diff --git a/duckdb-latest/join-duckdb-latest.R b/duckdb-latest/join-duckdb-latest.R
index c461907e..40dd62aa 100755
--- a/duckdb-latest/join-duckdb-latest.R
+++ b/duckdb-latest/join-duckdb-latest.R
@@ -21,26 +21,26 @@ src_jn_y = setNames(file.path("data", paste(y_data_name, "csv", sep=".")), names
 stopifnot(length(src_jn_y)==3L)
 cat(sprintf("loading datasets %s\n", paste(c(data_name, y_data_name), collapse=", ")))
 
-attach_and_use <- function(con, db_file, db) {
-  if (on_disk) {
-    # in case a previous solution failed during query execution and left the file around.
-    if (file.exists(db_file)) {
-      unlink(db_file)
-    }
-    dbExecute(con, sprintf("ATTACH '%s'", db_file))
-  } else {
-    dbExecute(con, sprintf("CREATE SCHEMA %s", db))
-  }
-}
-
-detach_and_drop <- function(con, db_file, db) {
-  if (on_disk) {
-    dbExecute(con, sprintf("DETACH %s", db))
-    unlink(db_file)
-  } else {
-    dbExecute(con, sprintf("DROP SCHEMA %s CASCADE", db))
-  }
-}
+# attach_and_use <- function(con, db_file, db) {
+#   if (on_disk) {
+#     # in case a previous solution failed during query execution and left the file around.
+#     if (file.exists(db_file)) {
+#       unlink(db_file)
+#     }
+#     dbExecute(con, sprintf("ATTACH '%s'", db_file))
+#   } else {
+#     dbExecute(con, sprintf("CREATE SCHEMA %s", db))
+#   }
+# }
+
+# detach_and_drop <- function(con, db_file, db) {
+#   if (on_disk) {
+#     dbExecute(con, sprintf("DETACH %s", db))
+#     unlink(db_file)
+#   } else {
+#     dbExecute(con, sprintf("DROP SCHEMA %s CASCADE", db))
+#   }
+# }
 
 duckdb_join_db = sprintf('%s_%s_%s.db', gsub("-","_",solution), task, data_name)
 if (file.exists(duckdb_join_db)) {
@@ -64,6 +64,7 @@ ncores = parallel::detectCores()
 if (less_cores) {
   ncores = min(ncores, 40)
 }
+
 invisible(dbExecute(con, sprintf("PRAGMA THREADS=%d", ncores)))
 invisible(dbExecute(con, "SET memory_limit='200GB'"))
 git = dbGetQuery(con, "SELECT source_id FROM pragma_version()")[[1L]]
@@ -82,53 +83,50 @@ if (file.exists(clean_db_name)) {
   unlink(clean_db_name)
 }
 
-if (!uses_NAs) {
-  if (on_disk) {
-    unlink(clean_db_name)
-    invisible(dbExecute(con, sprintf("attach '%s'", clean_db_name)))
-    db_name = clean_schema_name
-  }
-  else {
-    db_name = ""
-  }
-
-  id4_enum_statement = "SELECT id4 FROM x_csv UNION ALL SELECT id4 FROM small_csv UNION ALL SELECT id4 from medium_csv UNION ALL SELECT id4 from big_csv"
-  id5_enum_statement = "SELECT id5 FROM x_csv UNION ALL SELECT id5 from medium_csv UNION ALL SELECT id5 from big_csv"
-  invisible(dbExecute(con, sprintf("CREATE TYPE id4ENUM AS ENUM (%s)", id4_enum_statement)))
-  invisible(dbExecute(con, sprintf("CREATE TYPE id5ENUM AS ENUM (%s)", id5_enum_statement)))
-
-  invisible(dbExecute(con, sprintf("CREATE TABLE %ssmall(id1 INT64, id4 id4ENUM, v2 DOUBLE)", db_name)))
-  invisible(dbExecute(con, sprintf("INSERT INTO %ssmall (SELECT * from small_csv)", db_name)))
-
-  invisible(dbExecute(con, sprintf("CREATE TABLE %smedium(id1 INT64, id2 INT64, id4 id4ENUM, id5 id5ENUM, v2 DOUBLE)", db_name)))
-  invisible(dbExecute(con, sprintf("INSERT INTO %smedium (SELECT * FROM medium_csv)", db_name)))
