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https://issues.apache.org/jira/browse/JENA-1552?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16497957#comment-16497957
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Andy Seaborne commented on JENA-1552:
-------------------------------------

Preliminary figures for an integeated phased loader with parallelism within 
phases.

"Phased" here means one pass data->node table->SPO and one pass to build POS 
and OSP from SPO.

||Loader||Data size||Storage||Time (s)||Rate (Triples per second)||
| TDB2 phased  |  200m  | Disk  |  2,899  |   69,010  |
| TDB2 phased  |  200m  | SSD   |  1,640  |  121,963  |
| TDB2 phased  |  25m   |  SSD  |  214    |  117,013  |

The machine remained usable for other work while these loads were happening.


> Bulk loader for TDB2 (phased loading)
> -------------------------------------
>
>                 Key: JENA-1552
>                 URL: https://issues.apache.org/jira/browse/JENA-1552
>             Project: Apache Jena
>          Issue Type: Improvement
>          Components: TDB2
>            Reporter: Andy Seaborne
>            Assignee: Andy Seaborne
>            Priority: Major
>
> Following on from JENA-1550, this ticket is for phased loading which combined 
> features of the sequential loader and the parallel loader.
> When building all the persistent datastructures (parallel loader), the work 
> on different indexes at the same time is competing for hardware resources, 
> RAM and I/O bandwidth.  As the size to load grows, this becomes a noticeable 
> slowdown.
> The sequential loader is the other extreme of the design spectrum. It does 
> work on one index at a time so as to maximize caching efficiency.
> Phased loading has parallel operation per phase and splits work into subsets 
> of indexes.
> At 200m and loading to rotational disk, an experimental phased loader working 
> with 2 indexes at a time, starts to become faster than parallel on the same 
> hardware as used for the [figures in 
> JENA-1550|https://issues.apache.org/jira/browse/JENA-1550#comment-16484269] 
> (56K parallel, 76K phased).



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