causal_reads does not work with servers that update their state via
mechanisms other than the standard replication. In practice this is just
another Galera limitation.
The documentation stated that MVCC reads weren't safe with
transaction_replay when in reality they are not safe in general and
transaction_replay has no effect on it.
This commit adds a new parameter that, when enabled, prunes the session
command history to a known length. This makes it possible to keep a
client-side pooled connection open indefinitely at the cost of making
reconnections theoretically unsafe. In practice the maximum history length
can be set to a value that encompasses a single session using the pooled
connection with no risk to session state integrity. The default history
length of 50 commands is quite likely to be adequate for the majority of
use-cases.
Both the replication lag and the message printing state are saved in SERVER,
although the values are mostly used by readwritesplit. A log message is printed
both when a server goes over the limit and when it comes back below.
Because of concurrency issues, a message may be printed multiple times before
different threads detect the new message state.
Documentation updated to explain the change.
The TOC was added only to the long documentation files to make them easier
to navigate. Also modified the headings for Avro and Binlog routers and did
some minor cleanup.
Enabling the feature by default prevents the master connection from dying
during times when there are very little or no writes. Having a modest ping
interval of 300 seconds serves to minimize the amount of extra work that
both MaxScale and the server have to do while still keeping the
connections in good shape.
The causal_reads_timeout default value is too long when considering the
behavioral changes that MXS-2141 introduced. With a 10 second default
value, a result is returned to the client in a reasonable amount of time.
With causal_reads enabled, the query would return with an error if the
slave was not able to catch up to the master fast enough. By automatically
retrying the query on the master, we're guaranteed that a valid result is
always returned to the client.
Added the `transaction_replay_max_size` parameter that controls the
maximum size of a transaction that can be replayed. If the limit is
exceeded, the stored statements are released thus preventing the
transaction from being replayed.
This limitation prevents accidental misuse of the transaction replaying
system when autocommit is disabled. It also allows the user to control the
amount of memory that MaxScale will use.
The transaction retrying behavior is now configurable and documented. The
`transaction_replay` parameter implicitly enables the required
functionality in the router that it needs.
Enabling the session command history but limiting it to a history of 50
commands allows reconnections for sessions that don't change the state too
often.
As pooled connections will exceed this limit quite fast, they are not able
to reconnect to servers once connections are lost. To solve this problem,
the session command history needs a compaction process that removes
redundant history.
As they are deprecated, they should not be mentioned in the examples. Also
moved the router_options documentation under a Legacy Configuration
heading.
With the `allow_master_change` parameter enabled, sessions can start using
a different master node if one is available. This will not prevent
sessions from closing if a write query is received while no master
replacement is available.
The default value for strict_multi_stmt prevents compound statements and
atomic multi-statement commands from being executed without completely
disabling load balancing. As the new default value will have no practical
effect on all correct uses of readwritesplit, this is a relatively safe
thing to change.
The new parameter allows the session to be "locked" to the master server
after a stored procedure is called. This will keep the session state
consistent if the stored procedure call modifies the state of the session.
The readwritesplit now sends COM_PING queries to backend servers that have
been idle for too long. The option is configured with the
`connection_keepalive` parameter.
The combination of the default values of `disable_sescmd_history=false`
and `max_slave_connections=100%` does not make sense as it is not possible
to find a replacement slave in case an active one fails.
The max_slave_replication_lag parameter for readwritesplit only works for
monitors that detect replication lag. As the MySQL monitor is the only one
that implements this functionality, the parameter only has meaning when
used with master-slave clusters.
The parameters that readwritesplit uses now use the new system. This
removes the need for the qualified parameter processing found in config.c.
All values for router_options are now also accepted as parameters. The
router_options is deprecated and support for it will be removed in a
future version.
If a slave fails while a non-critical read is being executed, the read is
retried on a different server. This is controlled by the new
`retry_failed_reads` option.
Only selects done that are done outside of a transaction and with
autocommit enabled are retried.
The change in readwritesplit routing priorities, where hints have the
highest priority, gives users more options to control how readwritesplit
acts.
For example, this allows read-only stored procedures to be routed to
slaves by adding a hint to the query:
CALL myproc(); -- maxscale route to slave
The readwritesplit documentation also warns the user not to use routing
hints unless they can be absolutely sure that no damage will be done.