-
-  invisible(dbExecute(con, sprintf("CREATE TABLE %sbig(id1 INT64, id2 INT64, id3 INT64, id4 id4ENUM, id5 id5ENUM, id6 VARCHAR, v2 DOUBLE)", db_name)))
-  invisible(dbExecute(con, sprintf("INSERT INTO %sbig (Select * from big_csv)", db_name)))
-
-  invisible(dbExecute(con, sprintf("CREATE TABLE %sx(id1 INT64, id2 INT64, id3 INT64, id4 id4ENUM, id5 id5ENUM, id6 VARCHAR, v1 DOUBLE)", db_name)))
-  invisible(dbExecute(con, sprintf("INSERT INTO %sx (SELECT * FROM x_csv);", db_name)))
-
-  # drop all the csv ingested tables
-  invisible({
-    dbExecute(con, "DROP TABLE x_csv")
-    dbExecute(con, "DROP TABLE small_csv")
-    dbExecute(con, "DROP TABLE medium_csv")
-    dbExecute(con, "DROP TABLE big_csv")
-  })
-
-  if (on_disk) {
-    dbDisconnect(con, shutdown=TRUE)
-    unlink(duckdb_join_db)
-    con <- dbConnect(duckdb(), dbdir=clean_db_name)
-  }
+if (on_disk) {
+  unlink(clean_db_name)
+  invisible(dbExecute(con, sprintf("attach '%s'", clean_db_name)))
+  db_name = clean_schema_name
 } else {
-  invisible({
-    dbExecute(con, "ALTER TABLE x_csv RENAME TO x")
-    dbExecute(con, "ALTER TABLE small_csv RENAME TO small")
-    dbExecute(con, "ALTER TABLE medium_csv RENAME TO medium")
-    dbExecute(con, "ALTER TABLE big_csv RENAME TO big")
-  })
+  db_name = ""
+}
+
+id4_enum_statement = "SELECT id4 FROM x_csv where id4 is not null UNION ALL SELECT id4 FROM small_csv where id4 is not null UNION ALL SELECT id4 from medium_csv where id4 is not null UNION ALL SELECT id4 from big_csv where id4 is not null"
+id5_enum_statement = "SELECT id5 FROM x_csv where id5 is not null UNION ALL SELECT id5 from medium_csv where id5 is not null UNION ALL SELECT id5 from big_csv where id5 is not null"
+invisible(dbExecute(con, sprintf("CREATE TYPE id4ENUM AS ENUM (%s)", id4_enum_statement)))
+invisible(dbExecute(con, sprintf("CREATE TYPE id5ENUM AS ENUM (%s)", id5_enum_statement)))
+
+invisible(dbExecute(con, sprintf("CREATE TABLE %ssmall(id1 INT64, id4 id4ENUM, v2 DOUBLE)", db_name)))
+invisible(dbExecute(con, sprintf("INSERT INTO %ssmall (SELECT * from small_csv)", db_name)))
+
+invisible(dbExecute(con, sprintf("CREATE TABLE %smedium(id1 INT64, id2 INT64, id4 id4ENUM, id5 id5ENUM, v2 DOUBLE)", db_name)))
+invisible(dbExecute(con, sprintf("INSERT INTO %smedium (SELECT * FROM medium_csv)", db_name)))
+
+invisible(dbExecute(con, sprintf("CREATE TABLE %sbig(id1 INT64, id2 INT64, id3 INT64, id4 id4ENUM, id5 id5ENUM, id6 VARCHAR, v2 DOUBLE)", db_name)))
+invisible(dbExecute(con, sprintf("INSERT INTO %sbig (Select * from big_csv)", db_name)))
+
+invisible(dbExecute(con, sprintf("CREATE TABLE %sx(id1 INT64, id2 INT64, id3 INT64, id4 id4ENUM, id5 id5ENUM, id6 VARCHAR, v1 DOUBLE)", db_name)))
+invisible(dbExecute(con, sprintf("INSERT INTO %sx (SELECT * FROM x_csv);", db_name)))
+
+# drop all the csv ingested tables
+invisible({
+  dbExecute(con, "DROP TABLE x_csv")
+  dbExecute(con, "DROP TABLE small_csv")
+  dbExecute(con, "DROP TABLE medium_csv")
+  dbExecute(con, "DROP TABLE big_csv")
+})
+
+if (on_disk) {
+  # disconnect from the clean_db. open a in-memory connection and injest the tables again.
