This is important both to reset the magic to 0, so that it will not
match if the structure is not explicitly set, and to initialize other
things we may add like counters and such.
The size of the node depends on the node level, however it is not stored
into the node itself, is an implicit information, so we use
zmalloc_size() in order to compute the sorted set size.
The new SAMPLES option is added, defaulting to 5, and with 0 being a
special value to scan the whole set of elements.
Fixes to the object size computation were made since the original PR
assumed data structures still contaning robj structures, while now after
the lazyfree changes, are all SDS strings.
Notes by @antirez:
This patch was picked from a larger commit by Oran and adapted to change
the API a bit. The basic idea is to avoid double lookups when there is
to use the value of the deleted entry.
BEFORE:
entry = dictFind( ... ); /* 1st lookup. */
/* Do somethjing with the entry. */
dictDelete(...); /* 2nd lookup. */
AFTER:
entry = dictUnlink( ... ); /* 1st lookup. */
/* Do somethjing with the entry. */
dictFreeUnlinkedEntry(entry); /* No lookups!. */
This code was extracted from @oranagra PR #3223 and modified in order
to provide only certain amounts of information compared to the original
code. It was also moved from DEBUG to the newly introduced MEMORY
command. Thanks to Oran for the implementation and the PR.
It implements detailed memory usage stats that can be useful in both
provisioning and troubleshooting memory usage in Redis.
For most tasks, we need the memory estimation to be O(1) by default.
This commit also implements an initial MEMORY command.
Note that objectComputeSize() takes the number of samples to check as
argument, so MEMORY should be able to get the sample size as option
to make precision VS CPU tradeoff tunable.
Related to: PR #3223.
Technically as soon as Redis 64 bit gets proper support for loading
collections and/or DBs with more than 2^32 elements, the 32 bit version
should be modified in order to check if what we read from rdbLoadLen()
overflows. This would only apply to huge RDB files created with a 64 bit
instance and later loaded into a 32 bit instance.
This is an attempt at mitigating problems due to cross protocol
scripting, an attack targeting services using line oriented protocols
like Redis that can accept HTTP requests as valid protocol, by
discarding the invalid parts and accepting the payloads sent, for
example, via a POST request.
For this to be effective, when we detect POST and Host: and terminate
the connection asynchronously, the networking code was modified in order
to never process further input. It was later verified that in a
pipelined request containing a POST command, the successive commands are
not executed.
RedisModule_StringRetain() allows, when automatic memory management is
on, to keep string objects living after the callback returns. Can also
be used in order to use Redis reference counting of objects inside
modules.
The reason why this is useful is that sometimes when implementing new
data types we want to reference RedisModuleString objects inside the
module private data structures, so those string objects must be valid
after the callback returns even if not referenced inside the Redis key
space.
This feature is useful, especially in deployments using Sentinel in
order to setup Redis HA, where the slave is executed with NAT or port
forwarding, so that the auto-detected port/ip addresses, as listed in
the "INFO replication" output of the master, or as provided by the
"ROLE" command, don't match the real addresses at which the slave is
reachable for connections.
By grepping the continuous integration errors log a number of GEORADIUS
tests failures were detected.
Fortunately when a GEORADIUS failure happens, the test suite logs enough
information in order to reproduce the problem: the PRNG seed,
coordinates and radius of the query.
By reproducing the issues, three different bugs were discovered and
fixed in this commit. This commit also improves the already good
reporting of the fuzzer and adds the failure vectors as regression
tests.
The issues found:
1. We need larger squares around the poles in order to cover the area
requested by the user. There were already checks in order to use a
smaller step (larger squares) but the limit set (+/- 67 degrees) is not
enough in certain edge cases, so 66 is used now.
2. Even near the equator, when the search area center is very near the
edge of the square, the north, south, west or ovest square may not be
able to fully cover the specified radius. Now a test is performed at the
edge of the initial guessed search area, and larger squares are used in
case the test fails.
3. Because of rounding errors between Redis and Tcl, sometimes the test
signaled false positives. This is now addressed.
Whenever possible the original code was improved a bit in other ways. A
debugging example stanza was added in order to make the next debugging
session simpler when the next bug is found.
In a previous commit the replication code was changed in order to
centralize the BGSAVE for replication trigger in replicationCron(),
however after further testings, the 1 second delay imposed by this
change is not acceptable.
So now the BGSAVE is only delayed if the AOF rewriting process is
active. However past comments made sure that replicationCron() is always
able to trigger the BGSAVE when needed, making the code generally more
robust.
The new code is more similar to the initial @oranagra patch where the
BGSAVE was delayed only if an AOF rewrite was in progress.
Trivia: delaying the BGSAVE uncovered a minor Sentinel issue that is now
fixed.
