SQLcmd on my Mac: Seg fault
trying to connect to SQL Server from my Mac so install sqlcmd: brew tap microsoft/mssql-release https://github.com/Microsoft/homebrew-mssql-release brew update brew install mssql-tools then get error $...
View ArticleIndex Advisor ? PostgreSQL, Oracle and SQL Server : yes , MySQL : no
How does one check if there are missing indexes in a database? Is there a programatic way to do it? Explain Plan Most blogs on the subject will say look at the explain plan for your query. Basic...
View ArticleOracle Imp (import) to RDS
Had and old export dump file I wanted to import into RDS. I first tried to use S3 as a hosting site for the .dmp file and use rdsadmin.rdsadmin_s3_tasks.download_from_s3 to copy the file to the RDS...
View ArticleClik here to view.
Indexes for Joins on Oracle
Looking at ways to programmatically analyze explain plans to see if adding indexes would help. The analysis is straight forward for for full table scans with strong predicate filters. If there is a...
View ArticleIndexes on Joins for MySQL
MySQL is simpler than the Oracle example because MySQL only has Nested Loops and doesn’t have Hash Join. Here is the query, like on the Oracle example from the last blog post select max(t1.data) from...
View ArticleWhere to add Index on Postgres
Summary Goal in this post is to layout a methodology that can be implemented to scan the explain plans and identify opportunities to optimize the sql execution with additional indexes. The missing...
View ArticleClik here to view.
Granularity impact on visualization
The longer the timeline we show in the graph, either the more points we show or the larger granularity we use. For example if I show 1 hour of data, then I can show 60 points of 1 minute each...
View ArticleCovering Indexes in Postgres
Covering indexes are where all the columns needed are in the index and, in theory, only the index needs to be accessed. This seemingly straight forward strategy is much tricker on Postgres. Let’s take...
View ArticleClik here to view.
Postgres performance gone south but nothing changed !
Postgres seems pretty cool as open source databases go. I’m finding a much greater affinity for Postgres than say MySQL. On the other hand, coming from an Oracle background there are a few things that...
View ArticleMySQL waits and CPU
Question: how do I know that one user is waiting for a lock and another user is burning CPU on MySQL? i.e. how can I create active session history on MySQL like on Oracle? Two simple cases I’m looking...
View ArticleMySQL -> what to do with NESTING_EVENT_ID
How does one use NESTING_EVENT_ID? Below I’ve selected from events_waits_history_long for a thread, but none of the NESTING_EVENT_ID values show up in EVENT_ID or END_EVENT_ID mysql> select ->...
View ArticleMySQL : events_waits_current – who is waiting and who is on CPU
Anyone familiar with Oracle performance tuning know about ASH , aka active session history. ASH saves a history of every session that is active every collection, which by default is once per second....
View Articleintroducing network latency on Docker (SQL Server Always On testing)
I am testing out Always On replication on SQL Server with a cool docker setup that includes primary and secondary https://github.com/rafaelrodrigues3092/docker-mssql-alwayson When I created data on the...
View ArticleSetting up Always ON (SQL Server)
There is a great little docker setup that starts Always On (SQL Servers instance replication not to be confused with their article i.e. table replication). The docker setup creates a primary and a...
View ArticleProtected: DataDog – the marriage of ASH, Query Stats and UI
This content is password protected. To view it please enter your password below: Password:
View ArticleJDBC Request: Cannot load JDBC driver class’com.mysql.jdbc.Driver’ solution
Just quick post to document a troublesome error when running Jmeter on Mysql JDBC Request: Cannot load JDBC driver class’com.mysql.jdbc.Driver’ solution Should be pretty simple, it’s just a...
View ArticleClik here to view.
Are some MySQL wait events actually CPU time ?
Sure, wait event times in any database will include some CPU time, though ideally it should be minimal. Waits should be instrumented as close to the off CPU wait event as possible, i.e. if I’m doing an...
View ArticleClik here to view.
New works by John Williams Waterhouse “discovered”
Is there an artist you liked, but would love to have seen more works by? I always liked John William Waterhouse and wished there were more pieces. You may be familiar the works of Waterhouse like Hylas...
View Article