Switch to individual transactions per table row. Interstingly results in only  single datom due to using :part :db.part/db in temp id creating rather than :db.part/user.

postgres2datomic.core=> (do (require (ns-name *ns*) :reload-all)(main "mdl_user"))
({:idnumber "1"} {:idnumber "2"})
({:mdl_user/idnumber "1", :db/id {:part :db.part/db, :idx -1001364}}
 {:mdl_user/idnumber "2", :db/id {:part :db.part/db, :idx -1001365}})
{:db-before datomic.db.Db@1530b6ac,
 :db-after datomic.db.Db@dc28ff2c,
 :tx-data
 [#Datum{:e 13194139534313 :a 50 :v #inst "2013-10-19T03:04:15.819-00:00" :tx 13194139534313 :added true} #Datum{:e 113 :a 65 :v "1" :tx 13194139534313 :added true}],
 :tempids {-9223367638809266068 113}}
{:db-before datomic.db.Db@dc28ff2c,
 :db-after datomic.db.Db@82501069,
 :tx-data
 [#Datum{:e 13194139534314 :a 50 :v #inst "2013-10-19T03:04:15.840-00:00" :tx 13194139534314 :added true} #Datum{:e 113 :a 65 :v "2" :tx 13194139534314 :added true} #Datum{:e 113 :a 65 :v "1" :tx 13194139534314 :added false}],
 :tempids {-9223367638809266069 113}}
{:db-before datomic.db.Db@82501069,
 :db-after datomic.db.Db@d212defc,
 :tx-data
 [#Datum{:e 13194139534315 :a 50 :v #inst "2013-10-19T03:04:15.855-00:00" :tx 13194139534315 :added true} #Datum{:e 113 :a 65 :v "3" :tx 13194139534315 :added true} #Datum{:e 113 :a 65 :v "2" :tx 13194139534315 :added false}],
 :tempids {-9223367638809266070 113}}
{:db-before datomic.db.Db@d212defc,
 :db-after datomic.db.Db@3035d546,
 :tx-data
 [#Datum{:e 13194139534316 :a 50 :v #inst "2013-10-19T03:04:15.869-00:00" :tx 13194139534316 :added true} #Datum{:e 113 :a 65 :v "4" :tx 13194139534316 :added true} #Datum{:e 113 :a 65 :v "3" :tx 13194139534316 :added false}],
 :tempids {-9223367638809266071 113}}
{:db-before datomic.db.Db@3035d546,
 :db-after datomic.db.Db@f4e575fe,
 :tx-data
 [#Datum{:e 13194139534317 :a 50 :v #inst "2013-10-19T03:04:15.884-00:00" :tx 13194139534317 :added true} #Datum{:e 113 :a 65 :v "5" :tx 13194139534317 :added true} #Datum{:e 113 :a 65 :v "4" :tx 13194139534317 :added false}],
 :tempids {-9223367638809266072 113}}
{:db-before datomic.db.Db@f4e575fe,
 :db-after datomic.db.Db@e84dc15,
 :tx-data
 [#Datum{:e 13194139534318 :a 50 :v #inst "2013-10-19T03:04:15.898-00:00" :tx 13194139534318 :added true} #Datum{:e 113 :a 65 :v "6" :tx 13194139534318 :added true} #Datum{:e 113 :a 65 :v "5" :tx 13194139534318 :added false}],
 :tempids {-9223367638809266073 113}}
{:db-before datomic.db.Db@e84dc15,
 :db-after datomic.db.Db@c10bd963,
 :tx-data
 [#Datum{:e 13194139534319 :a 50 :v #inst "2013-10-19T03:04:15.912-00:00" :tx 13194139534319 :added true} #Datum{:e 113 :a 65 :v "7" :tx 13194139534319 :added true} #Datum{:e 113 :a 65 :v "6" :tx 13194139534319 :added false}],
 :tempids {-9223367638809266074 113}}
{:db-before datomic.db.Db@c10bd963,
 :db-after datomic.db.Db@30dbbdb3,
 :tx-data
 [#Datum{:e 13194139534320 :a 50 :v #inst "2013-10-19T03:04:15.933-00:00" :tx 13194139534320 :added true} #Datum{:e 113 :a 65 :v "8" :tx 13194139534320 :added true} #Datum{:e 113 :a 65 :v "7" :tx 13194139534320 :added false}],
 :tempids {-9223367638809266075 113}}
{:db-before datomic.db.Db@30dbbdb3,
 :db-after datomic.db.Db@1151c684,
 :tx-data
 [#Datum{:e 13194139534321 :a 50 :v #inst "2013-10-19T03:04:15.956-00:00" :tx 13194139534321 :added true} #Datum{:e 113 :a 65 :v "9" :tx 13194139534321 :added true} #Datum{:e 113 :a 65 :v "8" :tx 13194139534321 :added false}],
 :tempids {-9223367638809266076 113}}
{:db-before datomic.db.Db@1151c684,
 :db-after datomic.db.Db@5fb6f284,
 :tx-data
 [#Datum{:e 13194139534322 :a 50 :v #inst "2013-10-19T03:04:15.976-00:00" :tx 13194139534322 :added true} #Datum{:e 113 :a 65 :v "10" :tx 13194139534322 :added true} #Datum{:e 113 :a 65 :v "9" :tx 13194139534322 :added false}],
