27381 Commits

Author SHA1 Message Date
Dvir Volk
ec8fd6e5e4 fixed sizeof in allocating io RedisModuleCtx* 2016-10-31 18:48:16 +02:00
Dvir Volk
3b7e7aa13b fixed sizeof in allocating io RedisModuleCtx* 2016-10-31 18:48:16 +02:00
antirez
9481b398e9 Test: regression test for #3564 added. 2016-10-31 15:46:58 +01:00
antirez
9749e96f42 Test: regression test for #3564 added. 2016-10-31 15:46:58 +01:00
antirez
47396311df Test: regression test for #3564 added. 2016-10-31 15:46:58 +01:00
Salvatore Sanfilippo
cb0beafe75 Merge pull request #3565 from sunheehnus/bitfield-fix-highest_write_offset
bitops.c/bitfieldCommand: update higest_write_offset with check
2016-10-31 15:40:46 +01:00
Salvatore Sanfilippo
77b1abf185 Merge pull request #3565 from sunheehnus/bitfield-fix-highest_write_offset
bitops.c/bitfieldCommand: update higest_write_offset with check
2016-10-31 15:40:46 +01:00
Salvatore Sanfilippo
97c0733917 Merge pull request #3565 from sunheehnus/bitfield-fix-highest_write_offset
bitops.c/bitfieldCommand: update higest_write_offset with check
2016-10-31 15:40:46 +01:00
Salvatore Sanfilippo
b0e41203bd Merge pull request #3573 from jybaek/module-io-context
Add missing fclose()
2016-10-31 15:36:38 +01:00
Salvatore Sanfilippo
f48ca5581e Merge pull request #3573 from jybaek/module-io-context
Add missing fclose()
2016-10-31 15:36:38 +01:00
Salvatore Sanfilippo
84c9cbea61 Merge pull request #3573 from jybaek/module-io-context
Add missing fclose()
2016-10-31 15:36:38 +01:00
Salvatore Sanfilippo
24f6137332 Merge pull request #3579 from guybe7/unstable
Fixed wrong sizeof(client) in object.c
2016-10-31 15:34:16 +01:00
Salvatore Sanfilippo
fbfa0a12ee Merge pull request #3579 from guybe7/unstable
Fixed wrong sizeof(client) in object.c
2016-10-31 15:34:16 +01:00
Salvatore Sanfilippo
958465f0b3 Merge pull request #3579 from guybe7/unstable
Fixed wrong sizeof(client) in object.c
2016-10-31 15:34:16 +01:00
Guy Benoish
7145d161a0 Fixed wrong sizeof(client) in object.c 2016-10-31 15:08:17 +02:00
Guy Benoish
8b070b5d12 Fixed wrong sizeof(client) in object.c 2016-10-31 15:08:17 +02:00
Guy Benoish
7365268efa Fixed wrong sizeof(client) in object.c 2016-10-31 15:08:17 +02:00
deep
40282ba22d fix a bug for quicklistDup() function 2016-10-28 19:47:29 +08:00
deep
7f1bb22ef3 fix a bug for quicklistDup() function 2016-10-28 19:47:29 +08:00
deep
4504493445 fix a bug for quicklistDup() function 2016-10-28 19:47:29 +08:00
jybaek
55642839f0 Add missing fclose() 2016-10-28 10:42:54 +09:00
jybaek
a06d59b583 Add missing fclose() 2016-10-28 10:42:54 +09:00
jybaek
2025738ce2 Add missing fclose() 2016-10-28 10:42:54 +09:00
Michel Tresseras
f5e79864b6 Typo 2016-10-24 17:27:48 +02:00
Michel Tresseras
20feafda09 Typo 2016-10-24 17:27:48 +02:00
Michel Tresseras
c9ffc440c8 Typo 2016-10-24 17:27:48 +02:00
sunhe
c7fc514f03 bitops.c/bitfieldCommand: update higest_write_offset with check 2016-10-22 01:54:46 +08:00
sunhe
949a274817 bitops.c/bitfieldCommand: update higest_write_offset with check 2016-10-22 01:54:46 +08:00
sunhe
0ab42c2c00 bitops.c/bitfieldCommand: update higest_write_offset with check 2016-10-22 01:54:46 +08:00
antirez
3d406f151d Remove "Hey!" warning... 2016-10-19 10:43:40 +02:00
antirez
f39e7d4d7e Remove "Hey!" warning... 2016-10-19 10:43:40 +02:00
antirez
f487fca502 Remove "Hey!" warning... 2016-10-19 10:43:40 +02:00
antirez
78495fefde Better target MacOS on __atomic macros conditional compilation. 2016-10-17 16:41:39 +02:00
antirez
a9f50a389b Better target MacOS on __atomic macros conditional compilation. 2016-10-17 16:41:39 +02:00
antirez
0a051ea1c1 Better target MacOS on __atomic macros conditional compilation. 2016-10-17 16:41:39 +02:00
Salvatore Sanfilippo
a1cd0c42c3 Merge pull request #3560 from melo/fix-macos-10-8-compile
Fixes compilation on MacOS 10.8.5, Clang tags/Apple/clang-421.0.57
2016-10-17 16:11:00 +02:00
Salvatore Sanfilippo
ea95262d8d Merge pull request #3560 from melo/fix-macos-10-8-compile
Fixes compilation on MacOS 10.8.5, Clang tags/Apple/clang-421.0.57
2016-10-17 16:11:00 +02:00
Salvatore Sanfilippo
ef45eeea0d Merge pull request #3560 from melo/fix-macos-10-8-compile
Fixes compilation on MacOS 10.8.5, Clang tags/Apple/clang-421.0.57
2016-10-17 16:11:00 +02:00
Pedro Melo
180574ebeb Fixes compilation on MacOS 10.8.5, Clang tags/Apple/clang-421.0.57
Redis fails to compile on MacOS 10.8.5 with Clang 4, version 421.0.57
(based on LLVM 3.1svn).

