total        used        free      shared  buff/cache   available
Mem:        4041652      495636     2778952       25772      767064     3272828
Swap:             0           0           0

Database header page information:
        Flags                   0
        Generation              55541707
        System Change Number    0
        Page size               16384
        ODS version             12.0
        Oldest transaction      398573877
        Oldest active           398573878
        Oldest snapshot         398573878
        Next transaction        398597261
        Sequence number         0
        Next attachment ID      263
        Implementation          HW=AMD/Intel/x64 little-endian OS=Linux CC=gcc
        Shadow count            0
        Page buffers            0
        Next header page        0
        Database dialect        3
        Creation date           Apr 4, 2021 21:16:22
        Attributes

    Variable header data:
        Sweep interval:         5000
        *END*

...
call gensql.bat | isql -user ... -password ... -role ... server:alias
...

@ECHO OFF 

SETLOCAL

echo commit;
:Loop
	title %time%
	set starttick=
	for /f %%s in ('checktime start') do set starttick=%%s

	echo set transaction wait READ ONLY;
	echo select count(*) from PR_GET('lala', 0, 0);
	echo commit;
	
	set check=
	for /f %%s in ('checktime check %starttick% 300') do set check=%%s
	if defined check (
		echo %time% %check% >> delays.log
	)
	sleep 50
	goto :Loop
echo quit;
GOTO :EOF

>fbstat /var/lib/firebird/3.0/system/security3.fdb

Database "/var/lib/firebird/3.0/system/security3.fdb"
Gstat execution time Thu May 27 14:29:58 2021

Database header page information:
        Flags                   0
        Generation              1616
        System Change Number    0
        Page size               8192
        ODS version             12.0
        Oldest transaction      28161
        Oldest active           28162
        Oldest snapshot         28162
        Next transaction        28162
        Sequence number         0
        Next attachment ID      3333
        Implementation          HW=AMD/Intel/x64 little-endian OS=Linux CC=gcc
        Shadow count            0
        Page buffers            0
        Next header page        0
        Database dialect        3
        Creation date           Aug 25, 2020 12:14:06
        Attributes              force write

    Variable header data:
        *END*