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If a dshash table grows very large (e.g., the dshash table for cumulative statistics when there are millions of tables), resizing it may fail with an error like: ERROR: invalid DSA memory alloc request size 1073741824 To fix, permit dshash resizing to allocate more than 1 GB by providing the DSA_ALLOC_HUGE flag. Reported-by: Andreas Scherbaum Author: Matthias van de Meent Reviewed-by: Cédric Villemain, Michael Paquier, Andres Freund Discussion: https://postgr.es/m/80a12d59-0d5e-4c54-866c-e69cd6536471%40pgug.de Backpatch-through: 13
This directory contains a general purpose data structures, for use anywhere in the backend: binaryheap.c - a binary heap bipartite_match.c - Hopcroft-Karp maximum cardinality algorithm for bipartite graphs bloomfilter.c - probabilistic, space-efficient set membership testing dshash.c - concurrent hash tables backed by dynamic shared memory areas hyperloglog.c - a streaming cardinality estimator ilist.c - single and double-linked lists integerset.c - a data structure for holding large set of integers knapsack.c - knapsack problem solver pairingheap.c - a pairing heap rbtree.c - a red-black tree stringinfo.c - an extensible string type Aside from the inherent characteristics of the data structures, there are a few practical differences between the binary heap and the pairing heap. The binary heap is fully allocated at creation, and cannot be expanded beyond the allocated size. The pairing heap on the other hand has no inherent maximum size, but the caller needs to allocate each element being stored in the heap, while the binary heap works with plain Datums or pointers. The linked-lists in ilist.c can be embedded directly into other structs, as opposed to the List interface in nodes/pg_list.h.