Hi Sergey,
One of the ways to make clean revision is (!!! assuming nobody else is using this tree): (on rev.3914) bzr uncommit edit mdl.h bzr commit bzr push --overwrite lp:~kentokushiba/maria/10.0.6-metadata_lock_info
Thank you for your advice. I just overwrote. Is it OK? Thanks, Kentoku 2013/12/10 Sergey Vojtovich <svoj@mariadb.org>
Hi Kentoku,
On Tue, Dec 10, 2013 at 11:38:15PM +0900, kentoku wrote:
Hi Sergey,
looks great now. Just one minor thing: rev.3914 overwrites mdl.h with DOS line endings (CRLF), which are not permitted by coding guidelines.
Sorry. No problems.
If you fix this file, I can merge your revision as is. Or I can fix it myself, but I'll have to submit metadata_lock_info on my behalf.
I just fixed and pushed. Please start the merge process.
This way we'll loose all history of mdl.h modifications. In other words bzr annotate says all lines were added revision 3915.
I meant we either need clean revision or I can pick these changes myself.
One of the ways to make clean revision is (!!! assuming nobody else is using this tree): (on rev.3914) bzr uncommit edit mdl.h bzr commit bzr push --overwrite lp:~kentokushiba/maria/10.0.6-metadata_lock_info
Regards, Sergey
Thanks, Kentoku
2013/12/10 Sergey Vojtovich <svoj@mariadb.org>
Hi Kentoku,
looks great now. Just one minor thing: rev.3914 overwrites mdl.h with DOS line endings (CRLF), which are not permitted by coding guidelines.
If you fix this file, I can merge your revision as is. Or I can fix it myself, but I'll have to submit metadata_lock_info on my behalf.
When the above is solved, I will start the merge process.
Thanks, Sergey
On Mon, Dec 09, 2013 at 04:08:48AM +0900, kentoku wrote:
Hi Sergey,
I just pushed again. Please review it. lp:~kentokushiba/maria/10.0.6-metadata_lock_info
Thanks, Kentoku
2013/11/8 Sergey Vojtovich <svoj@mariadb.org>
Hi Kentoku,
On Fri, Nov 08, 2013 at 04:18:51AM +0900, kentoku wrote:
Hi Sergey,
> please find iterator prototype attached. I didn't test it. Thanks a lot. I'll try it.
> > > - Roberto suggests to add QUERY_ID column and I agree > > > > Not fixed. Where can I get locker's QUERY_ID? > It is mdl_ctx->get_owner()->get_thd()->query_id.
I think it is owner thread's current query_id. This query_id
be
query_id when lock was taken. Why do you need query_id in this
You're right. Probably query_id is not applicable for this table. I was thinking about possibility to kill stale queries by query_id, like in https://mariadb.atlassian.net/browse/MDEV-4911
Anyway it is not a requirement, one can join I_S.PROCESSLIST to get query_id.
> > > - Roberto suggests to add LOCK_DURATION column and I agree > > > > Fixed. If calling find_ticket() for getting LOCK_DURATION is
costly, I
will > > change it. Please review it. > It's a bit heavy indeed. What is the other option you're considering?
On debug build, MDL_ticket class has enum_mdl_duration. I think
enum_mdl_duration can use for non debug build, if remove "#ifndef DBUG_OFF" for enum_mdl_duration. How do you think about it? It could be an option, but I'd go with find_ticket() for now.
Regards, Sergey
Thanks, Kentoku
2013/11/7 Sergey Vojtovich <svoj@mariadb.org>
> Kentoku, > > please find iterator prototype attached. I didn't test it. > > Regards, > Sergey > > On Thu, Nov 07, 2013 at 03:18:04PM +0400, Sergey Vojtovich
> > Hi Kentoku, > > > > thanks for implementing these requests. Technically it looks much better > now. > > Though I believe it is a good idea to keep mdl private classes
wrote: private.
