reverbrain / eblob

Eblob is an append-only low-level IO library, which saves data in blob files. Created as low-level backend for elliptics

GNU Lesser General Public License v3.0

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Extend eblob summary statistics for defragmentation status #128

Open shaitan opened 9 years ago

shaitan commented 9 years ago

Current state

Currently, eblob summary has follow statistics:

records_removed - total number of removed records in all blobs
records_removed_size - total size of all removed records in all blobs
want_defrag - sum of want_defrag of all blobs
Problem

There is no statistics that shows the need and potential profit from defragmentation:

want_defrag is useless because it mixes want_defrag of all blobs
records_removed and records_removed_size are about all removed records from all blobs and don't show how many space will be freed by defragmentation
What is wanted to be changed

Add new statistics or change current statistics if it is possible. These statistics should show:

the need for defragmentation: 0 - defragmentation is useless now, 1 - defragmentation will make a profit
current profit from defragmentation: how many resources will be freed (disk space, fd etc.)

agodin commented 9 years ago

like!

shaitan commented 9 years ago

Update

"profit from defragmentation" won't be implemented
summary:want_defrag will take one of follow values:
- 1 - when there is at least one unsorted blob or blob with want_defrag equal to 1 (EBLOB_DEFRAG_NEEDED) or 2 (EBLOB_REMOVE_NEEDED)
- 0 - in all other cases