X-Git-Url: http://www.git.stargrave.org/?a=blobdiff_plain;f=lib%2FPublicInbox%2FOver.pm;h=0957cbdd78cca6290832f93e25b7203977904456;hb=6e2da35b9e9e5510e3156b07e91ebc835146758c;hp=a2f0411776ac9f2b413aedbeb6daea72aa3273fc;hpb=adf0f449f1ee7638423cdfe38e9f3f20754767fe;p=public-inbox.git

diff --git a/lib/PublicInbox/Over.pm b/lib/PublicInbox/Over.pm
index a2f04117..0957cbdd 100644
--- a/lib/PublicInbox/Over.pm
+++ b/lib/PublicInbox/Over.pm
@@ -6,7 +6,7 @@
 # tweaked/updated over time and rebuilt.
 package PublicInbox::Over;
 use strict;
-use warnings;
+use v5.10.1;
 use DBI;
 use DBD::SQLite;
 use PublicInbox::Smsg;
@@ -42,7 +42,28 @@ sub dbh_new {
 		$st = pack('dd', $st[0], $st[1]);
 	} while ($st ne $self->{st} && $tries++ < 3);
 	warn "W: $f: .st_dev, .st_ino unstable\n" if $st ne $self->{st};
-	$dbh->do('PRAGMA synchronous = OFF') if ($rw // 0) > 1;
+
+	if ($rw) {
+		# TRUNCATE reduces I/O compared to the default (DELETE).
+		#
+		# Do not use WAL by default since we expect the case
+		# where any users may read via read-only daemons
+		# (-httpd/-imapd/-nntpd); but only a single user has
+		# write permissions for -watch/-mda.
+		#
+		# Read-only WAL support in SQLite 3.22.0 (2018-01-22)
+		# doesn't do what we need: it is only intended for
+		# immutable read-only media (e.g. CD-ROM) and not
+		# usable for our use case described above.
+		#
+		# If an admin is willing to give read-only daemons R/W
+		# permissions; they can enable WAL manually and we will
+		# respect that by not clobbering it.
+		my $jm = $dbh->selectrow_array('PRAGMA journal_mode');
+		$dbh->do('PRAGMA journal_mode = TRUNCATE') if $jm ne 'wal';
+
+		$dbh->do('PRAGMA synchronous = OFF') if $rw > 1;
+	}
 	$dbh;
 }
 
@@ -51,7 +72,7 @@ sub new {
 	bless { filename => $f }, $class;
 }
 
-sub disconnect {
+sub dbh_close {
 	my ($self) = @_;
 	if (my $dbh = delete $self->{dbh}) {
 		delete $self->{-get_art};
@@ -59,7 +80,7 @@ sub disconnect {
 	}
 }
 
-sub connect { $_[0]->{dbh} //= $_[0]->dbh_new }
+sub dbh ($) { $_[0]->{dbh} //= $_[0]->dbh_new } # dbh_new may be subclassed
 
 sub load_from_row ($;$) {
 	my ($smsg, $cull) = @_;
@@ -76,10 +97,9 @@ sub load_from_row ($;$) {
 
 sub do_get {
 	my ($self, $sql, $opts, @args) = @_;
-	my $dbh = $self->connect;
 	my $lim = (($opts->{limit} || 0) + 0) || DEFAULT_LIMIT;
 	$sql .= "LIMIT $lim";
-	my $msgs = $dbh->selectall_arrayref($sql, { Slice => {} }, @args);
+	my $msgs = dbh($self)->selectall_arrayref($sql, { Slice => {} }, @args);
 	my $cull = $opts->{cull};
 	load_from_row($_, $cull) for @$msgs;
 	$msgs
@@ -114,7 +134,7 @@ sub nothing () { wantarray ? (0, []) : [] };
 
 sub get_thread {
 	my ($self, $mid, $prev) = @_;
-	my $dbh = $self->connect;
+	my $dbh = dbh($self);
 	my $opts = { cull => 1 };
 
 	my $id = $dbh->selectrow_array(<<'', undef, $mid);
@@ -181,7 +201,7 @@ ORDER BY $sort_col DESC
 # returns true if we have IDs, undef if not
 sub expand_thread {
 	my ($self, $ctx) = @_;
-	my $dbh = $self->connect;
+	my $dbh = dbh($self);
 	do {
 		defined(my $num = $ctx->{ids}->[0]) or return;
 		my ($tid) = $dbh->selectrow_array(<<'', undef, $num);
@@ -224,21 +244,15 @@ sub recent {
 			$s = '+num > 0 ORDER BY ts DESC';
 		}
 	}
-	my $msgs = do_get($self, <<"", $opts, @v);
+	do_get($self, <<"", $opts, @v);
 SELECT ts,ds,ddd FROM over WHERE $s
 
-	return $msgs unless wantarray;
-
-	my $nr = $self->{dbh}->selectrow_array(<<'');
-SELECT COUNT(num) FROM over WHERE num > 0
-
-	($nr, $msgs);
 }
 
 sub get_art {
 	my ($self, $num) = @_;
 	# caching $sth ourselves is faster than prepare_cached
-	my $sth = $self->{-get_art} //= $self->connect->prepare(<<'');
+	my $sth = $self->{-get_art} //= dbh($self)->prepare(<<'');
 SELECT num,tid,ds,ts,ddd FROM over WHERE num = ? LIMIT 1
 
 	$sth->execute($num);
@@ -248,7 +262,7 @@ SELECT num,tid,ds,ts,ddd FROM over WHERE num = ? LIMIT 1
 
 sub next_by_mid {
 	my ($self, $mid, $id, $prev) = @_;
-	my $dbh = $self->connect;
+	my $dbh = dbh($self);
 
 	unless (defined $$id) {
 		my $sth = $dbh->prepare_cached(<<'', undef, 1);
@@ -272,7 +286,7 @@ ORDER BY num ASC LIMIT 1
 # IMAP search, this is limited by callers to UID_SLICE size (50K)
 sub uid_range {
 	my ($self, $beg, $end, $sql) = @_;
-	my $dbh = $self->connect;
+	my $dbh = dbh($self);
 	my $q = 'SELECT num FROM over WHERE num >= ? AND num <= ?';
 
 	# This is read-only, anyways; but caller should verify it's
@@ -284,7 +298,7 @@ sub uid_range {
 
 sub max {
 	my ($self) = @_;
-	my $sth = $self->connect->prepare_cached(<<'', undef, 1);
+	my $sth = dbh($self)->prepare_cached(<<'', undef, 1);
 SELECT MAX(num) FROM over WHERE num > 0
 
 	$sth->execute;
@@ -293,7 +307,7 @@ SELECT MAX(num) FROM over WHERE num > 0
 
 sub imap_exists {
 	my ($self, $uid_base, $uid_end) = @_;
-	my $sth = $self->connect->prepare_cached(<<'', undef, 1);
+	my $sth = dbh($self)->prepare_cached(<<'', undef, 1);
 SELECT COUNT(num) FROM over WHERE num > ? AND num <= ?
 
 	$sth->execute($uid_base, $uid_end);
@@ -308,7 +322,7 @@ sub check_inodes {
 		my $st = pack('dd', $st[0], $st[1]);
 
 		# don't actually reopen, just let {dbh} be recreated later
-		disconnect($self) if $st ne ($self->{st} // $st);
+		dbh_close($self) if $st ne ($self->{st} // $st);
 	} else {
 		warn "W: stat $f: $!\n";
 	}