+  dbDisconnect(con, shutdown=TRUE)
+  unlink(duckdb_join_db)
+  con <- dbConnect(duckdb())
+  dbExecute(con, sprintf("ATTACH '%s'", clean_db_name))
+  dbExecute(con, sprintf("CREATE table x as select * from %sx", db_name))
+  dbExecute(con, sprintf("CREATE table small as select * from %ssmall", db_name))
+  dbExecute(con, sprintf("CREATE table medium as select * from %smedium", db_name))
+  dbExecute(con, sprintf("CREATE table big as select * from %sbig", db_name))
+  dbExecute(con, sprintf("DETACH %s", sub('clean.', 'clean', clean_schema_name)))
 }
 
 print(in_nr<-dbGetQuery(con, "SELECT count(*) AS cnt FROM x")$cnt)
@@ -143,133 +141,133 @@ question = "small inner on int" # q1
 fun = "inner_join"
 
 
-attach_and_use(con, 'q1.db', 'q1')
+# attach_and_use(con, 'q1.db', 'q1')
 t = system.time({
-  dbExecute(con, "CREATE TABLE q1.ans AS SELECT x.*, small.id4 AS small_id4, v2 FROM x JOIN small USING (id1)")
-  print(c(nr<-dbGetQuery(con, "SELECT count(*) AS cnt FROM q1.ans")$cnt, nc<-ncol(dbGetQuery(con, "SELECT * FROM q1.ans LIMIT 0"))))
+  dbExecute(con, "CREATE TABLE ans AS SELECT x.*, small.id4 AS small_id4, v2 FROM x JOIN small USING (id1)")
+  print(c(nr<-dbGetQuery(con, "SELECT count(*) AS cnt FROM ans")$cnt, nc<-ncol(dbGetQuery(con, "SELECT * FROM ans LIMIT 0"))))
 })[["elapsed"]]
 m = memory_usage()
-chkt = system.time(chk<-dbGetQuery(con, "SELECT SUM(v1) AS v1, SUM(v2) AS v2 FROM q1.ans"))[["elapsed"]]
+chkt = system.time(chk<-dbGetQuery(con, "SELECT SUM(v1) AS v1, SUM(v2) AS v2 FROM ans"))[["elapsed"]]
 write.log(run=1L, task=task, data=data_name, in_rows=in_nr, question=question, out_rows=nr, out_cols=nc, solution=solution, version=ver, git=git, fun=fun, time_sec=t, mem_gb=m, cache=cache, chk=make_chk(chk), chk_time_sec=chkt, on_disk=on_disk)
-invisible(dbExecute(con, "DROP TABLE IF EXISTS q1.ans"))
-detach_and_drop(con, 'q1.db', 'q1')
-attach_and_use(con, 'q1.db', 'q1')
+invisible(dbExecute(con, "DROP TABLE IF EXISTS ans"))
+# detach_and_drop(con, 'db', 'q1')
+# attach_and_use(con, 'db', 'q1')
 t = system.time({
-  dbExecute(con, "CREATE TABLE q1.ans AS SELECT x.*, small.id4 AS small_id4, v2 FROM x JOIN small USING (id1)")
-  print(c(nr<-dbGetQuery(con, "SELECT count(*) AS cnt FROM q1.ans")$cnt, nc<-ncol(dbGetQuery(con, "SELECT * FROM q1.ans LIMIT 0"))))
+  dbExecute(con, "CREATE TABLE ans AS SELECT x.*, small.id4 AS small_id4, v2 FROM x JOIN small USING (id1)")
+  print(c(nr<-dbGetQuery(con, "SELECT count(*) AS cnt FROM ans")$cnt, nc<-ncol(dbGetQuery(con, "SELECT * FROM ans LIMIT 0"))))
 })[["elapsed"]]
 m = memory_usage()
-chkt = system.time(chk<-dbGetQuery(con, "SELECT SUM(v1) AS v1, SUM(v2) AS v2 FROM q1.ans"))[["elapsed"]]
+chkt = system.time(chk<-dbGetQuery(con, "SELECT SUM(v1) AS v1, SUM(v2) AS v2 FROM ans"))[["elapsed"]]
