Let user set how many nodes to *not* compress.
We can specify a compression "depth" of how many nodes
to leave uncompressed on each end of the quicklist.
Depth 0 = disable compression.
Depth 1 = only leave head/tail uncompressed.
- (read as: "skip 1 node on each end of the list before compressing")
Depth 2 = leave head, head->next, tail->prev, tail uncompressed.
- ("skip 2 nodes on each end of the list before compressing")
Depth 3 = Depth 2 + head->next->next + tail->prev->prev
- ("skip 3 nodes...")
etc.
This also:
- updates RDB storage to use native quicklist compression (if node is
already compressed) instead of uncompressing, generating the RDB string,
then re-compressing the quicklist node.
- internalizes the "fill" parameter for the quicklist so we don't
need to pass it to _every_ function. Now it's just a property of
the list.
- allows a runtime-configurable compression option, so we can
expose a compresion parameter in the configuration file if people
want to trade slight request-per-second performance for up to 90%+
memory savings in some situations.
- updates the quicklist tests to do multiple passes: 200k+ tests now.
Added field 'ql_nodes' and 'ql_avg_per_node'.
ql_nodes is the number of quicklist nodes in the quicklist.
ql_avg_node is the average fill level in each quicklist node. (LLEN / QL_NODES)
Sample output:
127.0.0.1:6379> DEBUG object b
Value at:0x7fa42bf2fed0 refcount:1 encoding:quicklist serializedlength:18489 lru:8983768 lru_seconds_idle:3 ql_nodes:430 ql_avg_per_node:511.73
127.0.0.1:6379> llen b
(integer) 220044
Previously, the old test ran 5,000 loops and used about 500k.
With quicklist, storing those same 5,000 loops takes up 24k, so the
"large value check" failed!
This increases the test to 20,000 loops which makes the object dump 96k.
Turns out it's a huge improvement during save/reload/migrate/restore
because, with compression enabled, we're compressing 4k or 8k
chunks of data consisting of multiple elements in one ziplist
instead of compressing series of smaller individual elements.
Use the existing memory space for an SDS to convert it to a regular
character buffer so we don't need to allocate duplicate space just
to extract a usable buffer for native operations.
Fill factor now has two options:
- negative (1-5) for size-based ziplist filling
- positive for length-based ziplist filling with implicit size cap.
Negative offsets define ziplist size limits of:
-1: 4k
-2: 8k
-3: 16k
-4: 32k
-5: 64k
Positive offsets now automatically limit their max size to 8k. Any
elements larger than 8k will be in individual nodes.
Positive ziplist fill factors will keep adding elements
to a ziplist until one of:
- ziplist has FILL number of elements
- or -
- ziplist grows above our ziplist max size (currently 8k)
When using positive fill factors, if you insert a large
element (over 8k), that element will automatically allocate
an individual quicklist node with one element and no other elements will be
in the same ziplist inside that quicklist node.
When using negative fill factors, elements up to the size
limit can be added to one quicklist node. If an element
is added larger than the max ziplist size, that element
will be allocated an individual ziplist in a new quicklist node.
Tests also updated to start testing at fill factor -5.
This started out as #2158 by sunheehnus, but I kept rewriting it
until I could understand things more easily and get a few more
correctness guarantees out of the readability flow.
The original commit created and returned a new ziplist with the contents of
both input ziplists, but I prefer to grow one of the input ziplists
and destroy the other one.
So, instead of malloc+copy as in #2158, the merge now reallocs one of
the existing ziplists and copies the other ziplist into the new space.
Also added merge test cases to ziplistTest()
This replaces individual ziplist vs. linkedlist representations
for Redis list operations.
Big thanks for all the reviews and feedback from everybody in
https://github.com/antirez/redis/pull/2143
The previous test wasn't returning the new ziplist, so the test
was invalid. Now the test works properly.
These problems were simultaenously discovered in #2154 and that
PR also had an additional fix we included here.
zipEntry was returning a struct, but that caused some
problems with tests under 32 bit builds.
The tests run better if we operate on structs allocated in the
caller without worrying about copying on return.
Previously, many files had individual main() functions for testing,
but each required being compiled with their own testing flags.
That gets difficult when you have 8 different flags you need
to set just to run all tests (plus, some test files required
other files to be compiled aaginst them, and it seems some didn't
build at all without including the rest of Redis).
Now all individual test main() funcions are renamed to a test
function for the file itself and one global REDIS_TEST define enables
testing across the entire codebase.
Tests can now be run with:
- `./redis-server test <test>`
e.g. ./redis-server test ziplist
If REDIS_TEST is not defined, then no tests get included and no
tests are included in the final redis-server binary.
1. Server unxtime may remain not updated while loading AOF, so ETA is
not updated correctly.
2. Number of processed byte was not initialized.
3. Possible division by zero condition (likely cause of issue #1932).
1. memory leak in t_set.c has been fixed
2. end-of-line spaces has been removed (from all over the place)
3. for loops have been ordered up to match existing Redis style (less weird)
4. comments format has been fixed (added * in the beggining of every comment line)
setTypeRandomElements() now returns unsigned long, and also uses unsigned long for anything related to count of members.
spopWithCountCommand() now uses unsigned long elements_returned instead of int, for values returned from setTypeRandomElements()
If we woke up to accept a connection, but we can't
accept it, inform the user of the error going on
with their networking.
(The previous message was the same for success or error!)
spopCommand() now runs spopWithCountCommand() in case the <count> param is found.
Added intsetRandomMembers() to Intset: Copies N random members from the set into inputted 'values' array. Uses either the Knuth or Floyd sample algos depending on ratio count/size.
Added setTypeRandomElements() to SET type: Returns a number of random elements from a non empty set. This is a version of setTypeRandomElement() that is modified in order to return multiple entries, using dictGetRandomKeys() and intsetRandomMembers().
Added tests for SPOP with <count>: unit/type/set, unit/scripting, integration/aof
--
Cleaned up code a bit to match with required Redis coding style
Otherwise there are security risks, especially when providing Redis as a
service, the user may "sniff" for admin commands renamed to an
unguessable string via rename-command in redis.conf.
