Here is a reproducible example.

create table t1(v0 int, v1 char(1));

insert into t1 values (1,'a'),(2,'b'),(3,'c');

create ordered index index_t1_v1 on t1(v1);

create table t2(v1 char(1));

insert into t2 values ('a');

1) gives "Error in optimizer garbageCollector"

create temp table t3 as

(select t1.v0 from t1,t2 where trim(t2.v1)=t1.v1)

on commit preserve rows;

2) works as expected

create temp table t3 as

(select t1.v0 from t1,t2 where t2.v1=t1.v1)

on commit preserve rows;

3) works as expected

select t1.v0 from t1,t2 where trim(t2.v1)=t1.v1;

4) works as expected

drop index index_t1_v1;

create temp table t3 as

(select t1.v0 from t1,t2 where trim(t2.v1)=t1.v1)

on commit preserve rows;

I am using the latest MonetDB version:

MonetDB 5 server v11.29.3 "Mar2018" (64-bit, 128-bit integers)

Visit https://www.monetdb.org/ for further information

Found 31.3GiB available memory, 4 available cpu cores

Libraries:

libpcre: 8.32 2012-11-30 (compiled with 8.32)

openssl: OpenSSL 1.0.2k 26 Jan 2017 (compiled with )

libxml2: 2.9.1 (compiled with 2.9.1)

Compiled by: mockbuild@ (x86_64-redhat-linux-gnu)

Compilation: gcc -std=gnu99 -O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector-strong --param=ssp-buffer-size=4 -grecord-gcc-switches -m64 -mtune=generic

Linking : /usr/bin/ld -m elf_x86_64 -Wl,-z,relro -Wl,-Bsymbolic-functions

Thanks,

Anton