In `beginResultEmission`, -1 means the result length is not known in
advance. But after #12185, if we pass -1 to `zrangeResultBeginStore`, it
will convert to SIZE_MAX in `zsetTypeCreate` and try to `dictExpand`.
Although `dictExpand` won't succeed because the size overflows, I think
we'd better to avoid this wrong conversion.
This bug can be triggered when the source of `zrangestore` doesn't exist
or we use `zrangestore` command with `byscore` or `bylex`.
The impact is that dst keys will be converted to use skiplist instead of
listpack.
Users who abuse lua error_reply will generate a new error object on each
error call, which can make server.errors get bigger and bigger. This
will
cause the server to block when calling INFO (we also return errorstats
by
default).
To prevent the damage it can cause, when a misuse is detected, we will
print a warning log and disable the errorstats to avoid adding more new
errors. It can be re-enabled via CONFIG RESETSTAT.
Because server.errors may be very large (it may be better now since we
have the limit), config resetstat may block for a while. So in
resetErrorTableStats, we will try to lazyfree server.errors.
See the related discussion at the end of #8217.
After #13072, there is an use-after-free error. In expireScanCallback, we
will delete the dict, and then in dictScan we will continue to use the dict,
like we will doing `dictResumeRehashing(d)` in the end, this casued an error.
In this PR, in freeDictIfNeeded, if the dict's pauserehash is set, don't
delete the dict yet, and then when scan returns try to delete it again.
At the same time, we noticed that there will be similar problems in iterator.
We may also delete elements during the iteration process, causing the dict
to be deleted, so the part related to iter in the PR has also been modified.
dictResetIterator was also missing from the previous kvstoreIteratorNextDict,
we currently have no scenario that elements will be deleted in kvstoreIterator
process, deal with it together to avoid future problems. Added some simple
tests to verify the changes.
In addition, the modification in #13072 omitted initTempDb and emptyDbAsync,
and they were also added. This PR also remove the slow flag from the expire
test (consumes 1.3s) so that problems can be found in CI in the future.
In some cases, users will abuse lua eval. Each EVAL call generates
a new lua script, which is added to the lua interpreter and cached
to redis-server, consuming a large amount of memory over time.
Since EVAL is mostly the one that abuses the lua cache, and these
won't have pipeline issues (i.e. the script won't disappear
unexpectedly,
and cause errors like it would with SCRIPT LOAD and EVALSHA),
we implement a plain FIFO LRU eviction only for these (not for
scripts loaded with SCRIPT LOAD).
### Implementation notes:
When not abused we'll probably have less than 100 scripts, and when
abused we'll have many thousands. So we use a hard coded value of 500
scripts. And considering that we don't have many scripts, then unlike
keys, we don't need to worry about the memory usage of keeping a true
sorted LRU linked list. We compute the SHA of each script anyway,
and put the script in a dict, we can store a listNode there, and use
it for quick removal and re-insertion into an LRU list each time the
script is used.
### New interfaces:
At the same time, a new `evicted_scripts` field is added to
INFO, which represents the number of evicted eval scripts. Users
can check it to see if they are abusing EVAL.
### benchmark:
`./src/redis-benchmark -P 10 -n 1000000 -r 10000000000 eval "return
__rand_int__" 0`
The simple abuse of eval benchmark test that will create 1 million EVAL
scripts. The performance has been improved by 50%, and the max latency
has dropped from 500ms to 13ms (this may be caused by table expansion
inside Lua when the number of scripts is large). And in the INFO memory,
it used to consume 120MB (server cache) + 310MB (lua engine), but now
it only consumes 70KB (server cache) + 210KB (lua_engine) because of
the scripts eviction.
For non-abusive case of about 100 EVAL scripts, there's no noticeable
change in performance or memory usage.
### unlikely potentially breaking change:
in theory, a user can maybe load a
script with EVAL and then use EVALSHA to call it (by calculating the
SHA1 value on the client side), it could be that if we read the docs
carefully we'll realized it's a valid scenario, but we suppose it's
extremely rare. So it may happen that EVALSHA acts on a script created
by EVAL, and the script is evicted and EVALSHA returns a NOSCRIPT error.
that is if you have more than 500 scripts being used in the same
transaction / pipeline.
This solves the second point in #13102.
