Server Information

SQL Server

With SQL Server there is no server character set or socket, so those lines don't appear; the collation is the server's default one.

PostgreSQL

With PostgreSQL the character set is the server encoding, the collation is the connected database's, and there is no socket line.

ClickHouse

With ClickHouse there is no character set, collation, socket or connection id, so those lines don't appear, and there are four tabs instead of six: Session variables and Session status don't exist, because the HTTP interface has no session.

Oracle

With Oracle there is no data directory, socket or server collation, so those lines do not appear, and the version comment is the instance name. The connection limit is the sessions parameter, which can only be read with permission on V$PARAMETER: without it, the line is left out.

SQL Server

With SQL Server, Global variables are sys.configurations —what sp_configure changes, with the value in use— and the server properties, prefixed SERVERPROPERTY.; Global status holds the performance counters and sys.dm_os_sys_info; Session variables are your connection's SET options, and Session status is your session's row in sys.dm_exec_sessions.

PostgreSQL

With PostgreSQL, Global variables are all of pg_settings, with the unit next to the value; Global status adds up pg_stat_database across databases and counts connections from pg_stat_activity; Session variables lists only what your connection has changed, so it is usually empty, and Session status is your connection's row in pg_stat_activity.

ClickHouse

With ClickHouse, Global status gathers system.metrics —what is happening now, with the prefix metrics.—, system.events —accumulated since startup, events.— and system.asynchronous_metrics —sampled every second, asynchronous_metrics.—; Global variables gathers system.settings (settings.) and system.server_settings (server_settings.).

Oracle

With Oracle, Global variables is V$PARAMETER; Global status is the V$SYSSTAT counters, accumulated since startup; Session variables are NLS_SESSION_PARAMETERS and the SYS_CONTEXT('USERENV', …) values, prefixed USERENV., and Session status is the V$SESSTAT counters of the connection doing the read. The V$ views require SELECT_CATALOG_ROLE: without it, the three tabs that use them say why they are empty, with the server's text, and only Session variables fills in.

MySQLMariaDBAurora

A last column gives each table's storage engine. The figures come from information_schema, so they need permissions on it, and the rows of an InnoDB table are an estimate.

SQL Server

With SQL Server it lists every database your login can open, with its schema (demo.dbo), and the size counts data and indexes. There is no storage engine column.

PostgreSQL

With PostgreSQL it lists the tables of the connected database in every schema, pg_catalog included; the size counts indexes and TOAST, and the rows are the planner's estimate: a table that has never been analyzed shows —. There is no storage engine column.

ClickHouse

With ClickHouse the figures add up the active parts in system.parts, so the rows are exact and not an estimate, and the Compression column says how many times larger the uncompressed table is than what it takes on disk. The Engine column names each table's engine (MergeTree, ReplicatedMergeTree…).

Oracle

With Oracle the size adds up the segments of the table, its LOBs and its indexes. With permission to read DBA_SEGMENTS every schema is listed; without it, only the tables in your own schema, and other schemas don't appear. Rows are the last gathered statistics, so the column is called Rows (estimated) and Statistics from sits next to it with its date; a table that has never been analyzed shows —. There is no storage engine column.

MySQLMariaDBAurora

With MySQL, MariaDB and Aurora the flagged counters are the aborted connections, the table lock waits, the connection errors and the InnoDB deadlocks.