[PATCH 8/9] extsearchidx: reindex releases over.sqlite3 handles properly

[Eric Wong <e@80x24.org>]

When checkpointing and yielding the lock to other processes,
we need to ensure any open DB statement handles are closed,
since they reference and prevent DB FDs from being closed
and unlocked.

And clean up some progress reporting while we're at it.
---
 lib/PublicInbox/ExtSearchIdx.pm | 147 +++++++++++++++++++++-----------
 lib/PublicInbox/V2Writable.pm   |   3 +
 2 files changed, 100 insertions(+), 50 deletions(-)

diff --git a/lib/PublicInbox/ExtSearchIdx.pm b/lib/PublicInbox/ExtSearchIdx.pm
index d5295735..b5024823 100644
--- a/lib/PublicInbox/ExtSearchIdx.pm
+++ b/lib/PublicInbox/ExtSearchIdx.pm
@@ -29,6 +29,7 @@ use PublicInbox::InboxWritable;
 use PublicInbox::ContentHash qw(content_hash);
 use PublicInbox::Eml;
 use File::Spec;
+use PublicInbox::DS qw(now);
 use DBI qw(:sql_types); # SQL_BLOB
 
 sub new {
@@ -518,6 +519,11 @@ BUG? #$docid $smsg->{blob} is not referenced by inboxes during reindex
 	$self->git->cat_async($xr3->[$req->{ix}]->[2], \&_reindex_oid, $req);
 }
 
+sub checkpoint_due ($) {
+	my ($sync) = @_;
+	${$sync->{need_checkpoint}} || (now() > $sync->{next_check});
+}
+
 sub eidxq_process ($$) { # for reindexing
 	my ($self, $sync) = @_;
 
@@ -531,13 +537,16 @@ sub eidxq_process ($$) { # for reindexing
 		my $max = $dbh->selectrow_array('SELECT MAX(docid) FROM eidxq');
 		$pr->("Xapian indexing $min..$max (total=$tot)\n");
 	}
-	my %id2pos;
-	my $pos = 0;
-	$id2pos{$_->{-ibx_id}} = $pos++ for @{$self->{ibx_list}};
-	$sync->{id2pos} = \%id2pos;
-
-	my $del = $dbh->prepare('DELETE FROM eidxq WHERE docid = ?');
-	my $iter = $dbh->prepare('SELECT docid FROM eidxq ORDER BY docid ASC');
+	$sync->{id2pos} //= do {
+		my %id2pos;
+		my $pos = 0;
+		$id2pos{$_->{-ibx_id}} = $pos++ for @{$self->{ibx_list}};
+		\%id2pos;
+	};
+	my ($del, $iter);
+restart:
+	$del = $dbh->prepare('DELETE FROM eidxq WHERE docid = ?');
+	$iter = $dbh->prepare('SELECT docid FROM eidxq ORDER BY docid ASC');
 	$iter->execute;
 	while (defined(my $docid = $iter->fetchrow_array)) {
 		last if $sync->{quit};
@@ -549,8 +558,12 @@ sub eidxq_process ($$) { # for reindexing
 		$del->execute($docid);
 		++${$sync->{nr}};
 
-		# this is only for SIGUSR1, shards do their own accounting:
-		reindex_checkpoint($self, $sync) if ${$sync->{need_checkpoint}};
+		if (checkpoint_due($sync)) {
+			$dbh = $del = $iter = undef;
+			reindex_checkpoint($self, $sync); # release lock
+			$dbh = $self->{oidx}->dbh;
+			goto restart;
+		}
 	}
 	$self->git->async_wait_all;
 	$pr->("reindexed ${$sync->{nr}}/$tot\n") if $pr;
@@ -589,16 +602,28 @@ sub reindex_unseen ($$$$) {
 sub _reindex_check_unseen ($$$) {
 	my ($self, $sync, $ibx) = @_;
 	my $ibx_id = $ibx->{-ibx_id};
-	my ($beg, $end) = (1, 1000);
+	my $slice = 1000;
+	my ($beg, $end) = (1, $slice);
 
