DROP DATABASE fails half done with ER_DB_DROP_RMDIR when another connection discovers a new table of the database

--source include/have_s3.inc

--source include/have_innodb.inc

# How this test works

#

# 1. DROP DATABASE drop_race lists the tables of drop_race (only t0), takes

#    the exclusive lock on the database, and waits for the metadata lock on

#    t0, which an open transaction holds.

# 2. aria_s3_copy puts test.t1 into the bucket as drop_race.t1, as a second

#    server sharing the bucket would.

# 3. A SELECT from drop_race.t1 opens the table for the first time:

#    discovery writes t1.frm into the directory of drop_race. The open takes

#    no lock on the database, so it does not wait for the DROP.

# 4. The transaction commits. DROP DATABASE drops t0 and fails on rmdir with

#    ER_DB_DROP_RMDIR, because t1.frm is in the directory.

create database drop_race comment 'set before the DROP';

create table drop_race.t0 (a int) engine=innodb;

create table test.t1 (a int) engine=aria transactional=0 row_format=page;

flush tables test.t1;

let MYSQLD_DATADIR= `select @@datadir`;

--echo # Park DROP DATABASE after it has listed the tables of drop_race

connect (holder,localhost,root,,drop_race);

begin;

select count(*) from t0;

connect (dropper,localhost,root,,test);

--send drop database drop_race

connection default;

let $wait_condition= select count(*) = 1 from information_schema.processlist

  where state = 'Waiting for table metadata lock' and info = 'drop database drop_race';

--source include/wait_condition.inc

--echo # Put test.t1 into the bucket as drop_race.t1, outside the server

--perl

my $copy = $ENV{MARIA_CHK};

$copy =~ s/aria_chk/aria_s3_copy/;

my @cmd = (split(' ', $copy), "--no-defaults", "--op=to_s3", "--database=drop_race",

  "--s3-host-name=$ENV{S3_HOST_NAME}", "--s3-port=$ENV{S3_PORT}",

  "--s3-bucket=$ENV{S3_BUCKET}", "--s3-access-key=$ENV{S3_ACCESS_KEY}",

  "--s3-secret-key=$ENV{S3_SECRET_KEY}", "--s3-region=$ENV{S3_REGION}",

  "--s3-protocol-version=$ENV{S3_PROTOCOL_VERSION}",

  ($ENV{S3_USE_HTTP} eq "ON" ? ("--s3-use-http") : ()),

  "$ENV{MYSQLD_DATADIR}/test/t1");

my $out = `@cmd 2>&1`;

die "aria_s3_copy failed ($?): $out" if $? != 0;

EOF

--echo # First open of drop_race.t1 while DROP DATABASE waits

connect (opener,localhost,root,,test);

--send select count(*) from drop_race.t1

--echo # Wait until t1.frm is written; an open that waits for DROP DATABASE never writes it

connection default;

--perl

my $f = "$ENV{MYSQLD_DATADIR}/drop_race/t1.frm";

for (1 .. 100) { last if -e $f; select(undef, undef, undef, 0.1); }

EOF

--list_files $MYSQLD_DATADIR/drop_race

connection holder;

commit;

connection dropper;

--error ER_DB_DROP_RMDIR

--reap

connection opener;

--reap

--echo # Left: t0 and the database options are gone, the directory stays with t1.frm

connection default;

--list_files $MYSQLD_DATADIR/drop_race

select schema_name, schema_comment from information_schema.schemata where schema_name = 'drop_race';

show tables from drop_race;

--echo # A second DROP DATABASE lists t1 and succeeds

drop database drop_race;

drop table test.t1;

disconnect holder;

disconnect dropper;

disconnect opener;

connection dropper;

ERROR HY000: Error dropping database (can't rmdir './drop_race', errno: 39 "Directory not empty")

...

# Left: t0 and the database options are gone, the directory stays with t1.frm

connection default;

t1.frm

select schema_name, schema_comment from information_schema.schemata where schema_name = 'drop_race';

schema_name	schema_comment

drop_race	

show tables from drop_race;

Tables_in_drop_race

t1

DROP DATABASE drop_race                   select count(*) from drop_race.t1

mysql_rm_db_internal, sql/sql_db.cc       open_table

lock_schema_name                  

  MDL_EXCLUSIVE on schema drop_race

find_db_tables_and_rm_known_files

  list: t0

lock_table_names                 

  waits for MDL on t0

  |                                       [aria_s3_copy puts t1 into the bucket]

  |                                       open_table_get_mdl_lock

  |                                         MDL on t1 only, none on the schema

  |                                       tdc_acquire_share

  |                                         ha_discover_table

  |                                         s3_discover_table

  |                                           writes drop_race/t1.frm 

[holder commits: MDL on t0 is free]

rm_dir_w_symlink                  :1214

  ER_DB_DROP_RMDIR, errno 39      :1511