python - Unable to complete the operation against any hosts cassandra -


i have tried previous solutions stated here , here. using cassandra-driver datastax. version of cassandra 2.2.8.i have created keyspace ct_keyspace , ct_table within it. inserted values in ct_table through cqlsh prompt. following python code retrieving rows

from cassandra.cluster import cluster cluster = cluster() session = cluster.connect('ct_keyspace') result = session.execute("select * ct_table") print result.attribute, result.value

following output of describe ct_keyspace:

cqlsh> describe ct_keyspace  create keyspace ct_keyspace replication = {'class': 'simplestrategy', 'replication_factor': '1'}  , durable_writes = true;  create table ct_keyspace.ct_table (     attribute text primary key,     value int ) bloom_filter_fp_chance = 0.01     , caching = '{"keys":"all", "rows_per_partition":"none"}'     , comment = ''     , compaction = {'class': 'org.apache.cassandra.db.compaction.sizetieredcompactionstrategy'}     , compression = {'sstable_compression': 'org.apache.cassandra.io.compress.lz4compressor'}     , dclocal_read_repair_chance = 0.1     , default_time_to_live = 0     , gc_grace_seconds = 864000     , max_index_interval = 2048     , memtable_flush_period_in_ms = 0     , min_index_interval = 128     , read_repair_chance = 0.0     , speculative_retry = '99.0percentile';

following error getting:

traceback (most recent call last):   file "connection.py", line 4, in <module>     result = session.execute("select * ct_table")   file "/usr/local/lib/python2.7/dist-packages/cassandra/cluster.py", line 1998, in execute     return self.execute_async(query, parameters, trace, custom_payload, timeout, execution_profile, paging_state).result()   file "/usr/local/lib/python2.7/dist-packages/cassandra/cluster.py", line 3781, in result     raise self._final_exception cassandra.cluster.nohostavailable: ('unable complete operation against hosts', {})

any appreciated.

this happening because providing wrong keyspace name in connect. use "ct_keyspace" instead of "ct_keyspace". may recall unquoted identifiers case-insensitive in cql (such select statement). however, in context of parameter passing (as in cluster.connect(<keyspace>)) literal not case-insensitive.

if enable logging, see driver continually failing set keyspace on connection. created ticket improve error handling in scenario: https://datastax-oss.atlassian.net/browse/python-665


Comments

Post a Comment

Popular posts from this blog

aws api gateway - SerializationException in posting new Records via Dynamodb Proxy Service in API -

i getting "__type": "com.amazon.coral.service#serializationexception" as reply in postman & in test console in api gateway trying post record directly dynamodb using api proxy services.. referring aws article - https://aws.amazon.com/blogs/compute/using-amazon-api-gateway-as-a-proxy-for-dynamodb/ here's mapping { "tablename": "tablenamegoeshere", "item": { "id" : "$context.requestid" "eventname" : "$input.path('$.eventname')", "timestamp" : $input.path('$.timestamp'), "answers": "$util.parsejson($input.path('$.answers'))" } } update: did asked ... , worked if try add array of json objects gives me above same error - here's trying now. please - couldnt find on google well #set($inputroot = $input.path('$')) { "tablename": "answer", "item": {
Read more

asp.net - Problems sending emails from forum -

i have been redesigning site has message board, has been written guy looked after site. it has few problems , written in .asp , uses .mdb files database. you can see whole thing here . feel free post if helps, test thing have set using original files , new database. the basic problem when posts message, supposed email sent them, have posted it. when replies, originator supposed message, replier has been posted. i’d have thought @ point in process there should script/file in postmessage.asp? the postmessage.asp page below. <% option explicit %> <!-- #include virtual="common/adovbs.inc" --> <html> <head> <meta http-equiv="content-type" content="text/html; charset=windows-1252"> <meta name="generator" content="microsoft frontpage 4.0"> <meta name="progid" content="frontpage.editor.document"> <title>new page 2</title> <base target="_self"
Read more