Re: Less rows returned with (flat, BNLH join) in maria-5.3-mwl128
Test case. Substituting with shorter strings did not reproduce the error.

SET SESSION optimizer_use_mrr = 'force';
SET SESSION join_cache_level = 4;
SET SESSION join_buffer_size = 136;
SET SESSION debug = '';

CREATE TABLE t1 (
col_varchar_1024_latin1_key varchar(1024) CHARACTER SET latin1 COLLATE latin1_bin DEFAULT NULL,
col_int int(11) DEFAULT NULL,
KEY col_varchar_1024_latin1_key (col_varchar_1024_latin1_key(1000))
) ENGINE=MyISAM DEFAULT CHARSET=latin1;
INSERT INTO t1 VALUES ('g',-1908473856),('well',9),('lepjojqjimlkhzeovotuhuhzvsgjnsvdtiiwlpaggansqwqtbxtrpgkdpijbzurzgrlxvqbscsaimikytvjicemytfyewkryzhrkkjhsokfyddhrmywsxnmlhgivrtyenhxxtvvntghzdeungnbutdinrrouazkoxzmwerytbeulzoficenbzpmbqpudjultxifchvapbvcfzewzqwqsavgwcxlseeptrfbpgkknwkoyoqfleqqkcufztfbitxcpnkpxqzouvjmycxskadadukleyuszjahybahjvqqzoziqzaqbpkgqnjlkvfcjohurkugnbijejanippjcljmwirnkaklnonpxbnemrqzaoehmetdhqriwagigriyhwtmenggyhnsollaeffqovjygruxqksilutlnaputcactqxgkecbxegtzqhvmmrsbumbxxrhylxjiccfujvwhdihcnrnphyoversbmjcexzabqahgyqfgeiufpvdafhhngktujlmqphjblpzuqirupbphcncnlvdkpimgvsdzcpwbxskjnuqysnefooxbpdqbhmkzgfzcqsvzjdhnhuinutvyjdwjzlzgarwewpsxtrsuhvqlzhhgmgajtsioxgugvqdnfaseqhubzraycetcdfbhfkuevtfqippyrffbthlbslvsdkfbzljkfcjgetsjzbujldobktajagkujozwnrewtptteztiyfyqdmiifqvbhrfzbsjmxvaksteofjphnslkaeqtinmusqkhvuuqsvgaapaiqsqflovvigczaihpxgpluquhiqiikunfbffzumhuqmzayeokagcgqbplza',84738048),('dutlepjojqjimlkhzeovotuhuhzvsgjnsvdtiiwlpaggansqwqtbxtrpgkdpijbzurzgrlxvqbscsaimikytvjicemytfyewkryzhrkkjhsokfyddhrmywsxnmlhgivrtyenhxxtvvntghzdeungnbutdinrrouazkoxzmwerytbeulzoficenbzpmbqpudjultxifchvapbvcfzewzqwqsavgwcxlseeptrfbpgkknwkoyoqfleqqkcufztfbitxcpnkpxqzouvjmycxskadadukleyuszjahybahjvqqzoziqzaqbpkgqnjlkvfcjohurkugnbijejanippjcljmwirnkaklnonpxbnemrqzaoehmetdhqriwagigriyhwtmenggyhnsollaeffqovjygruxqksilutlnaputcactqxgkecbxegtzqhvmmrsbumbxxrhylxjiccfujvwhdihcnrnphyoversbmjcexzabqahgyqfgeiufpvdafhhngktujlmqphjblpzuqirupbphcncnlvdkpimgvsdzcpwbxskjnuqysnefooxbpdqbhmkzgfzcqsvzjdhnhuinutvyjdwjzlzgarwewpsxtrsuhvqlzhhgmgajtsioxgugvqdnfaseqhubzraycetcdfbhfkuevtfqippyrffbthlbslvsdkfbzljkfcjgetsjzbujldobktajagkujozwnrewtptteztiyfyqdmiifqvbhrfzbsjmxvaksteofjphnslkaeqtinmusqkhvuuqsvgaapaiqsqflovvigczaihpxgpluquhiqiikunfbffzumhuqmzayeokagcg',-1675952128),('p',NULL),('y',NULL),('n',NULL);
CREATE TABLE t2 (
col_varchar_1024_latin1_key varchar(1024) CHARACTER SET latin1 COLLATE latin1_bin DEFAULT NULL,
col_int int(11) DEFAULT NULL,
KEY col_varchar_1024_latin1_key (col_varchar_1024_latin1_key)
) ENGINE=Aria DEFAULT CHARSET=latin1 PAGE_CHECKSUM=1;
