I have a problem with an ADF table component in my jspx page.
In my table each row contains 2 LOV component (seleconechoice).Table row selection value is "single". After clicking the row table activates editing the current row after 5 seconds or more times. This table is the most used component in my page. Information entance is provided by this component. So i need to improve performance of this component.
I try some of the techniques above but can't find a solution yet.
Viewobject tuning
Iterator range size and fetch size is equivalent
table content delivery = "immediate" ... so on.
In page definition iterator range size ="50"
table fetchSize="50"
This table is the detail table of another view object in my page.
Any idea?
you need to profile your apps to understand which part of your code causing it.
Try to reduce number of max rows retrieved from database.
Example: VO -> general -> tuning -> only up to row number 10
Related
Dears,
I really need your help with this one as it's driving me crazy, I have 3 queries loaded as tables under each other in my excel workbook.
when I choose the properties option: insert cells for new data, delete unused cells from properties >> it shows an error message in refresh (it would move cells in a table on your worksheet).
and when I go for the second option: insert entire rows for new data, it refreshes but leaves many blank rows between each table and the second one.
What shall I do to refresh all queries in the workbook without messing up the form .. as I just need to leave 1 empty row between each loaded table?
I have made a view that changes it's columns frequently with dynamic SQL. I use a pivot to make rows into columns. I display the view in an interactive grid. The SQL query that is executed:
select * from <DB>.<VIEWNAME>.
On refresh it updates the ROWS in the grid, but not the COLUMNS. The select * does not take column changes into account, BUT if I alter the SQL query by adding a space ( or any other thing in the query) and then saving the page in the page designer, the columns sync up to the view.
Does someone know a good solution to my problem? Where can I find the procedure that executes this refresh? If I know where it is I can possiby use it after the insertion of a column (or delete / update). Any tips? Warning, I am a total novice in oracle apex and sql developer.
Thanks in advance!
This is the wrong way to go about this. In Apex, and in Oracle in general, columns are determined when the query is parsed. If you change the underlying structure, your query has to be reparsed and only then do the columns change.
Think about it. If the first column in your result set was a DATE and you had your Apex column attributes set up to format and display that data, then your query changed to a NUMBER, its not clear what would happen.
What you probably want to do is create your region based on a function that returns a sql query as a VARCHAR2. (I think you can do this in 18.x; I'm still mostly using 5.2.) Your function gets parsed when the region is displayed. You can even use another function to return a colon-separated list of column headers if the names are dynamic.
I need to update the some tables in my application from some other warehouse tables which would be updating weekly or biweekly. I should update my tables based on those. And these are having foreign keys in another tables. So I cannot just truncate the table and reinsert the whole data every time. So I have to take the delta and update accordingly based on few primary key columns which doesn't change. Need some inputs on how to implement this approach.
My approach:
Check the last updated time of those tables, views.
If it is most recent then compare each row based on the primary key in my table and warehouse table.
update each column if it is different.
Do nothing if there is no change in columns.
insert if there is a new record.
My Question:
How do I implement this? Writing a PL/SQL code is it a good and efficient way? as the expected number of records are around 800K.
Please provide any sample code or links.
I would go for Pl/Sql and bulk collect forall method. You can use minus in your cursor in order to reduce data size and calculating difference.
You can check this site for more information about bulk collect, forall and engines: http://www.oracle.com/technetwork/issue-archive/2012/12-sep/o52plsql-1709862.html
There are many parts to your question above and I will answer as best I can:
While it is possible to disable referencing foreign keys, truncate the table, repopulate the table with the updated data then reenable the foreign keys, given your requirements described above I don't believe truncating the table each time to be optimal
Yes, in principle PL/SQL is a good way to achieve what you are wanting to
achieve as this is too complex to deal with in native SQL and PL/SQL is an efficient alternative
Conceptually, the approach I would take is something like as follows:
Initial set up:
create a sequence called activity_seq
Add an "activity_id" column of type number to your source tables with a unique constraint
Add a trigger to the source table/s setting activity_id = activity_seq.nextval for each insert / update of a table row
create some kind of master table to hold the "last processed activity id" value
Then bi/weekly:
retrieve the value of "last processed activity id" from the master
table
select all rows in the source table/s having activity_id value > "last processed activity id" value
iterate through the selected source rows and update the target if a match is found based on whatever your match criterion is, or if
no match is found then insert a new row into the target (I assume
there is no delete as you do not mention it)
on completion, update the master table "last processed activity id" to the greatest value of activity_id for the source rows
processed in step 3 above.
