Richard Hipp wrote:
> When there are no indices, SQLite can put the rows into the database in
> any order it wants, and it chooses to put them in ascending order. Thus,
> each insert becomes a constant-time append. (Approximately - the truth is
> a little more complicated, but by waving our arms vigorously, we can still
> claim constant time per row.) But if there are indices, each row must be
> inserted in index order, which involves a b-tree search to find the right
> spot and possible a rebalancing operation - O(logN) per row.
Again, my observation is that you are *not* doing constant-time inserts
when there are no indices.
What do you mean, "ascending order"?
The only constraint on the relevant table is a foreign-key ref to a tiny
table. But the asymptotic behavior is the same with pragma foreign_keys
off or on.
I double-checked sqlite_master and there are no indices (not even
auto-indices) on the table.
Inserts are *faster* at high row counts when there *are* indices.
I am using 3.6.23.1. I haven't tested earlier versions (waiting on a
reply in another thread to find out where to get them).
How vigorously are you waving? Can you describe the real algorithm, or
at least a second-order approximation?
Eric
--
Eric A. Smith
What the hell is it good for?
-- Robert Lloyd (engineer of the Advanced Computing Systems
Division of IBM), to colleagues who insisted that the
microprocessor was the wave of the future, c. 1968
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