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From:Venu Kalyan Date:February 24 2010 6:32pm
Subject:Re: question on HA_EXTRA_IGNORE_DUP_KEY
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Hi

On Wed, Feb 24, 2010 at 10:20 AM, Zardosht Kasheff <zardosht@stripped> wrote:
> Ok, so if I understand this correctly, the following if clause:
>
> thd->lex->ignore && thd->lex->duplicates == SQL_ERROR
>
> if it evaluates to true, I can assume that the user is doing "insert ignore".
>
> How I plan to use this is as follows. Suppose I have a table, (a int,
> b int, primary key (a)), that has the element (1,1) inserted.
>
> Given the following statements:
> insert ignore into table values (2,2), (1,2);
> select * from table;
>
> The expected result of the select * is to return (1,1),(2,2). The
> insert will make two calls to handler::write_row. For (2,2),
> handler::write_row will insert the element, and return success. With
> other storage engines, for (1,2), handler::write_row will insert
> nothing and return HA_ERR_FOUND_DUPP_KEY. What my change will do is
> still insert nothing, but instead of returning HA_ERR_FOUND_DUPP_KEY,
> it will return success.
>
> I assume there is nothing wrong with this?

Yup; that's one way of optimizing for faster loads especially dealing
with bulk data and/or to avoid cost of searching for dups.

I still do this using storage engine controlled variable though; but
that's up to you guys to decide...

