Hi Jørgen,
OK to push, no comments except for the ones made by Guilhem. However, I think
that you should replace log10f() in the code. There is no particular need to
increase the set of system functions used in the codebase.
Thanks,
Roy
On 25.08.10 11.45, Guilhem Bichot wrote:
> Hello,
>
> Jorgen Loland a écrit, Le 18.08.2010 11:01:
>> #At file:///export/home/jl208045/mysql/mysql-next-mr-bugfixing-30597/ based on
>> revid:joerg@stripped
>>
>> 3220 Jorgen Loland 2010-08-18
>> Bug#30597: Change EXPLAIN output to include extrema of UNION components
>
>> === modified file 'sql/sql_lex.h'
>> --- a/sql/sql_lex.h 2010-08-16 18:21:24 +0000
>> +++ b/sql/sql_lex.h 2010-08-18 09:01:38 +0000
>> @@ -712,6 +712,13 @@ public:
>> }
>> st_select_lex* outer_select();
>> st_select_lex* next_select() { return (st_select_lex*) next; }
>> +
>> + inline st_select_lex* last_select() {
>
> you can declare this function "const", it doesn't change data.
>
>> + st_select_lex* last= this;
>> + for (; last->next_select(); last= last->next_select());
>> + return last; + }
>> +
>> st_select_lex* next_select_in_list() {
>> return (st_select_lex*) link_next;
>>
>> === modified file 'sql/sql_select.cc'
>> --- a/sql/sql_select.cc 2010-08-12 13:55:41 +0000
>> +++ b/sql/sql_select.cc 2010-08-18 09:01:38 +0000
>> @@ -22048,10 +22048,21 @@ void select_describe(JOIN *join, bool ne
>> cs));
>> /* table */
>> {
>> + SELECT_LEX *last_select= join->unit->first_select()->last_select();
>> + // # characters needed to print select_number of last select
>> + int last_length= log10f((float)last_select->select_number)+1;
>
> log10f is not yet used in MySQL ("grep" says).
> But log10 is, somewhere in item_func.cc.
> You can use log10f and time will tell whether it's available on all platforms
> where we build (my 'man' page says that log10f is a C99 requirement), or use
> log10 (which would work for the job, as it takes a double argument).
>
>> SELECT_LEX *sl= join->unit->first_select();
>> uint len= 6, lastop= 0;
>> memcpy(table_name_buffer, STRING_WITH_LEN("<union"));
>> - for (; sl && len + lastop + 5 < NAME_LEN; sl= sl->next_select())
>> + /*
>> + - len + lastop: current position in table_name_buffer
>> + - 6 + last_length: the number of characters needed to print
>> + '...,'<last_select->select_number>'>\0'
>> + */
>> + for (; + sl && len + lastop + 6 + last_length < NAME_LEN; + sl=
>> sl->next_select())
>> {
>> len+= lastop;
>> lastop= my_snprintf(table_name_buffer + len, NAME_LEN - len,
>> @@ -22059,14 +22070,13 @@ void select_describe(JOIN *join, bool ne
>> }
>> if (sl || len + lastop >= NAME_LEN)
>> {
>> - memcpy(table_name_buffer + len, STRING_WITH_LEN("...>") + 1);
>> + memcpy(table_name_buffer + len, STRING_WITH_LEN("...,") + 1);
>
> in STRING_WITH_LEN we have sizeof (=5) - 1 =4, and it's enough to copy
> the 4 characters without the end zero (as we add more chars with my_snprintf
> below).
> So "+ 1" is probably not needed. But you can keep it.
>
>> len+= 4;
>> + lastop= my_snprintf(table_name_buffer + len, NAME_LEN - len,
>> + "%u,", last_select->select_number);
>> }
>> - else
>> - {
>> - len+= lastop;
>> - table_name_buffer[len - 1]= '>'; // change ',' to '>'
>> - }
>> + len+= lastop;
>> + table_name_buffer[len - 1]= '>'; // change ',' to '>'
>> item_list.push_back(new Item_string(table_name_buffer, len, cs));
>> }
>> /* partitions */
>
> Ok to push.
>