During the initial handshake with the master a slave will report to have
a very high disconnection time from its master (since technically it was
disconnected since forever, so the current UNIX time in seconds is
reported).
However when the slave is connected again the Sentinel may re-scan the
INFO output again only after 10 seconds, which is a long time. During
this time Sentinels will consider this instance unable to failover, so
a useless delay is introduced.
Actaully this hardly happened in the practice because when a slave's
master is down, the INFO period for slaves changes to 1 second. However
when a manual failover is attempted immediately after adding slaves
(like in the case of the Sentinel unit test), this problem may happen.
This commit changes the INFO period to 1 second even in the case the
slave's master is not down, but the slave reported to be disconnected
from the master (by publishing, last time we checked, a master
disconnection time field in INFO).
This change is required as a result of an unrelated change in the
replication code that adds a small delay in the master-slave first
synchronization.
This patch, written in collaboration with Oran Agra (@oranagra) is a companion
to 780a8b1. Together the two patches should avoid that the AOF and RDB saving
processes can be spawned at the same time. Previously conditions that
could lead to two saving processes at the same time were:
1. When AOF is enabled via CONFIG SET and an RDB saving process is
already active.
2. When the SYNC command decides to start an RDB saving process ASAP in
order to serve a new slave that cannot partially resynchronize (but
only if we have a disk target for replication, for diskless
replication there is not such a problem).
Condition "1" is not very severe but "2" can happen often and is
definitely good at degrading Redis performances in an unexpected way.
The two commits have the effect of always spawning RDB savings for
replication in replicationCron() instead of attempting to start an RDB
save synchronously. Moreover when a BGSAVE or AOF rewrite must be
performed, they are instead just postponed using flags that will try to
perform such operations ASAP.
Finally the BGSAVE command was modified in order to accept a SCHEDULE
option so that if an AOF rewrite is in progress, when this option is
given, the command no longer returns an error, but instead schedules an
RDB rewrite operation for when it will be possible to start it.
This makes the replication code conceptually simpler by removing the
synchronous BGSAVE trigger in syncCommand(). This also means that
socket and disk BGSAVE targets are handled by the same code.
It is possible to get better results by using the pool like in the LRU
case. Also from tests during the morning I believe the current
implementation has issues in the frequency decay function that should
decrease the counter at periodic intervals.
The LRU eviction code used to make local choices: for each DB visited it
selected the best key to evict. This was repeated for each DB. However
this means that there could be DBs with very frequently accessed keys
that are targeted by the LRU algorithm while there were other DBs with
many better candidates to expire.
This commit attempts to fix this problem for the LRU policy. However the
TTL policy is still not fixed by this commit. The TTL policy will be
fixed in a successive commit.
This is an initial (partial because of TTL policy) fix for issue #2647.
To destroy and recreate the pool[].key element is slow, so we allocate
in pool[].cached SDS strings that can account up to 255 chars keys and
try to reuse them. This provides a solid 20% performance improvement
in real world workload alike benchmarks.
We start from the end of the pool to the initial item, zero-ing
every entry we use or every ghost entry, there is nothing to memmove
since to the right everything should be already set to NULL.
The rio structure is referenced in the global 'riostate' structure
in order for the logging functions to be always able to access the state
of the "pseudo-loading" of the RDB, needed for the check.
Courtesy of Valgrind.
They were under /deps since they originate from a different source tree,
however at this point they are very modified and we took ownership of
both the files making changes, fixing bugs, so there is no upgrade path
from the original code tree.
Given that, better to move the code under /src with proper dependencies
and with a more simpler editing experience.
strict_strtoll() has a bug that reports the empty string as ok and
parses it as zero.
Apparently nobody ever replaced this old call with the faster/saner
string2ll() which is used otherwise in the rest of the Redis core.
This commit close#3333.
In issues #3361 / #3365 a problem was reported / fixed with redis-cli
not updating correctly the current DB on error after SELECT.
In theory this bug was fixed in 0042fb0e, but actually the commit only
fixed the prompt updating, not the fact the state was set in a wrong
way.
This commit removes the check in the prompt update, now that hopefully
it is the state that is correct, there is no longer need for this check.
This commit both fixes the crash reported with issue #3364 and
also properly closes the old links after the Sentinel address for the
other masters gets updated.
The two problems where:
1. The Sentinel that switched address may not monitor all the masters,
it is possible that there is no match, and the 'match' variable is
NULL. Now we check for no match and 'continue' to the next master.
2. By ispecting the code because of issue "1" I noticed that there was a
problem in the code that disconnects the link of the Sentinel that
needs the address update. Basically link->disconnected is non-zero
even if just *a single link* (cc -- command link or pc -- pubsub
link) are disconnected, so to check with if (link->disconnected)
in order to close the links risks to leave one link connected.
I was able to manually reproduce the crash at "1" and verify that the
commit resolves the issue.
Close#3364.
