chore: remove cmd name from the list of arguments
Signed-off-by: Vladislav Oleshko <vlad@dragonflydb.io>
Co-authored-by: Roman Gershman <roman@dragonflydb.io>
fix:Return an error, instead of crashing, for requests trying to rename a key to the same key.
Fixes#850
---------
Co-authored-by: Shahar Mike <shmike@google.com>
Specifically, pass OpaqueObj to parsing routines so that they could fill it instead of creating it.
In addition, this change improves the interface between generic_family and RdbLoad code:
it removes reliance on the internal Item class.
Signed-off-by: Roman Gershman <roman@dragonflydb.io>
Signed-off-by: Roman Gershman <roman@dragonflydb.io>
SSCAN command support count and match parameters fixes#426
Signed-off-by: adi_holden <adi@dragonflydb.io>
Signed-off-by: adi_holden <adi@dragonflydb.io>
Partially implements #6.
Before, each shard lazily updated its clock used for the expiry evaluation.
Now, the clock value is set during the transaction scheduling phase and is assigned
to each transaction. From now on DbSlice methods use this value when checking whether
the entry is expired via passed DbContext argument.
Also, implemented transactionally consistent TIME command and
verify that time is the same during the transaction. See
https://ably.com/blog/redis-keys-do-not-expire-atomically for motivation.
Still have not implemented any lamport style updates for background processes
(not sure if it's the right way to proceed).
Before this change Dragonfly evicted items only when it was low on memory and had to grow its main dictionary.
It is not enough because in many cases Dragonfly can grow in memory even when the main dictionary does not grow.
For example, when its dictionary is less than 90% utilized, but the newly added objects require lots of memory.
In addition, the dashtable adds additional segments, when other segments have enough available slots to fill the rest of the free memory.
This change adds another layer of defense that allows evicting items even when dictionary segments are not full.
The eviction is still local with respect to a segment. On my tests it seems that it's much harder to cross maxmemory limit than before.
In addition, we tightened the heuristic that allowes the dashtable to grow. Now it takes into account the average bytes per item
in order to project how much memory the full table takes before adding to it new segments.
This really improves dashtable utilization.
There are still things to improve:
1. the eviction behavior is rough. Once an insert does the eviction it tries to free enough objects to bring memory back.
This may result in very spiky insertion/eviction patterns.
2. The eviction procedure, even though it's limited to a single segment, is quite heavy because it goes over all buckets
in the segment. This may result in weird artifacts where we evict just enough to be under the limit, then add and evict
again and so on.
3. Therefore, we may need a periodic eviction that will compliment this emergency eviction step.
Fixes#224 and partially addresses #256
Signed-off-by: Roman Gershman <roman@dragonflydb.io>
1. No entries data is written into a journal yet.
2. Introduced a state machine to start and stop journal using a new auxillary command "dfly".
3. string_family currently calls an universal command Journal::RecordEntry that should
save the current key/value of that entry. Please note that we won't use it for all the operations
because for some it's more efficient to record the action itself than the final value.
4. no locking information is recorded yet so atomicity of multi-key operations is not preserved for now.
Signed-off-by: Roman Gershman <roman@dragonflydb.io>
1. Make EngineShardSet to be a process singleton instead of a variable passed everywhere.
2. Implement a heuristic of updating free memory per shard.
3. Make sure that SET command returns OOM when a database reaches its limits.
1. Added support of loading of compressed strings.
2. Verified we load expiry info.
3. Extended supported expiry period to 4 years (previously I set 1 year).
1. Sets do not use anymore redis encoding constants in our codebase.
2. rdb_save serializes now expiry information as well.
3. db_slice provides a simplified api to translate from absolute time to ExpirePeriod.
4. common_types.h is renamed to common.h. cached memory usage variables are moved there.
