The eBPF technology of the Linux kernel allows it to monitor applications with minimal overhead. UProbes can be used to trace the invocation and exit of functions in programs. Modern tools to observe databases (like pg-lock-tracer) are built on top of eBPF. However, these fully flagged tools are often written in C and Python and require some development effort. Sometimes, a ‘quick and dirty’ solution for a particular observation would be sufficient. With bpftrace, users can create eBPF programs with a few lines of code. In this article, we develop a simple bpftrace program to observe the execution of vacuum calls in PostgreSQL and analyze the delay.

To store sets of integer values efficiently, PostgreSQL uses internally a data structure called Bitmapset. A wide range of operations are supported on the Bitmapset.

The Database Management System PostgreSQL uses lightweight locks (LWLocks) to control access to shared memory data structures. In this article, the tool pg_lw_lock_trace is presented that allows tracing these kinds of locks. The tool can be downloaded from the website of the project. This is the second article that deals with tracing PostgreSQL locks. The first article deals with the tracing of heavyweight locks and can be found here.

The DBMS PostgreSQL uses locks to synchronize access to resources like tables. To get more information about the locks, the table pg_locks shows which relation is currently locked by which process. However, this relation shows only the current state of the locks. To show the locking activity in real-time, the new lock tracing tool pg_lock_tracer can be used. pg_lock_tracer is an open-source tool that I have just recently created. It can be downloaded from the website of the project.

Reading and writing data from mass storage (volumes) is a quite common pattern in software. However, some time elapses between starting the I/O request (i.e., reading or writing data) and the completion of the request. The elapsed time to complete the request is called I/O latency. Older magnetic hard disks need some time to position the head on the right track of the magnetic disk. Also, newer flash-based disks like SSDs need some time to read the data. In addition, at common cloud providers, different types of block volumes are available that provide a different I/O latency. With the software ioping, this latency can be measured.