 write.log(run=2L, task=task, data=data_name, in_rows=in_nr, question=question, out_rows=nr, out_cols=nc, solution=solution, version=ver, git=git, fun=fun, time_sec=t, mem_gb=m, cache=cache, chk=make_chk(chk), chk_time_sec=chkt, on_disk=on_disk)
-print(dbGetQuery(con, "SELECT * FROM q1.ans LIMIT 3"))                                      ## head
-print(dbGetQuery(con, "SELECT * FROM q1.ans WHERE ROWID > (SELECT count(*) FROM q1.ans) - 4")) ## tail
-invisible(dbExecute(con, "DROP TABLE IF EXISTS q1.ans"))
-detach_and_drop(con, 'q1.db', 'q1')
+print(dbGetQuery(con, "SELECT * FROM ans LIMIT 3"))                                      ## head
+print(dbGetQuery(con, "SELECT * FROM ans WHERE ROWID > (SELECT count(*) FROM ans) - 4")) ## tail
+invisible(dbExecute(con, "DROP TABLE IF EXISTS ans"))
+# detach_and_drop(con, 'q1.db', 'q1')
 
 question = "medium inner on int" # q2
 fun = "inner_join"
 
 
-attach_and_use(con, 'q2.db', 'q2')
+# attach_and_use(con, 'q2.db', 'q2')
 t = system.time({
-  dbExecute(con, "CREATE TABLE q2.ans AS SELECT x.*, medium.id1 AS medium_id1, medium.id4 AS medium_id4, medium.id5 AS medium_id5, v2 FROM x JOIN medium USING (id2)")
-  print(c(nr<-dbGetQuery(con, "SELECT count(*) AS cnt FROM q2.ans")$cnt, nc<-ncol(dbGetQuery(con, "SELECT * FROM q2.ans LIMIT 0"))))
+  dbExecute(con, "CREATE TABLE ans AS SELECT x.*, medium.id1 AS medium_id1, medium.id4 AS medium_id4, medium.id5 AS medium_id5, v2 FROM x JOIN medium USING (id2)")
+  print(c(nr<-dbGetQuery(con, "SELECT count(*) AS cnt FROM ans")$cnt, nc<-ncol(dbGetQuery(con, "SELECT * FROM ans LIMIT 0"))))
 })[["elapsed"]]
 m = memory_usage()
-chkt = system.time(chk<-dbGetQuery(con, "SELECT SUM(v1) AS v1, SUM(v2) AS v2 FROM q2.ans"))[["elapsed"]]
+chkt = system.time(chk<-dbGetQuery(con, "SELECT SUM(v1) AS v1, SUM(v2) AS v2 FROM ans"))[["elapsed"]]
 write.log(run=1L, task=task, data=data_name, in_rows=in_nr, question=question, out_rows=nr, out_cols=nc, solution=solution, version=ver, git=git, fun=fun, time_sec=t, mem_gb=m, cache=cache, chk=make_chk(chk), chk_time_sec=chkt, on_disk=on_disk)
-invisible(dbExecute(con, "DROP TABLE IF EXISTS q2.ans"))
-detach_and_drop(con, 'q2.db', 'q2')
-attach_and_use(con, 'q2.db', 'q2')
+invisible(dbExecute(con, "DROP TABLE IF EXISTS ans"))
+# detach_and_drop(con, 'q2.db', 'q2')
+# attach_and_use(con, 'q2.db', 'q2')
 t = system.time({
-  dbExecute(con, "CREATE TABLE q2.ans AS SELECT x.*, medium.id1 AS medium_id1, medium.id4 AS medium_id4, medium.id5 AS medium_id5, v2 FROM x JOIN medium USING (id2)")
-  print(c(nr<-dbGetQuery(con, "SELECT count(*) AS cnt FROM q2.ans")$cnt, nc<-ncol(dbGetQuery(con, "SELECT * FROM q2.ans LIMIT 0"))))