> I think > > we should add logics of i_s_metadata_lock_info_fill_table() to mdl.cc. > I'll do > > that and get back to you when ready. > > > > More comments inline. > > > > On Fri, Nov 01, 2013 at 05:28:32AM +0900, kentoku wrote: > > > Hi Sergey and Roberto, > > > > > > Thank you for reviewing and suggesting! > > > Currently, branch is the following. > > > lp:~kentokushiba/maria/10.0.4-metadata_lock_info > > > > > > > The most important thing I'm worried about is that there is no > protection > > > > of ticket lists: lists may be updated while we iterate
and
it
> may > > > cause > > > > server crash in concurrent environment. From what I can see > MDL_context is > > > > mostly supposed to be accessed only by thread which owns
> context. As > > > such > > > > it is not protected by any locks. > > > > > > > > I believe we should use global lists instead, something
> > > > mysql_mutex_lock(&mdl_locks.m_mutex); > > > > iterate mdl_locks.m_locks (hash of MDL_lock) > > > > { > > > > mysql_prlock_rdlock(&lock->m_rwlock); > > > > iterate lock->m_granted (list of MDL_ticket) > > > > { > > > > // store data > > > > } > > > > mysql_prlock_unlock(&lock->m_rwlock); > > > > } > > > > mysql_mutex_lock(&mdl_locks.m_mutex); > > > > > > Fixed. > > > > > > > A few more suggestions in no particular order: > > > > - instead of making m_tickets public I'd suggest to try to make > > > > i_s_metadata_lock_info_fill_table() a friend function > > > > (shouldn't be relevant anymore) > > > > > > Fixed. > > > > > > > - why check for thd->killed? > > > > (shouldn't be relevant anymore) > > > > > > Fixed. > > > > > > > - metadata_lock_info_lock_mode_length[] includes ending zero, and > then > > > > we store e.g. "MDL_SHARED\0" whereas we should store "MDL_SHARED" > > > > > > > > I'd suggest to declare these arrays as following: > > > > static const LEX_STRING
> > > > { > > > > STRING_WITH_LEN("MDL_INTENTION_EXCLUSIVE"), // or > C_STRING_WITH_LEN() > > > > ... > > > > }; > > > > > > Fixed. > > > > > > > - Roberto suggests to rename ID to THREAD_ID and I agree > > > > > > Fixed. > > > > > > > - Roberto suggests to add QUERY_ID column and I agree > > > > > > Not fixed. Where can I get locker's QUERY_ID? > > It is mdl_ctx->get_owner()->get_thd()->query_id. > > > > > > > > > - Roberto suggests to add LOCK_DURATION column and I agree > > > > > > Fixed. If calling find_ticket() for getting LOCK_DURATION is costly, I > will > > > change it. Please review it. > > It's a bit heavy indeed. What is the other option you're considering? > > > > Regards, > > Sergey > > > > > > > > > - Roberto suggests to use m_namespace_to_wait_state_name instead of > > > > metadata_lock_info_lock_names, but I tend to disagree because the > > > former says > > > > "Waiting for...". Though I'd suggest to make array of LEX_STRING's > to > > > avoid > > > > calling strdup(). > > > > > > Fixed. > > > > > > > - Roberto suggests to replace DB with KEY and NAME with SUB_KEY, but > I > > > tend to > > > > disagree since in most cases it is db and table name. I'd vote for > > > > TABLE_SCHEMA and TABLE_NAME to stay in line with the rest I_S > tables. > > > > > > Fixed. > > > > > > Thanks, > > > Kentoku > > > > > > > > > 2013/10/30 Roberto Spadim <roberto@spadim.com.br> > > > > > > > =) no problem about disagree, i'm agree now hehe > > > > thanks guys! :) > > > > > > > > > > > > 2013/10/29 Sergey Vojtovich <svoj@mariadb.org> > > > > > > > >> Hi Kentoku, > > > >> > > > >> thanks for your contribution and sorry for this long delay. I > finally > > > >> managed > > > >> to go through your code. > > > >> > > > >> The most important thing I'm worried about is that
no
> protection > > > >> of ticket lists: lists may be updated while we iterate
should table? this them this like: metadata_lock_info_lock_mode_str[]= there is them
it
> may > > > >> cause > > > >> server crash in concurrent environment. From what I can see > MDL_context is > > > >> mostly supposed to be accessed only by thread which owns
> context. As > > > >> such > > > >> it is not protected by any locks. > > > >> > > > >> I believe we should use global lists instead, something
