Greetings!
Just doing some more digging around MonetDB, and have a couple of questions.
(1) If I am managing multiple BATs that are (supposedly) synced, how do I manage appends and the syncing?
For example, I have a_p1 = BAT[void, int] and a_p2 = BAT[void, int]
(a_p1 = <a> type things with property p1) (a_p2 = <a> type things with property p2)
I wish to insert a new <a>=(1,2) thing. Do I do? bat("a_p1").append(1); bat("a_p2").append(2);
How do I ensure that the "voids" are always synced? Is this just "assumed"?
What if I fail in the middle of operations (such that a_p1 has an extra row) and stuck with dirty tables? Do I do a global "abort();" or a "clean();" to get back to a safe state? Will this reset the seqbase? (Is this documented someplace? I am trying to look at the architecture docs but cannot find anything that concretely answers similar questions.)
(2) How does sync() work?
Do I do a: sync(bat("a_p1"), bat("a_p2"));
once and only once? After every update/append to the tables?
There is the phrase "When two BATs effectively contain the same sequence of head elements, we call them 'synced'. This is implemented by storing a very large OID for each column. An update to the column destroys this OID.". This sounds as if any update/append breaks the correspondence, and also that it will limit the number of rows in the table (as an OID is a 32-bit number of 32-bit systems).
If I have 10 properties I am tracking, would I pick one as the "primary" BAT, and sync() all others to it?
Regards! Ed