+  dbExecute(con, "CREATE TABLE ans AS SELECT x.*, medium.id1 AS medium_id1, medium.id4 AS medium_id4, medium.id5 AS medium_id5, v2 FROM x JOIN medium USING (id2)")
+  print(c(nr<-dbGetQuery(con, "SELECT count(*) AS cnt FROM ans")$cnt, nc<-ncol(dbGetQuery(con, "SELECT * FROM ans LIMIT 0"))))
 })[["elapsed"]]
 m = memory_usage()
-chkt = system.time(chk<-dbGetQuery(con, "SELECT SUM(v1) AS v1, SUM(v2) AS v2 FROM q2.ans"))[["elapsed"]]
+chkt = system.time(chk<-dbGetQuery(con, "SELECT SUM(v1) AS v1, SUM(v2) AS v2 FROM ans"))[["elapsed"]]
 write.log(run=2L, task=task, data=data_name, in_rows=in_nr, question=question, out_rows=nr, out_cols=nc, solution=solution, version=ver, git=git, fun=fun, time_sec=t, mem_gb=m, cache=cache, chk=make_chk(chk), chk_time_sec=chkt, on_disk=on_disk)
-print(dbGetQuery(con, "SELECT * FROM q2.ans LIMIT 3"))                                      ## head
-print(dbGetQuery(con, "SELECT * FROM q2.ans WHERE ROWID > (SELECT count(*) FROM q2.ans) - 4")) ## tail
-invisible(dbExecute(con, "DROP TABLE IF EXISTS q2.ans"))
-detach_and_drop(con, 'q2.db', 'q2')
+print(dbGetQuery(con, "SELECT * FROM ans LIMIT 3"))                                      ## head
+print(dbGetQuery(con, "SELECT * FROM ans WHERE ROWID > (SELECT count(*) FROM ans) - 4")) ## tail
+invisible(dbExecute(con, "DROP TABLE IF EXISTS ans"))
+# detach_and_drop(con, 'q2.db', 'q2')
 
 question = "medium outer on int" # q3
 fun = "left_join"
 
-attach_and_use(con, 'q3.db', 'q3')
+# attach_and_use(con, 'q3.db', 'q3')
 t = system.time({
-  dbExecute(con, "CREATE TABLE q3.ans AS SELECT x.*, medium.id1 AS medium_id1, medium.id4 AS medium_id4, medium.id5 AS medium_id5, v2 FROM x LEFT JOIN medium USING (id2)")
-  print(c(nr<-dbGetQuery(con, "SELECT count(*) AS cnt FROM q3.ans")$cnt, nc<-ncol(dbGetQuery(con, "SELECT * FROM q3.ans LIMIT 0"))))
+  dbExecute(con, "CREATE TABLE ans AS SELECT x.*, medium.id1 AS medium_id1, medium.id4 AS medium_id4, medium.id5 AS medium_id5, v2 FROM x LEFT JOIN medium USING (id2)")
+  print(c(nr<-dbGetQuery(con, "SELECT count(*) AS cnt FROM ans")$cnt, nc<-ncol(dbGetQuery(con, "SELECT * FROM ans LIMIT 0"))))
 })[["elapsed"]]
 m = memory_usage()
-chkt = system.time(chk<-dbGetQuery(con, "SELECT SUM(v1) AS v1, SUM(v2) AS v2 FROM q3.ans"))[["elapsed"]]
+chkt = system.time(chk<-dbGetQuery(con, "SELECT SUM(v1) AS v1, SUM(v2) AS v2 FROM ans"))[["elapsed"]]
 write.log(run=1L, task=task, data=data_name, in_rows=in_nr, question=question, out_rows=nr, out_cols=nc, solution=solution, version=ver, git=git, fun=fun, time_sec=t, mem_gb=m, cache=cache, chk=make_chk(chk), chk_time_sec=chkt, on_disk=on_disk)
-invisible(dbExecute(con, "DROP TABLE IF EXISTS q3.ans"))
-detach_and_drop(con, 'q3.db', 'q3')
-attach_and_use(con, 'q3.db', 'q3')
+invisible(dbExecute(con, "DROP TABLE IF EXISTS ans"))
