The connection to the server was lost. Attempting reset: Failed.

[Yessica Brinkmann <yessica.brinkmann@xxxxxxxxx>]

Good afternoon,
I am doing a thesis from the University. My thesis is the modification of the Gurjeet Index Adviser, to add some features.
At the moment I am modifying one of the .c files and adding a function called get_columnames that returns the names of the columns of a table, passing it the numbers of the attributes.
I really thought a lot, but I don't understand why but the function fails after the _expression_ is executed:
appendStringInfo (& cols, "% s a.attnum =% d", (i> 0? "OR": ""), idxcd-> varattno [i]);
The error appears only to me when entering the cycle:
foreach (cell, candidates) / * foreach cell in candidates * /
more than once, that is, when you have more than one candidate index. If the cycle is entered only once, the function works correctly.
The error that appears to me is that the connection to the PostgreSQL server is directly lost. I proved that the error occurs in that statement, printing some values.
The error that appears to me is the following:
The connection to the server was lost. Attempting reset: Failed.
I attach the source code of the function (function.c) and the log file with the output of the last executions.
I clarify that the foreach cycle for the c language is defined in #include "nodes / pg_list.h"
I am using Postgresql 8.3.23.
I clarify that I use that version because it is compatible with the Index Adviser, which I am modifying for my University thesis.
 I was analyzing and researching on the compilation without optimizations, with symbols and also on the use of gbd. Very interesting everything.
My query is now if all this can be applied the same if a Makefile is used. Because the Index Adviser comes with a Makefile that runs for compilation. That is, as I read it is more or less easy to apply all this if I'm going to compile from the command line but having the Makefile, the truth is that I don't know how to apply it. I am new with Linux.
The Linux distribution I use is Debian 9.x 64-bit.
And the version of C (gcc) that I use is 6.3.0
I will greatly appreciate an answer please,
I also attach the Index Adviser Makefile.
I would greatly appreciate a help please. I really am not knowing how to move forward.
As I commented, my function works for the case in which the foreach is entered only once. But when you enter more than once, it doesn't work. That is, when you have more than one candidate index, it gives me that error.
This means that, for example, for a simple Select type statement or that has an AND it works for me. But for the case where the Select statement has an OR for example, it doesn't work. Because you already have more than one candidate index and enter the foreach more than once.
I will be very grateful if anyone can help me please.
I already thought a lot why the mistake could happen but I can't really find a reason.
Best regards,

