maria-discuss team mailing list archive

[Justin Swanhart <greenlion@xxxxxxxxx>]

You have a sharded table.  You could probably use shard-query.  If all tables are in same schema, you will need to create a new "fake" schema for each table:

Create schema s1;
Create view s1.the_table as select * from real_schema.table1;

Create schema s2;
Create view s2.the_table as select * from real_schema.table2;



Set up shard query with N shards, each pointing to on of the "fake" schema.

Select from the_table in Shard-Query to access all  the tables.   When you set up shard-query, use a fake shard-key so that all tables are always searched (they will be searched in parallel).


OR

Use a stored procedure.   It can use dynamic SQL to search each table and return a result set from each, since SP can return more than one result set.   This is slower (no parallelism) but simpler.

Sent from my iPhone

> On Sep 23, 2015, at 2:32 AM, <Rhys.Campbell@xxxxxxxxxxxx> <Rhys.Campbell@xxxxxxxxxxxx> wrote:
> 
> Best thing to do it to try it but I suspect your hunch is correct.
>  
> Really, it would be a good idea to merge all your data into a single table. Perhaps use partitioning https://dev.mysql.com/doc/refman/5.5/en/partitioning.html which the optimizer should be able to take advantage of.
>  
> From: Maria-discuss [mailto:maria-discuss-bounces+rhys.campbell=swisscom.com@xxxxxxxxxxxxxxxxxxx] On Behalf Of Roberto Spadim
> Sent: Wednesday, September 23, 2015 4:06 AM
> To: Maria Discuss
> Subject: [Maria-discuss] doubt about merge table (10000+) with same structure
>  
> Hi again guys :)
>  
> i'm with a new problem
>  
> i have MANY (10000+) tables with same struct, and i want to execute a select from "some" (100+) tables 
>  
> i was thinking about creating a view with all tables, something like:
>  
> CREATE VIEW view_name AS 
> SELECT * FROM table1 WHERE primary_key=<a value only at table1>
> UNION ALL
> SELECT * FROM table2 WHERE primary_key=<a value only at table2>
> UNION ALL
> SELECT * FROM table3 WHERE primary_key=<a value only at table3>
> UNION ALL
> SELECT * FROM table4 WHERE primary_key=<a value only at table4>
> UNION ALL
> ...
> SELECT * FROM tablen WHERE primary_key=<a value only at tablen>
>  
>  
> but i don't know if mysql optimizer will do a good job when i execute something like:
>  
> SELECT * FROM view_name WHERE primary_key=<a value only located at table1>
>  
> and just execute the query at table1 instead of alllllllll 10000+ tables
>  
> i'm considering restruture database to a spider engine or any other method if i don't have other option
>  
> any idea is well come
>  
> --
> Roberto Spadim
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