+# detach_and_drop(con, 'q3.db', 'q3')
+# attach_and_use(con, 'q3.db', 'q3')
 t = system.time({
-  dbExecute(con, "CREATE TABLE q3.ans AS SELECT x.*, medium.id1 AS medium_id1, medium.id4 AS medium_id4, medium.id5 AS medium_id5, v2 FROM x LEFT JOIN medium USING (id2)")
-  print(c(nr<-dbGetQuery(con, "SELECT count(*) AS cnt FROM q3.ans")$cnt, nc<-ncol(dbGetQuery(con, "SELECT * FROM q3.ans LIMIT 0"))))
+  dbExecute(con, "CREATE TABLE ans AS SELECT x.*, medium.id1 AS medium_id1, medium.id4 AS medium_id4, medium.id5 AS medium_id5, v2 FROM x LEFT JOIN medium USING (id2)")
+  print(c(nr<-dbGetQuery(con, "SELECT count(*) AS cnt FROM ans")$cnt, nc<-ncol(dbGetQuery(con, "SELECT * FROM ans LIMIT 0"))))
 })[["elapsed"]]
 m = memory_usage()
-chkt = system.time(chk<-dbGetQuery(con, "SELECT SUM(v1) AS v1, SUM(v2) AS v2 FROM q3.ans"))[["elapsed"]]
+chkt = system.time(chk<-dbGetQuery(con, "SELECT SUM(v1) AS v1, SUM(v2) AS v2 FROM ans"))[["elapsed"]]
 write.log(run=2L, task=task, data=data_name, in_rows=in_nr, question=question, out_rows=nr, out_cols=nc, solution=solution, version=ver, git=git, fun=fun, time_sec=t, mem_gb=m, cache=cache, chk=make_chk(chk), chk_time_sec=chkt, on_disk=on_disk)
-print(dbGetQuery(con, "SELECT * FROM q3.ans LIMIT 3"))                                      ## head
-print(dbGetQuery(con, "SELECT * FROM q3.ans WHERE ROWID > (SELECT count(*) FROM q3.ans) - 4")) ## tail
-invisible(dbExecute(con, "DROP TABLE IF EXISTS q3.ans"))
-detach_and_drop(con, 'q3.db', 'q3')
+print(dbGetQuery(con, "SELECT * FROM ans LIMIT 3"))                                      ## head
+print(dbGetQuery(con, "SELECT * FROM ans WHERE ROWID > (SELECT count(*) FROM ans) - 4")) ## tail
+invisible(dbExecute(con, "DROP TABLE IF EXISTS ans"))
+# detach_and_drop(con, 'q3.db', 'q3')
 
 question = "medium inner on factor" # q4
 fun = "inner_join"
 
-attach_and_use(con, 'q4.db', 'q4')
+# attach_and_use(con, 'q4.db', 'q4')
 t = system.time({
-  dbExecute(con, "CREATE TABLE q4.ans AS SELECT x.*, medium.id1 AS medium_id1, medium.id2 AS medium_id2, medium.id4 AS medium_id4, v2 FROM x JOIN medium USING (id5)")
-  print(c(nr<-dbGetQuery(con, "SELECT count(*) AS cnt FROM q4.ans")$cnt, nc<-ncol(dbGetQuery(con, "SELECT * FROM q4.ans LIMIT 0"))))
+  dbExecute(con, "CREATE TABLE ans AS SELECT x.*, medium.id1 AS medium_id1, medium.id2 AS medium_id2, medium.id4 AS medium_id4, v2 FROM x JOIN medium USING (id5)")
+  print(c(nr<-dbGetQuery(con, "SELECT count(*) AS cnt FROM ans")$cnt, nc<-ncol(dbGetQuery(con, "SELECT * FROM ans LIMIT 0"))))
 })[["elapsed"]]
 m = memory_usage()
-chkt = system.time(chk<-dbGetQuery(con, "SELECT SUM(v1) AS v1, SUM(v2) AS v2 FROM q4.ans"))[["elapsed"]]
+chkt = system.time(chk<-dbGetQuery(con, "SELECT SUM(v1) AS v1, SUM(v2) AS v2 FROM ans"))[["elapsed"]]
