Bug#20198490 : LOWER_CASE_TABLE_NAMES=0 ON WINDOWS LEADS TO

               PROBLEMS

Description:- Server variable "--lower_case_tables_names"
when set to "0" on windows platform which does not support
case sensitive file operations leads to problems. A warning
message is printed in the error log while starting the
server with "--lower_case_tables_names=0". Also according to
the documentation, seting "lower_case_tables_names" to "0"
on a case-insensitive filesystem might lead to index
corruption.

Analysis:- The problem reported in the bug is:-
Creating an INNODB table 'a' and executing a query, "INSERT
INTO a SELECT a FROM A;" on a server started with
"--lower_case_tables_names=0" and running on a
case-insensitive filesystem leads innodb to flat spin.
Optimizer thinks that "a" and "A" are two different tables
as the variable "lower_case_table_names" is set to "0". As a
result, optimizer comes up with a plan which does not need a
temporary table. If the same table is used in select and
insert, a temporary table is needed. This incorrect
optimizer plan leads to infinite insertions.

Fix:- If the server is started with
"--lower_case_tables_names" set to 0 on a case-insensitive
filesystem, an error, "The server option
'lower_case_table_names'is configured to use case sensitive
table names but the data directory is on a case-insensitive
file system which is an unsupported combination. Please
consider either using a case sensitive file system for your
data directory or switching to a case-insensitive table name
mode.", is printed in the server error log and the server
exits.

0 files changed, 0 insertions, 0 deletions