* [PATCH 17/26] xapcmd: avoid EXDEV when finalizing changes
2019-05-23 9:36 7% [PATCH 00/26] xcpdb: ease Xapian DB format migrations Eric Wong
@ 2019-05-23 9:36 7% ` Eric Wong
0 siblings, 0 replies; 2+ results
From: Eric Wong @ 2019-05-23 9:36 UTC (permalink / raw)
To: meta
By creating temporary directories as deep as possible,
we can allow v2 repositories to have `xap$SCHEMA_VERSION'
(e.g. `xap15') reside on a separate FS.
We also check st_dev ahead-of-time to avoid doing work which
will fail with EXDEV. Of course, another process may still
move/change things around.
---
lib/PublicInbox/Xapcmd.pm | 59 ++++++++++++++++++++++++++-------------
1 file changed, 40 insertions(+), 19 deletions(-)
diff --git a/lib/PublicInbox/Xapcmd.pm b/lib/PublicInbox/Xapcmd.pm
index 697221d..860f90a 100644
--- a/lib/PublicInbox/Xapcmd.pm
+++ b/lib/PublicInbox/Xapcmd.pm
@@ -8,31 +8,36 @@ use PublicInbox::Over;
use PublicInbox::Search;
use File::Temp qw(tempdir);
use File::Path qw(remove_tree);
+use File::Basename qw(dirname);
# support testing with dev versions of Xapian which installs
# commands with a version number suffix (e.g. "xapian-compact-1.5")
our $XAPIAN_COMPACT = $ENV{XAPIAN_COMPACT} || 'xapian-compact';
-sub commit_changes ($$$$) {
- my ($ibx, $old, $new, $opt) = @_;
+sub commit_changes ($$$) {
+ my ($ibx, $tmp, $opt) = @_;
my $reindex = $opt->{reindex};
my $im = $ibx->importer(0);
$im->lock_acquire if $reindex;
- my @st = stat($old) or die "failed to stat($old): $!\n";
+ while (my ($old, $new) = each %$tmp) {
+ my @st = stat($old) or die "failed to stat($old): $!\n";
- my $over = "$old/over.sqlite3";
- if (-f $over) {
- $over = PublicInbox::Over->new($over);
- $over->connect->sqlite_backup_to_file("$new/over.sqlite3");
- $over = undef;
- }
- rename($old, "$new/old") or die "rename $old => $new/old: $!\n";
- chmod($st[2] & 07777, $new) or die "chmod $old: $!\n";
- rename($new, $old) or die "rename $new => $old: $!\n";
- remove_tree("$old/old") or die "failed to remove $old/old: $!\n";
+ my $over = "$old/over.sqlite3";
+ if (-f $over) { # only for v1, v2 over is untouched
+ $over = PublicInbox::Over->new($over);
+ my $tmp_over = "$new/over.sqlite3";
+ $over->connect->sqlite_backup_to_file($tmp_over);
+ $over = undef;
+ }
+ rename($old, "$new/old") or die "rename $old => $new/old: $!\n";
+ chmod($st[2] & 07777, $new) or die "chmod $old: $!\n";
+ rename($new, $old) or die "rename $new => $old: $!\n";
+ my $prev = "$old/old";
+ remove_tree($prev) or die "failed to remove $prev: $!\n";
+ }
if ($reindex) {
$opt->{-skip_lock} = 1;
PublicInbox::Admin::index_inbox($ibx, $opt);
@@ -94,19 +99,23 @@ sub progress_prepare ($) {
}
}
+sub same_fs_or_die ($$) {
+ my ($x, $y) = @_;
+ return if ((stat($x))[0] == (stat($y))[0]); # 0 - st_dev
+ die "$x and $y reside on different filesystems\n";
+}
+
sub run {
my ($ibx, $cmd, $env, $opt) = @_;
progress_prepare($opt ||= {});
my $dir = $ibx->{mainrepo} or die "no mainrepo in inbox\n";
my $exe = $cmd->[0];
- my $pfx = $exe;
runnable_or_die($XAPIAN_COMPACT) if $opt->{compact};
my $reindex; # v1:{ from => $x40 }, v2:{ from => [ $x40, $x40, .. ] } }
my $from; # per-epoch ranges
if (ref($exe) eq 'CODE') {
- $pfx = 'CODE';
$reindex = $opt->{reindex} = {};
$from = $reindex->{from} = [];
require Search::Xapian::WritableDatabase;
@@ -116,16 +125,28 @@ sub run {
$ibx->umask_prepare;
my $old = $ibx->search->xdir(1);
-d $old or die "$old does not exist\n";
- my $new = tempdir("$pfx-XXXXXXXX", DIR => $dir);
+
+ my $tmp = {}; # old partition => new (tmp) partition
my $v = $ibx->{version} ||= 1;
my @cmds;
+
+ # we want temporary directories to be as deep as possible,
+ # so v2 partitions can keep "xap$SCHEMA_VERSION" on a separate FS.
if ($v == 1) {
- push @cmds, [@$cmd, $old, $new];
+ my $old_parent = dirname($old);
+ same_fs_or_die($old_parent, $old);
+ $tmp->{$old} = tempdir('xapcmd-XXXXXXXX', DIR => $old_parent);
+ push @cmds, [ @$cmd, $old, $tmp->{$old} ];
} else {
opendir my $dh, $old or die "Failed to opendir $old: $!\n";
while (defined(my $dn = readdir($dh))) {
if ($dn =~ /\A\d+\z/) {
- push @cmds, [@$cmd, "$old/$dn", "$new/$dn"];
+ my $tmpl = "$dn-XXXXXXXX";
+ my $dst = tempdir($tmpl, DIR => $old);
+ same_fs_or_die($old, $dst);
+ my $cur = "$old/$dn";
+ push @cmds, [@$cmd, $cur, $dst ];
+ $tmp->{$cur} = $dst;
} elsif ($dn eq '.' || $dn eq '..') {
} elsif ($dn =~ /\Aover\.sqlite3/) {
} else {
@@ -158,7 +179,7 @@ sub run {
die join(' ', @$x)." failed: $?\n" if $?;
}
}
- commit_changes($ibx, $old, $new, $opt);
+ commit_changes($ibx, $tmp, $opt);
});
}
--
EW
^ permalink raw reply related [relevance 7%]
* [PATCH 00/26] xcpdb: ease Xapian DB format migrations
@ 2019-05-23 9:36 7% Eric Wong
2019-05-23 9:36 7% ` [PATCH 17/26] xapcmd: avoid EXDEV when finalizing changes Eric Wong
0 siblings, 1 reply; 2+ results
From: Eric Wong @ 2019-05-23 9:36 UTC (permalink / raw)
To: meta
I've noticed performance problems in Xapian's old chert
backend which seem alleviated with the new glass backend;
particularly related to phrase searches.
Unfortunately, the tool distributed with Xapian for updating DB
formats, copydatabase(1), is extremely slow and blocking updates
for hours at a time to perform the migration is not acceptable.
(That's right, "copydatabase" is NOT a Postgres command!)
So, I've written "public-inbox-xcpdb" and gotten it to perform
the bulk copy operation without holding inbox.lock and have it
deal gracefully with Xapian DB modifications. xcpdb is still
slow, but I've (finally!) implemented partial reindexing to
allow it to minimize the lock time and not stall -mda or -watch
processes while it is working.
There's a bunch of cleanups along the way, too; and it should
make future changes to repartition the Xapian DB on existing v2
inboxes easier.
Eric Wong (26):
t/convert-compact: skip on missing xapian-compact(1)
v1writable: retire in favor of InboxWritable
doc: document the reason for --no-renumber
search: reenable phrase search on non-chert Xapian
xapcmd: new module for wrapping Xapian commands
admin: hoist out resolve_inboxes for -compact and -index
xapcmd: support spawn options
xcpdb: new tool which wraps Xapian's copydatabase(1)
xapcmd: do not cleanup on errors
admin: move index_inbox over
xcpdb: implement using Perl bindings
xapcmd: xcpdb supports compaction
v2writable: hoist out log_range sub for readability
xcpdb: use fine-grained locking
xcpdb: implement progress reporting
xcpdb: cleanup error handling and diagnosis
xapcmd: avoid EXDEV when finalizing changes
doc: xcpdb: update to reflect the current state
xapcmd: use "print STDERR" for progress reporting
xcpdb: show re-indexing progress
xcpdb: remove temporary directories on aborts
compact: reuse infrastructure from xcpdb
xcpdb|compact: support some xapian-compact switches
xapcmd: cleanup on interrupted xcpdb "--compact"
xcpdb|compact: support --jobs/-j flag like gmake(1)
xapcmd: do not reset %SIG until last Xtmpdir is done
Documentation/include.mk | 6 +-
Documentation/public-inbox-v1-format.pod | 4 +
Documentation/public-inbox-v2-format.pod | 4 +
Documentation/public-inbox-xcpdb.pod | 57 ++++
MANIFEST | 4 +-
lib/PublicInbox/Admin.pm | 66 ++++
lib/PublicInbox/InboxWritable.pm | 35 ++-
lib/PublicInbox/Search.pm | 48 +--
lib/PublicInbox/SearchIdx.pm | 34 ++-
lib/PublicInbox/V1Writable.pm | 34 ---
lib/PublicInbox/V2Writable.pm | 109 ++++---
lib/PublicInbox/Xapcmd.pm | 370 +++++++++++++++++++++++
script/public-inbox-compact | 102 +------
script/public-inbox-index | 102 +------
script/public-inbox-init | 13 +-
script/public-inbox-xcpdb | 19 ++
t/cgi.t | 4 +-
t/convert-compact.t | 4 +
t/indexlevels-mirror.t | 27 +-
t/init.t | 4 +-
t/nntpd.t | 15 +-
t/search.t | 1 +
t/v2mirror.t | 1 +
23 files changed, 740 insertions(+), 323 deletions(-)
create mode 100644 Documentation/public-inbox-xcpdb.pod
delete mode 100644 lib/PublicInbox/V1Writable.pm
create mode 100644 lib/PublicInbox/Xapcmd.pm
create mode 100755 script/public-inbox-xcpdb
--
EW
^ permalink raw reply [relevance 7%]
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