 write.log(run=1L, task=task, data=data_name, in_rows=in_nr, question=question, out_rows=nr, out_cols=nc, solution=solution, version=ver, git=git, fun=fun, time_sec=t, mem_gb=m, cache=cache, chk=make_chk(chk), chk_time_sec=chkt, on_disk=on_disk)
-invisible(dbExecute(con, "DROP TABLE IF EXISTS q4.ans"))
-detach_and_drop(con, 'q4.db', 'q4')
-attach_and_use(con, 'q4.db', 'q4')
+invisible(dbExecute(con, "DROP TABLE IF EXISTS ans"))
+# detach_and_drop(con, 'q4.db', 'q4')
+# attach_and_use(con, 'q4.db', 'q4')
 t = system.time({
-  dbExecute(con, "CREATE TABLE q4.ans AS SELECT x.*, medium.id1 AS medium_id1, medium.id2 AS medium_id2, medium.id4 AS medium_id4, v2 FROM x JOIN medium USING (id5)")
-  print(c(nr<-dbGetQuery(con, "SELECT count(*) AS cnt FROM q4.ans")$cnt, nc<-ncol(dbGetQuery(con, "SELECT * FROM q4.ans LIMIT 0"))))
+  dbExecute(con, "CREATE TABLE ans AS SELECT x.*, medium.id1 AS medium_id1, medium.id2 AS medium_id2, medium.id4 AS medium_id4, v2 FROM x JOIN medium USING (id5)")
+  print(c(nr<-dbGetQuery(con, "SELECT count(*) AS cnt FROM ans")$cnt, nc<-ncol(dbGetQuery(con, "SELECT * FROM ans LIMIT 0"))))
 })[["elapsed"]]
 m = memory_usage()
-chkt = system.time(chk<-dbGetQuery(con, "SELECT SUM(v1) AS v1, SUM(v2) AS v2 FROM q4.ans"))[["elapsed"]]
+chkt = system.time(chk<-dbGetQuery(con, "SELECT SUM(v1) AS v1, SUM(v2) AS v2 FROM ans"))[["elapsed"]]
 write.log(run=2L, task=task, data=data_name, in_rows=in_nr, question=question, out_rows=nr, out_cols=nc, solution=solution, version=ver, git=git, fun=fun, time_sec=t, mem_gb=m, cache=cache, chk=make_chk(chk), chk_time_sec=chkt, on_disk=on_disk)
-print(dbGetQuery(con, "SELECT * FROM q4.ans LIMIT 3"))                                      ## head
-print(dbGetQuery(con, "SELECT * FROM q4.ans WHERE ROWID > (SELECT count(*) FROM q4.ans) - 4")) ## tail
-invisible(dbExecute(con, "DROP TABLE IF EXISTS q4.ans"))
-detach_and_drop(con, 'q4.db', 'q4')
+print(dbGetQuery(con, "SELECT * FROM ans LIMIT 3"))                                      ## head
+print(dbGetQuery(con, "SELECT * FROM ans WHERE ROWID > (SELECT count(*) FROM ans) - 4")) ## tail
+invisible(dbExecute(con, "DROP TABLE IF EXISTS ans"))
+# detach_and_drop(con, 'q4.db', 'q4')
 
 question = "big inner on int" # q5
 fun = "inner_join"
 
-attach_and_use(con, 'q5.db', 'q5')
+# attach_and_use(con, 'q5.db', 'q5')
 t = system.time({
-  dbExecute(con, "CREATE TABLE q5.ans AS SELECT x.*, big.id1 AS big_id1, big.id2 AS big_id2, big.id4 AS big_id4, big.id5 AS big_id5, big.id6 AS big_id6, v2 FROM x JOIN big USING (id3)")
-  print(c(nr<-dbGetQuery(con, "SELECT count(*) AS cnt FROM q5.ans")$cnt, nc<-ncol(dbGetQuery(con, "SELECT * FROM q5.ans LIMIT 0"))))