 	# first, check if we missed any messages in target $ibx
-	my $inx3 = $self->{oidx}->dbh->prepare(<<'');
-SELECT DISTINCT(docid) FROM xref3 WHERE ibx_id = ? AND xnum = ? AND oidbin = ?
-
 	my $msgs;
+	my $pr = $sync->{-opt}->{-progress};
+	my $ekey = $ibx->eidx_key;
+	$sync->{-regen_fmt} = "$ekey checking unseen %u/".$ibx->over->max."\n";
+	${$sync->{nr}} = 0;
+
 	while (scalar(@{$msgs = $ibx->over->query_xover($beg, $end)})) {
+		${$sync->{nr}} = $beg;
 		$beg = $msgs->[-1]->{num} + 1;
-		$end = $beg + 1000;
+		$end = $beg + $slice;
+		if (checkpoint_due($sync)) {
+			reindex_checkpoint($self, $sync); # release lock
+		}
+
+		my $inx3 = $self->{oidx}->dbh->prepare_cached(<<'', undef, 1);
+SELECT DISTINCT(docid) FROM xref3 WHERE
+ibx_id = ? AND xnum = ? AND oidbin = ?
+
 		for my $xsmsg (@$msgs) {
 			my $oidbin = pack('H*', $xsmsg->{blob});
 			$inx3->bind_param(1, $ibx_id);
@@ -623,49 +648,69 @@ SELECT DISTINCT(docid) FROM xref3 WHERE ibx_id = ? AND xnum = ? AND oidbin = ?
 
 sub _reindex_check_stale ($$$) {
 	my ($self, $sync, $ibx) = @_;
-
-	# now, check if there's stale xrefs
-	my $get_xnum = $self->{oidx}->dbh->prepare(<<'');
-SELECT docid,xnum,oidbin FROM xref3 WHERE ibx_id = ? ORDER BY docid ASC
-
-	$get_xnum->execute($ibx->{-ibx_id});
-	my $del_xref3 = $self->{oidx}->dbh->prepare(<<'');
+	my $min = 0;
+	my $pr = $sync->{-opt}->{-progress};
+	my $fetching;
+	my $ekey = $ibx->eidx_key;
+	$sync->{-regen_fmt} =
+			"$ekey check stale/missing %u/".$ibx->over->max."\n";
+	${$sync->{nr}} = 0;
+	do {
+		if (checkpoint_due($sync)) {
+			reindex_checkpoint($self, $sync); # release lock
+		}
+		# now, check if there's stale xrefs
+		my $iter = $self->{oidx}->dbh->prepare_cached(<<'', undef, 1);
+SELECT docid,xnum,oidbin FROM xref3 WHERE ibx_id = ? AND docid > ?
+ORDER BY docid,xnum ASC LIMIT 10000
+
+		$iter->execute($ibx->{-ibx_id}, $min);
+		$fetching = undef;
+
+		while (my ($docid, $xnum, $oidbin) = $iter->fetchrow_array) {
+			return if $sync->{quit};
+			${$sync->{nr}} = $xnum;
+
+			$fetching = $min = $docid;
+			my $smsg = $ibx->over->get_art($xnum);
+			my $oidhex = unpack('H*', $oidbin);
+			my $err;
+			if (!$smsg) {
+				$err = 'stale';
+			} elsif ($smsg->{blob} ne $oidhex) {
+				$err = "mismatch (!= $smsg->{blob})";
+			} else {
+				next; # likely, all good
+			}
+			# current_info already has eidx_key
+			warn "$xnum:$oidhex (#$docid): $err\n";
+			my $del = $self->{oidx}->dbh->prepare_cached(<<'');
 DELETE FROM xref3 WHERE ibx_id = ? AND xnum = ? AND oidbin = ?
 
