I asked a C developer to change source and backup detail.work file right before deleting. I noticed the skipped packets are already there in detail.work file, but they are not being read by buffered-sql module and then are deleted. developer also added a new debug line which is "Backup to mybackup.log". this line is always shown right before "Unlinking /var/log/freeradius/radacct/detail.work" except in the skipped packets which are shown before or while receiving accounting request. following is the debug for a packet which is not read from detail.work. Wed Feb 1 15:28:40 2017 : Debug: (35371) Received Accounting-Request Id 13 from 82.21.11.91:28342 to 82.21.11.50:1813 length 108 Wed Feb 1 15:28:40 2017 : Debug: (35371) User-Name = "mks539293" Wed Feb 1 15:28:40 2017 : Debug: (35371) NAS-IP-Address = 82.21.11.91 Wed Feb 1 15:28:40 2017 : Debug: (35371) NAS-Port = 8884 Wed Feb 1 15:28:40 2017 : Debug: (35371) Acct-Status-Type = Stop Wed Feb 1 15:28:40 2017 : Debug: (35371) Framed-IP-Address = 10.8.0.62 Wed Feb 1 15:28:40 2017 : Debug: (35371) Acct-Input-Gigawords = 0 Wed Feb 1 15:28:40 2017 : Debug: (35371) Acct-Input-Octets = 25093 Wed Feb 1 15:28:40 2017 : Debug: (35371) Acct-Output-Octets = 40276 Wed Feb 1 15:28:40 2017 : Debug: (35371) Acct-Session-Id = "daivfc6wehcv" Wed Feb 1 15:28:40 2017 : Debug: (35371) Acct-Output-Gigawords = 0 Wed Feb 1 15:28:40 2017 : Debug: (35371) Calling-Station-Id = "88.230.19.102" Wed Feb 1 15:28:40 2017 : Debug: (35371) # Executing section preacct from file /etc/freeradius/sites-enabled/default Wed Feb 1 15:28:40 2017 : Debug: (35371) preacct { Wed Feb 1 15:28:40 2017 : Debug: (35371) modsingle[preacct]: calling preprocess (rlm_preprocess) Wed Feb 1 15:28:40 2017 : Debug: (35371) modsingle[preacct]: returned from preprocess (rlm_preprocess) Wed Feb 1 15:28:40 2017 : Debug: detail (/var/log/freeradius/radacct/detail-*): Backup to mybackup.log Wed Feb 1 15:28:40 2017 : Debug: (35371) [preprocess] = ok Wed Feb 1 15:28:40 2017 : Debug: (35371) policy acct_unique { Wed Feb 1 15:28:40 2017 : Debug: (35371) update request { Wed Feb 1 15:28:40 2017 : Debug: (35371) Tmp-String-9 := "ai:" Wed Feb 1 15:28:40 2017 : Debug: (35371) } # update request = noop Wed Feb 1 15:28:40 2017 : Debug: (35371) if (("%{hex:&Class}" =~ /^%{hex:&Tmp-String-9}/) && ("%{string:&Class}" =~ /^ai:([0-9a-f]{32})/i)) { Wed Feb 1 15:28:40 2017 : Debug: (35371) EXPAND %{hex:&Class} Wed Feb 1 15:28:40 2017 : Debug: (35371) --> Wed Feb 1 15:28:40 2017 : Debug: (35371) EXPAND ^%{hex:&Tmp-String-9} Wed Feb 1 15:28:40 2017 : Debug: (35371) --> ^61693a Wed Feb 1 15:28:40 2017 : Debug: (35371) if (("%{hex:&Class}" =~ /^%{hex:&Tmp-String-9}/) && ("%{string:&Class}" =~ /^ai:([0-9a-f]{32})/i)) -> FALSE Wed Feb 1 15:28:40 2017 : Debug: (35371) else { Wed Feb 1 15:28:40 2017 : Debug: (35371) update request { Wed Feb 1 15:28:40 2017 : Debug: (35371) EXPAND %{md5:%{Acct-Session-ID},%{%{NAS-IPv6-Address}:-%{NAS-IP-Address}},%{NAS-Identifier},%{NAS-Port-ID},%{NAS-Port}} Wed