Hello, I encounter from time to time that one of our ESQL/C clients hangs with the details described below for ever, while accessing on startup a table 'sisisinst' which has only some 50 rows, all of CHAR columns. Other ESQL/C clients start up fine (they all check this table 'sisisinst' on startup to verify the correct version of our application) Also SQL works fine. What can I do to get to the source of the problem? Thanks matthias ESQL/C statement: EXEC SQL PREPARE sid_sisisinst FROM :select_anw; host variable :select_anw contains: (gdb) p select_anw $2 = "SELECT ctid, * from sisisinst WHERE version = :v1", '\000' process PID 23957 is hanging in poll() on network socket to PostgreSQL server: (Version 11.4 on Linux) (gdb) bt #0 0x00007ff9020c2664 in poll () from /lib64/libc.so.6 #1 0x00007ff90144c22f in pqSocketPoll () from /usr/local/sisis-pap/pgsql/lib/libpq.so.5 #2 0x00007ff90144c0ff in pqSocketCheck () from /usr/local/sisis-pap/pgsql/lib/libpq.so.5 #3 0x00007ff90144bf83 in pqWaitTimed () from /usr/local/sisis-pap/pgsql/lib/libpq.so.5 #4 0x00007ff90144bf55 in pqWait () from /usr/local/sisis-pap/pgsql/lib/libpq.so.5 #5 0x00007ff901447d3a in PQgetResult () from /usr/local/sisis-pap/pgsql/lib/libpq.so.5 #6 0x00007ff901448478 in PQexecFinish () from /usr/local/sisis-pap/pgsql/lib/libpq.so.5 #7 0x00007ff90144819a in PQprepare () from /usr/local/sisis-pap/pgsql/lib/libpq.so.5 #8 0x00007ff901cc788d in prepare_common () from /usr/local/sisis-pap/pgsql/lib/libecpg.so.6 #9 0x00007ff901cc7a26 in ECPGprepare () from /usr/local/sisis-pap/pgsql/lib/libecpg.so.6 #10 0x00007ff9044a86ee in select_record (scroll=1, lock=0, key=2, sel_anw=0x7ffed86186c0 "SELECT ctid, * from %s", where_anw=0x7ffed8617330 "%s = :v1", p_daten=0x7ff904dd7700 <hrec_sisisinst>, i_between=0, p_oben=0x7ffed86171d0, order_by=0x0, auf_ab=0x0, group_by=0x0, having=0x0, into_temp=0x0, count=0x7ffed8617328) at sisisinst.pgc:925 #11 0x00007ff9044a7a8d in sisisinst (zugriff=1, scroll=1, lock=0, key=2, sto=-20000, p_daten=0x7ffed8618c30, sel_anw=0x7ffed86186c0 "SELECT ctid, * from %s", where_anw=0x7ffed8617330 "%s = :v1", p_btw_daten=0x0, order_by=0x0, auf_ab=0x0, group_by=0x0, having=0x0, into_temp=0x0, count=0x7ffed8617328) at sisisinst.pgc:450 #12 0x00007ff9043718a5 in DB_rdir (tabmodul=0x7ff9044a7639 <sisisinst>, key=2, scroll=1, lock=0, p_daten=0x7ffed8618c30) at dbcall.pgc:1665 #13 0x00007ff90436f6c9 in DB_ChkVer () at dbcall.pgc:307 #14 0x00007ff9043708d3 in DB_opdbP (mode=1) at dbcall.pgc:840 #15 0x00007ff90436fff8 in DB_opdb () at dbcall.pgc:543 #16 0x0000000000405efa in InitIndex (setid=FSTAB_Personen) at ./INDEX.c:1000 #17 0x0000000000405241 in main (argc=2, argv=0x7ffed8619fa8) at ./INDEX.c:412 running PostgreSQL processes: # ps ax | grep postgres: 329 pts/13 S+ 0:00 grep --color=auto postgres: 2354 ? Ss 0:17 postgres: checkpointer 2355 ? Ss 0:09 postgres: background writer 2356 ? Ss 0:10 postgres: walwriter 2357 ? Ss 0:04 postgres: autovacuum launcher 2358 ? Ss 0:00 postgres: archiver last was 000000010000000F00000062 2359 ? Ss 0:31 postgres: stats collector 2360 ? Ss 0:00 postgres: logical replication launcher 14044 ? Ss 0:00 postgres: sisis sisis ::1(53426) idle 14100 ? Ss 0:00 postgres: sisis sisis ::1(53432) idle 16852 ? Ss 0:00 postgres: sisis sisis ::1(53486) idle 17575 ? Ss 0:00 postgres: sisis sisis ::1(48736) idle 17577 ? Ss 0:00 postgres: sisis sisis ::1(48742) idle 17583 ? Ss 0:00 postgres: sisis sisis 10.23.33.19(49630) idle 17584 ? Ss 0:00 postgres: sisis sisis 10.23.33.19(49632) idle 17585 ? Ss 0:00 postgres: sisis sisis 10.23.33.19(49634) idle 17587 ? Ss 0:00 postgres: sisis sisis ::1(48762) idle 17590 ? Ss 0:00 postgres: sisis sisis ::1(48770) idle 17593 ? Ss 0:00 postgres: sisis sisis ::1(48778) idle 17609 ? Ss 0:04 postgres: sisis sisis ::1(48794) idle 17612 ? Ss 0:00 postgres: sisis sisis ::1(48802) idle 17615 ? Ss 0:04 postgres: sisis sisis ::1(48810) idle 17618 ? Ss 0:00 postgres: sisis sisis ::1(48818) idle 17621 ? Ss 0:08 postgres: sisis sisis ::1(48826) idle 17866 ? Ss 0:00 postgres: sisis sisis 10.23.33.19(49758) idle 17868 ? Ss 0:00 postgres: sisis sisis ::1(48886) idle 17907 ? Ss 0:00 postgres: sisis sisis ::1(48900) idle 17948 ? Ss 0:00 postgres: sisis sisis ::1(48914) idle 21457 ? Ss 0:00 postgres: sisis sisis ::1(53664) idle 23958 ? Ss 0:00 postgres: sisis sisis ::1(53742) idle ^^^^^ lsof -P -p 23957 | grep 5432 INDEX 23957 sisis 2u IPv6 117475261 0t0 TCP localhost:53742->localhost:5432 (ESTABLISHED) -- Matthias Apitz, ✉ guru@xxxxxxxxxxx, http://www.unixarea.de/ +49-176-38902045 Public GnuPG key: http://www.unixarea.de/key.pub May, 9: Спаси́бо освободители! Thank you very much, Russian liberators!