6/11/2023 0 Comments Cleanexit from sql![]() There has long been a discussion about whether this is a good thing or not. Many people use these functions to handle data directly in SQL. PostgreSQL allows end users to store BLOBs (binary large objects) in the database. Blobs bytea_output lo_import lo_unlink max_locks_per_transaction pg_largeobject postgresql vacuumlo Oct 28 05:31:25 systemd: Starting Microsoft SQL Server Database Engine… Oct 28 05:31:25 systemd: Started Microsoft SQL Server Database Engine. Oct 28 05:31:25 systemd: rvice holdoff time over, scheduling restart. Oct 28 05:31:25 systemd: Unit rvice entered failed state. Oct 28 05:31:25 systemd: rvice: main process exited, code=exited, status=1/FAILURE This is an informational message only no user action is required. Oct 28 05:31:24 sqlservr: 05:31:24.22 spid51 SQL Trace was stopped due to server shutdown. Oct 28 05:31:24 sqlservr: 05:31:24.22 spid51 Server shut down by NOWAIT request from login sa. Oct 28 05:28:00 systemd: Starting Microsoft SQL Server Database Engine… Oct 28 05:28:00 systemd: Started Microsoft SQL Server Database Engine. Oct 28 05:28:00 systemd: rvice holdoff time over, scheduling restart. Oct 28 05:28:00 systemd: Unit rvice entered failed state. Oct 28 05:28:00 systemd: rvice: main process exited, code=exited, status=1/FAILURE Oct 28 05:27:58 sqlservr: 05:27:58.37 spid51 SQL Trace was stopped due to server shutdown. Oct 28 05:27:58 sqlservr: 05:27:58.37 spid51 Server shut down by request from login sa. Let’s say we initiate a shutdown in SQL Server the T-SQL command SHUTDOWN here’s what we’ll get in journald. Let’s see what happens in certain exit conditions from SQL Server on Linux. systemd is the parent process of the sqlservr process and receives it’s exit code. Now when things go wrong, that’s when process return a non-zero value. In a relational database system this is significant, in that, we really do want our systems to shut down cleanly. This means all is well in the world and the process has shut down. When a process exits, it will return an integer value to the parent process. If a process terminates cleanly, it conventionally returns 0 to the parent process. We’ll save those discussions for another day. There are other conditions that cause it to restart such as responding to unclean signals, watchdog and also service timeouts. What Restart=on-failure option does, is if a systemd unit returns an unclean exit code, systemd will automatically restart the service. Inside that file we have the following configuration: Service units in systemd are configured in unit files and SQL Server on Linux’s unit file lives in the file /usr/lib/systemd/system/rvice. Journalctl -u mssql-server –no-pager | more We’ll use this command in the next section. To get the text to wrap, use the following code…then pipe the output into a pager like more or less because you know… less is more. Running just journalctl will cause the text output to run off the side of the screen without wrapping the text in your terminal. We can query the information stored in journald with the command journalctl and below is the syntax to query a particular service unit’s log in journald. The SQL Server Error Log lands in here because it’s written to standard out and by default, a service unit’s standard out is written into the journal. Now with respect to SQL Server on Linux, the information logged into journald is systemd’s information about our rvice unit and also the SQL Server Error Log. Journald stores logging information from systemd units. It does much more than that, in fact, one of it’s other core components is journald. Meaning, it’s responsible for the orderly starting of services on a Linux system. Systemd is an initialization daemon, it’s job is to bring the system to usable state. ![]() My friend and SQL Server guru Argenis Fernandez – about this behavior on Twitter and I’ve been meaning to write this post, so here you go! Also, there’s a Connect item filed by Argenis on this here. In this blog post we’re going to cover systemd, process exit codes and highlight how systemd reacts in certain exit conditions from SQL Server on Linux.
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