Replying to davidsarah:
Note that in https://github.com/davidsarah/tahoe-lafs/commit/b7cea9a3f86c5cc4cfd3910d0300a1008b7b5a13, I got rid of the AUTOINCREMENT key on the leases table, replacing it with a semantic primary key. So there are no longer any AUTOINCREMENT keys on leasedb tables where records are created at all frequently. Therefore, I think there is no available performance improvement from this change, at least for leasedb.
If you (zooko or warner) agree, I'll just close this ticket as invalid.
It seems to me that we should make this change:
zooko@spark ~/playground/tahoe-lafs $ git diff
diff --git a/docs/backupdb.rst b/docs/backupdb.rst
index 5a36b51..e47ca3b 100644
--- a/docs/backupdb.rst
+++ b/docs/backupdb.rst
@@ -61,7 +61,7 @@ The database contains the following tables::
CREATE TABLE caps
(
- fileid integer PRIMARY KEY AUTOINCREMENT,
+ fileid integer PRIMARY KEY,
filecap varchar(256) UNIQUE -- URI:CHK:...
);
diff --git a/src/allmydata/scripts/backupdb.py b/src/allmydata/scripts/backupdb.py
index 75ee0d9..37180f9 100644
--- a/src/allmydata/scripts/backupdb.py
+++ b/src/allmydata/scripts/backupdb.py
@@ -27,7 +27,7 @@ CREATE TABLE local_files -- added in v1
CREATE TABLE caps -- added in v1
(
- fileid INTEGER PRIMARY KEY AUTOINCREMENT,
+ fileid INTEGER PRIMARY KEY,
filecap VARCHAR(256) UNIQUE -- URI:CHK:...
);
Not primarily for efficiency (since creation of new caps during a backup, or a future "sync" or a future "cp -r --with-db" is not high frequency), but primarily for simplicity. We don't need the AUTOINCREMENT feature of sqlite, so we shouldn't say that we want it (and it might slow a backupdb file-creation operation down by a few hundred nanoseconds occasionally).
Daira, Brian: what do you say?
