- 21 Jul, 2016 3 commits
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antirez authored
This patch, written in collaboration with Oran Agra (@oranagra) is a companion to 780a8b1d. 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.
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antirez authored
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.
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antirez authored
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- 20 Jul, 2016 3 commits
- 18 Jul, 2016 5 commits
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antirez authored
Verified to have better real world performances with power-law access patterns because of the data accumulated across calls.
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antirez authored
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antirez authored
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.
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antirez authored
This way it is possible from an observer to tell when the key is replaced with a new one having the same name.
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antirez authored
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- 15 Jul, 2016 1 commit
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antirez authored
Implementation of LFU maxmemory policy for anything related to Redis objects. Still no actual eviction implemented.
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- 14 Jul, 2016 4 commits
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antirez authored
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antirez authored
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antirez authored
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antirez authored
We have 24 total bits of space in each object in order to implement an LFU (Least Frequently Used) eviction policy. We split the 24 bits into two fields: 8 bits 16 bits +--------+----------------+ | LOG_C | Last decr time | +--------+----------------+ LOG_C is a logarithmic counter that provides an indication of the access frequency. However this field must also be deceremented otherwise what used to be a frequently accessed key in the past, will remain ranked like that forever, while we want the algorithm to adapt to access pattern changes. So the remaining 16 bits are used in order to store the "decrement time", a reduced-precision unix time (we take 16 bits of the time converted in minutes since we don't care about wrapping around) where the LOG_C counter is halved if it has an high value, or just decremented if it has a low value. New keys don't start at zero, in order to have the ability to collect some accesses before being trashed away, so they start at COUNTER_INIT_VAL. The logaritmic increment performed on LOG_C takes care of COUNTER_INIT_VAL when incrementing the key, so that keys starting at COUNTER_INIT_VAL (or having a smaller value) have a very high chance of being incremented on access. The simulation starts with a power-law access pattern, and later converts into a flat access pattern in order to see how the algorithm adapts. Currenty the decrement operation period is 1 minute, however note that it is not guaranteed that each key will be scanned 1 time every minute, so the actual frequency can be lower. However under high load, we access 3/5 keys every newly inserted key (because of how Redis eviction works). This is a work in progress at this point to evaluate if this works well.
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- 13 Jul, 2016 1 commit
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antirez authored
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.
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- 12 Jul, 2016 5 commits
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antirez authored
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.
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antirez authored
Local scope is always better when possible.
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antirez authored
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antirez authored
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antirez authored
Disabled by default, can be activated with -e. Maybe the reverse was more safe but departs from the past behavior.
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- 11 Jul, 2016 4 commits
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antirez authored
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.
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antirez authored
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antirez authored
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antirez authored
1. Scan keys with pause to account for actual LRU precision. 2. Test cross-DB with 100 keys allocated in DB1. 3. Output results that don't fluctuate depending on number of keys. 4. Output results in percentage to make more sense. 5. Save file instead of outputting to STDOUT. 6. Support running multiple times with average of outputs. 7. Label each square (DIV) with its ID as HTML title.
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- 06 Jul, 2016 13 commits
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antirez authored
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.
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antirez authored
Otherwise Valgrind will complain a memory leak under certain tests where RDB checking is invoked from within Redis.
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antirez authored
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antirez authored
The function removed also had potential bugs related to signess of the expression, and is not used anyway.
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antirez authored
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antirez authored
Without the right feature macros M_PI is not defined in math.h.
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antirez authored
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.
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antirez authored
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antirez authored
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antirez authored
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antirez authored
Normally we used to update it from time to time. Too fragile... better to generate dependencies at every run and delete them on 'make clean'.
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antirez authored
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antirez authored
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.
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- 05 Jul, 2016 1 commit
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antirez authored
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.
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