Using OntoDB

Settings

\set prints the settings and \set knob value changes one. Settings last for the shell process.

Settings

OntoDB> \set
backend mem
pool_size 64
lru_k 2
join auto
isolation rc

Knob	Values	Default	Effect today
`backend`	`mem`, `indexed`	`mem`	`indexed` moves the triples onto pages and B+ trees in a temporary file; `mem` moves them back. A persistent database stays on `mem` until PLAN 8
`pool_size`	frames	`64`	Frames in the indexed backend's pool, read when the backend is switched on
`lru_k`	positive integer	`2`	The indexed backend's LRU-K `k`, read when the backend is switched on
`join`	`auto`, `nlj`, `inlj`, `hash`	`auto`	Join operator. `auto` lets the optimizer choose per join; the others force one operator everywhere
`isolation`	`ru`, `rc`, `rr`, `ser`	`rc`	Stored for transactions, which are being built

A setting that is accepted prints ok. An unknown knob or value prints an error and changes nothing.

Timing

\timing on prints time: N ms after each statement's result. \timing off stops it.

Statistics

OntoDB> \stats
page reads: 0
page writes: 0
buffer hits: 0
buffer misses: 0
log flushes: 0

log flushes counts physical log writes in a persistent database; one flush can carry many commits. The page and buffer counters stay at zero until the buffer pool exists.