MDEV-36373 Bogus Warning: ... storage is corrupted

ha_innobase::statistics_init(), ha_innobase::info_low(): Correctly handle a DB_READ_ONLY return value from dict_stats_save(). Fixes up commit 6e6a1b3 (MDEV-35000)

Author: dr-m

mysql-test/suite/innodb/r/stat_tables.result

@@ -101,3 +101,13 @@ DROP TABLE t1;
 CREATE TABLE t1 (c1 INT) ENGINE=InnoDB STATS_PERSISTENT 1;
 DROP TABLE t1;
 # End of 10.6 tests
+#
+# MDEV-36373 Warning: ... persistent statistics storage is corrupted
+#
+CREATE TABLE t1 (c INT) ENGINE=InnoDB;
+SET STATEMENT tx_read_only=1 FOR ANALYZE TABLE t1;
+Table	Op	Msg_type	Msg_text
+test.t1	analyze	status	Engine-independent statistics collected
+test.t1	analyze	status	OK
+DROP TABLE t1;
+# End of 10.11 tests

mysql-test/suite/innodb/t/stat_tables.test

@@ -110,3 +110,12 @@ CREATE TABLE t1 (c1 INT) ENGINE=InnoDB STATS_PERSISTENT 1;
 DROP TABLE t1;
 
 --echo # End of 10.6 tests
+
+--echo #
+--echo # MDEV-36373 Warning: ... persistent statistics storage is corrupted
+--echo #
+CREATE TABLE t1 (c INT) ENGINE=InnoDB;
+SET STATEMENT tx_read_only=1 FOR ANALYZE TABLE t1;
+DROP TABLE t1;
+
+--echo # End of 10.11 tests

storage/innobase/handler/ha_innodb.cc

@@ -5872,7 +5872,7 @@ dberr_t ha_innobase::statistics_init(dict_table_t *table, bool recalc)
  if (err == DB_STATS_DO_NOT_EXIST && table->stats_is_auto_recalc())
  goto recalc;
  }
- if (err == DB_SUCCESS)
+ if (err == DB_SUCCESS || err == DB_READ_ONLY)
  return err;
  if (!recalc)
  break;
@@ -14934,6 +14934,7 @@ ha_innobase::info_low(
 ret = statistics_init(ib_table, is_analyze);
 switch (ret) {
 case DB_SUCCESS:
+case DB_READ_ONLY:
 break;
 default:
 goto error;