Yessica Brinkmann

FATAL:  the database system is in recovery mode
LOG:  database system is ready to accept connections
LOG:  autovacuum launcher started
LOG:  database system was shut down at 2019-10-04 00:58:21 CEST
LOG:  database system is ready to accept connections
LOG:  autovacuum launcher started
LOG:  server process (PID 1245) was terminated by signal 11: Segmentation fault
LOG:  terminating any other active server processes
LOG:  all server processes terminated; reinitializing
LOG:  database system was interrupted; last known up at 2019-10-04 02:08:57 CEST
LOG:  database system was not properly shut down; automatic recovery in progress
FATAL:  the database system is in recovery mode
LOG:  redo starts at 0/BEE6A00
LOG:  record with zero length at 0/BEFA848
LOG:  redo done at 0/BEFA818
LOG:  last completed transaction was at log time 2019-10-04 02:11:33.931119+02
LOG:  database system is ready to accept connections
LOG:  autovacuum launcher started
LOG:  server process (PID 1388) was terminated by signal 11: Segmentation fault
LOG:  terminating any other active server processes
LOG:  all server processes terminated; reinitializing
LOG:  database system was interrupted; last known up at 2019-10-04 02:11:44 CEST
LOG:  database system was not properly shut down; automatic recovery in progress
LOG:  redo starts at 0/BEFA890
LOG:  record with zero length at 0/BF0F940
LOG:  redo done at 0/BF0F910
LOG:  last completed transaction was at log time 2019-10-04 02:17:13.560035+02
FATAL:  the database system is in recovery mode
LOG:  database system is ready to accept connections
LOG:  autovacuum launcher started
LOG:  received smart shutdown request
LOG:  received SIGHUP, reloading configuration files
LOG:  autovacuum launcher shutting down
LOG:  shutting down
LOG:  database system is shut down
LOG:  database system was shut down at 2019-10-04 02:36:09 CEST
LOG:  database system is ready to accept connections
LOG:  autovacuum launcher started
LOG:  server process (PID 1271) was terminated by signal 11: Segmentation fault
LOG:  terminating any other active server processes
LOG:  all server processes terminated; reinitializing
LOG:  database system was interrupted; last known up at 2019-10-04 15:44:07 CEST
LOG:  database system was not properly shut down; automatic recovery in progress
FATAL:  the database system is in recovery mode
LOG:  redo starts at 0/BF0F9D0
LOG:  unexpected pageaddr 0/5F14000 in log file 0, segment 11, offset 15810560
LOG:  redo done at 0/BF13140
LOG:  last completed transaction was at log time 2019-10-04 15:46:27.151167+02
LOG:  database system is ready to accept connections
LOG:  autovacuum launcher started
LOG:  server process (PID 1565) was terminated by signal 11: Segmentation fault
LOG:  terminating any other active server processes
LOG:  all server processes terminated; reinitializing
LOG:  database system was interrupted; last known up at 2019-10-04 15:46:53 CEST
LOG:  database system was not properly shut down; automatic recovery in progress
FATAL:  the database system is in recovery mode
LOG:  redo starts at 0/BF13998
LOG:  record with zero length at 0/BF2A1C0
LOG:  redo done at 0/BF2A190
LOG:  last completed transaction was at log time 2019-10-04 16:05:58.835759+02
LOG:  database system is ready to accept connections
LOG:  autovacuum launcher started
LOG:  server process (PID 1847) was terminated by signal 11: Segmentation fault
LOG:  terminating any other active server processes
LOG:  all server processes terminated; reinitializing
LOG:  database system was interrupted; last known up at 2019-10-04 16:06:07 CEST
LOG:  database system was not properly shut down; automatic recovery in progress
FATAL:  the database system is in recovery mode
LOG:  redo starts at 0/BF2A208
LOG:  record with zero length at 0/BF3FAD0
LOG:  redo done at 0/BF3FAA0
LOG:  last completed transaction was at log time 2019-10-04 16:24:48.038614+02
LOG:  database system is ready to accept connections
LOG:  autovacuum launcher started
LOG:  received smart shutdown request
LOG:  received SIGHUP, reloading configuration files
LOG:  autovacuum launcher shutting down
LOG:  shutting down
LOG:  database system is shut down
LOG:  database system was shut down at 2019-10-04 16:29:42 CEST
LOG:  database system is ready to accept connections
LOG:  autovacuum launcher started
LOG:  received smart shutdown request
LOG:  received SIGHUP, reloading configuration files
LOG:  autovacuum launcher shutting down
LOG:  shutting down
LOG:  database system is shut down

Attachment: función.c
Description: Binary data

#
# PostgreSQL Adviser top level makefile
#

PGFILEDESC = "PostgreSQL Index Advisor"

ifdef USE_PGXS
PGXS := $(shell pg_config --pgxs)
include $(PGXS)
else
subdir = contrib/adviser
top_builddir = ../..
include $(top_builddir)/src/Makefile.global
include $(top_srcdir)/contrib/contrib-global.mk
endif


all:
	$(MAKE) -C index_adviser $@
	$(MAKE) -C pg_advise $@
	$(MAKE) -C resources $@
	@echo "PostgreSQL Index Advisor successfully made. Ready to install."

install:
	$(MAKE) -C index_adviser $@
	$(MAKE) -C pg_advise $@
	$(MAKE) -C resources $@
	@echo "PostgreSQL Index Advisor installed."

uninstall:
	$(MAKE) -C index_adviser $@
	$(MAKE) -C pg_advise $@
	$(MAKE) -C resources $@
	@echo "PostgreSQL Index Advisor uninstalled."

clean:
	$(MAKE) -C index_adviser $@
	$(MAKE) -C pg_advise $@
	$(MAKE) -C resources $@