After https://github.com/redis/redis/pull/13816, we make a new API to
defrag RedisModuleDict.
Currently, we only support incremental defragmentation of the dictionary
itself, but the defragmentation of values is still not incremental. If
the values are very large, it could lead to significant blocking.
Therefore, in this PR, we have added incremental defragmentation for the
values.
The main change is to the `RedisModuleDefragDictValueCallback`, we
modified the return value of this callback.
When the callback returns 1, we will save the `seekTo` as the key of the
current unfinished node, and the next time we enter, we will continue
defragmenting this node.
When the return value is 0, we will proceed to the next node.
## Test
Since each dictionary in the global dict originally contained only 10
strings, but now it has been changed to a nested dictionary, each
dictionary now has 10 sub-dictionaries, with each sub-dictionary
containing 10 strings, this has led to a corresponding reduction in the
defragmentation time obtained from other tests.
Therefore, the other tests have been modified to always wait for
defragmentation to be turned off before the test begins, then start it
after creating fragmentation, ensuring that they can always run for a
full defragmentation cycle.
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Co-authored-by: ephraimfeldblum <ephraim.feldblum@redis.com>
Now attributes are added as well. Moreover the code no longer uses
the first node to guess the size of the items, but does an average
of the few first items/attributes found. Still O(1) but more precise.
1) Enable the callback to be NULL for RM_DefragRedisModuleDict()
Because the dictionary may store only the key without the value.
2) Reduce the system calls of RM_DefragShouldStop()
The API checks the following thresholds before performing a time check:
over 512 defrag hits, or over 1024 defrag misses, and performs the time
judgment if any of these thresholds are reached.
3) Added defragmentation statistics for dictionary items to cover the
associated code for RM_DefragRedisModuleDict().
4) Removed `module_ctx` from `defragModuleCtx` struct, which can be
replaced by a temporary variable.
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Co-authored-by: oranagra <oran@redislabs.com>
Recently encountered some errors as bellow,
HGETEX/HSETEX with PXAT/EXAT options, after getting ttl, we calculate
current time by `[clock seconds]` that may have a delay that causes
results greater than expected.
Dismiss memory test error, now we introduced rdb-channel replication,
the full synchronization might finish before the child process exits. So
we may fail if calling `bgsave` immediately after full sync.
antirez