Some times it was not released on error, sometimes it was released two
times because the error path expected the "di" var to be NULL if the
iterator was already released. Thanks to @oranagra for pinging me about
potential problems of this kind inside rdb.c.
Some times it was not released on error, sometimes it was released two
times because the error path expected the "di" var to be NULL if the
iterator was already released. Thanks to @oranagra for pinging me about
potential problems of this kind inside rdb.c.
This is a big win for caching use cases, since on reloading Redis will
still have some idea about what is worth to evict and what not.
However this only solves part of the problem because the information is
only partially propagated to slaves (on write operations). Reads will
not affect slaves LFU and LRU counters, so after a failover the eviction
decisions are kinda random until keys start to collect some aging/freq info.
However since new slaves are initially populated via RDB file transfer,
this means that if we spin up a new slave from a master, and perform an
immediate manual failover (for instance in order to upgrade the master),
the slave will have eviction informations to use for some time.
The LFU/LRU info is persisted only if the maxmemory policy is set to one
of the relevant type, even if no actual "maxmemory" memory limit is
set.
This is a big win for caching use cases, since on reloading Redis will
still have some idea about what is worth to evict and what not.
However this only solves part of the problem because the information is
only partially propagated to slaves (on write operations). Reads will
not affect slaves LFU and LRU counters, so after a failover the eviction
decisions are kinda random until keys start to collect some aging/freq info.
However since new slaves are initially populated via RDB file transfer,
this means that if we spin up a new slave from a master, and perform an
immediate manual failover (for instance in order to upgrade the master),
the slave will have eviction informations to use for some time.
The LFU/LRU info is persisted only if the maxmemory policy is set to one
of the relevant type, even if no actual "maxmemory" memory limit is
set.
- protocol parsing (processMultibulkBuffer) was limitted to 32big positions in the buffer
readQueryFromClient potential overflow
- rioWriteBulkCount used int, although rioWriteBulkString gave it size_t
- several places in sds.c that used int for string length or index.
- bugfix in RM_SaveAuxField (return was 1 or -1 and not length)
- RM_SaveStringBuffer was limitted to 32bit length
- protocol parsing (processMultibulkBuffer) was limitted to 32big positions in the buffer
readQueryFromClient potential overflow
- rioWriteBulkCount used int, although rioWriteBulkString gave it size_t
- several places in sds.c that used int for string length or index.
- bugfix in RM_SaveAuxField (return was 1 or -1 and not length)
- RM_SaveStringBuffer was limitted to 32bit length
The function in its initial form, and after the fixes for the PSYNC2
bugs, required code duplication in multiple spots. This commit modifies
it in order to always compute the script name independently, and to
return the SDS of the SHA of the body: this way it can be used in all
the places, including for SCRIPT LOAD, without duplicating the code to
create the Lua function name. Note that this requires to re-compute the
body SHA1 in the case of EVAL seeing a script for the first time, but
this should not change scripting performance in any way because new
scripts definition is a rare event happening the first time a script is
seen, and the SHA1 computation is anyway not a very slow process against
the typical Redis script and compared to the actua Lua byte compiling of
the body.
Note that the function used to assert() if a duplicated script was
loaded, however actually now two times over three, we want the function
to handle duplicated scripts just fine: this happens in SCRIPT LOAD and
in RDB AUX "lua" loading. Moreover the assert was not defending against
some obvious failure mode, so now the function always tests against
already defined functions at start.
The function in its initial form, and after the fixes for the PSYNC2
bugs, required code duplication in multiple spots. This commit modifies
it in order to always compute the script name independently, and to
return the SDS of the SHA of the body: this way it can be used in all
the places, including for SCRIPT LOAD, without duplicating the code to
create the Lua function name. Note that this requires to re-compute the
body SHA1 in the case of EVAL seeing a script for the first time, but
this should not change scripting performance in any way because new
scripts definition is a rare event happening the first time a script is
seen, and the SHA1 computation is anyway not a very slow process against
the typical Redis script and compared to the actua Lua byte compiling of
the body.
Note that the function used to assert() if a duplicated script was
loaded, however actually now two times over three, we want the function
to handle duplicated scripts just fine: this happens in SCRIPT LOAD and
in RDB AUX "lua" loading. Moreover the assert was not defending against
some obvious failure mode, so now the function always tests against
already defined functions at start.
In the case of slaves loading the RDB from master, or in other similar
cases, the script is already defined, and the function registering the
script should not fail in the assert() call.
In the case of slaves loading the RDB from master, or in other similar
cases, the script is already defined, and the function registering the
script should not fail in the assert() call.
We used to have the master ID stored at the start of the listpack,
however using the key directly makes more sense in order to create a
space efficient representation: anyway the key at the radix tree is very
unlikely to change because of how the stream is implemented. Moreover on
nodes merging, to rewrite the merged listpacks is anyway the most
sensible operation, and we can use the iterator and the append-to-stream
function in order to avoid re-implementing the code needed for merging.
This commit also adds two items at the start of the listpack: the
number of valid items inside the listpack, and the number of items
marked as deleted. This means that there is no need to scan a listpack
in order to understand if it's a good candidate for garbage collection,
if the ration between valid/deleted items triggers the GC.
We used to have the master ID stored at the start of the listpack,
however using the key directly makes more sense in order to create a
space efficient representation: anyway the key at the radix tree is very
unlikely to change because of how the stream is implemented. Moreover on
nodes merging, to rewrite the merged listpacks is anyway the most
sensible operation, and we can use the iterator and the append-to-stream
function in order to avoid re-implementing the code needed for merging.
This commit also adds two items at the start of the listpack: the
number of valid items inside the listpack, and the number of items
marked as deleted. This means that there is no need to scan a listpack
in order to understand if it's a good candidate for garbage collection,
if the ration between valid/deleted items triggers the GC.
After a few attempts it looked quite saner to just add the last item ID
at the end of the serialized listpacks, instead of scanning the last
listpack loaded from head to tail just to fetch it. It's a disk space VS
CPU-and-simplicity tradeoff basically.
After a few attempts it looked quite saner to just add the last item ID
at the end of the serialized listpacks, instead of scanning the last
listpack loaded from head to tail just to fetch it. It's a disk space VS
CPU-and-simplicity tradeoff basically.