Allow using `+` as a special ID for last item in stream on XREAD
command.
This would allow to iterate on a stream with XREAD starting with the
last available message instead of the next one which `$` is used for.
I.e. the caller can use `BLOCK` and `+` on the first call, and change to
`$` on the next call.
Closes#7388
---------
Co-authored-by: Felipe Machado <462154+felipou@users.noreply.github.com>
Sometimes it's useful to compute a key's cluster slot in a module.
This API function is just like the command CLUSTER KEYSLOT (but faster).
A "reverse" API is also added:
`RedisModule_ClusterCanonicalKeyNameInSlot`. Given a slot, it returns a
short string that we can call a canonical key for the slot.
Since lua_Number is not explicitly an integer or a double, we need to
make an effort
to convert it as an integer when that's possible, since the string could
later be used
in a context that doesn't support scientific notation (e.g. 1e9 instead
of 100000000).
Since fpconv_dtoa converts numbers with the equivalent of `%f` or `%e`,
which ever is shorter,
this would break if we try to pass a long integer number to a command
that takes integer.
we'll get an implicit conversion to string in Lua, and then the parsing
in getLongLongFromObjectOrReply will fail.
```
> eval "redis.call('hincrby', 'key', 'field', '1000000000')" 0
(nil)
> eval "redis.call('hincrby', 'key', 'field', tonumber('1000000000'))" 0
(error) ERR value is not an integer or out of range script: ac99c32e4daf7e300d593085b611de261954a946, on @user_script:1.
```
Switch to using ll2string if the number can be safely represented as a
long long.
The problem was introduced in #10587 (Redis 7.2).
closes#13113.
---------
Co-authored-by: Binbin <binloveplay1314@qq.com>
Co-authored-by: debing.sun <debing.sun@redis.com>
Co-authored-by: Oran Agra <oran@redislabs.com>
`CONFIG SET oom-score-adj handles configuration failures` test failed in
some CI jobs today.
Failed CI: https://github.com/redis/redis/actions/runs/8152519326
Not sure why the github action's docker image perssions have changed,
but the issue is similar to #12887,
where we can't assume the range of oom_score_adj that a user can change.
## Solution:
Modify the way of determining whether the current user has no privileges
or not,
instead of relying on whether the user id is 0 or not.
After #13013
### This PR make effort to defrag the pubsub kvstore in the following
ways:
1. Till now server.pubsub(shard)_channels only share channel name obj
with the first subscribed client, now change it so that the clients and
the pubsub kvstore share the channel name robj.
This would save a lot of memory when there are many subscribers to the
same channel.
It also means that we only need to defrag the channel name robj in the
pubsub kvstore, and then update
all client references for the current channel, avoiding the need to
iterate through all the clients to do the same things.
2. Refactor the code to defragment pubsub(shard) in the same way as
defragment of keys and EXPIRES, with the exception that we only
defragment pubsub(without shard) when slot is zero.
### Other
Fix an overlook in #11695, if defragment doesn't reach the end time, we
should wait for the current
db's keys and expires, pubsub and pubsubshard to finish before leaving,
now it's possible to exit
early when the keys are defragmented.
---------
Co-authored-by: oranagra <oran@redislabs.com>
Sometimes we need to make fast judgement about why Redis is suddenly
taking more memory. One of the reasons is main DB's dicts doing
rehashing.
We may use `MEMORY STATS` to monitor the overhead memory of each DB, but
there still lacks a total sum to show an overall trend. So this PR adds
the total overhead of all DBs to `INFO MEMORY` section, together with
the total count of rehashing DB dicts, providing some intuitive metrics
about main dicts rehashing.
This PR adds the following metrics to INFO MEMORY
* `mem_overhead_db_hashtable_rehashing` - only size of ht[0] in
dictionaries we're rehashing (i.e. the memory that's gonna get released
soon)
and a similar ones to MEMORY STATS:
* `overhead.db.hashtable.lut` (complements the existing
`overhead.hashtable.main` and `overhead.hashtable.expires` which also
counts the `dictEntry` structs too)
* `overhead.db.hashtable.rehashing` - temporary rehashing overhead.
* `db.dict.rehashing.count` - number of top level dictionaries being
rehashed.
