cache lookup failed for attribute -5 of relation *****

Products

• VMware Tanzu Greenplum
• Greenplum

Issue/Introduction

Customer received the following error while trying to revoke privileges on a relation after migrating to 7.x .

 

prod=# REVOKE ALL ON public.table1 from admin;
ERROR:  cache lookup failed for attribute -5 of relation 66668 (aclchk.c:1765)

Environment

Greenplum 7.3 

Cause

This is  due to an `ALTER TABLE <ao_or_co_table> SET ACCESS METHOD heap` or `ALTER TABLE <ao_or_co_table> SET WITH (appendonly=false)` operation. 

We don't create the missing system attributes exclusive to heap (namely xmin, cmin, xmax and cmax) when making this transition.

 

 

Checking pg_attribute for this relation we see the following, attribute number -2, -3, -4, and -5 as per the error is missing. 

dssprod=# select attrelid,attname,attnum from pg_attribute where attrelid = public.table1'::regclass order by attnum;
  attrelid |    attname    | attnum
 ----------+---------------+--------
     68373 | gp_segment_id |     -7
     68373 | tableoid      |     -6
     68373 | ctid          |     -1
     68373 | chain_id      |      1
     68373 | pe_name       |      2
     68373 | job_name      |      3
     68373 | prcs_start_ts |      4
     68373 | prcs_end_ts   |      5
     68373 | prcs_status   |      6
 (9 rows)

 

Checking the pg_attribute for other relations that were not altered we see the following 

 

dssprod=#  select attrelid,attname,attnum from pg_attribute where attrelid = 'public.table2'::regclass order by attnum;
  attrelid  |    attname    | attnum
 -----------+---------------+--------
  296887567 | gp_segment_id |     -7
  296887567 | tableoid      |     -6
  296887567 | cmax          |     -5
  296887567 | xmax          |     -4
  296887567 | cmin          |     -3
  296887567 | xmin          |     -2
  296887567 | ctid          |     -1
  296887567 | chain_id      |      1
  296887567 | pe_name       |      2
  296887567 | job_name      |      3
  296887567 | prcs_start_ts |      4
  296887567 | prcs_end_ts   |      5
  296887567 | prcs_status   |      6

 

 

Resolution

As a workaround 

create table as select * from broken_table 

This fix will be included in a future Greenplum Code version as of November 2024