I am using the Paradox 9 app as bundled with WordPerfect 2000. After deleting thousands of records from the table, the filesize remains at 500 kB even though there are now only 12 records. Is there a way to decrease the filesize to what it would be as if I had re-created the table and entered the 12 records from scratch?
Open the table in Paradox 9. Go to Format --> Restructure Table. Check the "Pack Table" checkbox, then click Save.
Related
Preconditions:
Table dimensions: HUGE 13 million records and still growing.
System: oracle.
Problem:
Today we faced with a serious problem when we dropped a column from that table it took almost 20 minutes. A time that is critical for our delpoyment of some modifications. Without getting in more details is partitioning the table after column a solution for a faster DROP of column ?
P.S. The method presented in: https://oracle-base.com/articles/8i/dropping-columns where we can drop first logical and then physical is not approachable in this case.
I have reached the file size limit on my SQL Server 2008 R2 Express database which I believe is 10Gb. I know this because I see Event ID 1101 in the event log.
Could not allocate a new page for database 'ExchangeBackup' because of insufficient disk space in filegroup 'PRIMARY'
I have removed some historic data to work around the problem for now but it is only a temporary fix. One table (PP4_MailBackup) is much larger than the others so when I created this database 12 months ago, I converted this table to be a Filestream table and the data is stored outside the FileGroup in the File System. This appeared to be working successfully until I received the error and new data was no longer being added to my database.
When I do a report on table sizes I see the Reserved(KB) column adds up to almost 10GB.
The folder that holds my FileStream data is 176 GB
The database .mdf file is indeed 10GB.
Does anyone have any idea why the table PP4_MailBackup is still using nearly 7GB?
Here is the "Standard Reports -> Disk Usage report" for this database:
Thanks in advance
David
Update
Here is some more info.
There are 868,520 rows in this table.
This cmd returns 1 so I'm assuming Ansipadding is on. I have never changed this from the default.
SELECT SESSIONPROPERTY('ANSI_PADDING')
The columns are defined like this
Even if every record for every column filled the full record size, by my rough calculation the table would be around 4,125,470,000 bytes. I understand that the nvarchar columns only use the actual space required.
I'm still missing a lot of space.
Not really an answer but more of a conclusion.
I have given up on this problem and resided myself to remove data to stay under the 10GB Primary file size limit. I figured out that the nvarchar columns store 2 bytes per character in order to deal with Unicode characters although they do only use the space required and don't pad out the column with spaces. So this would account for some of the space I can't find.
I tried to convert my char(500) columns to varchar(500) by adding new columns with the correct type copying data into them and then removing the old column. This worked but the table actually got bigger because removing the column is only a Meta data change and does not actually remove the data. To recover the space I would need to create a new table and copy the data across then remove the old table of course I don't have enough space in the primary file to do that.
I thought about copying the table to temp db removing the original table then copying it back but temp db doesn't support filestream columns (at least to my knowledge) so I would need to hold all 170GB within the temp db table. This sounded like a dubious solution and my test server didn't have enough space on the partition where temp db was stored. I couldn't find anything on the files size limit of tempdb on sql 2008 Express, but at this point it was all getting too hard.
I have a very simple table that has an ID (generated by a sequence), and a NAME. I inserted a couple rows which got cached but after a while I wanted to remove them because I wanted to redo my table so I issued a couple of DELETE statements to remove all records (I don't have the privileges to do a TRUNCATE).
After deleting the old rows, I again inserted a couple other records but I didn't bother resetting the sequence.
On PHP, when I SELECT everything on that table, I still get those old deleted rows. But on PL/SQL when I SELECT on that table, it only shows me the new records.
Is the problematic cache on the PHP or Oracle side? If it's on the Oracle side, how do I clear it out?
Thanks!
This is a new issue that I haven't run into before.
I have a table that at one point contained over 100k records, it's an event log for a dev environment.
it took up to 10 seconds to load the table (simply clicking on it to view the data in the table).
I removed all but 30 rows and it still takes 7 seconds to load.
I'm using Toad, and it gives me a dialog box that says "Statement Processing..."
Any ideas?
The following are some select statements and how long they took
select * from log; 21 rows in 10 secs
select * from log where id = 120000; 1 row in 1 msec
select * from log where user = 35000; 9 rows in 7 sec
The id is the pk, there is no index on the user field.
I have a table view that contains all of the fields sitting ontop of this table as well and it runs just as slow.
If you issue a "select * from event_log_table", then you are scanning the entire table with a full table scan. It has to scan through all allocated segments to see if there are rows in there. If your table once contained over 100K rows, then it has allocated at least the amount of space to be able to hold those 100K+ rows. Please see: http://download.oracle.com/docs/cd/B19306_01/server.102/b14231/schema.htm#sthref2100
Now if you delete rows, the space is still allocated to this table, and Oracle still has to scan all space. It works like a high water mark.
To reduce the high water mark, you can issue a TRUNCATE TABLE command, which resets the high water mark. But then you'll lose ALL rows.
And there is an option to shrink the space in the table. You can read about it and its preconditions here:
http://download.oracle.com/docs/cd/B19306_01/server.102/b14200/statements_3001.htm#sthref5117
Regards,
Rob.
I would better understand this if you started off with a 100M records table. But just in case, try running Oracle stats. If this doesn't help, drop and recreate indices on that table.
I have a table in an oracle database with 15 fields.
This table had 3500000 inserts. I deleted them all.
delete
from table
After that, whenever I execute a select statement
I get a very slow response (7 sec) even though the table is empty.
I get a normal response only in the case that I search
according to an indexed field.
Why?
As Gritem says, you need to understand high water marks etc
If you do not want to truncate the table now (because fresh data has been inserted), use alter table xyz shrink space documented here for 10g
Tom Kyte has a good explanation of this issue:
http://asktom.oracle.com/pls/asktom/f?p=100:11:0::::P11_QUESTION_ID:492636200346818072
It should help you understand deletes, truncates, and high watermarks etc.
In sql when you want to completely clear out a table, you should use truncate instead of delete. Let's say you have your table with 3.5 million rows in it and there is an index (unique identifier) on a column of bigint that increments for each row. Truncating the table will completely clear out the table and reset the index to 0. Delete will not clear the index and will continue at 3,500,001 when the next record is inserted. Truncate is also much faster than delete. Read the articles below to understand the differences.
Read this article Read this article that explains the difference between truncate and delete. There are times to use each one. Here is another article from an Oracle point of view.