-	while (my ($docid, $xnum, $oidbin) = $get_xnum->fetchrow_array) {
-		last if $sync->{quit};
-		my $smsg = $ibx->over->get_art($xnum);
-		my $oidhex = unpack('H*', $oidbin);
-		my $err;
-		if (!$smsg) {
-			$err = 'stale';
-		} elsif ($smsg->{blob} ne $oidhex) {
-			$err = "mismatch (!= $smsg->{blob})";
-		} else {
-			next; # likely, all good
-		}
-		warn $ibx->eidx_key . ":$xnum:$oidhex (#$docid): $err\n";
-		$del_xref3->bind_param(1, $ibx->{-ibx_id});
-		$del_xref3->bind_param(2, $xnum);
-		$del_xref3->bind_param(3, $oidbin, SQL_BLOB);
-		$del_xref3->execute;
-
-		# get_xref3 over-fetches, but this is a rare path:
-		my $xr3 = $self->{oidx}->get_xref3($docid);
-		my $idx = $self->idx_shard($docid);
-		if (scalar(@$xr3) == 0) { # all gone
-			$self->{oidx}->delete_by_num($docid);
-			$self->{oidx}->eidxq_del($docid);
-			$idx->shard_remove($docid);
-		} else { # enqueue for reindex of remaining messages
-			$idx->shard_remove_eidx_info($docid, $ibx->eidx_key);
-			$self->{oidx}->eidxq_add($docid); # yes, add
+			$del->bind_param(1, $ibx->{-ibx_id});
+			$del->bind_param(2, $xnum);
+			$del->bind_param(3, $oidbin, SQL_BLOB);
+			$del->execute;
+
+			# get_xref3 over-fetches, but this is a rare path:
+			my $xr3 = $self->{oidx}->get_xref3($docid);
+			my $idx = $self->idx_shard($docid);
+			if (scalar(@$xr3) == 0) { # all gone
+				$self->{oidx}->delete_by_num($docid);
+				$self->{oidx}->eidxq_del($docid);
+				$idx->shard_remove($docid);
+			} else { # enqueue for reindex of remaining messages
+				$idx->shard_remove_eidx_info($docid,
+							$ibx->eidx_key);
+				$self->{oidx}->eidxq_add($docid); # yes, add
+			}
 		}
-	}
+	} while (defined $fetching);
 }
 
 sub _reindex_inbox ($$$) {
 	my ($self, $sync, $ibx) = @_;
+	local $self->{current_info} = $ibx->eidx_key;
 	_reindex_check_unseen($self, $sync, $ibx);
 	_reindex_check_stale($self, $sync, $ibx) unless $sync->{quit};
 	delete @$ibx{qw(over mm search git)}; # won't need these for a bit
@@ -694,6 +739,8 @@ sub eidx_sync { # main entry point
 	$self->{oidx}->rethread_prepare($opt);
 	my $sync = {
 		need_checkpoint => \(my $need_checkpoint = 0),
+		check_intvl => 10,
+		next_check => now() + 10,
 		-opt => $opt,
 		# DO NOT SET {reindex} here, it's incompatible with reused
 		# V2Writable code, reindex is totally different here
diff --git a/lib/PublicInbox/V2Writable.pm b/lib/PublicInbox/V2Writable.pm
index 97dbf328..992305c5 100644
--- a/lib/PublicInbox/V2Writable.pm
+++ b/lib/PublicInbox/V2Writable.pm
@@ -896,6 +896,9 @@ sub reindex_checkpoint ($$) {
 
 	# allow -watch or -mda to write...
 	$self->idx_init($sync->{-opt}); # reacquire lock
+	if (my $intvl = $sync->{check_intvl}) { # eidx
+		$sync->{next_check} = PublicInbox::DS::now() + $intvl;
+	}
 	$mm_tmp->atfork_parent if $mm_tmp;
 }