(please note that, depending on your environment and the number of rows processed, the above process may need to be split and repeated over a number of transactions)
I hope this proves helpful
In Oracle 10g, does it matter what order create index and alter table comes in?
Say i have a query Q with a where clause on column C in table T. Now i perform one of the following scenarios:
I create index I(C) and then add columns X,Y,Z.
Add columns X,Y,Z then create index I(C).
Q is 'select * from T where C = whatever'
Between 1 and 2 will there be a significant difference in performance of Q on table T when T contains a very large number of rows?
I personally make it a practice to do #2 but others seem to have a different opinion.
thanks
It makes no difference if you add columns to a table before or after creating an index. The optimizer should pick the same plan for the query and the execution time should be unchanged.
Depending on the physical storage parameters of the table, it is possible that adding the additional columns and populating them with data may force quite a bit of row migration to take place. That row migration will generate changes to the indexes on the table. If the index exists when you are populating the three new columns with data, it is possible that populating the data in X, Y, and Z will take a bit longer because of the additional index maintenance.
If you add columns without populating them, then it is pretty quick as it is just a metadata change. Adding an index does require the table to be read (or potentially another index) so that can be very time consuming and of much greater impact than the simple metadata change of recording the new index details.
If the new columns are going to be populated as part of the ALTER TABLE, it is a different matter.
The database may undergo an unplanned shutdown during the course of adding that data to every row of the table data
The server memory may not have room to record every row changed in that table
Therefore those row changes may be written to datafiles before commit, and are therefore written as dirty blocks
The next read of those blocks, after the ALTER table has successfully completed will do a delayed block cleanout (ie record the fact that the change has been committed)
If you add the columns (with data) first, then the create index will (probably) read the table and do the added work of the delayed block cleanout.
If you create the index first then add the columns, the create index may be faster but the delayed block cleanout won't happen and that housekeeping will be picked up by the application later (potentially by the select * from T where C = whatever)
I have two tables one inside the other. When there are no detail rows in the inner table i am making it invisible. but i am not able to make the external table invisible.
In detail My inner table heading row and footer is visible even when there are no detail rows so i made the table visibility to true when no detail rows. But i am not able to make the external table invisible with the same logic. it is because even though the inner table is invisible the detail and footer is there so when i say no detail rows no visibility it is not working. so how can i hide the external table when the internal table is invisible?
I would try Binding the data set to the external table and making an aggregation that counts the number of rows in the data set.
Click on the Table
go to Binding in the Property Editor
click Add Aggregation
I called the Column Binding Name RowCount and set the Function to COUNT. Set the Expression to one of the columns from your dataset that you have included in the binding. In my case, I set Expression to row["columnname"].
Click on your table.
go to Visibility in the Property Editor.
check Hide Element and set the Expression to:
row["RowCount"]==0 || row["RowCount"]==null
The element will only display when the RowCount aggregation counts more than 1 row in your dataset.
My solution for this was to create a function that counts the records that meet the desired criterion, in my case select count(*) from my_table where user_id = id.
Then I inserted this function as a detail component that gets the count based on the selected table record.
Then I used the result of the count as a visibility rule. count > 0. this way I can hide the tables that return empty.
Using this trick is possible to hide the secondary table but the count details component will be still there, if you want to hide it you have to put it in a flexbox component. then in the visibility rules you an access you flexbox component and include the rule count > 0