When compiling zmalloc.c, we get these warnings:

        CC zmalloc.o
    zmalloc.c:109:5: warning: implicit declaration of function '__atomic_add_fetch' is invalid in C99 [-Wimplicit-function-declaration]
        update_zmalloc_stat_alloc(zmalloc_size(ptr));
        ^
    zmalloc.c:75:9: note: expanded from macro 'update_zmalloc_stat_alloc'
            atomicIncr(used_memory,__n,used_memory_mutex); \
            ^
    ./atomicvar.h:57:37: note: expanded from macro 'atomicIncr'
    #define atomicIncr(var,count,mutex) __atomic_add_fetch(&var,(count),__ATOMIC_RELAXED)
                                        ^
    zmalloc.c:145:5: warning: implicit declaration of function '__atomic_sub_fetch' is invalid in C99 [-Wimplicit-function-declaration]
        update_zmalloc_stat_free(oldsize);
        ^
    zmalloc.c:85:9: note: expanded from macro 'update_zmalloc_stat_free'
            atomicDecr(used_memory,__n,used_memory_mutex); \
            ^
    ./atomicvar.h:58:37: note: expanded from macro 'atomicDecr'
    #define atomicDecr(var,count,mutex) __atomic_sub_fetch(&var,(count),__ATOMIC_RELAXED)
                                        ^
    zmalloc.c:205:9: warning: implicit declaration of function '__atomic_load_n' is invalid in C99 [-Wimplicit-function-declaration]
            atomicGet(used_memory,um,used_memory_mutex);
            ^
    ./atomicvar.h:60:14: note: expanded from macro 'atomicGet'
        dstvar = __atomic_load_n(&var,__ATOMIC_RELAXED); \
                 ^
    3 warnings generated.

Also on lazyfree.c:

        CC lazyfree.o
    lazyfree.c:68:13: warning: implicit declaration of function '__atomic_add_fetch' is invalid in C99 [-Wimplicit-function-declaration]
                atomicIncr(lazyfree_objects,1,lazyfree_objects_mutex);
                ^
    ./atomicvar.h:57:37: note: expanded from macro 'atomicIncr'
    #define atomicIncr(var,count,mutex) __atomic_add_fetch(&var,(count),__ATOMIC_RELAXED)
                                        ^
    lazyfree.c:111:5: warning: implicit declaration of function '__atomic_sub_fetch' is invalid in C99 [-Wimplicit-function-declaration]
        atomicDecr(lazyfree_objects,1,lazyfree_objects_mutex);
        ^
    ./atomicvar.h:58:37: note: expanded from macro 'atomicDecr'
    #define atomicDecr(var,count,mutex) __atomic_sub_fetch(&var,(count),__ATOMIC_RELAXED)
                                        ^
    2 warnings generated.