Feb 1 15:28:40 2017 : Debug: (35371) --> fcc3dd2a5b00a62e7d6fc0b5f35316a4 Wed Feb 1 15:28:40 2017 : Debug: (35371) &Acct-Unique-Session-Id := fcc3dd2a5b00a62e7d6fc0b5f35316a4 Wed Feb 1 15:28:40 2017 : Debug: (35371) } # update request = noop Wed Feb 1 15:28:40 2017 : Debug: (35371) } # else = noop Wed Feb 1 15:28:40 2017 : Debug: (35371) } # policy acct_unique = noop Wed Feb 1 15:28:40 2017 : Debug: (35371) modsingle[preacct]: calling suffix (rlm_realm) Wed Feb 1 15:28:40 2017 : Debug: (35371) suffix: Checking for suffix after "@" Wed Feb 1 15:28:40 2017 : Debug: (35371) suffix: No '@' in User-Name = "mks539293", looking up realm NULL Wed Feb 1 15:28:40 2017 : Debug: (35371) suffix: No such realm "NULL" Wed Feb 1 15:28:40 2017 : Debug: (35371) modsingle[preacct]: returned from suffix (rlm_realm) Wed Feb 1 15:28:40 2017 : Debug: (35371) [suffix] = noop Wed Feb 1 15:28:40 2017 : Debug: (35371) } # preacct = ok Wed Feb 1 15:28:40 2017 : Debug: (35371) # Executing section accounting from file /etc/freeradius/sites-enabled/default Wed Feb 1 15:28:40 2017 : Debug: (35371) accounting { Wed Feb 1 15:28:40 2017 : Debug: (35371) modsingle[accounting]: calling detail (rlm_detail) Wed Feb 1 15:28:40 2017 : Debug: /var/log/freeradius/radacct/detail-%S Wed Feb 1 15:28:40 2017 : Debug: Parsed xlat tree: Wed Feb 1 15:28:40 2017 : Debug: literal --> /var/log/freeradius/radacct/detail- Wed Feb 1 15:28:40 2017 : Debug: percent --> S Wed Feb 1 15:28:40 2017 : Debug: (35371) detail: EXPAND /var/log/freeradius/radacct/detail-%S Wed Feb 1 15:28:40 2017 : Debug: (35371) detail: --> /var/log/freeradius/radacct/detail-2017-02-01 15:28:40 Wed Feb 1 15:28:40 2017 : Debug: (35371) detail: /var/log/freeradius/radacct/detail-%S expands to /var/log/freeradius/radacct/detail-2017-02-01 15:28:40 Wed Feb 1 15:28:40 2017 : Debug: %t Wed Feb 1 15:28:40 2017 : Debug: Parsed xlat tree: Wed Feb 1 15:28:40 2017 : Debug: percent --> t Wed Feb 1 15:28:40 2017 : Debug: (35371) detail: EXPAND %t Wed Feb 1 15:28:40 2017 : Debug: (35371) detail: --> Wed Feb 1 15:28:40 2017 Wed Feb 1 15:28:40 2017 : Debug: (35371) modsingle[accounting]: returned from detail (rlm_detail) Wed Feb 1 15:28:40 2017 : Debug: (35371) [detail] = ok Wed Feb 1 15:28:40 2017 : Debug: (35371) modsingle[accounting]: calling detail2 (rlm_detail) Wed Feb 1 15:28:40 2017 : Debug: /var/log/freeradius/radacct/debug/%{%{Packet-Src-IP-Address}:-%{Packet-Src-IPv6-Address}}/detail-%Y%m%d Wed Feb 1 15:28:40 2017 : Debug: Parsed xlat tree: Wed Feb 1 15:28:40 2017 : Debug: literal --> /var/log/freeradius/radacct/debug/ Wed Feb 1 15:28:40 2017 : Debug: XLAT-IF { Wed Feb 1 15:28:40 2017 : Debug: attribute --> Packet-Src-IP-Address Wed Feb 1 15:28:40 2017 : Debug: } Wed Feb 1 15:28:40 2017 : Debug: XLAT-ELSE { Wed Feb 1 15:28:40 2017 : Debug: attribute --> Packet-Src-IPv6-Address Wed Feb 1 15:28:40 2017 : Debug: } Wed Feb 1 15:28:40 2017 : Debug: literal --> /detail- Wed Feb 1 15:28:40 2017 : Debug: percent --> Y Wed Feb 1 15:28:40 2017 : Debug: