Why has nobody mentioned that the profile on moodle.org has a field called Mastodon?
Visvanath Ratnaweera
Posts made by Visvanath Ratnaweera
Moodle in English -> Hardware and performance -> Slow query challenge ;-) -> Slow query challenge ;-)
by Visvanath Ratnaweera -
Hi Sergio
What you say is not new to me. I only wonder where I said all that: that _all_ queries need to be optimized or there should be no _slow queries_. (What is a slow query? Longer than 1 sec? Longer than 10? .. The number is just arbitrary.) But thanks, you give me the opportunity explain what I want in detail.
In fact I started the OP with, "I'm in the process of catching a spurious slow query coming from the quiz corner." That one is, "I'm looking for the cause of a sudden sharp rise in the load, ramping up many readings like number of threads, load average, interrupts vertically, It was during a busy morning with many tests and exams going on. But they are divided in to small classes, 10 to 20 students each, so the overall distribution is fairly even. Although one could argue that they all coincided in a time slot of a couple of minutes duration, I looked at the DB site and discovered that a massive slow query must have been run at this minute, blocking many things. Unfortunately slow query logging wasn't active." See Hunting slow queries in the quiz sub-system. I have a whole gallery of monitory charts, which show a phenomen, the first if its kind (for me). A huge spike, the tip of a needle, in #threads, memory allocation doing a back flip, it all look like I've rebooted the DBMS (I haven't, it recovered within minutes, I was watching everything in the shell), and clear vertical slow query diagram. Unfortunately the query itself was not logged. (The logging was not active, all these monitoring could be counterproductive.)
What you say is not new to me. I only wonder where I said all that: that _all_ queries need to be optimized or there should be no _slow queries_. (What is a slow query? Longer than 1 sec? Longer than 10? .. The number is just arbitrary.) But thanks, you give me the opportunity explain what I want in detail.
In fact I started the OP with, "I'm in the process of catching a spurious slow query coming from the quiz corner." That one is, "I'm looking for the cause of a sudden sharp rise in the load, ramping up many readings like number of threads, load average, interrupts vertically, It was during a busy morning with many tests and exams going on. But they are divided in to small classes, 10 to 20 students each, so the overall distribution is fairly even. Although one could argue that they all coincided in a time slot of a couple of minutes duration, I looked at the DB site and discovered that a massive slow query must have been run at this minute, blocking many things. Unfortunately slow query logging wasn't active." See Hunting slow queries in the quiz sub-system. I have a whole gallery of monitory charts, which show a phenomen, the first if its kind (for me). A huge spike, the tip of a needle, in #threads, memory allocation doing a back flip, it all look like I've rebooted the DBMS (I haven't, it recovered within minutes, I was watching everything in the shell), and clear vertical slow query diagram. Unfortunately the query itself was not logged. (The logging was not active, all these monitoring could be counterproductive.)
I know you have expertise in this field, appreciate your comments in that (Hunting slow queries..) thread.
This thread is broader and more to satisfy own curiosity, "During that exercise came across these slow queries - if anybody is looking for a challenge", and at the same time to collect some good practice. For example, I need to tell the local site admins not to run reports when during peak hours, especially like now, December, when everybody is running tests and exams. Kind of obvious, but never told them explicitly. Now too late to be 100% certain whether that was the case. Or, I didn't know that Custom reports are timed. So it makes sense to set the time to off-hours. (Still learning, see https://moodle.org/mod/forum/discuss.php?d=471218#p1891971 and https://moodle.org/mod/forum/discuss.php?d=471218#p1891890 )
This thread is broader and more to satisfy own curiosity, "During that exercise came across these slow queries - if anybody is looking for a challenge", and at the same time to collect some good practice. For example, I need to tell the local site admins not to run reports when during peak hours, especially like now, December, when everybody is running tests and exams. Kind of obvious, but never told them explicitly. Now too late to be 100% certain whether that was the case. Or, I didn't know that Custom reports are timed. So it makes sense to set the time to off-hours. (Still learning, see https://moodle.org/mod/forum/discuss.php?d=471218#p1891971 and https://moodle.org/mod/forum/discuss.php?d=471218#p1891890 )
Moodle in English -> Hardware and performance -> Slow query challenge ;-) -> Slow query challenge ;-)
by Visvanath Ratnaweera -
Hi Sergio
I don't get what you want to say. That reports need resources and specially their queries are not necessarily optimized like for the interactive use, those facts are clear to me.
I don't get what you want to say. That reports need resources and specially their queries are not necessarily optimized like for the interactive use, those facts are clear to me.
Moodle in English -> Hardware and performance -> Slow query challenge ;-) -> Slow query challenge ;-)
by Visvanath Ratnaweera -
https://docs.moodle.org/405/en/Custom_reports#Schedule_reports says, "Once you have created a report and decided who has access, you can schedule it from the Schedules tab. .. Decide when the report will first be sent out and how often to send it." https://docs.moodle.org/501/en/Custom_reports#Schedule_reports even has, "From Moodle 5.1., options include hourly, daily, daily weekdays, weekly monthly and annually."
Where is this "tab". Prod. on Moodle 4.5 LTS. Have a 5.1 Testing copy too.
Where is this "tab". Prod. on Moodle 4.5 LTS. Have a 5.1 Testing copy too.
Moodle in English -> Lounge -> ‘Put learners first’: Unesco calls for global ban on smartphones in schools -> Re: ‘Put learners first’: Unesco calls for global ban on smartphones in schools
by Visvanath Ratnaweera -
The world is a weird place. In one place the iPads "revolutionize" education, somewhere else, Why These Parents Want Schools to Stop Issuing iPads to Their Children?