---------
Co-authored-by: zhaozhao.zz <zhaozhao.zz@alibaba-inc.com>
Co-authored-by: Oran Agra <oran@redislabs.com>
In XREADGROUP ACK, because streamPropagateXCLAIM does not propagate
entries-read, entries-read will be inconsistent between master and
replicas.
I.e. if no entries were claimed, it would have propagated correctly, but
if some
were claimed, then the entries-read field would be inconsistent on the
replica.
The fix was suggested by guybe7, call streamPropagateGroupID
unconditionally,
so that we will normalize entries_read on the replicas. In the past, we
would
only set propagate_last_id when NOACK was specified. And in #9127,
XCLAIM did
not propagate entries_read in ACK, which would cause entries_read to be
inconsistent between master and replicas.
Another approach is add another arg to XCLAIM and let it propagate
entries_read,
but we decided not to use it. Because we want minimal damage in case
there's an
old target and new source (in the worst case scenario, the new source
doesn't
recognize XGROUP SETID ... ENTRIES READ and the lag is lost. If we
change XCLAIM,
the damage is much more severe).
In this patch, now if the user uses XREADGROUP .. COUNT 1 there will be
an additional
overhead of MULTI, EXEC and XGROUPSETID. We assume the extra command in
case of
COUNT 1 (4x factor, changing from one XCLAIM to
MULTI+XCLAIM+XSETID+EXEC), is probably
ok since reading just one entry is in any case very inefficient (a
client round trip
per record), so we're hoping it's not a common case.
Issue was introduced in #9127.
Implement #12699
This PR exposing Lua os.clock() api for getting the elapsed time of Lua
code execution.
Using:
```lua
local start = os.clock()
...
do something
...
local elpased = os.clock() - start
```
---------
Co-authored-by: Meir Shpilraien (Spielrein) <meir@redis.com>
Co-authored-by: Madelyn Olson <34459052+madolson@users.noreply.github.com>
Following #12568
In issue #9357, when inserting an element larger than 1GB, we currently
store it in a plain node instead of a listpack.
Presently, when we insert an element that exceeds the maximum size of a
packed node, it cannot be accommodated in any other nodes, thus ending
up isolated like a large element.
I.e. it's a node with only one element, but it's listpack encoded rather
than a plain buffer.
This PR lowers the threshold for considering an element as 'large' from
1GB to the maximum size of a node.
While this change doesn't completely resolve the bug mentioned in the
previous PR, it does mitigate its potential impact.
As a result of this change, we can now only use LSET to replace an
element with another element that falls below the maximum size
threshold.
In the worst-case scenario, with a fill of -5, the largest packed node
we can create is 2GB (32k * 64k):
* 32k: The smallest element in a listpack is 2 bytes, which allows us to
store up to 32k elements.
* 64k: This is the maximum size for a single quicklist node.
## Others
To fully fix#9357, we need more work, as discussed in #12568, when we
insert an element into a quicklistNode, it may be created in a new node,
put into another node, or merged, and we can't correctly delete the node
that was supposed to be deleted.
I'm not sure it's worth it, since it involves a lot of modifications.
There is a timing issue in the test, close may arrive late, or in
freeClientAsync we will free the client in async way, which will
lead to errors in watching_clients statistics, since we will only
unwatch all keys when we truly freeClient.
Add a wait here to avoid this problem. Also fixed some outdated
comments i saw. The test was introduced in #12966.
We can see that the past time here happens to be busy_time_limit,
causing the test to fail:
```
[err]: RM_Call from blocked client in tests/unit/moduleapi/blockedclient.tcl
Expected '50' to be more than '50' (context: type eval line 26 cmd {assert_morethan [expr [clock clicks -milliseconds]-$start] $busy_time_limit} proc ::test)
```
It is reasonable for them to be equal, so equal is added here.
It should be noted that in the previous `Busy module command` test,
we also used assert_morethan_equal, so this should have been missed
at the time.
Redis has some special commands that mark the client's state, such as
`subscribe` and `blpop`, which mark the client as `CLIENT_PUBSUB` or
`CLIENT_BLOCKED`, and we have metrics for the special use cases.
However, there are also other special commands, like `WATCH`, which
although do not have a specific flags, and should also be considered
stateful client types. For stateful clients, in many scenarios, the
connections cannot be shared in "connection pool", meaning connection
pool cannot be used. For example, whenever the `WATCH` command is
executed, a new connection is required to put the client into the "watch
state" because the watched keys are stored in the client.