Thanks
Venu Anuganti

>
> Thanks
> -Zardosht
>
> On Wed, Feb 24, 2010 at 1:05 PM, Venu Kalyan <mydb08@stripped> wrote:
>> Hi !
>>
>> On Tue, Feb 23, 2010 at 3:23 PM, Zardosht Kasheff <zardosht@stripped>
> wrote:
>>> But does this distinguish the commands "insert ignore" and "insert on
>>> duplicate key update"?
>>
>> Actually its contrary and unknown behavior even though MySQL allows
>> the synax to use IGNORE and ON DUPLICATE KEY / REPLACE together in
>> single statement, and it should in general through an error when used
>> together as server does not which one to prefer.
>>
>> In this case (Ignore and ON DUPLICATE KEY together in single insert)
>> ON DUPLICATE KEY takes precedence in the code due to the following
>> condition..
>>
>> if (duplic != DUP_ERROR || ignore)
>>      table->file->extra(HA_EXTRA_NO_IGNORE_DUP_KEY);
>>
>> For your case;  you can validate this using :
>>
>> if (thd->lex->ignore && thd->lex->duplicates == SQL_ERROR) {
>>  // safe to ignore my dups
>> }
>>
>> if (thd->lex->ignore && thd->lex->duplicates != SQL_ERROR) {
>> // used ignore together with IGNORE and ON KEY DUPLICATE / REPLACE
>> statements, I will decide what needs to be done here
>> }
>>
>> Hope this helps.
>>
>> Thanks
>> Venu Anuganti
>>
>>>
>>> On Tue, Feb 23, 2010 at 6:20 PM, Venu Kalyan <mydb08@stripped> wrote:
>>>> You should look for both sql_command type and lex->ignore value (both
> are
>>>> part of thd->lex->sql_command and thd->lex->ignore) to
> determine if the
>>>> storage engine can safely return success on dup cases. But remember,
> doing
>>>> so will result in wrong stats (number of rows inserted/updated)
>>>>
>>>> Apart from insert/replace, load data also uses the same logic.
>>>>
>>>> On Tue, Feb 23, 2010 at 12:07 PM, Zardosht Kasheff
> <zardosht@stripped>
>>>> wrote:
>>>>>
>>>>> Hello,
>>>>>
>>>>> Does anyone have any guidance here?
>>>>>
>>>>> Thanks
>>>>> -Zardosht
>>>>>
>>>>> On Wed, Feb 17, 2010 at 3:47 PM, Zardosht Kasheff
> <zardosht@stripped>
>>>>> wrote:
>>>>> > So it seems that just looking at this flag will not work,
> because
>>>>> > INSERT IGNORE and INSERT...ON DUPLICATE KEY UPDATE both set this
> flag.
>>>>> >
>>>>> > I guess what I am wondering is the following, is there any way
> for the
>>>>> > handler to know for sure that the user has called "insert
> ignore", and
>>>>> > if so, would it be ok for the handler to return success even if
>>>>> > internally a duplicate key is found?
>>>>> >
>>>>> > Thanks
>>>>> > -Zardosht
>>>>> >
>>>>> > On Fri, Feb 12, 2010 at 5:08 PM, Zardosht Kasheff
> <zardosht@stripped>
>>>>> > wrote:
>>>>> >> Hello all,
>>>>> >>
>>>>> >> I am trying to implement an optimization in our storage
> engine if
>>>>> >> HA_EXTRA_IGNORE_DUP_KEY is set. Would it be ok if
> handler::write_row
>>>>> >> returns success if this flag is set, the sql statement is
> NOT
>>>>> >> SQLCOM_REPLACE or SQLCOM_REPLACE_SELECT, and the row is not
> inserted
>>>>> >> if a duplicate is otherwise there.
>>>>> >>
>>>>> >> Basically, the question is if this flag is set, is it ok to
> not return
>>>>> >> HA_ERR_FOUND_DUPP_KEY in the cases where the statement is
> not "replace
>>>>> >> into".
>>>>> >>
>>>>> >> Thanks
>>>>> >> -Zardosht
>>>>> >>
>>>>> >
>>>>>
>>>>> --
>>>>> MySQL Internals Mailing List
>>>>> For list archives: http://lists.mysql.com/internals
>>>>> To unsubscribe:  
>  http://lists.mysql.com/internals?unsub=1
>>>>>
>>>>
>>>>
>>>
>>
>
Thread
question on HA_EXTRA_IGNORE_DUP_KEYZardosht Kasheff12 Feb
  • Re: question on HA_EXTRA_IGNORE_DUP_KEYZardosht Kasheff17 Feb
    • Re: question on HA_EXTRA_IGNORE_DUP_KEYZardosht Kasheff23 Feb
      • Re: question on HA_EXTRA_IGNORE_DUP_KEYVenu Kalyan24 Feb
Re: question on HA_EXTRA_IGNORE_DUP_KEYZardosht Kasheff24 Feb
  • Re: question on HA_EXTRA_IGNORE_DUP_KEYVenu Kalyan24 Feb
    • Re: question on HA_EXTRA_IGNORE_DUP_KEYZardosht Kasheff24 Feb
      • Re: question on HA_EXTRA_IGNORE_DUP_KEYVenu Kalyan24 Feb
        • Re: question on HA_EXTRA_IGNORE_DUP_KEYZardosht Kasheff25 Feb
      • Re: question on HA_EXTRA_IGNORE_DUP_KEYSergey Vojtovich25 Feb
        • Re: question on HA_EXTRA_IGNORE_DUP_KEYZardosht Kasheff25 Feb
          • Re: question on HA_EXTRA_IGNORE_DUP_KEYSergei Golubchik26 Feb
          • Re: question on HA_EXTRA_IGNORE_DUP_KEYSergey Vojtovich26 Feb
            • Re: question on HA_EXTRA_IGNORE_DUP_KEYZardosht Kasheff26 Feb
              • Re: question on HA_EXTRA_IGNORE_DUP_KEYSergey Vojtovich2 Mar
                • Re: question on HA_EXTRA_IGNORE_DUP_KEYZardosht Kasheff2 Mar
                  • Re: question on HA_EXTRA_IGNORE_DUP_KEYSergey Vojtovich2 Mar
                    • Re: question on HA_EXTRA_IGNORE_DUP_KEYMichael Widenius19 Mar
                      • Configure error during the buildHiromichi Watari21 Mar
                        • Re: Configure error during the buildMikiya Okuno21 Mar
                          • Re: Configure error during the buildHiromichi Watari22 Mar