Reference
Apache Cloudberry Internals
How the engine actually works, one subsystem at a time — read from the source tree rather than
summarised from the manual. Every code path carries a file and line reference, and every
psql
session is real captured output.
Most of it applies to Greenplum too. The lineage is shared, the catalogs and vocabulary are largely the same, and where Cloudberry has diverged the chapters say so explicitly.
Start here
Apache Cloudberry Architecture: How a Query Runs
Coordinator, segments, gangs and slices — how an MPP query is planned, dispatched and executed across an Apache Cloudberry cluster.
Part 1
Storage and Access Methods
Everything Cloudberry stores ends up as bytes in files on a segment. This part follows that path from the access methods down to the storage manager.
Part 2
Transactions, MVCC and Locking
A single-node transaction is hard enough. This part covers what changes when a transaction spans every segment in the cluster.
Part 3
Query Planning and Execution
The longest part of the book, and the one most performance questions land in: two optimizers, an executor, and the interconnect that moves tuples between segments.
Part 4
High Availability and Recovery
What keeps a cluster alive when a host dies, and what happens in the seconds after it does.
Part 5
Resource Management
Two managers, one question: who may use how much. Both are documented here from the source, including where each one falls short.