If different business logic requires watching different keys, separate
connections must be used; otherwise, there will be contamination. This
also means that if a user's business heavily relies on the `WATCH`
command, a large number of connections will be required.
Recently we have encountered this situation in our platform, where some
users consume a significant number of connections when using Redis
because of `WATCH`.
I hope we can have a way to observe these special use cases and special
client connections. Here I add a few monitoring metrics:
1. `watching_clients` in `INFO` reply: The number of clients currently
in the "watching" state.
2. `total_watched_keys` in `INFO` reply: The total number of keys being
watched.
3. `watch` in `CLIENT LIST` reply: The number of keys each client is
currently watching.
These tests have all failed in daily CI:
```
*** [err]: Blocking XREADGROUP for stream key that has clients blocked on stream - reprocessing command in tests/unit/type/stream-cgroups.tcl
Expected '1101' to be between to '1000' and '1100' (context: type eval line 23 cmd {assert_range [expr $end-$start] 1000 1100} proc ::test)
*** [err]: BLPOP unblock but the key is expired and then block again - reprocessing command in tests/unit/type/list.tcl
Expected '1101' to be between to '1000' and '1100' (context: type eval line 23 cmd {assert_range [expr $end-$start] 1000 1100} proc ::test)
*** [err]: BZPOPMIN unblock but the key is expired and then block again - reprocessing command in tests/unit/type/zset.tcl
Expected '1103' to be between to '1000' and '1100' (context: type eval line 23 cmd {assert_range [expr $end-$start] 1000 1100} proc ::test)
```
Increase the range to avoid failures, and improve the comment to be
clearer.
tests was introduced in #13004.
This test fails occasionally:
```
*** [err]: CLIENT KILL maxAGE will kill old clients in tests/unit/introspection.tcl
Expected 2 == 1 (context: type eval line 14 cmd {assert {$res == 1}} proc ::test)
```
This test is very likely to do a false positive if the execute time
takes longer than the max age, for example, if the execution time
between sleep and kill exceeds 1s, rd2 will also be killed due to
the max age.
The test can adjust the order of execution statements to increase
the probability of passing, but this is still will be a timing issue
in some slow machines, so decided give it a few more chances.
The test was introduced in #12299.
The test fails here and there:
```
*** [err]: expire scan should skip dictionaries with lot's of empty buckets in tests/unit/expire.tcl
scan didn't handle slot skipping logic.
```
There are two case:
1. In the case of passing the test, we use child process to avoid the
dict resize, but it can not completely limit it, since in the dictDelete
we still have chance to trigger the resize (hit the force radio). The
reason why our test passed before is because the expire dict is still
in the rehashing process, so the dictDelete, the dictShrinkIfNeeded can
not trigger the resize.
2. In the case of failing the test, the expire dict finished the
rehashing,
so the last dictDelete, the dictShrinkIfNeeded trigger the dict resize
since it hit the force radio, so the skipping logic fail.
This PR add a new DEBUG command to disbale the dict resize.
We forgot to call quicklistSetOptions after createQuicklistObject,
in the sort store scenario, we will create a quicklist with default
fill or compress options.
This PR adds fill and depth parameters to createQuicklistObject to
specify that options need to be set after creating a quicklist.
This closes#12871.
release notes:
> Fix lists created by SORT STORE to respect list compression and
packing configs.
Fix two crash introducted by #12955
When a quicklist node can't be inserted and split, we eventually merge
the current node with its neighboring
nodes after inserting, and compress the current node and its siblings.
1. When the current node is merged with another node, the current node
may become invalid and can no longer be used.
Solution: let `_quicklistMergeNodes()` return the merged nodes.
3. If the current node is a LZF quicklist node, its recompress will be
1. If the split node can be merged with a sibling node to become head or
tail, recompress may cause the head and tail to be compressed, which is
not allowed.
Solution: always recompress to 0 after merging.
The reason is the same as #13016. The reason is that in #12819,
in cron, in addition to trying to shrink, we will also tyring
to expand. The dict was expanded by cron before we trigger the
bgsave since we do have the enough keys (4096) to hit the radio.
