RE: SELECT query fails after pg_upgrade as the conditional operator fails

Thanks for the response Juan. Please find the requested details below:
All the steps are performed on the broken db after pg_upgrade

broken_db=# select * from xyz.job_attr where jobid = 'foo';
jobid | attr_name | attr_resource | attr_value | attr_flags
----------+-----------+---------------+------------+------------
(0 rows)

/* The query does not returns any error code and neither in the pg_log. But it returns zero number of rows */
/* where as a query with trim returns 59 rows with same text match */

broken_db=# select count(*) from xyz.job_attr where trim(jobid) = 'foo';
count
-------
59
(1 row)

/* explain analyse results */

broken_db=# explain analyze select * from xyz.job_attr where jobid = 'foo';
QUERY PLAN
----------------------------------------------------------------------------------------------------------------------
Bitmap Heap Scan on job_attr (cost=4.73..19.47 rows=59 width=57) (actual time=0.005..0.005 rows=0 loops=1)
Recheck Cond: (jobid = 'foo'::text)
-> Bitmap Index Scan on job_attr_idx (cost=0.00..4.72 rows=59 width=0) (actual time=0.005..0.005 rows=0 loops=1)
Index Cond: (jobid = 'foo'::text)
Planning time: 0.035 ms
Execution time: 0.025 ms
(6 rows)

broken_db=# explain analyze select * from xyz.job_attr where trim(jobid) = 'foo';
QUERY PLAN QUERY PLAN
-----------------------------------------------------------------------------------------------------
Seq Scan on job_attr (cost=0.00..28.20 rows=5 width=57) (actual time=0.117..0.148 rows=59 loops=1)
Filter: (btrim(jobid) = 'foo'::text)
Rows Removed by Filter: 888
Planning time: 0.026 ms
Execution time: 0.158 ms
(5 rows)

/* table definition */

broken_db=# \d xyz.job_attr;
Table "xyz.job_attr"
Column | Type | Modifiers
---------------+---------+-----------
jobid | text | not null
attr_name | text | not null
attr_resource | text |
attr_value | text |
attr_flags | integer | not null
Indexes:
"job_attr_idx" btree (jobid, attr_name, attr_resource)

/* However REINDEX is not successful neither against the table nor the index */

broken_db=# REINDEX TABLE xyz.job_attr;
ERROR: syntax error at or near "QUERY"
LINE 1: QUERY PLANREINDEX TABLE xyz.job_attr;

broken_db=# REINDEX INDEX job_attr_idx;
ERROR: relation "job_attr_idx" does not exist

/* then tried reindexing system tables, and it worked */

[root(at)sys workspace]# export PGOPTIONS="-P"
[root(at)sys workspace]# psql -d broken_db
psql (9.6.11)
Type "help" for help.
broken_db=# REINDEX DATABASE broken_db;
REINDEX

broken_db=# select count(*) from xyz.job_attr where jobid = 'foo';
count
-------
59
(1 row)

I can use reindexing as a work around. Thanks!

If this is not something expected and if you need any more information on this issue please let me know.

Best Regards,
Nithin.

From: Juan José Santamaría Flecha <juanjo(dot)santamaria(at)gmail(dot)com>
Sent: 14 April 2019 01:04
To: Nithin Johnson <nithin(dot)johnson(at)altair(dot)com>
Cc: pgsql-admin(at)lists(dot)postgresql(dot)org; Suresh Thelkar <suresh(dot)thelkar(at)altair(dot)com>; Subhasis Bhattacharya <subhasis(dot)bhattacharya(at)altair(dot)com>
Subject: Re: SELECT query fails after pg_upgrade as the conditional operator fails

The following query fails:
SELECT * from table where jobid = 'foo';

Whereas the following is passing:
SELECT * from table where jobid LIKE '%foo';
SELECT * from table where trim(jobid) = 'foo';

We were suspecting some leading invisible characters before 'foo'. but the following queries went well:
SELECT left(jobid, 1) from table where jobid LIKE '%foo';
SELECT ascii(jobid) from table where jobid LIKE '%foo';

Please post the error code, also the plan for the different queries and the description of the table.

Can you check if rebuilding the table's indexes solves the issue? If so, send output of that operation.

Regards,

Juan José Santamaría Flecha