Updating large recordsets takes long time in ms access database advance dating site for

Posted by / 10-Jul-2017 00:18

Updating large recordsets takes long time in ms access database

MSSQLSERVER\MSSQL\DATA\SUCCESS Offset: 6,225,805,312, Length: 16,384, I/O Flags: Non-cached, Write Through, Priority: Normal .0884897 1760 Write File C:\Program Files\Microsoft SQL Server\MSSQL10_50. LDF SUCCESS Offset: 4,589,289,472, Length: 8,388,608, I/O Flags: Non-cached, Write Through, Priority: Normal From using DBCC PAGE it seems to be reading from and writing to fields that look like table A's (or one of its indexes), but for different B_ID that 13. Edited 2: execution plan So I cancelled the query (actually deleted the DB and its files then restored it), and checked the execution plan for: The (estimated) execution plan is the same than for any B. The WHERE clause uses an index seek on a non-clustered index of B, the JOIN uses a clustered index seek on both PKs of the tables.The clustered index seek on A uses parallelism (x7) and represents 90% of the CPU time. X field), each one with its own clustered PK, and an other index which also includes the A. X means writing the 7 views and the 7 indexes they have that include the field.The rest looks the same: same UPDATE line waiting in sp_who2, same PAGEIOLATCH_EX wait type and same heavy HD usage from Next step is to delete all indexes and views and recreate them I think.B has 40k records, A has 4M records and they are related 1-to-n via A. So basically I am pre-calculating a field for data mining purposes. ID = @Id FETCH NEXT FROM Cursor B INTO @Id END Now I can see it running with a message with the id descending.Although I changed the name of the tables for this question, I didn't change the statement, it's really that simple. What happens is it takes around 5min to go from id=40k to id = 13 And then at id 13, for some reason, it seems to hang.Edited 4: deleting then rebuilding indexes So, I deleted all the indexed views I had on the table (7 of them, 2 indexes per view including the clustered one).I ran the initial script (without cursor), and it actually ran in 5 minutes.

Since disconnected recordsets use batch updates, this bug caused my client application to crash whenever it tried to update a record. The access times are significantly reduced, and I suspect the decrease will be even larger when the recordset contains more fields.The update scenario is always faster than using a procedure.Since you are updating column X of all rows in table A, make sure you drop the index on that one first.More importantly, actually executing the query with ID 13 is immediate. X field The views are filtered (with fields that are not in this equation), so I doubt there is any way the UPDATE A would the views themselves. Although the UPDATE is expected to be slower for this, there is no reason why a specific ID would be so much longer than the others.Edited 3: index fragmentation The structure of indexes is as follows: B has one clustered PK (not the ID field), and one non-clustered unique index, which first field is B. I checked the fragmentation for all the indexes, all were at loop.

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In situations like this SQL likes to hold onto the memory and not let it go...after said insert command may or may not have completed.