Adjust table_open_cache to avoid getting error 24 (too many open files)

MDEV--15609 engines/funcs.crash_manytables_number crashes with error 24
           (too many open files)
MDEV-10286  Adjustment of table_open_cache according to system limits
            does not work when open-files-limit option is provided

Fixed by adjusting tc_size downwards if there is not enough file
descriptors to use.

Other changes:
- Ensure that there is 30 (was 10) extra file descriptors for other usage
- Decrease TABLE_OPEN_CACHE_MIN to 200 as it's better to have a smaller
  table cache than getting error 24
- Increase minimum of max_connections and table_open_cache from 1 to 10
  as 1 is not usable for any real application, only for testing.

7 files changed, 18 insertions, 11 deletions

diff --git a/mysql-test/r/connect.result b/mysql-test/r/connect.result
index 315aea0ef46..cb66ff483e1 100644
--- a/mysql-test/r/connect.result
+++ b/mysql-test/r/connect.result
@@ -147,7 +147,7 @@ drop table t1;
 CREATE USER mysqltest_u1@localhost;
 GRANT USAGE ON *.* TO mysqltest_u1@localhost;
 
-SET GLOBAL max_connections = 3;
+SET GLOBAL max_connections = 10;
 SET GLOBAL event_scheduler = ON;
 
 # -- Waiting for Event Scheduler to start...
@@ -191,6 +191,13 @@ event_scheduler
 mysqltest_u1
 mysqltest_u1
 mysqltest_u1
+mysqltest_u1
+mysqltest_u1
+mysqltest_u1
+mysqltest_u1
+mysqltest_u1
+mysqltest_u1
+mysqltest_u1
 root
 
 # -- Resetting variables...
diff --git a/mysql-test/r/mdev375.result b/mysql-test/r/mdev375.result
index 32580804686..b3b83af0988 100644
--- a/mysql-test/r/mdev375.result
+++ b/mysql-test/r/mdev375.result
@@ -1,5 +1,5 @@
 SET GLOBAL log_warnings=4;
-SET GLOBAL max_connections=2;
+SET GLOBAL max_connections=10;
 SELECT 1;
 1
 1
diff --git a/mysql-test/r/myisam.result b/mysql-test/r/myisam.result
index e114f424ede..0f865c151fa 100644
--- a/mysql-test/r/myisam.result
+++ b/mysql-test/r/myisam.result
@@ -1906,9 +1906,9 @@ DROP TABLE t1;
 #
 # BUG#48438 - crash with error in unioned query against merge table and view...
 #
-SET GLOBAL table_open_cache=3;
+SET GLOBAL table_open_cache=10;
 CREATE TABLE t1(a INT);
-SELECT 1 FROM t1 AS a1, t1 AS a2, t1 AS a3, t1 AS a4 FOR UPDATE;
+SELECT 1 FROM t1 AS a1, t1 AS a2, t1 AS a3, t1 AS a4, t1 AS a5, t1 AS a6, t1 AS a7, t1 AS a8, t1 AS a9, t1 AS a10, t1 AS a11 FOR UPDATE;
 1
 SELECT TABLE_ROWS, DATA_LENGTH FROM INFORMATION_SCHEMA.TABLES
 WHERE TABLE_SCHEMA='test' AND TABLE_NAME='t1';
diff --git a/mysql-test/r/mysqld--help,win.rdiff b/mysql-test/r/mysqld--help,win.rdiff
index 06116a2e630..6e18d16feaf 100644
--- a/mysql-test/r/mysqld--help,win.rdiff
+++ b/mysql-test/r/mysqld--help,win.rdiff
@@ -121,10 +121,10 @@
  sync-relay-log 10000
  sync-relay-log-info 10000
  sysdate-is-now FALSE
--table-cache 431
+-table-cache 421
 +table-cache 2000
  table-definition-cache 400
--table-open-cache 431
+-table-open-cache 421
 +table-open-cache 2000
  tc-heuristic-recover OFF
  thread-cache-size 0
diff --git a/mysql-test/r/mysqld--help.result b/mysql-test/r/mysqld--help.result
index e84921bfa0a..7b78eae185e 100644
--- a/mysql-test/r/mysqld--help.result
+++ b/mysql-test/r/mysqld--help.result
@@ -1438,9 +1438,9 @@ sync-master-info 10000
 sync-relay-log 10000
 sync-relay-log-info 10000
 sysdate-is-now FALSE
-table-cache 431
+table-cache 421
 table-definition-cache 400
-table-open-cache 431
+table-open-cache 421
 tc-heuristic-recover OFF
 thread-cache-size 0
 thread-pool-idle-timeout 60
diff --git a/mysql-test/r/sp.result b/mysql-test/r/sp.result
index 57d704c36be..ad5bddda035 100644
--- a/mysql-test/r/sp.result
+++ b/mysql-test/r/sp.result
@@ -7946,7 +7946,7 @@ CLOSE cur1;
 end|
 set @tmp_toc= @@table_open_cache;
 set @tmp_tdc= @@table_definition_cache;
-set global table_open_cache=1;
+set global table_open_cache=10;
 set global table_definition_cache=1;
 Warnings:
 Warning	1292	Truncated incorrect table_definition_cache value: '1'
diff --git a/mysql-test/r/variables.result b/mysql-test/r/variables.result
index b621fc13ee4..a01c8f48a4d 100644
--- a/mysql-test/r/variables.result
+++ b/mysql-test/r/variables.result
@@ -748,10 +748,10 @@ Warnings:
 Warning	1292	Truncated incorrect table_open_cache value: '-1'
 SHOW VARIABLES LIKE 'table_open_cache';
 Variable_name	Value
-table_open_cache	1
+table_open_cache	10
 SELECT * FROM INFORMATION_SCHEMA.SESSION_VARIABLES WHERE VARIABLE_NAME LIKE 'table_open_cache';
 VARIABLE_NAME	VARIABLE_VALUE
-TABLE_OPEN_CACHE	1
+TABLE_OPEN_CACHE	10
 SET GLOBAL table_open_cache=DEFAULT;
 set character_set_results=NULL;
 select ifnull(@@character_set_results,"really null");