Hi
mos wrote:
If I have a large table with 20 million rows, is it going to be faster
to use one delete statement like:
delete from mytable where rcdid in(20,300,423, .... 99999)
to delete 10-100 random records using the primary index "RcdId"
or should I use separate delete statements for each RcdId as in:
delete from mytable where rcdid = 20;
delete from mytable where rcdid = 300;
delete from mytable where rcdid = 423;
...
delete from mytable where rcdid = 99999;
I'm concerned the IN() clause will cause a full table scan and that will
take quite a while to find the rows even though I'm using the primary
key RcdId.
You can convert it into an equivalent SELECT and use EXPLAIN to see if
it's using a table scan.
Baron
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