INSERT INTO t2 VALUES ('when',NULL),('vjunrmtxglywtdtmwusmdxbriojriuccnafrsvlqlbyytqclzerbozxudgwmpokbwtipmkbfaxdkoyvoyggkmunoaqlghgvqvgtpmhrrpoqrooawysynbanetgeaomrrclghbblncocgnwrsvbrgnguuprasottgbhvyoekahjevtmkjxnbbkdsmyzrznuhzrstbyvmtfishmjgykujvmaierowakbicjivvbexvrrrmqvjlekuocqzoxjyvwkumgagpwxgdhizgzyrmenuyyiwnaskweuhqtpyetueqerpqoocaivmodcpkgyghkflynckocwoefvoktepnncwwnggahibbrbruaahyesswxfltorwihqchdqzrilxqppzqtrmzdantttpvwoixlxnjfgsrgoceajvaknetptkchfbbfshllxkanxjmikmojncahkfikzdgiqmplnh',NULL),('ilvjunrmtxglywtdtmwusmdxbriojriuccnafrsvlqlbyytqclzerbozxudgwmpokbwtipmkbfaxdkoyvoyggkmunoaqlghgvqvgtpmhrrpoqrooawysynbanetgeaomrrclghbblncocgnwrsvbrgnguuprasottgbhvyoekahjevtmkjxnbbkdsmyzrznuhzrstbyvmtfishmjgykujvmaierowakbicjivvbexvrrrmqvjlekuocqzoxjyvwkumgagpwxgdhizgzyrmenuyyiwnaskweuhqtpyetueqerpqoocaivmodcpkgyghkflynckocwoefvoktepnncwwnggahibbrbruaahyesswxfltorwihqchdqzrilxqppzqtrmzdantttpvwoixlxnjfgsrgoceajvaknetptkchfbbfshllxkanxjmikmojncahkfikzdgiqmplnhoggyipisitiwnmlatvskdifehwiufwqgiedyeufebrvnfsjerrmcmmvpgdswacpyybvzaiykvvtzfpbugcakackkiisepiqkwvhbpubswoouoxbdwnoggwojndilvtfcxvcmqvtcyfyjrboxflexzgsmrviuwutnmoatzmodfhhqssspuezrwgqpwakmtesjvccfjsvrjjjzmkfgyihwhyixfqkzorobtqbhhneycnpilhgeipyvkenlnphaudkkwarmfpwkjamlalupigprdmzbufmeuwtrxwxzjfftccaqvpsifblshhkytjrgdutlepjojqjimlkhzeovotuhuhzvsgjnsvdtiiwlpaggansqwqtbxtrpgkdpijbzurzgrlxvqbscsaimikytvjicemytfyewkryzhrkkjhsokfyddhrmywsxnmlhgivrtyenhxxtvvntghzdeungnbutdinrrouazkoxzmwerytbeulzo',0),('can',-1754988544),('ekxoyiilvjunrmtxglywtdtmwusmdxbriojriuccnafrsvlqlbyytqclzerbozxudgwmpokbwtipmkbfaxdkoyvoyggkmunoaqlghgvqvgtpmhrrpoqrooawysynbanetgeaomrrclghbblncocgnwrsvbrgnguuprasottgbhvyoekahjevtmkjxnbbkdsmyzrznuhzrstbyvmtfishmjgykujvmaierowakbicjivvbexvrrrmqvjlekuocqzoxjyvwkumgagpwxgdhizgzyrmenuyyiwnaskweuhqtpyetueqerpqoocaivmodcpkgyghkflynckocwoefvoktepnncwwnggahibbrbruaahyesswxfltorwihqchdqzrilxqppzqtrmzdantttpvwoixlxnjfgsrgoceajvaknetptkchfbbfshllxkanxjmikmojncahkfikzdgiqmplnhoggyipisitiwnmlatvskdifehwiufwqgiedyeufebrvnfsjerrmcmmvpgdswacpyybvzaiykvvtzfpbugcakackkiisepiqkwvhbpubswoouoxbdwnoggwojndilvtfcxvcmqvtcyfyjrboxflexzgsmrviuwutnmoatzmodfhhqssspuezrwgqpwakmtesjvccfjsvrjjjzmkfgyihwhyixfqkzorobtqbhhneycnpilhgeipyvkenlnphaudkkwarmfpwkjamlalupigprdmzbufmeuwtrxwxzjfftccaqvpsifblshhkytjrgdutlepjojqjimlkhzeovotuhuhzvsgjnsvdtiiwlpaggansqwqtbxtrpgkdpijbzurzgrlxvqbscsaimikytvjicemytfyewkryzhr',NULL),('g',NULL),('u',-2116288512),('vcdkbsvxpekxoyiilvjunrmtxglywtdtmwusmdxbriojriuccnafrsvlqlbyytqclzerbozxudgwmpokbwtipmkbfaxdkoyvoyggkmunoaqlghgvqvgtpmhrrpoqrooawysynbanetgeaomrrclghbblncocgnwrsvbrgnguuprasottgbhvyoekahjevtmkjxnbbkdsmyzrznuhzrstbyvmtfishmjgykujvmaierowakbicjivvbexvrrrmqvjlekuocqzoxjyvwkumgagpwxgdhizgzyrmenuyyiwnaskweuhqtpyetueqerpqoocaivmodcpkgyghkflynckocwoefvoktepnncwwnggahibbrbruaahyesswxfltorwihqchdqzrilxqppzqtrmzdantttpvwoixlxnjfgsrgoceajvaknetptkchfbbfshllxkanxjmikmojncahkfikzdgiqmplnhoggyipisitiwnmlatvskdifehwiufwqgiedyeufebrvnfsjerrmcmmvpgdswacpyybvzaiykvvtzfpbugcakackkiisepiqkwvhbpubswoouoxbdwnoggwojndilvtfcxvcmqvtcyfyjrboxflexzgsmrviuwutnmoatzmodfhhqssspuezrwgqpwakmtesjvccfjsvrjjjzmkfgyih',NULL),('okay',1232273408),('they',849412096),('h',-922157056),('b',6),('h',1),('did',1469382656),('m',NULL),('lnbqivgfjxhxyxmrnmhrmeuvcdkbsvxpekxoyiilvjunrmtxglywtdtmwusmdxbriojriuccnafrsvlqlbyytqclzerbozxudgwmpokbwtipmkbfaxdkoyvoyggkmunoaqlghgvqvgtpmhrrpoqrooawysynbanetgeaomrrclghbblncocgnwrsvbrgnguuprasottgbhvyoekahjevtmkjxnbbkdsmyzrznuhzrstbyvmtfishmjgykujvmaierowakbicjivvbexvrrrmqvjlekuocqzoxjyvwkumgagpwxgdhizgzyrmenuyyiwnaskweuhqtpyetueqerpqoocaivmodcpkgyghkflynckocwoefvoktepnncwwnggahibbrbruaahyesswxfltorwihqchdqzrilxqppzqtrmzdantttpvwoixlxnjfgsrgoceajvaknetptkchfbbfshllxkanxjmikmojncahkfikzdgiqmplnhoggyipisitiwnmlatvskdifehwiufwqgiedyeufebrvnfsjerrmcmmv',-1982201856),('z',7),('m',NULL),('her',1361444864),('u',9);
INSERT INTO t2 VALUES ('snrbhtulnbqivgfjxhxyxmrnmhrmeuvcdkbsvxpekxoyiilvjunrmtxglywtdtmwusmdxbriojriuccnafrsvlqlbyytqclzerbozxudgwmpokbwtipmkbfaxdkoyvoyggkmunoaqlghgvqvgtpmhrrpoqrooawysynbanetgeaomrrclghbblncocgnwrsvbrgnguuprasottgbhvyoekahjevtmkjxnbbkdsmyzrznuhzrstbyvmtfishmjgykujvmaierowakbicjivvbexvrrrmqvjlekuocqzoxjyvwkumgagpwxgdhizgzyrmenuyyiwnaskweuhqtpyetueqerpqoocaivmodcpkgyghkflynckocwoefvoktepnncwwnggahibbrbruaahyesswxfltorwihqchdqzrilxqppzqtrmzdantttpvwoixlxnjfgsrgoceajvaknetptkchfbbfshllxkanxjmikmojncahkfikzdgiqmplnhoggyipisitiwnmlatvskdifehwiufwqgiedyeufebrvnfsjerrmcmmvpgdswacpyybvzaiykvvtzfpbugcakackkiisepiqkwvhbpubswoouoxbdwnoggwojndilvtfcxvcmqvtcyfyjrboxflexzgsmr',9),('udnftchmsnrbhtulnbqivgfjxhxyxmrnmhrmeuvcdkbsvxpekxoyiilvjunrmtxglywtdtmwusmdxbriojriuccnafrsvlqlbyytqclzerbozxudgwmpokbwtipmkbfaxdkoyvoyggkmunoaqlghgvqvgtpmhrrpoqrooawysynbanetgeaomrrclghbblncocgnwrsvbrgnguuprasottgbhvyoekahjevtmkjxnbbkdsmyzrznuhzrstbyvmtfishmjgykujvmaierowakbicjivvbexvrrrmqvjlekuocqzoxjyvwkumgagpwxgdhizgzyrmenuyyiwnaskweuhqtpyetueqerpqoocaivmodcpkgyghkflynckocwoefvoktepnncwwnggahibbrbruaahyesswxfltorwihqchdqzrilxqppzqtrmzdantttpvwoixlxnjfgsrgoceajvaknetptkchfbbfshllxkanxjmikmojncahkfikzdgiqmplnhoggyipisitiwnmlatvskdifehwiufwqgiedyeufebrvnfsjerrmcmmvpgdswacpyybvzaiykvvtzfpbugcakackkiisepiqkwvhbpubswoouoxbdwnoggwojndilvtfcxvcmqvtcyfyjrboxflexzgsmrviuwutnmoatzmodfhhqssspuezrwgqpwakmtes',NULL),('l',8),('y',NULL),('been',420478976);