percent --> m Wed Feb 1 15:28:40 2017 : Debug: percent --> d Wed Feb 1 15:28:40 2017 : Debug: (35371) detail2: EXPAND /var/log/freeradius/radacct/debug/%{%{Packet-Src-IP-Address}:-%{Packet-Src-IPv6-Address}}/detail-%Y%m%d Wed Feb 1 15:28:40 2017 : Debug: (35371) detail2: --> /var/log/freeradius/radacct/debug/82.21.11.91/detail-20170201 Wed Feb 1 15:28:40 2017 : Debug: (35371) detail2: /var/log/freeradius/radacct/debug/%{%{Packet-Src-IP-Address}:-%{Packet-Src-IPv6-Address}}/detail-%Y%m%d expands to /var/log/freeradius/radacct/debug/82.21.11.91/detail-20170201 Wed Feb 1 15:28:40 2017 : Debug: %t Wed Feb 1 15:28:40 2017 : Debug: Parsed xlat tree: Wed Feb 1 15:28:40 2017 : Debug: percent --> t Wed Feb 1 15:28:40 2017 : Debug: (35371) detail2: EXPAND %t Wed Feb 1 15:28:40 2017 : Debug: (35371) detail2: --> Wed Feb 1 15:28:40 2017 Wed Feb 1 15:28:40 2017 : Debug: (35371) modsingle[accounting]: returned from detail2 (rlm_detail) Wed Feb 1 15:28:40 2017 : Debug: (35371) [detail2] = ok Wed Feb 1 15:28:40 2017 : Debug: (35371) modsingle[accounting]: calling exec (rlm_exec) Wed Feb 1 15:28:40 2017 : Debug: (35371) modsingle[accounting]: returned from exec (rlm_exec) Wed Feb 1 15:28:40 2017 : Debug: (35371) [exec] = noop Wed Feb 1 15:28:40 2017 : Debug: (35371) modsingle[accounting]: calling attr_filter.accounting_response (rlm_attr_filter) Wed Feb 1 15:28:40 2017 : Debug: %{User-Name} Wed Feb 1 15:28:40 2017 : Debug: Parsed xlat tree: Wed Feb 1 15:28:40 2017 : Debug: attribute --> User-Name Wed Feb 1 15:28:40 2017 : Debug: (35371) attr_filter.accounting_response: EXPAND %{User-Name} Wed Feb 1 15:28:40 2017 : Debug: (35371) attr_filter.accounting_response: --> mks539293 Wed Feb 1 15:28:40 2017 : Debug: (35371) attr_filter.accounting_response: Matched entry DEFAULT at line 12 Wed Feb 1 15:28:40 2017 : Debug: (35371) modsingle[accounting]: returned from attr_filter.accounting_response (rlm_attr_filter) Wed Feb 1 15:28:40 2017 : Debug: (35371) [attr_filter.accounting_response] = updated Wed Feb 1 15:28:40 2017 : Debug: (35371) } # accounting = updated Wed Feb 1 15:28:40 2017 : Debug: (35371) Sent Accounting-Response Id 13 from 82.21.11.50:1813 to 82.21.11.91:28342 length 0 Wed Feb 1 15:28:40 2017 : Debug: (35371) Finished request Wed Feb 1 15:28:40 2017 : Debug: (35371) Cleaning up request packet ID 13 with timestamp +15280 Wed Feb 1 15:28:40 2017 : Info: Ready to process requests Wed Feb 1 15:28:40 2017 : Debug: detail (/var/log/freeradius/radacct/detail-*): Unlinking /var/log/freeradius/radacct/detail.work Wed Feb 1 15:28:40 2017 : Debug: detail (/var/log/freeradius/radacct/detail-*): Polling for detail file Wed Feb 1 15:28:40 2017 : Debug: detail (/var/log/freeradius/radacct/detail-*): Detail listener state unopened waiting 1.134560 sec Wed Feb 1 15:28:41 2017 : Debug: detail (/var/log/freeradius/radacct/detail-*): Polling for detail file Wed Feb 1 15:28:41 2017 : Debug: detail (/var/log/freeradius/radacct/detail-*): Detail listener state unopened waiting 1.117968 sec