Search Results

This should be a simple question, but surprisingly, I can't find much about it: the difference in MySQL thread states update vs updating. … The MySQL docs say: update: "The thread is getting ready to start updating the table." updating: "The thread is searching for rows to update and is updating them" MariaDB says: update: "About to start …

l.idLog = ld.idLog INNER JOIN dataAttributes da ON ld.idDataAttribute = da.idDataAttribute WHERE l.idSite = 2776 AND l.timestamp >= 1430438400 AND l.timestamp <= 1433116800 limit 100; On our VM with MySQL … On our Amazon RDS (MySQL 5.6, db.m3.large, 1500GB, 4500 IOPS on SSD), which is a copy of the first DB, this is very slow. It also causes a CPU spike, that is not visible on the MySQL 5.5 server. …

I'm looking into sync_binlog = 50 and innodb_flush_log_at_trx_commit = 2 to improve write performance. There is this question, but it doesn't address the specific problems with replication. I have an …

tables in use 1, locked 1 LOCK WAIT 5 lock struct(s), heap size 1184, 3 row lock(s), undo log entries 2 MySQL thread id 15503218, OS thread handle 0x2b6fcb273700, query id 3125430892 172.31.0.175 vrm_dev … tables in use 1, locked 1 4 lock struct(s), heap size 1184, 2 row lock(s), undo log entries 2 MySQL thread id 15503217, OS thread handle 0x2b6fcbf25700, query id 3125430894 172.31.0.175 vrm_dev update …

The write intention lock docs say (emphasis mine, and yes, MySQL 5.7, because 8.0 didn't exist at the time): An insert intention lock is a type of gap lock set by INSERT operations prior to row insertion …

My MySQL slave basically has 100% disk load all the time, and cannot get better than being a day behind. … I guess MySQL must be causing seeks. Edit2: I thing that might be useful: the thousands of new rows per minute are added using multi row insert statements. …

I still don't really know how to see what exactly the slave is spending time on, but I was able to let the slave catch up. The problem was the action of deleting old rows with DELETE FROM table WHER …

If you have as many MySQL threads as CPU threads, all CPUs will be in IOWAIT. But, that's not to say they can't do anything else. … Like this (example, NOT the actual MySQL server; it's not about the numbers shown): …

This kind of CPU vs IO, and the two graphs 'CPU load' and 'non CPU-load' are only reported when you have performance insight turned on, so it's reported by MySQL. …

Two things: 1) do you have indexes? What does show index from ping_results say? 2) Don't use subqueries. Convert the query to a join statement.

I would open up Mysql Workbench and do a graphical EXPLAIN on it, so you can see the query plan. You can then try the other situation too and compare the results. …

With MySQL secondary/primary, sync_binlog and innodb_flush_log_at_trx_commit control log and disk flushing, and are important to maintain consistency between primary and secondary (so that the secondary …

We have an application (on Amazon RDS MySQL 5.7; db.m5.24xlarge; 96 cores) that takes in a lot of data, in parallel processors+queues. … 47137720436480 has waited at lock0lock.cc line 6342 for 0 seconds the semaphore: Mutex at 0x2b2be1000058, Mutex LOCK_SYS created lock0lock.cc:454, lock var 1 and many more Edit: also interesting in the MySQL …

Test running the system on MySQL 8 shows a marked improvement: On a 96 core MySQL server, these are 64 queue processors (=64 processes) operating on the same table, but all on different rows (mostly updating …

We have a time-series application that also writes all the records to kind of a 'head' table in MySQL. This is somewhat of a legacy, but very interwoven and hard to get rid of. …