Then in the linking stage:

        LINK redis-server
    Undefined symbols for architecture x86_64:
      "___atomic_add_fetch", referenced from:
          _zmalloc in zmalloc.o
          _zcalloc in zmalloc.o
          _zrealloc in zmalloc.o
          _dbAsyncDelete in lazyfree.o
          _emptyDbAsync in lazyfree.o
          _slotToKeyFlushAsync in lazyfree.o
      "___atomic_load_n", referenced from:
          _zmalloc_used_memory in zmalloc.o
          _zmalloc_get_fragmentation_ratio in zmalloc.o
      "___atomic_sub_fetch", referenced from:
          _zrealloc in zmalloc.o
          _zfree in zmalloc.o
          _lazyfreeFreeObjectFromBioThread in lazyfree.o
          _lazyfreeFreeDatabaseFromBioThread in lazyfree.o
          _lazyfreeFreeSlotsMapFromBioThread in lazyfree.o
    ld: symbol(s) not found for architecture x86_64
    clang: error: linker command failed with exit code 1 (use -v to see invocation)
    make[1]: *** [redis-server] Error 1
    make: *** [all] Error 2

With this patch, the compilation is sucessful, no warnings.

Running `make test` we get a almost clean bill of health. Test pass with
one exception:

    [err]: Check for memory leaks (pid 52793) in tests/unit/dump.tcl
    [err]: Check for memory leaks (pid 53103) in tests/unit/auth.tcl
    [err]: Check for memory leaks (pid 53117) in tests/unit/auth.tcl
    [err]: Check for memory leaks (pid 53131) in tests/unit/protocol.tcl
    [err]: Check for memory leaks (pid 53145) in tests/unit/protocol.tcl
    [ok]: Check for memory leaks (pid 53160)
    [err]: Check for memory leaks (pid 53175) in tests/unit/scan.tcl
    [ok]: Check for memory leaks (pid 53189)
    [err]: Check for memory leaks (pid 53221) in tests/unit/type/incr.tcl
    .
    .
    .

Full debug log (289MB, uncompressed) available at
https://dl.dropboxusercontent.com/u/75548/logs/redis-debug-log-macos-10.8.5.log.xz

Most if not all of the memory leak tests fail. Not sure if this is
related. They are the only ones that fail. I belive they are not related,
but just the memory leak detector is not working properly on 10.8.5.

Signed-off-by: Pedro Melo <melo@simplicidade.org>
2016-10-17 14:58:23 +01:00
Pedro Melo
2000abc86f Fixes compilation on MacOS 10.8.5, Clang tags/Apple/clang-421.0.57
Redis fails to compile on MacOS 10.8.5 with Clang 4, version 421.0.57
(based on LLVM 3.1svn).

When compiling zmalloc.c, we get these warnings:

        CC zmalloc.o
    zmalloc.c:109:5: warning: implicit declaration of function '__atomic_add_fetch' is invalid in C99 [-Wimplicit-function-declaration]
        update_zmalloc_stat_alloc(zmalloc_size(ptr));
        ^
    zmalloc.c:75:9: note: expanded from macro 'update_zmalloc_stat_alloc'
            atomicIncr(used_memory,__n,used_memory_mutex); \
            ^
    ./atomicvar.h:57:37: note: expanded from macro 'atomicIncr'
    #define atomicIncr(var,count,mutex) __atomic_add_fetch(&var,(count),__ATOMIC_RELAXED)
                                        ^
    zmalloc.c:145:5: warning: implicit declaration of function '__atomic_sub_fetch' is invalid in C99 [-Wimplicit-function-declaration]
        update_zmalloc_stat_free(oldsize);
        ^
    zmalloc.c:85:9: note: expanded from macro 'update_zmalloc_stat_free'
            atomicDecr(used_memory,__n,used_memory_mutex); \
            ^
    ./atomicvar.h:58:37: note: expanded from macro 'atomicDecr'
    #define atomicDecr(var,count,mutex) __atomic_sub_fetch(&var,(count),__ATOMIC_RELAXED)
                                        ^
    zmalloc.c:205:9: warning: implicit declaration of function '__atomic_load_n' is invalid in C99 [-Wimplicit-function-declaration]
            atomicGet(used_memory,um,used_memory_mutex);
            ^
    ./atomicvar.h:60:14: note: expanded from macro 'atomicGet'
        dstvar = __atomic_load_n(&var,__ATOMIC_RELAXED); \
                 ^
    3 warnings generated.