Before the bgsave, we only add 4095 keys to avoid this issue.
Fix#12864
The main reason for this crash is that when replacing a element of a
quicklist packed node with lpReplace() method,
if the final size is larger than 4GB, lpReplace() will fail and returns
NULL, causing `node->entry` to be incorrectly set to NULL.
Since the inserted data is not a large element, we can't just replace it
like a large element, first quicklistInsertAfter()
and then quicklistDelIndex(), because the current node may be merged and
invalidated in quicklistInsertAfter().
The solution of this PR:
When replacing a node fails (listpack exceeds 4GB), split the current
node, create a new node to put in the middle, and try to merge them.
This is the same as inserting a large element.
In the worst case, its size will not exceed 4GB.
Currently, once active defrag starts, we can not adjust
active_defrag_running
downwards. This is because active_defrag_running will be dynamically
compute
based on the fragmentation, we think we should not lower the effort when
the
fragmentation drops.
However, we need to note that active_defrag_running will also be
dynamically
computed based on configurations. In this case, we are not respecting
cycle-min
or cycle-max. Some people may realize halfway through that defrag
consumes a
lot and want to adjust it.
Previously we could only turn off activedefrag and then turn it on again
to
adjust active_defrag_running downwards. So in this PR, when a active
defrag
configuration change is made, we will re-compute it.
These configuration items are:
- active-defrag-cycle-min
- active-defrag-cycle-max
- active-defrag-threshold-upper
# Description
Gather most of the scattered `redisDb`-related code from the per-slot
dict PR (#11695) and turn it to a new data structure, `kvstore`. i.e.
it's a class that represents an array of dictionaries.
# Motivation
The main motivation is code cleanliness, the idea of using an array of
dictionaries is very well-suited to becoming a self-contained data
structure.
This allowed cleaning some ugly code, among others: loops that run twice
on the main dict and expires dict, and duplicate code for allocating and
releasing this data structure.
# Notes
1. This PR reverts the part of https://github.com/redis/redis/pull/12848
where the `rehashing` list is global (handling rehashing `dict`s is
under the responsibility of `kvstore`, and should not be managed by the
server)
2. This PR also replaces the type of `server.pubsubshard_channels` from
`dict**` to `kvstore` (original PR:
https://github.com/redis/redis/pull/12804). After that was done,
server.pubsub_channels was also chosen to be a `kvstore` (with only one
`dict`, which seems odd) just to make the code cleaner by making it the
same type as `server.pubsubshard_channels`, see
`pubsubtype.serverPubSubChannels`
3. the keys and expires kvstores are currenlty configured to allocate
the individual dicts only when the first key is added (unlike before, in
which they allocated them in advance), but they won't release them when
the last key is deleted.
Worth mentioning that due to the recent change the reply of DEBUG
HTSTATS changed, in case no keys were ever added to the db.
before:
```
127.0.0.1:6379> DEBUG htstats 9
[Dictionary HT]
Hash table 0 stats (main hash table):
No stats available for empty dictionaries
[Expires HT]
Hash table 0 stats (main hash table):
No stats available for empty dictionaries
```
after:
```
127.0.0.1:6379> DEBUG htstats 9
[Dictionary HT]
[Expires HT]
```
When db->expires_cursor==0, it means the DB is done the scanning,
we should exit the loop to avoid the useless scanning.
It is easy to see the active expire timeout in the modified test,
for example, let's assume that there is only 1 expired key in the
DB, and the size / buckets ratio is less than 1%, which means that
we will skip it in isExpiryDictValidForSamplingCb, and the return
value of expires_cursor is 0.
Because `data.sampled == 0` is always true, so `repeat` is also
always true, we will keep scanning the DB, but every time it is
skipped by the previous judgment (expires_cursor = 0), until the
timelimit is finally exhausted.
Ci report this failure:
```
*** [err]: Don't rehash if used memory exceeds maxmemory after rehash in tests/unit/maxmemory.tcl
Expected '4098' to equal or match '4002'
WARNING: the new maxmemory value set via CONFIG SET (1176088) is smaller than the current memory usage (1231083)
```
It can be seen from the log that used_memory changed before we set
maxmemory.
The reason is that in #12819, in cron, in addition to trying to shrink,
we will
also tyring to expand. The dict was expanded by cron before we set
maxmemory,
causing the test to fail.
