[PATCH 51/52] extsearchidx: support --batch-size checkpoints

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

This is needed to limit the RSS of processes and ensure the
stored data in over.sqlite3 and Xapian DBs are consistent if
interrupted.  Without checkpoints, indexing lore causes shard
workers to take several GB of memory and thrash/OOM smaller
systems.
---
 lib/PublicInbox/ExtSearchIdx.pm | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/lib/PublicInbox/ExtSearchIdx.pm b/lib/PublicInbox/ExtSearchIdx.pm
index 050c4252..9d576adb 100644
--- a/lib/PublicInbox/ExtSearchIdx.pm
+++ b/lib/PublicInbox/ExtSearchIdx.pm
@@ -106,6 +106,18 @@ sub is_bad_blob ($$$$) {
 	$size == 0 ? 1 : 0; # size == 0 means purged
 }
 
+sub check_batch_limit ($) {
+	my ($req) = @_;
+	my $self = $req->{self};
+	my $new_smsg = $req->{new_smsg};
+
+	# {raw_bytes} may be unset, so just use {bytes}
+	my $n = $self->{transact_bytes} += $new_smsg->{bytes};
+
+	# set flag for PublicInbox::V2Writable::index_todo:
+	${$req->{need_checkpoint}} = 1 if $n >= $self->{batch_bytes};
+}
+
 sub do_xpost ($$) {
 	my ($req, $smsg) = @_;
 	my $self = $req->{self};
@@ -118,6 +130,7 @@ sub do_xpost ($$) {
 		my $xnum = $req->{xnum};
 		$self->{oidx}->add_xref3($docid, $xnum, $oid, $xibx->eidx_key);
 		$idx->shard_add_eidx_info($docid, $oid, $xibx, $eml);
+		check_batch_limit($req);
 	} else { # 'd'
 		$self->{oidx}->remove_xref3($docid, $oid, $xibx->eidx_key);
 		$idx->shard_remove_eidx_info($docid, $oid, $xibx, $eml);
@@ -141,6 +154,7 @@ sub index_unseen ($) {
 	my $ibx = delete $req->{ibx} or die 'BUG: {ibx} unset';
 	$self->{oidx}->add_xref3($docid, $req->{xnum}, $oid, $ibx->eidx_key);
 	$idx->index_raw(undef, $eml, $new_smsg, $ibx);
+	check_batch_limit($req);
 }
 
 sub do_finalize ($) {
@@ -301,7 +315,11 @@ sub eidx_sync { # main entry point
 	local $SIG{__WARN__} = sub {
 		$warn_cb->($self->{current_info}, ': ', @_);
 	};
-	_sync_inbox($self, $opt, $_) for (@{$self->{ibx_list}});
+
+	# don't use $_ here, it'll get clobbered by reindex_checkpoint
+	for my $ibx (@{$self->{ibx_list}}) {
+		_sync_inbox($self, $opt, $ibx);
+	}
 
 	$self->{oidx}->rethread_done($opt);