Also on lazyfree.c:

        CC lazyfree.o
    lazyfree.c:68:13: warning: implicit declaration of function '__atomic_add_fetch' is invalid in C99 [-Wimplicit-function-declaration]
                atomicIncr(lazyfree_objects,1,lazyfree_objects_mutex);
                ^
    ./atomicvar.h:57:37: note: expanded from macro 'atomicIncr'
    #define atomicIncr(var,count,mutex) __atomic_add_fetch(&var,(count),__ATOMIC_RELAXED)
                                        ^
    lazyfree.c:111:5: warning: implicit declaration of function '__atomic_sub_fetch' is invalid in C99 [-Wimplicit-function-declaration]
        atomicDecr(lazyfree_objects,1,lazyfree_objects_mutex);
        ^
    ./atomicvar.h:58:37: note: expanded from macro 'atomicDecr'
    #define atomicDecr(var,count,mutex) __atomic_sub_fetch(&var,(count),__ATOMIC_RELAXED)
                                        ^
    2 warnings generated.

Then in the linking stage:

        LINK redis-server
    Undefined symbols for architecture x86_64:
      "___atomic_add_fetch", referenced from:
          _zmalloc in zmalloc.o
          _zcalloc in zmalloc.o
          _zrealloc in zmalloc.o
          _dbAsyncDelete in lazyfree.o
          _emptyDbAsync in lazyfree.o
          _slotToKeyFlushAsync in lazyfree.o
      "___atomic_load_n", referenced from:
          _zmalloc_used_memory in zmalloc.o
          _zmalloc_get_fragmentation_ratio in zmalloc.o
      "___atomic_sub_fetch", referenced from:
          _zrealloc in zmalloc.o
          _zfree in zmalloc.o
          _lazyfreeFreeObjectFromBioThread in lazyfree.o
          _lazyfreeFreeDatabaseFromBioThread in lazyfree.o
          _lazyfreeFreeSlotsMapFromBioThread in lazyfree.o
    ld: symbol(s) not found for architecture x86_64
    clang: error: linker command failed with exit code 1 (use -v to see invocation)
    make[1]: *** [redis-server] Error 1
    make: *** [all] Error 2

With this patch, the compilation is sucessful, no warnings.

Running `make test` we get a almost clean bill of health. Test pass with
one exception:

    [err]: Check for memory leaks (pid 52793) in tests/unit/dump.tcl
    [err]: Check for memory leaks (pid 53103) in tests/unit/auth.tcl
    [err]: Check for memory leaks (pid 53117) in tests/unit/auth.tcl
    [err]: Check for memory leaks (pid 53131) in tests/unit/protocol.tcl
    [err]: Check for memory leaks (pid 53145) in tests/unit/protocol.tcl
    [ok]: Check for memory leaks (pid 53160)
    [err]: Check for memory leaks (pid 53175) in tests/unit/scan.tcl
    [ok]: Check for memory leaks (pid 53189)
    [err]: Check for memory leaks (pid 53221) in tests/unit/type/incr.tcl
    .
    .
    .

Full debug log (289MB, uncompressed) available at
https://dl.dropboxusercontent.com/u/75548/logs/redis-debug-log-macos-10.8.5.log.xz

Most if not all of the memory leak tests fail. Not sure if this is
related. They are the only ones that fail. I belive they are not related,
but just the memory leak detector is not working properly on 10.8.5.

Signed-off-by: Pedro Melo <melo@simplicidade.org>
2016-10-17 14:58:23 +01:00
Pedro Melo
5d5ce20ee6 Fixes compilation on MacOS 10.8.5, Clang tags/Apple/clang-421.0.57
Redis fails to compile on MacOS 10.8.5 with Clang 4, version 421.0.57
(based on LLVM 3.1svn).

