--
-- The index is stored in an SQLite3 database. This is its schema.
--- Index of all blocks which have been stored in one snapshot, by checksum.
+-- List of snapshots which have been created.
+create table snapshots (
+ snapshotid integer primary key,
+ name text not null,
+ scheme text,
+ timestamp real,
+ intent real
+);
+
+-- List of segments which have been created.
+create table segments (
+ segmentid integer primary key,
+ segment text unique not null,
+ path text,
+ checksum text,
+ mtime real,
+ size integer,
+ expire_time integer -- snapshotid of latest snapshot when expired
+);
+
+-- Index of all blocks which have been stored, by checksum.
create table block_index (
blockid integer primary key,
- segment text,
- object text,
+ segmentid integer not null,
+ object text not null,
checksum text,
- size integer
+ size integer,
+ timestamp real,
+ expired integer
);
create index block_content_index on block_index(checksum);
+create unique index block_name_index on block_index(segmentid, object);
+
+-- Summary of segment utilization for each snapshots.
+create table segments_used (
+ snapshotid integer not null,
+ segmentid integer not null,
+ utilization real
+);
+create unique index segments_used_index
+ on segments_used(snapshotid, segmentid);
+
+-- Overall estimate of segment utilization, for all snapshots combined.
+create view segment_info as
+select segmentid, mtime, size, expire_time,
+ cast(size * utilization as integer) as used, utilization
+from segments join
+ (select segmentid, max(utilization) as utilization
+ from segments_used group by segmentid)
+using (segmentid);