Incremental Sort
Extends an existing ordering by sorting groups that share the presorted key prefix.
Reading PG 18·Select a recorded version
- Core node tag
- T_IncrementalSort
- Structured EXPLAIN Node Type
- Incremental Sort
- Inputs
- One partly ordered child plan
- Output
- Tuples ordered by the full sort key
- Executor initializer
- ExecInitIncrementalSort
- Memory mechanism
- tuplesort
- evidence kind
- source and documentation
- explain names
- Incremental Sort
- explain prefixes
- Parallel, Async
- node tag
- T_IncrementalSort
- parallel callbacks
- ExecIncrementalSortEstimate, ExecIncrementalSortInitializeDSM, ExecIncrementalSortInitializeWorker, ExecIncrementalSortRetrieveInstrumentation
- partial modes
- Unknown
- runtime verified
- false
- strategies
- Unknown
Definition PG 18
Extends an existing ordering by sorting groups that share the presorted key prefix.
EXPLAIN labels in this source build
| Text-format label | Structured node identity |
|---|---|
| Incremental Sort | Incremental Sort |
Compare versions
Complete source facts
memory
{"description":"The node passes work_mem to tuplesort. Sorting can use memory or temporary files; the actual method and space use depend on the input and plan.","evidence":[{"archive_sha256":"555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f","label":"src/backend/executor/nodeIncrementalSort.c","path":"src/backend/executor/nodeIncrementalSort.c","sha256":"9fd15ce79cd3dd5c131c5bfb322039213cba9232fdfaa5b53e5f40e7d17195cf","url":"https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2"},{"archive_sha256":"555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f","label":"src/backend/utils/sort/tuplesort.c","path":"src/backend/utils/sort/tuplesort.c","sha256":"509d4cef598613bbf0725f697e1e1e33f3dfc8debed20169a6c4bf1ac9e5c2e3","url":"https://ftp.postgresql.org/pub/source/v18.6/postgresql-18.6.tar.bz2"}],"mechanism":"tuplesort","source_notes":["Incremental sort may be more efficient than plain sort, particularly on large datasets, as it reduces the amount of data to sort at once, making it more likely it fits into work_mem (eliminating the need to spill to disk). But the main advantage of incremental sort is that it can start producing rows early, before sorting the whole dataset, which is a significant benefit especially for queries with LIMIT.","Because incremental sort processes (potentially many) sort batches, we need to capture tuplesort stats each time we finalize a sort state. This summary data is later used for EXPLAIN ANALYZE output."]}source inventory
{"executor":"src/backend/executor/execProcnode.c","explain":"src/backend/commands/explain.c","implementation":"src/backend/executor/nodeIncrementalSort.c"}Source references
- src/backend/commands/explain.c:1525
- src/backend/executor/execProcnode.c:325
- src/backend/executor/nodeIncrementalSort.c
- src/include/nodes/plannodes.h
- src/backend/utils/sort/tuplesort.c
- PostgreSQL 18.6 · using-explain
Full definition and evidence JSON
Definition sources
center · PostgreSQL 18 · 555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f
Text language: en · 555610c24d53e4316da5b7d3fc25c279d96856d5e0e23ee308c328c5fa881d9f