Document the "-v/--verbose" option.

[cumulus.git] / schema.sql

diff --git a/schema.sql b/schema.sql
index 8529e32..9d2137e 100644 (file)
--- a/schema.sql
+++ b/schema.sql
@@ -7,7 +7,7 @@
 create table snapshots (
     snapshotid integer primary key,
     name text not null,
-    scheme text,
+    scheme text not null,
     timestamp real,
     intent real
 );
@@ -19,7 +19,8 @@ create table segments (
     path text,
     checksum text,
     mtime real,
-    size integer
+    size integer,
+    expire_time integer         -- snapshotid of latest snapshot when expired
 );
 
 -- Index of all blocks which have been stored, by checksum.
@@ -35,6 +36,21 @@ create table block_index (
 create index block_content_index on block_index(checksum);
 create unique index block_name_index on block_index(segmentid, object);
 
+-- Checksums for the decomposition of blocks into even smaller chunks
+-- (variable-sized, but generally ~8 kB, and maximum 64 kB).  Chunk boundaries
+-- are determined based on the contents using Rabin fingerprints.  These
+-- checksums can be used for computing sub-file incrementals.
+--
+-- Each block stored in block_index may have an entry in the
+-- subblock_signatures table.  The hash_data field is a binary blob consisting
+-- of a packed sequence of (chunk length [16-bit unsigned, big-endian],
+-- checksum [20 bytes for SHA-1]) tuples that should cover the entire block.
+create table subblock_signatures (
+    blockid integer primary key,
+    algorithm text not null,
+    signatures blob not null
+);
+
 -- Summary of segment utilization for each snapshots.
 create table segments_used (
     snapshotid integer not null,
@@ -46,8 +62,8 @@ create unique index segments_used_index
 
 -- Overall estimate of segment utilization, for all snapshots combined.
 create view segment_info as
-select segmentid, mtime, size, cast(size * utilization as integer) as used,
-       utilization
+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)