Mysql slave invalidating query cache entries

First, I want to thank everybody for attending the August 25 webinar.

The recording and slides for the webinar are available here.

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For example, the position is 999 and I want to analyze the previous five events. Q: We are having issues with inconsistencies over time.

We also have a lot of “waiting for table lock” statuses during high volume usage.

Would changing these tables to Inno DB help the replicated database remain consistent? Switching to Inno DB might help, but it depends on what types of queries you use.

For example, if you often use the error for Inno DB too.

Regarding data consistency between the master and slave, you need to use row-based replication.

Q: For semi-sync replication, what’s the master’s behavior when the master never received ACK from any of the slaves?A: It will timeout after milliseconds, and then switch to asynchronous replication. Would increasing these to eight offer better IO for slaves? A: Yes, an increased number of IO threads would most likely improve performance.Q: We’re using My SQL on r3.4xlarge EC2 instances (16 CPU). innodb_read_io_threads and innodb_write_io_threads =4. Other parameters that could help are similar to the ones discussed in “Inno DB Troubleshooting” and “Introduction to Troubleshooting Performance: What Affects Query Execution? You need to pay attention to Inno DB options that affect IO ( . A: What do you mean by “how many masters can [you] have working together”?Do you mean circular replication or a multi-master setup? For a multi-master setup you should ensure that the slave has enough resources to process all requests.For circular replication, ensure that each of the masters in the chain can handle the increasing number of writes as they replicate down the chain, and do not lead to permanently increasing slave lags. A: Follow the advice in the user manual: set to the number of servers and never update auto-incremented columns manually. Sometimes the replication lag keeps increasing while the slave was doing “invalidating query cache entries(table)”. A: The status means that the query cache is invalidating entries, and has been changed by a command currently being executed by the slave SQL thread.To avoid this issue, you need to keep the query cache small (not larger than 512 MB) and de-fragment it from time to time using the FLUSH QUERY CACHE command.

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