how can I change the logsecond parameter in an HADR system. as much I could understand, I would need to change the parameter by executing the following command first in primary and then in stand by server:
db2 update db cfg for db_name using LOGSECOND The_number_of_file
is this correct, please let me know as I have to make some changes.
Yes, that is correct. However, in order to take effect, it is necessary to recycle the database (stop: force connection, deactivate; start: connect OR activate)
Related
I have a very strange 'reload.sql' file that I need to use to build a database.
It references about 200 XXX.dat files with straight-up readable data (although useless without explanations regarding the meaning of the fields).
I have tried msssql server, mysql workbench (on a server local-hosted on wamp), and directly accessing it through DBeaver and IBConsole, but I cannot manage to execute/build it.
It uses a weird syntax. There are elements like
begin
...
end
go
that hinted me towards T-SQL, but using sqlcmd on it gave me thousands upon thousands of errors regarding keywords.
Specifically, the very first batch of executable lines says
SET OPTION date_order = 'YMD'
go
SET OPTION PUBLIC.preserve_source_format = 'OFF'
go
SET TEMPORARY OPTION tsql_outer_joins = 'ON'
go
SET TEMPORARY OPTION st_geometry_describe_type = 'binary'
go
SET TEMPORARY OPTION st_geometry_on_invalid = 'Ignore'
go
SET TEMPORARY OPTION non_keywords = 'attach,compressed,detach,kerberos,nchar,nvarchar,refresh,varbit'
go
which generates about 150 errors 'Incorrect syntax near OPTION keyword' on its own, and according to google is part of a 'rexx' procedure but 'date_order' should then be 'DATFMT', right?
Another track is that of SyBase, but I cannot for the life of me get it to work (through my trials I did manage to build a .db file, that, well, is useless to me since I can't build it either..).
I've tried accessing it through ODBC pilots as well but none worked (the paradox ODBC did not crash, but said there was an error with a FROM clause, which are generated automatically...).
I need to know a way to build a database from this file or directly access the data it references, which I can't really post since it contains private medical data.
Also what madman came up with this.
The very first google link (for me anyway) against 'st-geometry-describe-option' shows this is a SAP SQL Anywhere database i.e. http://dcx.sybase.com/1200/en/dbadmin/st-geometry-describe-option.html
So I would suggest starting from the SQL Anywhere documentation and you will need to install the database software beforehand.
In app config file. I used initial catalog ='jana' as database name.
Then i run it use it for some times.
Then later i changed initial catalog ='siva' as database name . That i changed database name alone and saved it. Whenever i run this 'siva' as initial catalog , select queries is using 'siva' database at the same time inserting /updating queries using my previous database 'jana'. Its really weird.
thanks for considering my query. I rectified mistake by myself.
Actually while inserting/updating queries , i have used databasename.dbo.tablename for all queries. That is the cause whenever i used different database , the one which i used on creating was always affected.
Hope u understand my scenario.
Thanks for all.
I have a Rails 4 application that I use in conjunction with sidekiq to run asynchronous jobs. One of the jobs I normally run outside of my Rails application is a large set of complex SQL queries that cannot really be modeled by ActiveRecord. The connection this set of SQL queries has with my Rails app is that it should be executed anytime one of my controller actions is invoked.
Ideally, I'd queue a job from my Rails application within the controller for Sidekiq to go ahead and run the queries. Right now they're stored in an external file, and I'm not entirely sure what the best way is to have Rails run the said SQL.
Any solutions are appreciated.
I agree with Sharagoz, if you just need to run a specific query, the best way is to send the query string directly into the connection, like:
ActiveRecord::Base.connection.execute(File.read("myquery.sql"))
If the query is not static and you have to compose it, I would use Arel, it's already present in Rails 4.x:
https://github.com/rails/arel
You didn't say what database you are using, so I'm going to assume MySQL.
You could shell out to the mysql binary to do the work:
result = `mysql -u #{user} --password #{password} #{database} < #{huge_sql_filename}`
Or use ActiveRecord::Base.connection.execute(File.read("huge.sql")), but it won't work out of the box if you have multiple SQL statements in your SQL file.
In order to run multiple statements you will need to create an initializer that monkey patches the ActiveRecord::Base.mysql2_connection to allow setting MySQL's CLIENT_MULTI_STATEMENTS and CLIENT_MULTI_RESULTS flags.
