src/include/partitioning/partdesc.h

   1 /*-------------------------------------------------------------------------
   2  *
   3  * partdesc.h
   4  *
   5  * Copyright (c) 1996-2025, PostgreSQL Global Development Group
   6  *
   7  * src/include/partitioning/partdesc.h
   8  *
   9  *-------------------------------------------------------------------------
  10  */
  11
  12 #ifndef PARTDESC_H
  13 #define PARTDESC_H
  14
  15 #include "partitioning/partdefs.h"
  16 #include "utils/relcache.h"
  17
  18 /*
  19  * Information about partitions of a partitioned table.
  20  *
  21  * For partitioned tables where detached partitions exist, we only cache
  22  * descriptors that include all partitions, including detached; when we're
  23  * requested a descriptor without the detached partitions, we create one
  24  * afresh each time.  (The reason for this is that the set of detached
  25  * partitions that are visible to each caller depends on the snapshot it has,
  26  * so it's pretty much impossible to evict a descriptor from cache at the
  27  * right time.)
  28  */
  29 typedef struct PartitionDescData
  30 {
  31         int                     nparts;                 /* Number of partitions */
  32         bool            detached_exist; /* Are there any detached partitions? */
  33         Oid                *oids;                       /* Array of 'nparts' elements containing
  34                                                                  * partition OIDs in order of their bounds */
  35         bool       *is_leaf;            /* Array of 'nparts' elements storing whether
  36                                                                  * the corresponding 'oids' element belongs to
  37                                                                  * a leaf partition or not */
  38         PartitionBoundInfo boundinfo;   /* collection of partition bounds */
  39
  40         /* Caching fields to cache lookups in get_partition_for_tuple() */
  41
  42         /*
  43          * Index into the PartitionBoundInfo's datum array for the last found
  44          * partition or -1 if none.
  45          */
  46         int                     last_found_datum_index;
  47
  48         /*
  49          * Partition index of the last found partition or -1 if none has been
  50          * found yet.
  51          */
  52         int                     last_found_part_index;
  53
  54         /*
  55          * For LIST partitioning, this is the number of times in a row that the
  56          * datum we're looking for a partition for matches the datum in the
  57          * last_found_datum_index index of the boundinfo->datums array.  For RANGE
  58          * partitioning, this is the number of times in a row we've found that the
  59          * datum we're looking for a partition for falls into the range of the
  60          * partition corresponding to the last_found_datum_index index of the
  61          * boundinfo->datums array.
  62          */
  63         int                     last_found_count;
  64 } PartitionDescData;
  65
  66
  67 extern PartitionDesc RelationGetPartitionDesc(Relation rel, bool omit_detached);
  68
  69 extern PartitionDirectory CreatePartitionDirectory(MemoryContext mcxt, bool omit_detached);
  70 extern PartitionDesc PartitionDirectoryLookup(PartitionDirectory, Relation);
  71 extern void DestroyPartitionDirectory(PartitionDirectory pdir);
  72
  73 extern Oid      get_default_oid_from_partdesc(PartitionDesc partdesc);
  74
  75 #endif                                                  /* PARTCACHE_H */