Before setting maxmemory, we only add 4095 keys to avoid triggering
resize.
When we use a timer to unblock a client in module, if the timer
period and the block timeout are very close, they will unblock the
client in the same event loop, and it will trigger the assertion.
The reason is that in moduleBlockedClientTimedOut we will protect
against re-processing, so we don't actually call updateStatsOnUnblock
(see #12817), so we are not able to reset the c->duration.
The reason is unblockClientOnTimeout() didn't realize that bc had
been unblocked. We add a function to the module to determine if bc
is blocked, and then use it in unblockClientOnTimeout() to exit.
There is the stack:
```
beforeSleep
blockedBeforeSleep
handleBlockedClientsTimeout
checkBlockedClientTimeout
unblockClientOnTimeout
unblockClient
resetClient
-- assertion, crash the server
'c->duration == 0' is not true
```
The block timeout is passed in the test case, but we do not pass
in the timeout_callback, and it will crash when unlocking. In this
case, in moduleBlockedClientTimedOut we will check timeout_callback.
There is the stack:
```
beforeSleep
blockedBeforeSleep
handleBlockedClientsTimeout
checkBlockedClientTimeout
unblockClientOnTimeout
replyToBlockedClientTimedOut
moduleBlockedClientTimedOut
-- timeout_callback is NULL, invalidFunctionWasCalled
bc->timeout_callback(&ctx,(void**)c->argv,c->argc);
```
Add a way to HSCAN a hash key, and get only the filed names.
Command syntax is now:
```
HSCAN key cursor [MATCH pattern] [COUNT count] [NOVALUES]
```
when `NOVALUES` is on, the command will only return keys in the hash.
---------
Co-authored-by: Viktor Söderqvist <viktor.soderqvist@est.tech>
Adds an ability to kill clients older than a specified age.
Also, fixed the age calculation in `catClientInfoString` to use
`commandTimeSnapshot`
instead of the old `server.unixtime`, and added missing documentation
for
`CLIENT KILL ID` to output of `CLIENT help`.
---------
Co-authored-by: Oran Agra <oran@redislabs.com>
tests consistently fail on timeout (sleep that's too short).
it now takes more time because in #12819 we iterate on all dicts, not
just non-empty ones.
it passed the PR's CI because it skips the `slow` tag, which might have
been misplaced, but now it is probably required.
with the fix, the tests take quite a lot of time:
```
[ok]: Redis can trigger resizing (1860 ms)
[ok]: Redis can rewind and trigger smaller slot resizing (744 ms)
```
before #12819:
```
[ok]: Redis can trigger resizing (309 ms)
[ok]: Redis can rewind and trigger smaller slot resizing (295 ms)
```
failure:
https://github.com/redis/redis/actions/runs/7704158180/job/20995931735
```
*** [err]: expire scan should skip dictionaries with lot's of empty buckets in tests/unit/expire.tcl
scan didn't handle slot skipping logic.
*** [err]: Redis can trigger resizing in tests/unit/other.tcl
Expected '[Dictionary HT]
Hash table 0 stats (main hash table):
table size: 128
number of elements: 5
[Expires HT]
Hash table 0 stats (main hash table):
No stats available for empty dictionaries
' to match '*table size: 8*' (context: type eval line 29 cmd {assert_match "*table size: 8*" [r debug HTSTATS 0]} proc ::test)
*** [err]: Redis can rewind and trigger smaller slot resizing in tests/unit/other.tcl
Expected '[Dictionary HT]
Hash table 0 stats (main hash table):
table size: 256
number of elements: 10
[Expires HT]
Hash table 0 stats (main hash table):
No stats available for empty dictionaries
' to match '*table size: 16*' (context: type eval line 27 cmd {assert_match "*table size: 16*" [r debug HTSTATS 0]} proc ::test)
```
In #11012, we will reprocess command when client is unblocked on keys,
in some blocking commands, for example, in the XREADGROUP BLOCK
scenario,
because of the re-processing command, we will recalculate the block
timeout,
causing the blocking time to be reset.
This commit add a new CLIENT_REPROCESSING_COMMAND clent flag, explicitly
let the command know that it is being re-processed, later in
blockForKeys
we will not reset the timeout.