+  dbExecute(con, "CREATE TABLE ans AS SELECT x.*, big.id1 AS big_id1, big.id2 AS big_id2, big.id4 AS big_id4, big.id5 AS big_id5, big.id6 AS big_id6, v2 FROM x JOIN big USING (id3)")
+  print(c(nr<-dbGetQuery(con, "SELECT count(*) AS cnt FROM ans")$cnt, nc<-ncol(dbGetQuery(con, "SELECT * FROM ans LIMIT 0"))))
 })[["elapsed"]]
 m = memory_usage()
-chkt = system.time(chk<-dbGetQuery(con, "SELECT SUM(v1) AS v1, SUM(v2) AS v2 FROM q5.ans"))[["elapsed"]]
+chkt = system.time(chk<-dbGetQuery(con, "SELECT SUM(v1) AS v1, SUM(v2) AS v2 FROM ans"))[["elapsed"]]
 write.log(run=1L, task=task, data=data_name, in_rows=in_nr, question=question, out_rows=nr, out_cols=nc, solution=solution, version=ver, git=git, fun=fun, time_sec=t, mem_gb=m, cache=cache, chk=make_chk(chk), chk_time_sec=chkt, on_disk=on_disk)
-invisible(dbExecute(con, "DROP TABLE IF EXISTS q5.ans"))
-detach_and_drop(con, 'q5.db', 'q5')
-attach_and_use(con, 'q5.db', 'q5')
+invisible(dbExecute(con, "DROP TABLE IF EXISTS ans"))
+# detach_and_drop(con, 'q5.db', 'q5')
+# attach_and_use(con, 'q5.db', 'q5')
 t = system.time({
-  dbExecute(con, "CREATE TABLE q5.ans AS SELECT x.*, big.id1 AS big_id1, big.id2 AS big_id2, big.id4 AS big_id4, big.id5 AS big_id5, big.id6 AS big_id6, v2 FROM x JOIN big USING (id3)")
-  print(c(nr<-dbGetQuery(con, "SELECT count(*) AS cnt FROM q5.ans")$cnt, nc<-ncol(dbGetQuery(con, "SELECT * FROM q5.ans LIMIT 0"))))
+  dbExecute(con, "CREATE TABLE ans AS SELECT x.*, big.id1 AS big_id1, big.id2 AS big_id2, big.id4 AS big_id4, big.id5 AS big_id5, big.id6 AS big_id6, v2 FROM x JOIN big USING (id3)")
+  print(c(nr<-dbGetQuery(con, "SELECT count(*) AS cnt FROM ans")$cnt, nc<-ncol(dbGetQuery(con, "SELECT * FROM ans LIMIT 0"))))
 })[["elapsed"]]
 m = memory_usage()
-chkt = system.time(chk<-dbGetQuery(con, "SELECT SUM(v1) AS v1, SUM(v2) AS v2 FROM q5.ans"))[["elapsed"]]
+chkt = system.time(chk<-dbGetQuery(con, "SELECT SUM(v1) AS v1, SUM(v2) AS v2 FROM ans"))[["elapsed"]]
 write.log(run=2L, task=task, data=data_name, in_rows=in_nr, question=question, out_rows=nr, out_cols=nc, solution=solution, version=ver, git=git, fun=fun, time_sec=t, mem_gb=m, cache=cache, chk=make_chk(chk), chk_time_sec=chkt, on_disk=on_disk)
-print(dbGetQuery(con, "SELECT * FROM q5.ans LIMIT 3"))                                      ## head
-print(dbGetQuery(con, "SELECT * FROM q5.ans WHERE ROWID > (SELECT count(*) FROM q5.ans) - 4")) ## tail
-invisible(dbExecute(con, "DROP TABLE IF EXISTS q5.ans"))
-detach_and_drop(con, 'q5.db', 'q5')
+print(dbGetQuery(con, "SELECT * FROM ans LIMIT 3"))                                      ## head
+print(dbGetQuery(con, "SELECT * FROM ans WHERE ROWID > (SELECT count(*) FROM ans) - 4")) ## tail
+invisible(dbExecute(con, "DROP TABLE IF EXISTS ans"))
+# detach_and_drop(con, 'q5.db', 'q5')
 
 dbDisconnect(con, shutdown=TRUE)