James Colvin jamesc127

Here is an example of several different kinds of C* tombstones. For reference, they are:

Partition
Row
Cell
Range

Intro

The obvious culprit of tombstone creation is DELETE, but there are other - less obvious - sources of the tombstone. Let’s see exacly what happens on disk when a tombstone is created. It's funny to say that a tombstone is created... aren't we deleting things? Remember, everything in C* is a write! A DELETE operation writes another sstable entry with a newer timestamp than all the other entries... and the most recent timestamp wins!

I’ve created a DataStax Studio notebook that complements this gist. You should be able to download it and run it for yourself :-) nodetool and sstabledump commands need to be run from a terminal on the node(s) you're working with.

Hybrid Search Example

Applications can filter users in a geographic area by filtering first on tag information, and then using an ANN query with geospatial vector embeddings

CREATE TABLE users ( 
id UUID PRIMARY KEY, 
state text, 
city int,
tags set<text>,
sem_vec vector<float, 384> 
);

	from cassandra.cluster import Cluster
	from cassandra.auth import PlainTextAuthProvider
	from langchain.memory import CassandraChatMessageHistory, ConversationBufferMemory
	from langchain.llms import OpenAI
	from langchain import LLMChain, PromptTemplate
	import json

	cloud_config= {
	'secure_connect_bundle': 'secure-connect-choose-your-own-adventure.zip'
	}

	# pip install langserve langchain openai uvicorn fastapi bs4 duckduckgo-search sse_starlette
	from langchain.chat_models import ChatOpenAI
	from langchain.prompts import ChatPromptTemplate
	from langchain.schema.output_parser import StrOutputParser
	import requests
	from bs4 import BeautifulSoup
	from langchain.schema.runnable import RunnablePassthrough, RunnableLambda
	from langchain.utilities import DuckDuckGoSearchAPIWrapper
	import json
	import os