I am planning to upgrade a sybase dataserver from 12.5 to 15 which shares a CIS link with another 12.5 sybase dataserver.These dataservers share some tables and hence a lot of joins are across dataservers including some #temp tables.These joins are taking a lot of time to execute when there is a procedure call from say dataserver A(12.5) to dataserver B(15) where A and B have a CIS(Component Integration Services) link.
what can be done to optimize these joins??
In ASE 15, enable 'join relocation' and see if that affects the performance.
Related
Is it possible to migrate T-SQL Stored procedure to Postgres database of version prior to 11, in any way? I know CREATE PROCEDURE supported from Postgres V 11 and above. Is there any other way we can achieve the same thing as we do in T-SQL Stored Procedure. We are planning to move to Amazon Aurora which supports Postgress 10.6 now. I am new to Postgres. Any suggestion would be appreciated .
Unsurprisingly, it depends on what you are trying to do. For most things, you will be able to use functions instead of procedures. If your stored procedures require transaction management, though, you won't be able to do that without procedures.
When I upgrade my database from PostgreSQL 9.6.5 to PostgreSQL 10.1 using pg_upgrade, some of my queries involving multiple tables suffer a massive performance degradation.
Running exactly the same query on exactly the same data with exactly the same indexes in 10.1 takes around 17 seconds compared to around 0.1 second in 9.6.
Looking at the EXPLAIN plan for the query, I can see that the plan between the two versions differs a lot - especially for a couple of sub-selects.
9.6 uses indexes a lot more than 10.1. 10.1 seems to favor full table scans over the indexes - even for tables with close to 1M records.
I have verified that the indexes haven't been "lost" during the upgrade. Also if I query the tables individually, the indexes are used.
Any insights?
Thanks,
Sebastian
Solved by doing pg_dump/pg_restore instead of pg_upgrade. Performance and query plans are back to normal.
The output of pg_upgrade includes this:
...
Upgrade Complete
----------------
Optimizer statistics are not transferred by pg_upgrade so,
once you start the new server, consider running:
./analyze_new_cluster.sh
...
We found horrible performance straight after the upgrade until we ran this, lesson learned to read the output :)
We are in a migration process from a Progress DB to use the Dataserver to a SQL Server database, and we have had a lot of issues, specifically with performance where the dataserver is not able to produce server side joins for a lot of queries.
In the datasheet for Openedge 11 it says this has been improved, but anyone has an idea of how much improvement they've made.
As an example, every query involving two buffers where the second one is FIRST/LAST wouldn't be joined at server side, has this been changed?
Many thanks,
Check page 175 of the OpenEdge Data Management for MS SQL Server PDF for an answer to this question - there are a whole pile of conditions that apply, as well as a number of control settings that'll affect performance.
We are using Oracle Express as our development DB. When 2 programmers try to connect to it via jdbc we get dropped connections. Is this a limitation or Oracle Express edition? If we have 2 separate logins we still have this issue.
No, there is no limitation in Oracle Express preventing two users to connect at the same time. In fact, I use as a quite alright production (more than 20 concurrent connections) database in some projects.
It might be something else.
If you want to check what is the number of sessions allowed in your database you can issue:
SELECT name, value
FROM v$parameter
WHERE name = 'sessions'
Does anyone know what substantial differences there are between the regular PostgreSQL and Postgres Plus?
The database is the same, meaning that the SQL is fully compatible to any other PostgreSQL installation around (save for the GIS data formats).
The main difference is that there is a bunch of modules and tools bundled with Postgres Plus that you would have to collect and install separately and by yourself otherwise. Thus the main advantage is easy and speedy installation.
Most of the bundled stuff looks like it's freely available from other sources. That Postgres Studio application looks suspiciously close to pgAdmin III.
One important difference is the licence:
Postgres Plus is only free for "non-production" use.
you can find detailed purchasing options here:
http://www.enterprisedb.com/products/purchase.do
Postgres PLUS is proprietary, PostgreSQL is Open source under permissive license (and that's why Postgres PLUS is proprietary).
Postgres PLUS has support for Oracle PL/SQL, while PostgreSQL does not, at least not officially.
Those are two most obvious differences.
I used 8.2 and when was the time to switch to 8.3 I tried PostGresPlus.
The Speed was a lot faster. LOT I mean queries that took 30 secs, takes now less than 2 seconds. I am not sure if it's 8.3 that is faster or the Enterprise Plus but I can tell you that I was impressed.
Other thing that I like is that I can debug proc stored. It cames with more tools.