When compiling zmalloc.c, we get these warnings:

        CC zmalloc.o
    zmalloc.c:109:5: warning: implicit declaration of function '__atomic_add_fetch' is invalid in C99 [-Wimplicit-function-declaration]
        update_zmalloc_stat_alloc(zmalloc_size(ptr));
        ^
    zmalloc.c:75:9: note: expanded from macro 'update_zmalloc_stat_alloc'
            atomicIncr(used_memory,__n,used_memory_mutex); \
            ^
    ./atomicvar.h:57:37: note: expanded from macro 'atomicIncr'
    #define atomicIncr(var,count,mutex) __atomic_add_fetch(&var,(count),__ATOMIC_RELAXED)
                                        ^
    zmalloc.c:145:5: warning: implicit declaration of function '__atomic_sub_fetch' is invalid in C99 [-Wimplicit-function-declaration]
        update_zmalloc_stat_free(oldsize);
        ^
    zmalloc.c:85:9: note: expanded from macro 'update_zmalloc_stat_free'
            atomicDecr(used_memory,__n,used_memory_mutex); \
            ^
    ./atomicvar.h:58:37: note: expanded from macro 'atomicDecr'
    #define atomicDecr(var,count,mutex) __atomic_sub_fetch(&var,(count),__ATOMIC_RELAXED)
                                        ^
    zmalloc.c:205:9: warning: implicit declaration of function '__atomic_load_n' is invalid in C99 [-Wimplicit-function-declaration]
            atomicGet(used_memory,um,used_memory_mutex);
            ^
    ./atomicvar.h:60:14: note: expanded from macro 'atomicGet'
        dstvar = __atomic_load_n(&var,__ATOMIC_RELAXED); \
                 ^
    3 warnings generated.

Also on lazyfree.c:

        CC lazyfree.o
    lazyfree.c:68:13: warning: implicit declaration of function '__atomic_add_fetch' is invalid in C99 [-Wimplicit-function-declaration]
                atomicIncr(lazyfree_objects,1,lazyfree_objects_mutex);
                ^
    ./atomicvar.h:57:37: note: expanded from macro 'atomicIncr'
    #define atomicIncr(var,count,mutex) __atomic_add_fetch(&var,(count),__ATOMIC_RELAXED)
                                        ^
    lazyfree.c:111:5: warning: implicit declaration of function '__atomic_sub_fetch' is invalid in C99 [-Wimplicit-function-declaration]
        atomicDecr(lazyfree_objects,1,lazyfree_objects_mutex);
        ^
    ./atomicvar.h:58:37: note: expanded from macro 'atomicDecr'
    #define atomicDecr(var,count,mutex) __atomic_sub_fetch(&var,(count),__ATOMIC_RELAXED)
                                        ^
    2 warnings generated.

Then in the linking stage:

        LINK redis-server
    Undefined symbols for architecture x86_64:
      "___atomic_add_fetch", referenced from:
          _zmalloc in zmalloc.o
          _zcalloc in zmalloc.o
          _zrealloc in zmalloc.o
          _dbAsyncDelete in lazyfree.o
          _emptyDbAsync in lazyfree.o
          _slotToKeyFlushAsync in lazyfree.o
      "___atomic_load_n", referenced from:
          _zmalloc_used_memory in zmalloc.o
          _zmalloc_get_fragmentation_ratio in zmalloc.o
      "___atomic_sub_fetch", referenced from:
          _zrealloc in zmalloc.o
          _zfree in zmalloc.o
          _lazyfreeFreeObjectFromBioThread in lazyfree.o
          _lazyfreeFreeDatabaseFromBioThread in lazyfree.o
          _lazyfreeFreeSlotsMapFromBioThread in lazyfree.o
    ld: symbol(s) not found for architecture x86_64
    clang: error: linker command failed with exit code 1 (use -v to see invocation)
    make[1]: *** [redis-server] Error 1
    make: *** [all] Error 2

With this patch, the compilation is sucessful, no warnings.