 :tempids {-9223367638809266077 113}}
{:db-before datomic.db.Db@5fb6f284,
 :db-after datomic.db.Db@a9d4722c,
 :tx-data
 [#Datum{:e 13194139534323 :a 50 :v #inst "2013-10-19T03:04:15.992-00:00" :tx 13194139534323 :added true} #Datum{:e 113 :a 65 :v "11" :tx 13194139534323 :added true} #Datum{:e 113 :a 65 :v "10" :tx 13194139534323 :added false}],
 :tempids {-9223367638809266078 113}}
{:db-before datomic.db.Db@a9d4722c,
 :db-after datomic.db.Db@88d9bb9,
 :tx-data
 [#Datum{:e 13194139534324 :a 50 :v #inst "2013-10-19T03:04:16.008-00:00" :tx 13194139534324 :added true} #Datum{:e 113 :a 65 :v "12" :tx 13194139534324 :added true} #Datum{:e 113 :a 65 :v "11" :tx 13194139534324 :added false}],
 :tempids {-9223367638809266079 113}}
{:db-before datomic.db.Db@88d9bb9,
 :db-after datomic.db.Db@9d25baaa,
 :tx-data
 [#Datum{:e 13194139534325 :a 50 :v #inst "2013-10-19T03:04:16.030-00:00" :tx 13194139534325 :added true} #Datum{:e 113 :a 65 :v "13" :tx 13194139534325 :added true} #Datum{:e 113 :a 65 :v "12" :tx 13194139534325 :added false}],
 :tempids {-9223367638809266080 113}}
{:db-before datomic.db.Db@9d25baaa,
 :db-after datomic.db.Db@5dcf53f6,
 :tx-data
 [#Datum{:e 13194139534326 :a 50 :v #inst "2013-10-19T03:04:16.045-00:00" :tx 13194139534326 :added true} #Datum{:e 113 :a 65 :v "14" :tx 13194139534326 :added true} #Datum{:e 113 :a 65 :v "13" :tx 13194139534326 :added false}],
 :tempids {-9223367638809266081 113}}
{:db-before datomic.db.Db@5dcf53f6,
 :db-after datomic.db.Db@1d4ef5dd,
 :tx-data
 [#Datum{:e 13194139534327 :a 50 :v #inst "2013-10-19T03:04:16.059-00:00" :tx 13194139534327 :added true} #Datum{:e 113 :a 65 :v "15" :tx 13194139534327 :added true} #Datum{:e 113 :a 65 :v "14" :tx 13194139534327 :added false}],
 :tempids {-9223367638809266082 113}}
{:db-before datomic.db.Db@1d4ef5dd,
 :db-after datomic.db.Db@33d0019a,
 :tx-data
 [#Datum{:e 13194139534328 :a 50 :v #inst "2013-10-19T03:04:16.078-00:00" :tx 13194139534328 :added true} #Datum{:e 113 :a 65 :v "16" :tx 13194139534328 :added true} #Datum{:e 113 :a 65 :v "15" :tx 13194139534328 :added false}],
 :tempids {-9223367638809266083 113}}
{:db-before datomic.db.Db@33d0019a,
 :db-after datomic.db.Db@de6bf295,
 :tx-data
 [#Datum{:e 13194139534329 :a 50 :v #inst "2013-10-19T03:04:16.094-00:00" :tx 13194139534329 :added true} #Datum{:e 113 :a 65 :v "17" :tx 13194139534329 :added true} #Datum{:e 113 :a 65 :v "16" :tx 13194139534329 :added false}],
 :tempids {-9223367638809266084 113}}
{:db-before datomic.db.Db@de6bf295,
 :db-after datomic.db.Db@75bca0b1,
 :tx-data
 [#Datum{:e 13194139534330 :a 50 :v #inst "2013-10-19T03:04:16.109-00:00" :tx 13194139534330 :added true} #Datum{:e 113 :a 65 :v "18" :tx 13194139534330 :added true} #Datum{:e 113 :a 65 :v "17" :tx 13194139534330 :added false}],
 :tempids {-9223367638809266085 113}}
{:db-before datomic.db.Db@75bca0b1,
 :db-after datomic.db.Db@edb757ec,
 :tx-data
 [#Datum{:e 13194139534331 :a 50 :v #inst "2013-10-19T03:04:16.132-00:00" :tx 13194139534331 :added true} #Datum{:e 113 :a 65 :v "19" :tx 13194139534331 :added true} #Datum{:e 113 :a 65 :v "18" :tx 13194139534331 :added false}],
 :tempids {-9223367638809266086 113}}
{:db-before datomic.db.Db@edb757ec,
 :db-after datomic.db.Db@17b62dd5,
 :tx-data
 [#Datum{:e 13194139534332 :a 50 :v #inst "2013-10-19T03:04:16.157-00:00" :tx 13194139534332 :added true} #Datum{:e 113 :a 65 :v "20" :tx 13194139534332 :added true} #Datum{:e 113 :a 65 :v "19" :tx 13194139534332 :added false}],
 :tempids {-9223367638809266087 113}}
"count all records with idnumber"
[[1]]
nil
Fix by switching temp id partition to :db.part/user