973b983 Merge branch 'release-2.0.0' into develop
255dd23 Make spinlock functions take const argument
6e23bab Fix bitmask reallocation
338c189 Rename and clean up slavelag filter
3ea8f28 Fix possible NULL pointer dereference
bfe6738 MXS-830: Add module information to logged messages
1fad962 Fix strncat usage
d38997a Adjust log throttling policy
0be4e4b Add hashtable_item_strcasecmp
726100e Take hashtable convenience functions into use
5e7744a Fix typo in maxadmin.md
c5778c8 Merge branch 'release-2.0.0' into develop
b5762af Move from tmpnam to mkstemp
d6f2c71 Add convenience functions to hashtable
359058a MXS-825: Add support for --execdir
636347c Enable runtime reconfiguration of log throttling
ef9fba9 Improve log throttling documentation
aef917a Implement log throttling
e3a5349 Remove shardrouter.c
8051e80 Remove custom qc_sqlite allocation functions
fd34d60 Initial implementation of the learning firewall
a8752a8 Removed "filestem option" from example
1ef2519 Removed "filestem option" from example
0815cc8 Cleanup spinlock.h
ab4dc99 Clean up hashtable.h
ef2c078 Add prototypes for hashtable copy and free functions
fb5cfaf Add 'log_throttling' configuration entry
300d823 Add proper prototypes for hashtable hash and cmp functions
1c649aa qc_mysqlembedded: Include skygw_...h without path.
d276160 Add missing RPM scripts
e70e644 Fix HTTPAuth installation
1b2b389 Combine utils into the server directory
3ff9913 Add missing utils headers to devel package
407efb2 Fix minor packaging problems
99aa6ad Split MaxScale into core, experimental and devel packages
1290386 Merge branch 'develop' of ssh://github.com/mariadb-corporation/maxscale-new into develop
e59f148 Make scripts POSIX sh compatible
7319266 Fixed SHOW SLAVE STATUS in bonlog router
f8d760a Update Binlogrouter.md
0a904ed Update Replication-Proxy-Binlog-Router-Tutorial.md
75d4202 Update Replication-Proxy-Binlog-Router-Tutorial.md
b8651fc Add missing newline in listmanager.h
c7ad047 Add note about user data caches to release notes
70ccc2b Merge branch 'release-2.0.0' into develop
575d1b6 Mistake - dummy session needs list markers set.
8364508 Merge branch 'develop' into binlog_server_semisync
868b902 Update MaxScale limitations
2c8b327 Store listener caches in separate directories
6e183ec Create unique user data caches for each listeners
f643685 Don't free orphaned tee filter sessions
4179afa Allow binlogrouter to be used without a listener
7ad79af Add function for freeing a listener
677a0a2 Move authentication data from services to listeners
4f12af7 Merge remote-tracking branch 'origin/MXS-677' into develop
1419b81 Semi-Sync support to binlog server: code review updtate
0ea0f01 Semi-Sync support to binlog server: added missing routine
4aad909 Semi-Sync support to binlog server
b824e1e Add authenticator support to httpd.c
705a688 Change tabs to spaces
d0c419e Change method of adding list fields to e.g. DCB
25504fc Document the changed routing priority of hints
41666d1 Remove use_ssl_if_enabled global option
a3584e9 Make routing hints have highest priority
34a1d24 Updated document with new binlog router option
01eedc5 Updated documentation with SSL usage
8a4c0f6 Update Replication-Proxy-Binlog-Router-Tutorial.md
4e374aa Update Replication-Proxy-Binlog-Router-Tutorial.md
f3f3c57 Update Replication-Proxy-Binlog-Router-Tutorial.md
617b79f Binlog Server: error messages typo fix
fa8dfae Binlog Server: error messages review
1b8819c Fix freeing of schemarouter session memory
07f49e1 MXS-788: new code review fix
1fd3b09 MXS-788: show services now displays SSL info
6ca2584 MXS-788 code review fix
ae6a7d0 MXS-788 code review
43d3474 Master server SSL connection
90b2377 Use correct variable in listmanager pre-allocation
9a5b238 Fix listmanager pre-allocation
9c78625 Fix a memory leak when backend authentication fails
e59a966 Fix hang in list_find_free
ff30223 Fix freeing of shared data in schemarouter
fc8f9d3 Add missing include in luafilter
ecf7f53 Add missing NULL value to filter parameter array
636d849 Update memory allocation approach
f0d1d38 Add new allocation functions
97d00a0 Fix writing of uninitialized data to logs
e72c9b2 Merge branch 'release-2.0.0' into develop
cf2b712 Merge branch 'release-2.0.0' into develop
8917c5c Change the logic behind valid list entry checks
c10deff Improve documentation about version_string
f59f1f7 Merge branch 'develop' of ssh://github.com/mariadb-corporation/maxscale-new into develop
c88edb3 Backend authentication failure improvement
abd5bee Revert "Backend authentication failure improvement"
5bb3107 Backend authentication failure improvement
b7f434a Add new allocation functions
3f022fa Fix stupid mistake
99c4317 Merge remote-tracking branch 'origin/MXS-677' into develop
3c1ded6 Added connection/authentication failure error reporting in SHOW SLAVE STATUS
0a60f7b Tidy up and deal with review points.