Running `make test` we get a almost clean bill of health. Test pass with
one exception:

    [err]: Check for memory leaks (pid 52793) in tests/unit/dump.tcl
    [err]: Check for memory leaks (pid 53103) in tests/unit/auth.tcl
    [err]: Check for memory leaks (pid 53117) in tests/unit/auth.tcl
    [err]: Check for memory leaks (pid 53131) in tests/unit/protocol.tcl
    [err]: Check for memory leaks (pid 53145) in tests/unit/protocol.tcl
    [ok]: Check for memory leaks (pid 53160)
    [err]: Check for memory leaks (pid 53175) in tests/unit/scan.tcl
    [ok]: Check for memory leaks (pid 53189)
    [err]: Check for memory leaks (pid 53221) in tests/unit/type/incr.tcl
    .
    .
    .

Full debug log (289MB, uncompressed) available at
https://dl.dropboxusercontent.com/u/75548/logs/redis-debug-log-macos-10.8.5.log.xz

Most if not all of the memory leak tests fail. Not sure if this is
related. They are the only ones that fail. I belive they are not related,
but just the memory leak detector is not working properly on 10.8.5.

Signed-off-by: Pedro Melo <melo@simplicidade.org>
2016-10-17 14:58:23 +01:00
antirez
d64b08bb64 Fix SELECT test, broken cause change in error msg. 2016-10-14 15:48:11 +02:00
antirez
f633212073 Fix SELECT test, broken cause change in error msg. 2016-10-14 15:48:11 +02:00
antirez
96dad4da1f Fix SELECT test, broken cause change in error msg. 2016-10-14 15:48:11 +02:00
antirez
cc6fcdd0ee SWAPDB command.
This new command swaps two Redis databases, so that immediately all the
clients connected to a given DB will see the data of the other DB, and
the other way around. Example:

    SWAPDB 0 1

This will swap DB 0 with DB 1. All the clients connected with DB 0 will
immediately see the new data, exactly like all the clients connected
with DB 1 will see the data that was formerly of DB 0.

MOTIVATION AND HISTORY
---

The command was recently demanded by Pedro Melo, but was suggested in
the past multiple times, and always refused by me.

The reason why it was asked: Imagine you have clients operating in DB 0.
At the same time, you create a new version of the dataset in DB 1.
When the new version of the dataset is available, you immediately want
to swap the two views, so that the clients will transparently use the
new version of the data. At the same time you'll likely destroy the
DB 1 dataset (that contains the old data) and start to build a new
version, to repeat the process.

This is an interesting pattern, but the reason why I always opposed to
implement this, was that FLUSHDB was a blocking command in Redis before
Redis 4.0 improvements. Now we have FLUSHDB ASYNC that releases the
old data in O(1) from the point of view of the client, to reclaim memory
incrementally in a different thread.

At this point, the pattern can really be supported without latency
spikes, so I'm providing this implementation for the users to comment.
In case a very compelling argument will be made against this new command
it may be removed.

BEHAVIOR WITH BLOCKING OPERATIONS
---

If a client is blocking for a list in a given DB, after the swap it will
still be blocked in the same DB ID, since this is the most logical thing
to do: if I was blocked for a list push to list "foo", even after the
swap I want still a LPUSH to reach the key "foo" in the same DB in order
to unblock.

However an interesting thing happens when a client is, for instance,
blocked waiting for new elements in list "foo" of DB 0. Then the DB
0 and 1 are swapped with SWAPDB. However the DB 1 happened to have
a list called "foo" containing elements. When this happens, this
implementation can correctly unblock the client.

It is possible that there are subtle corner cases that are not covered
in the implementation, but since the command is self-contained from the
POV of the implementation and the Redis core, it cannot cause anything
bad if not used.

Tests and documentation are yet to be provided.
2016-10-14 15:28:04 +02:00
antirez
c7a4e694ad SWAPDB command.
This new command swaps two Redis databases, so that immediately all the
clients connected to a given DB will see the data of the other DB, and
the other way around. Example:

    SWAPDB 0 1

This will swap DB 0 with DB 1. All the clients connected with DB 0 will
immediately see the new data, exactly like all the clients connected
with DB 1 will see the data that was formerly of DB 0.

MOTIVATION AND HISTORY
---

The command was recently demanded by Pedro Melo, but was suggested in
the past multiple times, and always refused by me.

