Exception with indexes that are represented as strings rather than arrays

[timdiggins]

Given you've got a postgresql table using full text search with a gin index on two columns: text and internal_notes

Which would be represented by rails in schema.rb as

    t.index "((to_tsvector('simple'::regconfig, COALESCE((name)::text, ''::text)) || to_tsvector('simple'::regconfig, COALESCE(internal_notes, ''::text))))", name: "index_clients_for_free_text_search", using: :gin

When you try to use if you use rake lol_dba find_indexes on this rails app - It will fail with an exception.

Full traceback:

/data/lol_dba/lib/lol_dba/index_finding/index_finder.rb:66:in `block in table_indexes'
/data/lol_dba/lib/lol_dba/index_finding/index_finder.rb:60:in `collect'
/data/lol_dba/lib/lol_dba/index_finding/index_finder.rb:60:in `table_indexes'
/data/lol_dba/lib/lol_dba/index_finding/index_finder.rb:55:in `existing_indexes'
/data/lol_dba/lib/lol_dba/index_finding/index_finder.rb:44:in `block in missing_indexes'
/data/lol_dba/lib/lol_dba/index_finding/index_finder.rb:42:in `each'
/data/lol_dba/lib/lol_dba/index_finding/index_finder.rb:42:in `missing_indexes'
/data/lol_dba/lib/lol_dba/index_finding/index_finder.rb:37:in `check_for_indexes'
/data/lol_dba/lib/lol_dba/index_finding/index_finder.rb:4:in `run'
/data/lol_dba/lib/tasks/lol_dba.rake:6:in `block (2 levels) in <main>'
/data/ruby/3.0.6/lib/ruby/gems/3.0.0/gems/rake-13.1.0/lib/rake/task.rb:281:in `block in execute'
/data/ruby/3.0.6/lib/ruby/gems/3.0.0/gems/rake-13.1.0/lib/rake/task.rb:281:in `each'
/data/ruby/3.0.6/lib/ruby/gems/3.0.0/gems/rake-13.1.0/lib/rake/task.rb:281:in `execute'
/data/project/Rakefile:12:in `block in execute_with_benchmark'
/data/ruby/3.0.6/lib/ruby/3.0.0/benchmark.rb:293:in `measure'
/data/project/Rakefile:12:in `execute_with_benchmark'
/data/ruby/3.0.6/lib/ruby/gems/3.0.0/gems/bugsnag-6.26.0/lib/bugsnag/integrations/rake.rb:20:in `execute'
/data/ruby/3.0.6/lib/ruby/gems/3.0.0/gems/rake-13.1.0/lib/rake/task.rb:219:in `block in invoke_with_call_chain'
/data/ruby/3.0.6/lib/ruby/gems/3.0.0/gems/rake-13.1.0/lib/rake/task.rb:199:in `synchronize'
/data/ruby/3.0.6/lib/ruby/gems/3.0.0/gems/rake-13.1.0/lib/rake/task.rb:199:in `invoke_with_call_chain'
/data/ruby/3.0.6/lib/ruby/gems/3.0.0/gems/rake-13.1.0/lib/rake/task.rb:188:in `invoke'
/data/ruby/3.0.6/lib/ruby/gems/3.0.0/gems/rake-13.1.0/lib/rake/application.rb:182:in `invoke_task'
/data/ruby/3.0.6/lib/ruby/gems/3.0.0/gems/rake-13.1.0/lib/rake/application.rb:138:in `block (2 levels) in top_level'
/data/ruby/3.0.6/lib/ruby/gems/3.0.0/gems/rake-13.1.0/lib/rake/application.rb:138:in `each'
/data/ruby/3.0.6/lib/ruby/gems/3.0.0/gems/rake-13.1.0/lib/rake/application.rb:138:in `block in top_level'
/data/ruby/3.0.6/lib/ruby/gems/3.0.0/gems/rake-13.1.0/lib/rake/application.rb:147:in `run_with_threads'
/data/ruby/3.0.6/lib/ruby/gems/3.0.0/gems/rake-13.1.0/lib/rake/application.rb:132:in `top_level'
/data/ruby/3.0.6/lib/ruby/gems/3.0.0/gems/rake-13.1.0/lib/rake/application.rb:83:in `block in run'
/data/ruby/3.0.6/lib/ruby/gems/3.0.0/gems/rake-13.1.0/lib/rake/application.rb:208:in `standard_exception_handling'
/data/ruby/3.0.6/lib/ruby/gems/3.0.0/gems/rake-13.1.0/lib/rake/application.rb:80:in `run'
/data/project/bin/rake:5:in `<main>'
/data/ruby/3.0.6/lib/ruby/gems/3.0.0/gems/activesupport-6.1.7.6/lib/active_support/fork_tracker.rb:10:in `block in fork'
/data/ruby/3.0.6/lib/ruby/gems/3.0.0/gems/activesupport-6.1.7.6/lib/active_support/fork_tracker.rb:10:in `block in fork'
/data/ruby/3.0.6/lib/ruby/gems/3.0.0/gems/activesupport-6.1.7.6/lib/active_support/fork_tracker.rb:8:in `fork'
/data/ruby/3.0.6/lib/ruby/gems/3.0.0/gems/activesupport-6.1.7.6/lib/active_support/fork_tracker.rb:8:in `fork'
/data/ruby/3.0.6/lib/ruby/gems/3.0.0/gems/activesupport-6.1.7.6/lib/active_support/fork_tracker.rb:27:in `fork'
/data/ruby/3.0.6/lib/ruby/gems/3.0.0/gems/activesupport-6.1.7.6/lib/active_support/fork_tracker.rb:8:in `fork'
/data/ruby/3.0.6/lib/ruby/gems/3.0.0/gems/activesupport-6.1.7.6/lib/active_support/fork_tracker.rb:27:in `fork'
<internal:/data/ruby/3.0.6/lib/ruby/3.0.0/rubygems/core_ext/kernel_require.rb>:85:in `require'
<internal:/data/ruby/3.0.6/lib/ruby/3.0.0/rubygems/core_ext/kernel_require.rb>:85:in `require'

This is because in the internal API ActiveRecord::Base.connection.indexes(table_name) will return an index with has an accessor columns that returns this string, NOT an array.

This can be fixed by testing for the type of index.columns before returning:

        if index.columns.is_a?(String)
          # eg. gin, tsvector...
          index.columns
        else
          index.columns.size > 1 ? index.columns.sort : index.columns.first
        end

https://github.com/plentz/lol_dba/blob/master/lib/lol_dba/index_finding/index_finder.rb#L61

I would contribute a PR, but am having trouble running the specs locally

[timdiggins]

draft PR @ #148 - but needs a spec writing for this case