ba103ff blr_slave.c: Update strncpy usage
467331e blr_master.c: Strncpy usage updates
d2b7c0c Merge remote-tracking branch 'origin/develop-nullauth-merge' into develop
5a8c1d0 qc: Measure execution time at the right place.
bccdb93 Merge branch 'NullAuthDeny' into develop
2e6511c Add 5.5.5 prefix to all version strings that lack it
314655a Improve DCB and session initialization and list handling
e1c43f0 MXS-655: Make MaxScale logging logrotate(8) compatible
ce36afd MXS-626: Don't log a header unless maxlog enabled
dcd47a7 blr_file.c: Replace uses of strncpy
6b8f576 bls_slave.c: Replace strncpy with memcpy
68a0039 Add list preallocation, tidy up, simplify init.
cb37d1b Fix copyright etc headers.
11a400d Tidy; comment; fix bad copies and mistakes.
7e36ec4 Add list manager files.
c4794e3 Initial code for list manager.
1b42e25 Merge remote-tracking branch 'origin/MXS-765' into develop
d50f617 Fix problems, extend tests, respond to review.
dcb4a91 Filter test folder removed
0b60dbe Add a couple of comments.
83cdba0 Fix overwriting problem.
ba5d353 Fix overwriting problem.
53671cb Small fixes in response to review.
173d049 blr.c: Review strncpy usage
4ff6ef2 binlog_common.c: Replace strncpy with memcpy
f238e03 maxbinlogcheck.s: Replace strncpy
9807f8d harness: Replace unnecessary use of strncpy
8c7fe6a avro: Modify strncpy usage
9b8008e Small improvements.
b7f784f Fix mistakes in testqueuemanager.c
cc26962 Restore missing poll.c code; add testqueuemanager.c.
2e91806 Format the filter harness
22059e6 Initial implementation connection queueing.
c604dc2 readwritesplit.c: Improve COM_INIT_DB handling
454d920 schemarouter.c: Replace strncpy with strcpy
8e85d66 sharding_common.c: Too long a database name handled explicitly
77f4446 Astyle schemarouter
491f7c2 maxinfo.c: Replace strncpy with memcpy
6b98105 maxinfo: Reformat with astyle
c1dbf08 Handle oversize user and database names
5fa4a0f Merge branch 'develop' of ssh://github.com/mariadb-corporation/maxscale-new into develop
706963b BLR_DBUSERS_TAIL new var in blr.h
d75b9af Tweak comments, remove trailing blanks.
ab2400a Optimise statistics gathering by inline & simpler fns.
fb59ddc Remove unnecessary strncpy/strncat usage in Binlog Server
bdcd551 resultset.c: Change strncpy to memcpy
c6b1c5e Reject rather than cut too long a path
6d8f112 Remove unnecessary strncpy/strncat usage
18bf5ed Remove unnecessary strncpy usage
dc0e2db Make maxpasswd more userfriendly
c9c8695 Fix calculation of padded_len in encryptPassword
2cfd2c6 dbusers.c: Check strncpy usage
7ab9342 Make more thorough checks in secrets_readKeys
be7d593 Format cli.c debugcli.c testroute.c webserver.c
1ee5efb config.c: Check usage of strncpy
3043b12 gq_utils.c: Unnecessary use of strncpy removed
77874ac Add help to maxkeys
38392a3 Update secrets_writeKeys documentation
2d1325c Make SSL optional in MaxScale's own communication
bda00da Fix avro build failures
b2cb31a Add more OOM macros
41ccf17 Fix strdup usage
a48f732 Fix realloc calls
20771f6 Add forgotten extern "C" block
8faf35a Add maxscale allocation functions
bb47890 Add macros for OOM logging
afea388 Fix silly mistakes.
6dafd22 Make deny default for null auth; move code from common to auth.