> > > >> mysql_mutex_lock(&mdl_locks.m_mutex); > > > >> iterate mdl_locks.m_locks (hash of MDL_lock) > > > >> { > > > >> mysql_prlock_rdlock(&lock->m_rwlock); > > > >> iterate lock->m_granted (list of MDL_ticket) > > > >> { > > > >> // store data > > > >> } > > > >> mysql_prlock_unlock(&lock->m_rwlock); > > > >> } > > > >> mysql_mutex_lock(&mdl_locks.m_mutex); > > > >> > > > >> A few more suggestions in no particular order: > > > >> - instead of making m_tickets public I'd suggest to try to make > > > >> i_s_metadata_lock_info_fill_table() a friend function > > > >> (shouldn't be relevant anymore) > > > >> > > > >> - why check for thd->killed? > > > >> (shouldn't be relevant anymore) > > > >> > > > >> - metadata_lock_info_lock_mode_length[] includes ending zero, and > then > > > >> we store e.g. "MDL_SHARED\0" whereas we should store "MDL_SHARED" > > > >> > > > >> I'd suggest to declare these arrays as following: > > > >> static const LEX_STRING
and this like: metadata_lock_info_lock_mode_str[]=
> > > >> { > > > >> STRING_WITH_LEN("MDL_INTENTION_EXCLUSIVE"), // or > C_STRING_WITH_LEN() > > > >> ... > > > >> }; > > > >> > > > >> - Roberto suggests to rename ID to THREAD_ID and I agree > > > >> - Roberto suggests to add QUERY_ID column and I agree > > > >> - Roberto suggests to add LOCK_DURATION column and I agree > > > >> - Roberto suggests to use m_namespace_to_wait_state_name instead of > > > >> metadata_lock_info_lock_names, but I tend to disagree because the > > > >> former says > > > >> "Waiting for...". Though I'd suggest to make array of > LEX_STRING's to > > > >> avoid > > > >> calling strdup(). > > > >> > > > >> - Roberto suggests to replace DB with KEY and NAME with SUB_KEY, > but I > > > >> tend to > > > >> disagree since in most cases it is db and table name. I'd vote for > > > >> TABLE_SCHEMA and TABLE_NAME to stay in line with the rest I_S > tables. > > > >> > > > >> Regards, > > > >> Sergey > > > >> > > > >> On Mon, Jul 01, 2013 at 03:46:22AM +0900, kentoku wrote: > > > >> > Hi Sergey, > > > >> > Sorry. I think this plugin needs more locks "mdl_locks.m_mutex", > > > >> > "mdl_locks.m_global_lock" and "mdl_locks.m_commit_lock". Is it > right? > > > >> Would > > > >> > you please teach me how can I use it? > > > >> > Thanks, > > > >> > Kentoku > > > >> > > > > >> > > > > >> > 2013/7/1 kentoku <kentokushiba@gmail.com> > > > >> > > > > >> > > Hi Sergey, > > > >> > > > > > >> > > I made new information schema plugin which named > "metadata_lock_info" > > > >> > > plugin. This plugin makes it possible knowing "who has metadata > > > >> locks". In > > > >> > > development stage, sometimes DBAs meet metadata locks when > using alter > > > >> > > table statement. This metadata locks are sometimes caused by GUI > > > >> tools. In > > > >> > > service stage, sometimes DBAs meet metadata locks when using > alter > > > >> table > > > >> > > statement. This metadata locks are sometimes caused by long > batch > > > >> > > processing. In many cases, the DBAs need to judge immediately. > So I > > > >> made it > > > >> > > for all DBAs. > > > >> > > Would you please review this plugin? > > > >> > > lp:~kentokushiba/maria/10.0.3-metadata_lock_info > > > >> > > Note: This plugin needs a change of sql/mdl.h > > > >> > > > > > >> > > Thanks, > > > >> > > Kentoku > > > >> > > > > > >> > > > >> _______________________________________________ > > > >> Mailing list: https://launchpad.net/~maria-developers > > > >> Post to : maria-developers@lists.launchpad.net > > > >> Unsubscribe : https://launchpad.net/~maria-developers > > > >> More help : https://help.launchpad.net/ListHelp > > > >> > > > > > > > > > > > > > > > > -- > > > > Roberto Spadim > > > > SPAEmpresarial > > > > > > > > _______________________________________________ > > Mailing list: https://launchpad.net/~maria-developers > > Post to : maria-developers@lists.launchpad.net > > Unsubscribe : https://launchpad.net/~maria-developers > > More help : https://help.launchpad.net/ListHelp >