I think this may be caused by the search in eZ Publish. When data is published, it'll automatically be indexed. This is probably causing the delay you're experiencing.
You can avoid this by either enabling delayed indexing ( http://ez.no/doc/ez_publish/technical_manual/3_10/reference/configuration_files/site_ini/searchsettings/delayedindexing + http://ez.no/doc/ez_publish/technical_manual/3_10/features/cronjobs/the_cronjob_scripts#indexcontent ), or try the eZ Find search extension ( http://ez.no/ezfind ). eZ Find may also be used with delayed indexing.
+1 for Kare, yes we had the same problem when indexing pdf files. disabling the "searchable" property for the attribute solved the problem for us (it wasn't really needed and more of a slip)
This thread saved my life, client was trying to upload 1,7M txt file and we didn't know why 120 sec is not enough for really fast server to publish document :) Because I prefer to leave "is searchable" flag marked on, it's possible to disable indexing of plain/txt files by adding into <i>settings/override </i> file <i>binaryfile.ini.append.php</i> with: