1 # Copyright (C) 2020-2021 all contributors <meta@public-inbox.org>
2 # License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
4 # fork()-friendly key-value store. Will be used for making
5 # augmenting Maildirs and mboxes less expensive, maybe.
6 # We use flock(2) to avoid SQLite lock problems (busy timeouts, backoff)
7 package PublicInbox::SharedKV;
10 use parent qw(PublicInbox::Lock);
11 use File::Temp qw(tempdir);
13 use PublicInbox::Spawn;
14 use File::Path qw(rmtree make_path);
17 my ($self, $lock) = @_;
19 my $f = $self->{filename};
20 $lock //= $self->lock_for_scope_fast;
21 my $dbh = DBI->connect("dbi:SQLite:dbname=$f", '', '', {
25 sqlite_use_immediate_transaction => 1,
26 # no sqlite_unicode here, this is for binary data
28 my $opt = $self->{opt} // {};
29 $dbh->do('PRAGMA synchronous = OFF') if !$opt->{fsync};
30 if (my $s = $opt->{cache_size}) {
31 $dbh->do("PRAGMA cache_size = $s");
33 $dbh->do('PRAGMA journal_mode = '.
34 ($opt->{journal_mode} // 'WAL'));
36 CREATE TABLE IF NOT EXISTS kv (
37 k VARBINARY PRIMARY KEY NOT NULL,
47 my ($cls, $dir, $base, $opt) = @_;
48 my $self = bless { opt => $opt }, $cls;
49 make_path($dir) if defined($dir) && !-d $dir;
50 $dir //= $self->{"tmp$$.$self"} = tempdir("skv.$$-XXXX", TMPDIR => 1);
52 my $f = $self->{filename} = "$dir/$base.sqlite3";
53 $self->{lock_path} = $opt->{lock_path} // "$dir/$base.flock";
55 PublicInbox::Spawn::nodatacow_dir($dir); # for journal/shm/wal
56 open my $fh, '+>>', $f or die "failed to open $f: $!";
57 PublicInbox::Spawn::nodatacow_fd(fileno($fh));
64 my $lock = $self->lock_for_scope_fast;
65 $self->dbh($lock)->do('CREATE INDEX IF NOT EXISTS idx_v ON kv (v)');
69 my ($self, $key, $val, $lock) = @_;
70 $lock //= $self->lock_for_scope_fast;
71 my $e = $self->{dbh}->prepare_cached(<<'')->execute($key, $val);
72 INSERT OR IGNORE INTO kv (k,v) VALUES (?, ?)
77 # caller calls sth->fetchrow_array
80 my $sth = $self->{dbh}->prepare_cached(<<'', undef, 1);
88 my ($self, @pfx) = @_;
89 my $sql = 'SELECT k FROM kv';
90 if (defined $pfx[0]) {
91 $sql .= ' WHERE k LIKE ? ESCAPE ?';
92 my $anywhere = !!$pfx[1];
94 $pfx[0] =~ s/([%_\\])/\\$1/g; # glob chars
96 substr($pfx[0], 0, 0, '%') if $anywhere;
98 @pfx = (); # [0] may've been undef
100 map { $_->[0] } @{$self->dbh->selectall_arrayref($sql, undef, @pfx)};
104 my ($self, $val, $lock) = @_;
105 $lock //= $self->lock_for_scope_fast;
106 $self->{dbh}->prepare_cached(<<'')->execute($val) + 0;
107 DELETE FROM kv WHERE v = ?
112 my ($self, $oldval, $newval, $lock) = @_;
113 $lock //= $self->lock_for_scope_fast;
114 $self->{dbh}->prepare_cached(<<'')->execute($newval, $oldval) + 0;
115 UPDATE kv SET v = ? WHERE v = ?
120 my ($self, $key, $val) = @_;
122 my $e = $self->{dbh}->prepare_cached(<<'')->execute($key, $val);
123 INSERT OR REPLACE INTO kv (k,v) VALUES (?,?)
125 $e == 0 ? undef : $e;
127 $self->{dbh}->prepare_cached(<<'')->execute($key);
128 DELETE FROM kv WHERE k = ?
134 my ($self, $key) = @_;
135 my $sth = $self->{dbh}->prepare_cached(<<'', undef, 1);
136 SELECT v FROM kv WHERE k = ?
139 $sth->fetchrow_array;
143 my ($self, $key, $newval, $lock) = @_;
144 $lock //= $self->lock_for_scope_fast;
145 my $oldval = get($self, $key);
146 if (defined $newval) {
147 set($self, $key, $newval);
149 $self->{dbh}->prepare_cached(<<'')->execute($key);
150 DELETE FROM kv WHERE k = ?
158 my $sth = $self->{dbh}->prepare_cached(<<'');
159 SELECT COUNT(k) FROM kv
162 $sth->fetchrow_array;
165 # faster than ->count due to how SQLite works
168 my @n = $self->{dbh}->selectrow_array('SELECT k FROM kv LIMIT 1');
169 scalar(@n) ? 1 : undef;
173 my ($self, $lock) = @_;
174 my $dbh = delete $self->{dbh} or return;
175 $lock //= $self->lock_for_scope_fast; # may be needed for WAL
176 %{$dbh->{CachedKids}} = (); # cleanup prepare_cached
183 my $dir = delete $self->{"tmp$$.$self"} or return;
187 eval { rmtree($dir) };
188 } while ($@ && $!{ENOENT} && $tries++ < 5);
189 warn "error removing $dir: $@" if $@;
190 warn "Took $tries tries to remove $dir\n" if $tries;