Mode 2 — Cassandra diagnostics

Use when the user has a running Cassandra cluster (or a DataStax / ScyllaDB deployment that can produce Cassandra-compatible diagnostics). This mode derives reads/writes per second from cumulative nodetool info counters and keyspace sizing from nodetool tablestats — neither can be guessed.

If either tablestats or info cannot be captured, fall back to Mode 1.

Intake table

Each ID matches a parse-cassandra.ts flag (--<id>) when passing paths explicitly.

ID	Captures	Run on	Output	If missing — ask	Default / escalation
`tablestats`	Live space + per-column-family details	any one node	`tablestats.txt`	—	Mandatory. Recapture. Without it, use Mode 1 — `parse-cassandra.ts` exits without `--tablestats`. A single representative tablestats file is sufficient; throughput is scaled by node count from `--info` files.
`info`	DC, host id, uptime; used with tablestats counters to derive reads/writes per second	every node	`info.txt`	—	Mandatory. Without it, use Mode 1 — RPS cannot be derived.
`status`	DC list, node count per DC	any one node	`status.txt`	How many DCs in the cluster? How many nodes per DC?	Capture preferred. Otherwise use the answers, or group `info` files by DC. If topology cannot be established, use Mode 1.
`schema`	DDL — feeds compatibility + replication factor	any one node	`schema.cql`	What replication factor for application keyspaces (per DC)?	If absent, parser uses RF=3 internally. Ask the user to confirm so intent matches estimate.
`rowsize`	Average row size per table	any one node	`rowsize.txt`	—	Default `1024` bytes. No further questions.
`prepared`	Prepared statements — drives compatibility (LWT-in-batch, aggregations) and the `USING TTL` pricing signal	any one node	`prepared_statements.ndjson`	—	Omit `--prepared`. No further questions.

Required vs optional

Mandatory: tablestats AND at least one info file.

Strongly recommended: status (topology), schema (compatibility + RF), prepared (compatibility signal + TTL pricing).

Optional: rowsize (per-table accuracy — defaults to 1024 bytes when absent).

Capture commands

See cassandra-capture-commands.md for the full set with <auth> shorthand.

Running the parser

Prefer --dir auto-detection — the parser's filename detectors (isTablestatsFile, isInfoFile, isStatusFile, isSchemaFile, isRowSizeFile, isPreparedStatementsFile) classify each file regardless of naming.

# Directory auto-detection (recommended)
cd scripts
npx ts-node --project tsconfig.scripts.json parse-cassandra.ts \
  --dir /path/to/diagnostics --region us-east-1 [--pitr] \
  | tee /tmp/keyspaces-calc.json

# Individual files (explicit)
npx ts-node --project tsconfig.scripts.json parse-cassandra.ts \
  --region us-east-1 \
  --tablestats tablestats.txt \
  --info node1-info.txt --info node2-info.txt \
  [--status status.txt] [--schema schema.cql] \
  [--rowsize rowsize.txt] [--prepared prepared.ndjson] \
  [--pitr] | tee /tmp/keyspaces-calc.json

Repeat --info once per node. When both --dir and explicit flags are provided, explicit wins.

Region selection

Pick --region by priority:

The DC name in status if it matches an AWS region (us-east-1, eu-west-1, …).
The Datacenter field in nodetool info.
The user's stated target region.
Default us-east-1.

Pass --region explicitly whenever inference is wrong or unclear.

Output

Same shape as Mode 1, plus:

source: "cassandra-diagnostic-files"
datacenters — array of { name, nodeCount } per DC.
per_datacenter — cost breakdown per DC.

compatibility — automatically populated when --schema or --prepared was supplied (or detected in --dir). Shape:

{
  "has_issues": true | false,
  "summary": {
    "total_issues": N,
    "schema":         { ... or null },
    "query_patterns": { ... or null }
  },
  "details": { "schema": { ... }, "query_patterns": { ... } }
}

Surface the compatibility block when present — see mode-3-compatibility.md for display rules.

Prepared-statement signal

A prepared_statements.ndjson capture changes two things:

Compatibility: detects LWT inside BEGIN UNLOGGED BATCH, aggregates (COUNT/MIN/MAX/SUM/AVG), and calls to user-defined functions (when schema is also supplied).
Pricing: INSERT … USING TTL and UPDATE … USING TTL mark tables as fully TTL-driven for write accounting, even when DDL lacks default_time_to_live. Tables with default_time_to_live already follow the rowsize-based TTL path.

Displaying results

Present in this order:

Cluster summary — DCs, node count per DC, region(s) inferred.
Per-keyspace breakdown — keyspace name, RF, storage, reads/s, writes/s.
Two-column cost table (same as Mode 1).
Recommendation — cheaper mode.
Compatibility findings if compatibility.has_issues is true.
Offer PDF per pdf-reporting.md.

Multi-cluster or re-runs

For two or more separate clusters, run parse-cassandra.ts once per cluster, writing to distinct /tmp/keyspaces-*.json files. Then a single generate-pdf.ts invocation with multiple --input flags produces a consolidated comparison PDF.

/amazon-keyspaces

referencesmode-2-cassandra-diagnostics.md