Create a new initializer config/initializers/mysql2.rb
module ActiveRecord
class Base
# Overriding ActiveRecord::Base.mysql2_connection
# method to allow passing options from database.yml
#
# Example of database.yml
#
# login: &login
# socket: /tmp/mysql.sock
# adapter: mysql2
# host: localhost
# encoding: utf8
# flags: 131072
#
# #param [Hash] config hash that you define in your
# database.yml
# #return [Mysql2Adapter] new MySQL adapter object
#
def self.mysql2_connection(config)
config[:username] = 'root' if config[:username].nil?
if Mysql2::Client.const_defined? :FOUND_ROWS
config[:flags] = config[:flags] ? config[:flags] | Mysql2::Client::FOUND_ROWS : Mysql2::Client::FOUND_ROWS
end
client = Mysql2::Client.new(config.symbolize_keys)
options = [config[:host], config[:username], config[:password], config[:database], config[:port], config[:socket], 0]
ConnectionAdapters::Mysql2Adapter.new(client, logger, options, config)
end
end
end
Then update config/database.yml to add flags:
development:
adapter: mysql2
database: app_development
username: user
password: password
flags: <%= 65536 | 131072 %>
I just tested this on Rails 4.1 and it works great.
Source: http://www.spectator.in/2011/03/12/rails2-mysql2-and-stored-procedures/
Executing one query is - as outlined by other people - quite simply done through
ActiveRecord::Base.connection.execute("SELECT COUNT(*) FROM users")
You are talking about a 20.000 line sql script of multiple queries. Assuming you have the file somewhat under control, you can extract the individual queries from it.
script = Rails.root.join("lib").join("script.sql").read # ah, Pathnames
# this needs to match the delimiter of your queries
STATEMENT_SEPARATOR = ";\n\n"
ActiveRecord::Base.transaction do
script.split(STATEMENT_SEPARATOR).each do |stmt|
ActiveRecord::Base.connection.execute(stmt)
end
end
If you're lucky, then the query delimiter could be ";\n\n", but this depends of course on your script. We had in another example "\x0" as delimiter. The point is that you split the script into queries to send them to the database. I wrapped it in a transaction, to let the database know that there is coming more than one statement. The block commits when no exception is raised while sending the script-queries.
If you do not have the script-file under control, start talking to those who control it to get a reliable delimiter. If it's not under your control and you cannot talk to the one who controls it, you wouldn't execute it, I guess :-).
UPDATE
This is a generic way to solve this. For PostgreSQL, you don't need to split the statements manually. You can just send them all at once via execute. For MySQL, there seem to be solutions to get the adapter into a CLIENT_MULTI_STATEMENTS mode.
If you want to execute raw SQL through active record you can use this API:
ActiveRecord::Base.connection.execute("SELECT COUNT(*) FROM users")
If you are running big SQL every time, i suggest you to create a sql view for it. It be boost the execution time. The other thing is, if possible try to split all those SQL query in such a way that it will be executed parallely instead of sequentially and then push it to sidekiq queue.
You have to use ActiveRecord::Base.connection.execute or ModelClass.find_by_sql to run custom SQL.
Also, put an eye on ROLLBACK transactions, you will find many places where you dont need such ROLLBACK feature. If you avoid that, the query will run faster but it is dangerous.
Thanks all i can suggest.
use available database tools to handle the complex queries, such as views, stored procedures etc and call them as other people already suggested (ActiveRecord::Base.connection.execute and ModelClass.find_by_sql for example)- it might very well cut down significantly on query preparation time in the DB and make your code easier to handle
http://dev.mysql.com/doc/refman/5.0/en/create-view.html
http://dev.mysql.com/doc/connector-cpp/en/connector-cpp-tutorials-stored-routines-statements.html
abstract your query input parameters into a hash so you can pass it on to sidekiq, don't send SQL strings as this will probably degrade performance (due to query preparation time) and make your life more complicated due to funny SQL driver parsing bugs
run your complex queries in a dedicated named queue and set concurrency to such a value that will prevent your database of getting overwhelmed by the queries as they smell like they could be pretty db heavy
https://github.com/mperham/sidekiq/wiki/API
https://github.com/mperham/sidekiq/wiki/Advanced-Options
have a look at Squeel, its a great addition to AR, it might be able to pull some of the things you are doing
https://github.com/activerecord-hackery/squeel
http://railscasts.com/episodes/354-squeel
I'll assume you use MySQL for now, but your mileage will vary depending on the DB type that you use. For example, Oracle has some good gems for handling stored procedures, views etc, for example https://github.com/rsim/ruby-plsql
Let me know if some of this stuff doesn't fit your use case and I'll expand
I see this post is kind of old. But I would like to add my solution to it. I was in a similar situation; I also needed a way to force feed "PRAGMA foreign_keys = on;" into my sqlite connection (I could not find a previous post that spelled it out how to do it.) Anywho, this worked like a charm for me. It allowed me to write "pretty" sql and still get it executed. Blank lines are ignored by the if statement.
