Hi,

1. will be good to see this query plans
2. will be good to see exact error message
3. also check your db by gfix –validate –full

regards,
Karol Bieniaszewski

From: mailto:firebird-support@yahoogroups.com 
Sent: Sunday, May 1, 2016 8:35 AM
To: firebird-support@yahoogroups.com 
Subject: [firebird-support] Migrating from Super Classic FB 2.5.2 to 
SuperServer FB 3.0 could have a problems

  
Hi all,

Just migrating from SC FB 2.5.2 to SS FB 3.0 (both in Win x64), i found a few 
problems :

1) Query that runs about 2-3 secs in SC FB 2.5.2, runs minutes in SS FB 3.0
Query is something like this :

Select a.col1,b.col1 from tbl1 a, tbl2 b where a.id = b.id and b.id in (select 
c.id from tbl3 c)

SS FB 3.0 uses different query plan that not use indices, no wonder it was so 
slow.

Changed query to :
Select a.col1,b.col1 from tbl1 a, tbl2 b, tbl3 c where a.id = b.id and b.id= 
c.id 

Runs around 1-2 secs in SS FB 3.0, but runs minutes in SC FB 2.5.2

2) Since in FB 3.0, SS is able to use SMP & shared Db Cache, I tried to set Db 
Cache to 512 MB via gfix. It was without error. 

First connection is OK & I could saw that the actual Db cache size is around 
300 MB. But after connection closed & tried to connect again, FB raised an 
error, something like connection lost.

Changed Db Cache to 256 MB fixed th e problem. I think, for modern computer, 
256 MB is too small.

Regards,
Anto.









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