From 8ef622d408d2e4d98ad3aada8466f539c9ac61ba Mon Sep 17 00:00:00 2001
From: Eric Wong <e@80x24.org>
Date: Tue, 6 Jul 2021 12:42:02 +0000
Subject: extindex: implement --dedupe to fix old extindices

This is intended to fix older indices that had deduplication
bugs for matching content.  It'll also make dealing with
future changes to ContentHash easier since that's never
guaranteed stable.

It also supports --dry-run to print changes only without
making them.
---
 lib/PublicInbox/ExtSearchIdx.pm | 96 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 96 insertions(+)

(limited to 'lib/PublicInbox/ExtSearchIdx.pm')

diff --git a/lib/PublicInbox/ExtSearchIdx.pm b/lib/PublicInbox/ExtSearchIdx.pm
index 29414e4a..495579a2 100644
--- a/lib/PublicInbox/ExtSearchIdx.pm
+++ b/lib/PublicInbox/ExtSearchIdx.pm
@@ -844,6 +844,98 @@ sub sync_inbox {
 	warn $err, "\n" if defined($err);
 }
 
+sub dd_smsg { # git->cat_async callback
+	my ($bref, $oid, $type, $size, $dd) = @_;
+	my $smsg = $dd->{smsg} // die 'BUG: dd->{smsg} missing';
+	my $self = $dd->{self} // die 'BUG: {self} missing';
+	my $per_mid = $dd->{per_mid} // die 'BUG: {per_mid} missing';
+	if ($type eq 'missing') {
+		_blob_missing($dd, $smsg);
+	} elsif (!is_bad_blob($oid, $type, $size, $smsg->{blob})) {
+		local $self->{current_info} = "$self->{current_info} $oid";
+		my $chash = content_hash(PublicInbox::Eml->new($bref));
+		push(@{$per_mid->{dd_chash}->{$chash}}, $smsg);
+	}
+	return if $per_mid->{last_smsg} != $smsg;
+	while (my ($chash, $ary) = each %{$per_mid->{dd_chash}}) {
+		my $keep = shift @$ary;
+		next if !scalar(@$ary);
+		$per_mid->{sync}->{dedupe_cull} += scalar(@$ary);
+		print STDERR
+			"# <$keep->{mid}> keeping #$keep->{num}, dropping ",
+			join(', ', map { "#$_->{num}" } @$ary),"\n";
+		next if $per_mid->{sync}->{-opt}->{'dry-run'};
+		my $oidx = $self->{oidx};
+		for my $smsg (@$ary) {
+			my $gone = $smsg->{num};
+			$oidx->merge_xref3($keep->{num}, $gone, $smsg->{blob});
+			$self->idx_shard($gone)->ipc_do('xdb_remove', $gone);
+			$oidx->delete_by_num($gone);
+		}
+	}
+}
+
+sub eidx_dedupe ($$) {
+	my ($self, $sync) = @_;
+	$sync->{dedupe_cull} = 0;
+	my $candidates = 0;
+	my $nr_mid = 0;
+	return unless eidxq_lock_acquire($self);
+	my $iter;
+	my $min_id = 0;
+	local $sync->{-regen_fmt} = "dedupe %u/".$self->{oidx}->max."\n";
+dedupe_restart:
+	$iter = $self->{oidx}->dbh->prepare(<<EOS);
+SELECT DISTINCT(mid),id FROM msgid WHERE id IN
+(SELECT id FROM id2num WHERE id > ? GROUP BY num HAVING COUNT(num) > 1)
+ORDER BY id
+EOS
+	$iter->execute($min_id);
+	local $SIG{__WARN__} = sub {
+		return if PublicInbox::Eml::warn_ignore(@_);
+		warn @_;
+	};
+	while (my ($mid, $id) = $iter->fetchrow_array) {
+		last if $sync->{quit};
+		$self->{current_info} = "dedupe $mid";
+		${$sync->{nr}} = $min_id = $id;
+		my ($n, $prv, @smsg);
+		while (my $x = $self->{oidx}->next_by_mid($mid, \$n, \$prv)) {
+			push @smsg, $x;
+		}
+		next if scalar(@smsg) < 2;
+		my $per_mid = {
+			dd_chash => {}, # chash => [ary of smsgs]
+			last_smsg => $smsg[-1],
+			sync => $sync
+		};
+		$nr_mid++;
+		$candidates += scalar(@smsg) - 1;
+		for my $smsg (@smsg) {
+			my $dd = {
+				per_mid => $per_mid,
+				smsg => $smsg,
+				self => $self,
+			};
+			$self->git->cat_async($smsg->{blob}, \&dd_smsg, $dd);
+		}
+		# need to wait on every single one
+		$self->git->async_wait_all;
+
+		# is checkpoint needed? $iter is a very expensive query to restart
+		if (0 && checkpoint_due($sync)) {
+			undef $iter;
+			reindex_checkpoint($self, $sync);
+			goto dedupe_restart;
+		}
+	}
+	my $n = delete $sync->{dedupe_cull};
+	if (my $pr = $sync->{-opt}->{-progress}) {
+		$pr->("culled $n/$candidates candidates ($nr_mid msgids)\n");
+	}
+	${$sync->{nr}} = 0;
+}
+
 sub eidx_sync { # main entry point
 	my ($self, $opt) = @_;
 
@@ -873,6 +965,10 @@ sub eidx_sync { # main entry point
 	for my $ibx (@{$self->{ibx_list}}) {
 		$ibx->{-ibx_id} //= $self->{oidx}->ibx_id($ibx->eidx_key);
 	}
+	if (delete($opt->{dedupe})) {
+		local $sync->{checkpoint_unlocks} = 1;
+		eidx_dedupe($self, $sync);
+	}
 	if (delete($opt->{reindex})) {
 		local $sync->{checkpoint_unlocks} = 1;
 		eidx_reindex($self, $sync);
-- 
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