Changeset 589 in code for trunk

Timestamp:

Sep 14, 2021, 4:38:58 PM (4 years ago)

Author:

hubert

Message:

Use NULL-tolerant comparison for DeliveryReceipts

Since NULL = NULL is always FALSE, this query needs to use IS instead.
This should fix the flood of DeliveryReceipts in the DB.

See ​https://www.sqlite.org/lang_expr.html

The IS and IS NOT operators work like = and != except when one or both
of the operands are NULL. In this case, if both operands are NULL,
then the IS operator evaluates to 1 (true) and the IS NOT operator
evaluates to 0 (false). If one operand is NULL and the other is not,
then the IS operator evaluates to 0 (false) and the IS NOT operator is
1 (true). It is not possible for an IS or IS NOT expression to
evaluate to NULL.

File:

• trunk/db_sqlite.go (modified) (1 diff)

trunk/db_sqlite.go

@@ -543 +543 @@
         defer tx.Rollback()
 
-        _, err = tx.Exec("DELETE FROM DeliveryReceipt WHERE network = ? AND client = ?",
+        _, err = tx.Exec("DELETE FROM DeliveryReceipt WHERE network = ? AND client IS ?",
                 networkID, toNullString(client))
         if err != nil {