Alexander Barkov wrote:
> Hello Øystein,
>
>
> Please find a new version of WL#2649 patch here:
>
> http://lists.mysql.com/commits/81141
>
> I fully rewrote it since the previous version,
> and it is much smaller now.
Great. I will look at it next week.
Have a nice week-end,
--
Øystein
>
> The new code change patch (i.e. without tests) is
> 98Kb in size and touches 20 source files
> vs the old version which was
> 170 Kb and modified 29 files.
>
>
> What was changed since the previous version:
>
>
> DIFFERENCE 1
> ============
> Now I don't force Items to return @@character_set_connection
> in many cases.
>
> For example:
>
> - Numeric constants: Item_int, Item_decimal, Item_float
> - Real, Integer and boolean functions, numeric operators
> (like +, -, *, /) and others.
> - DECIMAL, DATE, TIME, DATETIME type cast
>
> don't return @@character_set_connection.
> They return latin1 instead. This allowed to stay
> in 8-bit implementation without having to rewrite
> items to support multi-byte character sets results (e.g. UCS2).
> Basically the change for these items is to use latin1 instead
> of my_charset_bin.
>
>
> DIFFERENCE 2
> ============
> According to the WL description, string functions
> with numeric input must return a string using
> @@character_set_connection.
>
> For example:
>
> SET character_set_connection=ucs2;
> CREATE TABLE t1 AS SELECT concat(1); -- must create an UCS2 column
>
> To make this work, I fixed all string functions
> to make a special step when aggregating arguments:
>
> if ALL arguments are non-string (numeric, date/time types),
> then the string functions force conversion of the arguments to
> @@character_set_connection.
>
> For example:
>
> SET character_set_connection=ucs2;
> CREATE TABLE t1 AS SELECT concat(1, 2, 3);
>
> will actually work as:
>
> SET character_set_connection=ucs2;
> CREATE TABLE t1 AS SELECT
> concat(
> CONVERT(1 USING ucs2),
> CONVERT(2 USING ucs2)
> CONVERT(3 USING ucs2));
>
>
>
> From the user point of view
> ===========================
> The previous version and the new version look the same for users.
>
> - Various CREATE TABLE involving number-to-string conversion
> create exactly the same results.
>
> - User will see exactly the same metadata on the client side,
> because results are converted to @@character_set_results anyway.
>
>
>
> Can you please review the new version?
>
> Thank you very much.
>
>
--
Øystein Grøvlen, Senior Staff Engineer
Sun Microsystems, Database Group
Trondheim, Norway
