1;

‎src/backend/utils/activity/wait_event_names.txt

Lines changed: 12 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -276,6 +276,10 @@ Extension "Waiting in an extension."
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# This class of wait events has its own set of C structure, so these are
277277
# only used for the documentation.
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#
279+
# NB: Predefined LWLocks (i.e., those declared in lwlocknames.txt) must be
280+
# listed in the top section of locks and must be listed in the same order as in
281+
# lwlocknames.txt.
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#
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280284
Section: ClassName - WaitEventLWLock
281285

@@ -326,6 +330,14 @@ NotifyQueueTail "Waiting to update limit on <command>NOTIFY</command> message st
326330
WaitEventExtension "Waiting to read or update custom wait events information for extensions."
327331
WALSummarizer "Waiting to read or update WAL summarization state."
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333+
#
334+
# END OF PREDEFINED LWLOCKS (DO NOT CHANGE THIS LINE)
335+
#
336+
# Predefined LWLocks (i.e., those declared in lwlocknames.txt) must be listed
337+
# in the section above and must be listed in the same order as in
338+
# lwlocknames.txt. Other LWLocks must be listed in the section below.
339+
#
340+
329341
XactBuffer "Waiting for I/O on a transaction status SLRU buffer."
330342
CommitTsBuffer "Waiting for I/O on a commit timestamp SLRU buffer."
331343
SubtransBuffer "Waiting for I/O on a sub-transaction SLRU buffer."

‎src/include/storage/meson.build

Lines changed: 3 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,7 +1,9 @@
11
# Copyright (c) 2022-2024, PostgreSQL Global Development Group
22

33
lwlocknames = custom_target('lwlocknames',
4-
input: files('../../backend/storage/lmgr/lwlocknames.txt'),
4+
input: files(
5+
'../../backend/storage/lmgr/lwlocknames.txt',
6+
'../../backend/utils/activity/wait_event_names.txt'),
57
output: ['lwlocknames.h', 'lwlocknames.c'],
68
command: [
79
perl, files('../../backend/storage/lmgr/generate-lwlocknames.pl'),

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