# Example 677 — The column was dropped and the cascade took the view `the_column_was_dropped_and_the_cascade_took_the_view.eml` - Thirty-four repositories were searched for references to the column and none was found. What the drop removed is computed below. ## EML ```eml # Self-authored for the EML case corpus (no external origin). Thirty-four # repositories were searched for references to the column and none was found. # What the drop removed is computed below. # # The search was done properly. Every repository the organisation owns, not just # the obvious ones; the column name and its camel-case and snake-case spellings; # generated clients as well as hand-written ones; and the two hits it did find # were in a changelog and a migration that had already run. Zero live references # is a real zero and finding it took an afternoon. # # It searched CODE. The database holds objects of its own that reference the # column, and the drop refused until it was told to proceed anyway. # # `CASCADE` is not a force flag. It is a request to drop whatever depends on # this, and the statement does not say what that turned out to be. 34 => repositories_searched 0 => live_code_references_found 2 => hits_in_a_changelog_or_a_spent_migration 3 => database_objects_dropped_by_the_cascade 11 => dashboards_reading_the_view 9 => days_until_it_was_noticed "repositories searched : " + str(repositories_searched) ^0 "live code references found : " + str(live_code_references_found) ^0 "hits in a changelog or a spent migration : " + str(hits_in_a_changelog_or_a_spent_migration) ^0 "" ^0 "database objects the cascade dropped : " + str(database_objects_dropped_by_the_cascade) ^0 "dashboards reading the view : " + str(dashboards_reading_the_view) ^0 "days until it was noticed : " + str(days_until_it_was_noticed) ^0 "" ^0 # ---- what the search verified ---- "the reference search" ^0 " repositories : " + str(repositories_searched) + ", every one the organisation owns" ^0 " spellings : the column name, camel case, snake case" ^0 " generated clients : searched as well as hand-written code" ^0 " live references : " + str(live_code_references_found) ^0 " hits, both dead : " + str(hits_in_a_changelog_or_a_spent_migration) ^0 " verdict : UNREFERENCED" ^0 "" ^0 " this took an afternoon and it is the right way to do it" ^0 "" ^0 # ---- what it did not search ---- "the objects the search cannot see" ^0 " a view selecting the column : in the database" ^0 " an index on it : in the database" ^0 " a constraint mentioning it : in the database" ^0 " where their definitions live : the catalog, not a" ^0 " repository" ^0 " what the drop did when it met them : refused" ^0 "" ^0 " the refusal was the system reporting exactly this, and" ^0 " the response to a refusal is what turned it off" ^0 "" ^0 # ---- what CASCADE says ---- "the second attempt" ^0 " statement : the same drop, with CASCADE" ^0 " what CASCADE means : drop whatever depends on this too" ^0 " what it printed : that it had done so" ^0 " what it named : nothing" ^0 " objects removed : " + str(database_objects_dropped_by_the_cascade) ^0 "" ^0 " the flag reads as 'yes, I am sure about the column' and" ^0 " means 'and about everything downstream of it'" ^0 "" ^0 "dashboards on the dropped view : " + str(dashboards_reading_the_view) + ", all of them" ^0 "" ^0 # ---- why nine days ---- # The dashboards did not error. The view was gone, the query returned an # object-does-not-exist, and the panel rendered its empty state, which is what # it renders for a quiet week. "how a dropped view looks on a dashboard" ^0 " the query errors : yes" ^0 " the panel shows : its empty state" ^0 " what an empty state means the rest of the time : a quiet" ^0 " period" ^0 " an alert on no-data : not configured, because no-data is" ^0 " normal at night" ^0 "" ^0 # ---- null control ---- # The same drop, run without CASCADE, and the refusal read as a list. 0 => nc_objects_dropped_unknowingly database_objects_dropped_by_the_cascade => nc_objects_the_refusal_names "null control - the refusal read instead of overridden" ^0 " live code references : " + str(live_code_references_found) + ", unchanged" ^0 " objects the refusal names : " + str(nc_objects_the_refusal_names) ^0 " objects dropped unknowingly : " + str(nc_objects_dropped_unknowingly) ^0 " the search did not need to be better; the database had" ^0 " already produced the list the search could not" ^0 "" ^0 # ---- the rule ---- "what an exhaustive code search guarantees" ^0 " no code refers to this : exactly, and thoroughly" ^0 " nothing refers to this : not addressed; a database holds" ^0 " definitions of its own, and they are not in any" ^0 " repository" ^0 "" ^0 "a search covers the corpus it is run over; the objects most" ^0 "likely to be missed are the ones stored somewhere that is" ^0 "not a file, and the system that holds them will say so if" ^0 "the refusal is read rather than overridden" ^0 "" ^0 "The search covered all " + str(repositories_searched) + " repositories, three spellings and the generated" ^0 "clients, found " + str(live_code_references_found) + " live references and " + str(hits_in_a_changelog_or_a_spent_migration) + " dead ones, and took an afternoon." ^0 "The drop refused, CASCADE was added, and " + str(database_objects_dropped_by_the_cascade) + " database objects went with the column -" ^0 "including a view " + str(dashboards_reading_the_view) + " dashboards read, which showed their empty state for" ^0 str(days_until_it_was_noticed) + " days because an empty state is what a quiet period looks like." ^0 ``` ## Python (deterministic transpilation) ```python repositories_searched = 34 live_code_references_found = 0 hits_in_a_changelog_or_a_spent_migration = 2 database_objects_dropped_by_the_cascade = 3 dashboards_reading_the_view = 11 days_until_it_was_noticed = 9 print("repositories searched : " + str(repositories_searched)) print("live code references found : " + str(live_code_references_found)) print("hits in a changelog or a spent migration : " + str(hits_in_a_changelog_or_a_spent_migration)) print("") print("database objects the cascade dropped : " + str(database_objects_dropped_by_the_cascade)) print("dashboards reading the view : " + str(dashboards_reading_the_view)) print("days until it was noticed : " + str(days_until_it_was_noticed)) print("") print("the reference search") print(" repositories : " + str(repositories_searched) + ", every one the organisation owns") print(" spellings : the column name, camel case, snake case") print(" generated clients : searched as well as hand-written code") print(" live references : " + str(live_code_references_found)) print(" hits, both dead : " + str(hits_in_a_changelog_or_a_spent_migration)) print(" verdict : UNREFERENCED") print("") print(" this took an afternoon and it is the right way to do it") print("") print("the objects the search cannot see") print(" a view selecting the column : in the database") print(" an index on it : in the database") print(" a constraint mentioning it : in the database") print(" where their definitions live : the catalog, not a") print(" repository") print(" what the drop did when it met them : refused") print("") print(" the refusal was the system reporting exactly this, and") print(" the response to a refusal is what turned it off") print("") print("the second attempt") print(" statement : the same drop, with CASCADE") print(" what CASCADE means : drop whatever depends on this too") print(" what it printed : that it had done so") print(" what it named : nothing") print(" objects removed : " + str(database_objects_dropped_by_the_cascade)) print("") print(" the flag reads as 'yes, I am sure about the column' and") print(" means 'and about everything downstream of it'") print("") print("dashboards on the dropped view : " + str(dashboards_reading_the_view) + ", all of them") print("") print("how a dropped view looks on a dashboard") print(" the query errors : yes") print(" the panel shows : its empty state") print(" what an empty state means the rest of the time : a quiet") print(" period") print(" an alert on no-data : not configured, because no-data is") print(" normal at night") print("") nc_objects_dropped_unknowingly = 0 nc_objects_the_refusal_names = database_objects_dropped_by_the_cascade print("null control - the refusal read instead of overridden") print(" live code references : " + str(live_code_references_found) + ", unchanged") print(" objects the refusal names : " + str(nc_objects_the_refusal_names)) print(" objects dropped unknowingly : " + str(nc_objects_dropped_unknowingly)) print(" the search did not need to be better; the database had") print(" already produced the list the search could not") print("") print("what an exhaustive code search guarantees") print(" no code refers to this : exactly, and thoroughly") print(" nothing refers to this : not addressed; a database holds") print(" definitions of its own, and they are not in any") print(" repository") print("") print("a search covers the corpus it is run over; the objects most") print("likely to be missed are the ones stored somewhere that is") print("not a file, and the system that holds them will say so if") print("the refusal is read rather than overridden") print("") print("The search covered all " + str(repositories_searched) + " repositories, three spellings and the generated") print("clients, found " + str(live_code_references_found) + " live references and " + str(hits_in_a_changelog_or_a_spent_migration) + " dead ones, and took an afternoon.") print("The drop refused, CASCADE was added, and " + str(database_objects_dropped_by_the_cascade) + " database objects went with the column -") print("including a view " + str(dashboards_reading_the_view) + " dashboards read, which showed their empty state for") print(str(days_until_it_was_noticed) + " days because an empty state is what a quiet period looks like.") ``` ## stdout (executed) ```text repositories searched : 34 live code references found : 0 hits in a changelog or a spent migration : 2 database objects the cascade dropped : 3 dashboards reading the view : 11 days until it was noticed : 9 the reference search repositories : 34, every one the organisation owns spellings : the column name, camel case, snake case generated clients : searched as well as hand-written code live references : 0 hits, both dead : 2 verdict : UNREFERENCED this took an afternoon and it is the right way to do it the objects the search cannot see a view selecting the column : in the database an index on it : in the database a constraint mentioning it : in the database where their definitions live : the catalog, not a repository what the drop did when it met them : refused the refusal was the system reporting exactly this, and the response to a refusal is what turned it off the second attempt statement : the same drop, with CASCADE what CASCADE means : drop whatever depends on this too what it printed : that it had done so what it named : nothing objects removed : 3 the flag reads as 'yes, I am sure about the column' and means 'and about everything downstream of it' dashboards on the dropped view : 11, all of them how a dropped view looks on a dashboard the query errors : yes the panel shows : its empty state what an empty state means the rest of the time : a quiet period an alert on no-data : not configured, because no-data is normal at night null control - the refusal read instead of overridden live code references : 0, unchanged objects the refusal names : 3 objects dropped unknowingly : 0 the search did not need to be better; the database had already produced the list the search could not what an exhaustive code search guarantees no code refers to this : exactly, and thoroughly nothing refers to this : not addressed; a database holds definitions of its own, and they are not in any repository a search covers the corpus it is run over; the objects most likely to be missed are the ones stored somewhere that is not a file, and the system that holds them will say so if the refusal is read rather than overridden The search covered all 34 repositories, three spellings and the generated clients, found 0 live references and 2 dead ones, and took an afternoon. The drop refused, CASCADE was added, and 3 database objects went with the column - including a view 11 dashboards read, which showed their empty state for 9 days because an empty state is what a quiet period looks like. ``` ## Round-trip `ok: true` — round-trip fixpoint reached (python1 == python2) ## Trace event types eml:run:start · eml:assign · eml:output · eml:run:done