[Bigdata-developers] Bigdata & Deletions

[Rick M. <ri...@sw...>]

Hi all,

We've recently been evaluating quad-stores, and in particular are looking
for better storage layers, and Blazegraph looks like a promising option.

We have a linked data management system, which has several  management
workflows where by:

1. large named graphs can be moved around (renamed via a SPARQL Update MOVE
command).

2. large named graphs can be inserted, reviewed, deleted (repaired offline)
and reinserted again before finally being approved.

With this workflow there are two problems we have been finding with some of
the other quad stores:

The first is that renames are often implemented as a copy/delete; which
results in a slow linear-time (or worse) operation.  Ideally renaming
graphs would be constant time.

The second problem we have been encountering (which the first can compound)
is that some stores don't free storage on deletions, and don't even have a
mechanism for expunging deletions without taking the database offline.

I'm curious as to what Blazegraph's behaviour is in these two
circumstances, and whether or not the different journals have different
behaviours.

Many thanks,

R.