mariadb/mysql-test/r/bug12427262.result
Monty 34eb10e406 MDEV-10138 Support for decimals up to 38 digits
Decimals with float, double and decimal now works the following way:

- DECIMAL_NOT_SPECIFIED is used when declaring DECIMALS without a firm number
  of decimals.  It's only used in asserts and my_decimal_int_part.
- FLOATING_POINT_DECIMALS (31) is used to mark that a FLOAT or DOUBLE
  was defined without decimals. This is regarded as a floating point value.
- Max decimals allowed for FLOAT and DOUBLE is FLOATING_POINT_DECIMALS-1
- Clients assumes that float and double with decimals >= NOT_FIXED_DEC are
  floating point values (no decimals)
- In the .frm decimals=FLOATING_POINT_DECIMALS are used to define
  floating point for float and double (31, like before)

To ensure compatibility with old clients we do:

- When storing float and double, we change NOT_FIXED_DEC to
  FLOATING_POINT_DECIMALS.
- When creating fields from .frm we change for float and double
  FLOATING_POINT_DEC to NOT_FIXED_DEC
- When sending definition for a float/decimal field without decimals
  to the client as part of a result set we convert NOT_FIXED_DEC to
  FLOATING_POINT_DECIMALS.
- variance() and std() has changed to limit the decimals to
  FLOATING_POINT_DECIMALS -1 to not get the double converted floating point.
  (This was to preserve compatiblity)
- FLOAT and DOUBLE still have 30 as max number of decimals.

Bugs fixed:

variance() printed more decimals than we support for double values.

New behaviour:
- Strings now have 38 decimals instead of 30 when converted to decimal
- CREATE ... SELECT with a decimal with > 30 decimals will create a column
  with a smaller range than before as we are trying to preserve the number of
  decimals.


Other changes
- We are now using the obsolete bit FIELDFLAG_LEFT_FULLSCREEN to specify
  decimals > 31
- NOT_FIXED_DEC is now declared in one place
- For clients, NOT_FIXED_DEC is always 31 (to ensure compatibility).
  On the server NOT_FIXED_DEC is DECIMAL_NOT_SPECIFIED (39)
- AUTO_SEC_PART_DIGITS is taken from DECIMAL_NOT_SPECIFIED
- DOUBLE conversion functions are now using DECIMAL_NOT_SPECIFIED instead of
  NOT_FIXED_DEC
2016-06-22 22:04:55 +03:00

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#
# Bug#12427262 : 60961: SHOW TABLES VERY SLOW WHEN NOT IN SYSTEM DISK CACHE.
#
create database show_table_lw_db;
use show_table_lw_db;
create table t1 (c1 int);
create table t2 (c1 int);
create table t3 (c1 int);
create table t4 (c1 int);
create table t5 (c1 int);
create table t6 (c1 int);
create table t7 (c1 int);
create table t8 (c1 int);
create table t9 (c1 int);
create table t10 (c1 int);
select Sum(ALL(COUNT_READ)) from performance_schema.file_summary_by_instance where FILE_NAME
like "%show_table_lw_db%" AND FILE_NAME like "%.frm%" AND EVENT_NAME='wait/io/file/sql/FRM'
into @count_read_before;
show tables;
Tables_in_show_table_lw_db
t1
t10
t2
t3
t4
t5
t6
t7
t8
t9
select Sum(ALL(COUNT_READ)) from performance_schema.file_summary_by_instance where FILE_NAME
like "%show_table_lw_db%" AND FILE_NAME like "%.frm%" AND EVENT_NAME='wait/io/file/sql/FRM'
into @count_read_after;
select @count_read_after-@count_read_before;
@count_read_after-@count_read_before
0.00000000000000000000000000000000000000
show full tables;
Tables_in_show_table_lw_db Table_type
t1 BASE TABLE
t10 BASE TABLE
t2 BASE TABLE
t3 BASE TABLE
t4 BASE TABLE
t5 BASE TABLE
t6 BASE TABLE
t7 BASE TABLE
t8 BASE TABLE
t9 BASE TABLE
select Sum(ALL(COUNT_READ)) from performance_schema.file_summary_by_instance where FILE_NAME
like "%show_table_lw_db%" AND FILE_NAME like "%.frm%" AND EVENT_NAME='wait/io/file/sql/FRM'
into @count_read_after;
select @count_read_after-@count_read_before;
@count_read_after-@count_read_before
10.00000000000000000000000000000000000000
drop table t1;
drop database show_table_lw_db;