Commit graph

7 commits

Author SHA1 Message Date
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
Oleksandr Byelkin
e3982cead2 MDEV-6066: Merge new defaults from 5.6 and 5.7 (defaults changed, QC can be stopped with no-zero size) 2015-09-04 10:33:56 +02:00
Sergei Golubchik
5c9d2c6c9f MDEV-4332 Increase username length from 16 characters
10.0 part of the task, fix system tables
2013-11-03 16:31:52 +01:00
Sergei Golubchik
36c7535198 MDEV-4519 SHOW EVENTS and SHOW PROCEDURE STATUS truncate long user names
fix I_S table definitions in sql_show.cc
2013-06-13 20:18:40 +02:00
Sergei Golubchik
2533313895 MDEV-4515 Long user names are truncated to 48 symbols in error messages 2013-06-13 15:33:02 +02:00
Sergei Golubchik
66cc619609 MDEV-4514 After increasing user name length mysql.db is reported broken and event scheduler does not start 2013-05-13 16:11:39 +02:00
Sergei Golubchik
84ce6832e6 MDEV-4332 Increase username length from 16 characters 2013-04-18 22:17:29 +02:00