Affected BLOCK cases:
- list / zset / stream, added test cases for each.
Unaffected cases:
- module (never re-process the commands).
- WAIT / WAITAOF (never re-process the commands).
Fixes#12998.
The function `tryResizeHashTables` only attempts to shrink the dicts
that has keys (change from #11695), this was a serious problem until the
change in #12850 since it meant if all keys are deleted, we won't shrink
the dick.
But still, both dictShrink and dictExpand may be blocked by a fork child
process, therefore, the cron job needs to perform both dictShrink and
dictExpand, for not just non-empty dicts, but all dicts in DBs.
What this PR does:
1. Try to resize all dicts in DBs (not just non-empty ones, as it was
since #12850)
2. handle both shrink and expand (not just shrink, as it was since
forever)
3. Refactor some APIs about dict resizing (get rid of `htNeedsShrink`
`htNeedsShrink` `dictShrinkToFit`, and expose `dictShrinkIfNeeded`
`dictExpandIfNeeded` which already contains all the code of those
functions we get rid of, to make APIs more neat)
4. In the `Don't rehash if redis has child process` test, now that cron
would do resizing, we no longer need to write to DB after the child
process got killed, and can wait for the cron to expand the hash table.
Modules may want to handle allocation failures gracefully. Adding
RM_TryCalloc() and RM_TryRealloc() for it.
RM_TryAlloc() was added before:
https://github.com/redis/redis/pull/10541
#### Problem Statement:
For any read/update operation during rehashing, we're doing ~10+ random
DRAM lookups to do the rehashing, as we are using the `rehashidx` to
rehash 10 buckets, whose dict entries most likely aren't cached in the
CPU or near the bucket we are operating on. If these random bucket are
empty, the rehashing process during that command execution is skipped.
#### Implementation:
For reducing the performance recession while dict is rehashing, we
determine the index at which the key would be stored in the 0th HT, we
check if that index has already been rehashed, if not we will rehash the
bucket containing the key and the bucket will be moved from 0th HT to
the 1st HT.
If the key has already been rehashed, we perform the random access
bucket rehash (using `rehashidx`) and we again verify if rehashing is
still ongoing and look up the key in the respective HT.
This ensures rehashing is not skipped in any command call and that we
rehash a particular bucket or random bucket in each call.
#### Changes in this PR:
- Added a new method `dictBucketRehash` to perform rehash on a single
bucket.
- Helper function `moveKeysInBucketOldtoNew` for `dictRehash` and
`dictBucketRehash` to move all the keys in a bucket from the old to the
new hash HT.
- Helper function `verifyMoreRehashRequired` for `dictRehash` and
`dictBucketRehash` to check if we have already rehashed the whole table
and if more rehashing is required.
### Benchmark:
- This PR still shows **~13%** improvement in the latency during
rehashing.
- Rehashing is now **~2%** faster for this PR when compared to unstable.
---------
Co-authored-by: Oran Agra <oran@redislabs.com>
Co-authored-by: Madelyn Olson <34459052+madolson@users.noreply.github.com>
We have test cases for incr related commands with no key exist and
spaces in key and wrong type of key. However, we dont have test cases
covered for INCRBY INCRBYFLOAT DECRBY INCR DECR HINCRBY HINCRBYFLOAT
ZINCRBY with valid key and invalid value as argument, and float value to
incrby and decrby. So added test cases for the scenarios in incr.tcl.
Thank you!
In #11568 we removed the NOSCRIPT flag from commands, e.g. removing
NOSCRIPT flag from WAIT. Aiming to allow them in scripts and let them
implicitly behave in the non-blocking way.
This PR remove NOSCRIPT flag from WAITAOF just like WAIT (to be
symmetrical)).
And this PR also add BLOCKING flag for WAIT and WAITAOF.
This PR did some cleanups around function:
- drop the comment about Libraries Ctx, since we do have comment
in functionsLibCtx, no need to maintain multiple copies.
- remove outdated comment about the dropped Library description.
- remove unused desc and code vars in functionExtractLibMetaData.
- fix engines_nemory typo, changed it to engines_memory.
- remove outdated comment about FUNCTION CREATE and FUNCTION INFO,
FUNCTION CREATE was renamed to FUNCTION LOAD.
- Check in initServer whether the return of functionsInit is OK.