conn = ActiveRecord::Base.establish_connection(adapter:'sqlite3',database:DB_NAME)
sqls = File.read(DDL_NAME).split(';')
sqls.each {|sql| conn.connection.execute(sql<<';') unless sql.strip.size == 0 }
conn.connection.execute('PRAGMA foreign_keys = on;')
I had the same problem with a set of sql statements that I needed to execute all in one call to the server. What worked for me was to set up an initializer for Mysql2 adapter (as explained in infused answer) but also do some extra work to process multiple results. A direct call to ActiveRecord::Base.connection.executewould only retrieve the first result and issue an Internal Error.
My solution was to get the Mysql2 adapter and work directly with it:
client = ActiveRecord::Base.connection.raw_connection
Then, as explained here, execute the query and loop through the results:
client.query(multiple_stms_query)
while client.next_result
result = client.store_result
# do something with it ...
end
I need to rename a lot of similar named job names so i want to run an update statement to change the name column of msdb..sysjobs.
Editing system tables is something i am pretty aware of, but changing job names doesn't feel that dangerous, because i think the job_id is what counts. Is it safe to do it in this case?
I am using sql server 2008.
When you have the same jobs running in multiple environments, it's a better practice to refer to jobs by name rather than by ID, because a job with the same name will be created with a different ID in every environment.
If you change the name of the jobs, make sure that any scripts you use to manipulate those jobs also use the new name.
I think there is nothing to worry about, you can modify it.
Please find detail about sysjobs here.
It is NOT save to just rename it. Using sql profiler shows, that renaming a package using the object exlorer will start several procedures. It will create a new package using sp_add_dtspackage and drop it later using sp_drop_dtspackage. The package id is although set using a parameter, so setting it random really seems to be a potential risk.
I'm trying to pull user data from 2 tables, one locally and one on a linked server, but I get the wrong results when querying the remote server.
I've cut my query down to
select * from SQL2.USER.dbo.people where persId = 475785
for testing and found that when I run it I get no results even though I know the person exists.
(persId is an integer, db is SQL Server 2000 and dbo.people is a table by the way)
If I copy/ paste the query and run it on the same server as the database then it works.
It only seems to affect certain user ids as running for example
select * from SQL2.USER.dbo.people where persId = 475784
works fine for the user before the one I want.
Strangely I've found that
select * from SQL2.USER.dbo.people where persId like '475785'
also works but
select * from SQL2.USER.dbo.people where persId > 475784
brings back records with persIds starting at 22519 not 475785 as I'd expect.
Hope that made sense to somebody
Any ideas ?
UPDATE:
Due to internal concerns about doing any changes to the live people table, I've temporarily moved my database so they're both on the same server and so the linked server issue doesn't apply. Once the whole lot is migrated to a separate cluster I'll be able to investigate properly. I'll update the update once this happens and I can work my way through all the suggestions. Thanks for your help.
The fact that LIKE operates is not a major clue: LIKE forces integers to string (so you can say WHERE field LIKE '2%' and you will get all records that start with a 2, even when field is of integer type). Your incorrect comparisons would lead me to think your indexes are corrupt, but you say they work when not used via the link... however, the selected index might be different depending on the use? (I seem to recall an instance when I had duplicate indexes and only one was stale, although that was too long ago to recall the exact cause).
Nevertheless, I would try rebuilding your index using the DBCC DBREINDEX (tablenname) command. If it turns out that doing so fixes your query, you may want to rebuild them all: here is a script for rebuilding them all easily.
Is dbo.people a table or a view? I've seen something similar where the underlying table schema had been changed and dropping and recreating the view fixed the problem, although the fact that the query works if run directly on the linked server does indicate something index based..
Is the linked server using the same collation? Depending on the index used, I could see something like this perhaps happening if the servers were not collation compatible, but the linked server was set up with collation compatible (which tells Sql Server it can run the query on the remote server).
I would check the following:
Check your definition on the linked server, and confirm that SQL2 is the
server you expect it to be
Check and compare the execution plans both from the remote and local servers
Try linking by IP address rather than name, to ensure you have the proper machine
Put the code into a stored procedure on the remote machine, and try calling that instead
Sounds like a bug to me - I;ve read of some issues along these lines, btu can't remember specifically what. What version of SQL Server are you running?
select * from SQL2.USER.dbo.people where persId = 475785
for a PersID which fails how does:
SELECT *
FROM OpenQuery(SQL2, 'SELECT * FROM USER.dbo.people WHERE persId = 475785')
behave?