This commit introduces error returns in various places and is explicit
about closing persisted blocks.
{Index,Chunk,Tombstone}Readers are more consistent about their Close()
method. Whenever a reader is retrieved, the corresponding close method
must eventually be called. We use this to track pending readers against
persisted blocks.
Querier's against the DB no longer hold a read lock for their entire
lifecycle. This avoids long running queriers to starve new ones when we
have to acquire a write lock when reloading blocks.
* Expose Stone as it is used in an exported method.
* Move from tombstoneReader to []Stone for the same reason as above.
* Make WAL reading a little cleaner.
Signed-off-by: Goutham Veeramachaneni <cs14btech11014@iith.ac.in>
We need to recalculate the sorted ref list everytime we make a
Tombstones() call. This avoids that.
Signed-off-by: Goutham Veeramachaneni <cs14btech11014@iith.ac.in>