SELECT table2.col_int FROM t1 AS table1 JOIN t2 AS table2 ON table1.col_varchar_1024_latin1_key = table2.col_varchar_1024_latin1_key ;
EXPLAIN SELECT table2.col_int FROM t1 AS table1 JOIN t2 AS table2 ON table1.col_varchar_1024_latin1_key = table2.col_varchar_1024_latin1_key ;

SET join_cache_level=0;
ALTER TABLE t1 DISABLE KEYS;
ALTER TABLE t2 DISABLE KEYS;
SELECT table2.col_int FROM t1 AS table1 JOIN t2 AS table2 ON table1.col_varchar_1024_latin1_key = table2.col_varchar_1024_latin1_key ;
EXPLAIN SELECT table2.col_int FROM t1 AS table1 JOIN t2 AS table2 ON table1.col_varchar_1024_latin1_key = table2.col_varchar_1024_latin1_key ;

Re: Less rows returned with (flat, BNLH join) in maria-5.3-mwl128
Better test case:

SET SESSION join_cache_level = 4;
DROP TABLE IF EXISTS t1;
CREATE TABLE t1 (
col_varchar_1024_latin1_key varchar(1024) COLLATE latin1_bin,
col_int int(11),
KEY (col_varchar_1024_latin1_key)) ENGINE=MyISAM;
INSERT INTO t1 VALUES ('dutl','-');
INSERT INTO t1 VALUES ('y',NULL);

DROP TABLE IF EXISTS t2;
CREATE TABLE t2 (
col_varchar_1024_latin1_key varchar(1024) COLLATE latin1_bin,
col_int int(11),
KEY (col_varchar_1024_latin1_key)) ENGINE=Aria;
INSERT INTO t2 VALUES ('y',NULL);
INSERT INTO t2 VALUES ('b','4');

SELECT table2.col_int FROM t1 AS table1 JOIN t2 AS table2 ON table1.col_varchar_1024_latin1_key = table2.col_varchar_1024_latin1_key;

Launchpad bug id: 672551