Hi, Adrian.Today I have collected a tcpdump at client side with communications between application server and db server while the issue was occurring one time per second on another program.
I send you two files.The first one is a zipped tarball (.tgz) containing a text representation of the tcpdump starting at point where it reports the declaration of the failing cursor ("cu4" as you can see in the first line of the file) and subsequent fetch. Consider that the client application log detected the XX001 error on the first FETCH of the cursor at 2024-12-20 12:17:35.175 The second file (zipped tarball .tgz) is too big to be sent as attachment, so I provide a link where it can be downloaded. It is the fraction of tcpdump recorded during the program failure (occurred several times). It is in .pcap format so it is possible to open it with Wireshark or tcpdump -A -r Anyone interested can download it at https://cleislabs.cleistech.it/downloads/tcpdump_out009.pcap.tgz
Consider that during the dump several different cursor was declared with the name "cu4", but the one failing is the one of the first line. Maybe an expert (I'm not so expert) can see if the disconnection is really made by the client and/or if the data returned by the server are really corrupted as per XX001 SQLSTATE.
Best regards. Enrico Il 19/12/24 22:47, Adrian Klaver ha scritto:
On 12/19/24 11:40 AM, Enrico Schenone wrote:Hello, my answers in line along your message ... Thanks a lot again. EnricoOn 12/19/24 10:11, Enrico Schenone wrote:Good day, Adrian.I get the error inside the program by catching the exception and logging it with diagnostic info provided by the DVM (a runtime interpreter similar in concept to a JVM) that embed the PG driver.The 4Js DVM (Dynamic Virtual Machine) is that one https://4js.com/online_documentation/fjs-gas-manual-html/index.html#gas-topics/c_gas_what_is_dvm.htmlNo, it is a runtime interpreter for Linux, Windows, IBM AIX, macOS and other unix-like OSs. It ensures the portability of 4Js Genero compiled programs (p-code) on several OS platforms. 4Js Genero is a Low Code Application Platform. The programming language, named "BDL - Business Development Language", is an evolution of the Informix-4gl.In other words an Android client?Compiled programs needs a runtime interpreter (DVM) to be executed. The DVM embeds at low-level the DB drivers provided by several vendors,From previous post you mentioned: "Four Js support said <We use the standard C API provided by the DB vendor. In the case of PostgreSQL, we use the C API client " So are they building their own driver over libpq?and at BDL high level the application program can easily connect to the major DBs on the market thanks to its ODI (Open Database Interface).Please take a look to the attached text file, that is the full failing session log (filtered from the debug5 PostgreSQL server log).I can't give you info on what the DVM does at low level, but I can send you the distinct full session log fragment at server side, where it is quite easy to understand how the DVM translates the program's SQL queries end what PostgreSQL does.That might be useful.This is where it falls off the rails, but I can't see why?:2024-12-16 17:27:14.406 CET [2214722] cleistech@hh24odds_prod - 192.168.16.17900000676054e0.21cb42 LOCATION: ShowTransactionStateRec, xact.c:5510 2024-12-16 17:27:14.406 CET [2214722] cleistech@hh24odds_prod - 192.168.16.17900000676054e0.21cb42 STATEMENT: fetch forward 50 from cu6 2024-12-16 17:27:14.406 CET [2214722] cleistech@hh24odds_prod - 192.168.16.17900000676054e0.21cb42 LOG: 00000: statement: fetch forward 50 from cu6 2024-12-16 17:27:14.406 CET [2214722] cleistech@hh24odds_prod - 192.168.16.17900000676054e0.21cb42 LOCATION: exec_simple_query, postgres.c:1073 2024-12-16 17:27:14.406 CET [2214722] cleistech@hh24odds_prod - 192.168.16.17900000676054e0.21cb42 DEBUG: 00000: CommitTransaction(1) name: unnamed; blockState: STARTED; state: INPROGRESS, xid/subid/cid: 0/1/02024-12-16 17:27:14.406 CET [2214722] cleistech@hh24odds_prod - 192.168.16.17900000676054e0.21cb42 LOCATION: ShowTransactionStateRec, xact.c:5510 2024-12-16 17:27:14.406 CET [2214722] cleistech@hh24odds_prod - 192.168.16.17900000676054e0.21cb42 STATEMENT: fetch forward 50 from cu6 2024-12-16 17:27:14.407 CET [2214722] cleistech@hh24odds_prod - 192.168.16.17908006676054e0.21cb42 LOG: 08006: could not receive data from client: Connessione interrotta dal corrispondenteThanks again and best regards. Enrico
Attachment:
tcpdump_out_009_cu4.tgz
Description: application/compressed-tar
