Ultralite database size increases after multiples ALTER DATABASE SCHEMA FROM FILE executions

[Former Member]

Hello experts,

I've noticed that after an execution of an ALTER DATABASE SCHEMA FROM FILE command, the .udb size increases, even if no DML execution is done between the database's schema upgrades.

So I had known about this issue, I've executed a set of alter-database-schema commands many times, like this:

Version 0 -> upgrade schema -> Version 1 -> upgrade schema -> Version 2 -> upgrade schema -> Version 0

After the execution of 20 steps (no DML was done), the database size hasn't stabilized as I expected.

Why the database continues grows, even if no data was modified or inserted?

[former_SQLA_member1694876]

Yes, the size should stabilize.

How large is the database initially? Does it contain data? How much is the increase on each iteration?

[Former Member]

The database's initial size is 6.029.312 bytes and we've made the following operations:
1. Increase the size of a varchar column and of a numeric column
2. Create a new column
3. Create a new column, and after, add a foreign key reference
4. Remove a column different from the inserted before

Each one of these operations consists in a schema upgrade and after the step 4, the database's schema is upgraded to the initial one.

The database size's behavior for an Android client was:

| 1ª Execution | 2ª Execution | 3ª Execution | 20ª Execução |
| 6.029.312    | 6.094.848    | 6.160.384    | 6.422.528    |
| 6.094.848    | 6.094.848    | 6.160.384    | 6.422.528    |
| 6.094.848    | 6.094.848    | 6.160.384    | 6.422.528    |
| 6.094.848    | 6.160.384    | 6.160.384    | 6.422.528    |
| 6.094.848    | 6.160.384    | 6.160.384    | 6.422.528    |

I'm looking into a simple repro for this issue, but I couldn't do it yet.