The reason why it was asked: Imagine you have clients operating in DB 0.
At the same time, you create a new version of the dataset in DB 1.
When the new version of the dataset is available, you immediately want
to swap the two views, so that the clients will transparently use the
new version of the data. At the same time you'll likely destroy the
DB 1 dataset (that contains the old data) and start to build a new
version, to repeat the process.

This is an interesting pattern, but the reason why I always opposed to
implement this, was that FLUSHDB was a blocking command in Redis before
Redis 4.0 improvements. Now we have FLUSHDB ASYNC that releases the
old data in O(1) from the point of view of the client, to reclaim memory
incrementally in a different thread.

At this point, the pattern can really be supported without latency
spikes, so I'm providing this implementation for the users to comment.
In case a very compelling argument will be made against this new command
it may be removed.

BEHAVIOR WITH BLOCKING OPERATIONS
---

If a client is blocking for a list in a given DB, after the swap it will
still be blocked in the same DB ID, since this is the most logical thing
to do: if I was blocked for a list push to list "foo", even after the
swap I want still a LPUSH to reach the key "foo" in the same DB in order
to unblock.

However an interesting thing happens when a client is, for instance,
blocked waiting for new elements in list "foo" of DB 0. Then the DB
0 and 1 are swapped with SWAPDB. However the DB 1 happened to have
a list called "foo" containing elements. When this happens, this
implementation can correctly unblock the client.

It is possible that there are subtle corner cases that are not covered
in the implementation, but since the command is self-contained from the
POV of the implementation and the Redis core, it cannot cause anything
bad if not used.

Tests and documentation are yet to be provided.
2016-10-14 15:28:04 +02:00
antirez
a89f98b802 SWAPDB command.
This new command swaps two Redis databases, so that immediately all the
clients connected to a given DB will see the data of the other DB, and
the other way around. Example:

    SWAPDB 0 1

This will swap DB 0 with DB 1. All the clients connected with DB 0 will
immediately see the new data, exactly like all the clients connected
with DB 1 will see the data that was formerly of DB 0.

MOTIVATION AND HISTORY
---

The command was recently demanded by Pedro Melo, but was suggested in
the past multiple times, and always refused by me.

The reason why it was asked: Imagine you have clients operating in DB 0.
At the same time, you create a new version of the dataset in DB 1.
When the new version of the dataset is available, you immediately want
to swap the two views, so that the clients will transparently use the
new version of the data. At the same time you'll likely destroy the
DB 1 dataset (that contains the old data) and start to build a new
version, to repeat the process.

This is an interesting pattern, but the reason why I always opposed to
implement this, was that FLUSHDB was a blocking command in Redis before
Redis 4.0 improvements. Now we have FLUSHDB ASYNC that releases the
old data in O(1) from the point of view of the client, to reclaim memory
incrementally in a different thread.

At this point, the pattern can really be supported without latency
spikes, so I'm providing this implementation for the users to comment.
In case a very compelling argument will be made against this new command
it may be removed.

BEHAVIOR WITH BLOCKING OPERATIONS
---

If a client is blocking for a list in a given DB, after the swap it will
still be blocked in the same DB ID, since this is the most logical thing
to do: if I was blocked for a list push to list "foo", even after the
swap I want still a LPUSH to reach the key "foo" in the same DB in order
to unblock.

However an interesting thing happens when a client is, for instance,
blocked waiting for new elements in list "foo" of DB 0. Then the DB
0 and 1 are swapped with SWAPDB. However the DB 1 happened to have
a list called "foo" containing elements. When this happens, this
implementation can correctly unblock the client.

It is possible that there are subtle corner cases that are not covered
in the implementation, but since the command is self-contained from the
POV of the implementation and the Redis core, it cannot cause anything
bad if not used.

Tests and documentation are yet to be provided.
2016-10-14 15:28:04 +02:00
antirez
8b65d03e17 Modules: use RedisModule_AbortBlock() in the example. 2016-10-13 17:00:45 +02:00
antirez
a3b3ca7c21 Modules: use RedisModule_AbortBlock() in the example. 2016-10-13 17:00:45 +02:00
antirez
0d55b08656 Modules: use RedisModule_AbortBlock() in the example. 2016-10-13 17:00:45 +02:00