Line data    Source code

       1             : /*-------------------------------------------------------------------------
       2             :  *
       3             :  * extendplan.c
       4             :  *    Extend core planner objects with additional private state
       5             :  *
       6             :  * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
       7             :  * Portions Copyright (c) 1994-5, Regents of the University of California
       8             :  *
       9             :  * The interfaces defined in this file make it possible for loadable
      10             :  * modules to store their own private state inside of key planner data
      11             :  * structures -- specifically, the PlannerGlobal, PlannerInfo, and
      12             :  * RelOptInfo structures. This can make it much easier to write
      13             :  * reasonably efficient planner extensions; for instance, code that
      14             :  * uses set_join_pathlist_hook can arrange to compute a key intermediate
      15             :  * result once per joinrel rather than on every call.
      16             :  *
      17             :  * IDENTIFICATION
      18             :  *    src/backend/optimizer/util/extendplan.c
      19             :  *
      20             :  *-------------------------------------------------------------------------
      21             :  */
      22             : #include "postgres.h"
      23             : 
      24             : #include "optimizer/extendplan.h"
      25             : #include "port/pg_bitutils.h"
      26             : #include "utils/memutils.h"
      27             : 
      28             : static const char **PlannerExtensionNameArray = NULL;
      29             : static int  PlannerExtensionNamesAssigned = 0;
      30             : static int  PlannerExtensionNamesAllocated = 0;
      31             : 
      32             : /*
      33             :  * Map the name of a planner extension to an integer ID.
      34             :  *
      35             :  * Within the lifetime of a particular backend, the same name will be mapped
      36             :  * to the same ID every time. IDs are not stable across backends. Use the ID
      37             :  * that you get from this function to call the remaining functions in this
      38             :  * file.
      39             :  */
      40             : int
      41          12 : GetPlannerExtensionId(const char *extension_name)
      42             : {
      43             :     /* Search for an existing extension by this name; if found, return ID. */
      44          12 :     for (int i = 0; i < PlannerExtensionNamesAssigned; ++i)
      45           0 :         if (strcmp(PlannerExtensionNameArray[i], extension_name) == 0)
      46           0 :             return i;
      47             : 
      48             :     /* If there is no array yet, create one. */
      49          12 :     if (PlannerExtensionNameArray == NULL)
      50             :     {
      51          12 :         PlannerExtensionNamesAllocated = 16;
      52          12 :         PlannerExtensionNameArray = (const char **)
      53          12 :             MemoryContextAlloc(TopMemoryContext,
      54             :                                PlannerExtensionNamesAllocated
      55             :                                * sizeof(char *));
      56             :     }
      57             : 
      58             :     /* If there's an array but it's currently full, expand it. */
      59          12 :     if (PlannerExtensionNamesAssigned >= PlannerExtensionNamesAllocated)
      60             :     {
      61           0 :         int         i = pg_nextpower2_32(PlannerExtensionNamesAssigned + 1);
      62             : 
      63           0 :         PlannerExtensionNameArray = (const char **)
      64           0 :             repalloc(PlannerExtensionNameArray, i * sizeof(char *));
      65           0 :         PlannerExtensionNamesAllocated = i;
      66             :     }
      67             : 
      68             :     /* Assign and return new ID. */
      69          12 :     PlannerExtensionNameArray[PlannerExtensionNamesAssigned] = extension_name;
      70          12 :     return PlannerExtensionNamesAssigned++;
      71             : }
      72             : 
      73             : /*
      74             :  * Store extension-specific state into a PlannerGlobal.
      75             :  */
      76             : void
      77           0 : SetPlannerGlobalExtensionState(PlannerGlobal *glob, int extension_id,
      78             :                                void *opaque)
      79             : {
      80             :     Assert(extension_id >= 0);
      81             : 
      82             :     /* If there is no array yet, create one. */
      83           0 :     if (glob->extension_state == NULL)
      84             :     {
      85             :         MemoryContext planner_cxt;
      86             :         Size        sz;
      87             : 
      88           0 :         planner_cxt = GetMemoryChunkContext(glob);
      89           0 :         glob->extension_state_allocated =
      90           0 :             Max(4, pg_nextpower2_32(extension_id + 1));
      91           0 :         sz = glob->extension_state_allocated * sizeof(void *);
      92           0 :         glob->extension_state = MemoryContextAllocZero(planner_cxt, sz);
      93             :     }
      94             : 
      95             :     /* If there's an array but it's currently full, expand it. */
      96           0 :     if (extension_id >= glob->extension_state_allocated)
      97             :     {
      98             :         int         i;
      99             : 
     100           0 :         i = pg_nextpower2_32(extension_id + 1);
     101           0 :         glob->extension_state = (void **)
     102           0 :             repalloc0(glob->extension_state,
     103           0 :                       glob->extension_state_allocated * sizeof(void *),
     104             :                       i * sizeof(void *));
     105           0 :         glob->extension_state_allocated = i;
     106             :     }
     107             : 
     108           0 :     glob->extension_state[extension_id] = opaque;
     109           0 : }
     110             : 
     111             : /*
     112             :  * Store extension-specific state into a PlannerInfo.
     113             :  */
     114             : void
     115          84 : SetPlannerInfoExtensionState(PlannerInfo *root, int extension_id,
     116             :                              void *opaque)
     117             : {
     118             :     Assert(extension_id >= 0);
     119             : 
     120             :     /* If there is no array yet, create one. */
     121          84 :     if (root->extension_state == NULL)
     122             :     {
     123             :         Size        sz;
     124             : 
     125          42 :         root->extension_state_allocated =
     126          42 :             Max(4, pg_nextpower2_32(extension_id + 1));
     127          42 :         sz = root->extension_state_allocated * sizeof(void *);
     128          42 :         root->extension_state = MemoryContextAllocZero(root->planner_cxt, sz);
     129             :     }
     130             : 
     131             :     /* If there's an array but it's currently full, expand it. */
     132          84 :     if (extension_id >= root->extension_state_allocated)
     133             :     {
     134             :         int         i;
     135             : 
     136           0 :         i = pg_nextpower2_32(extension_id + 1);
     137           0 :         root->extension_state = (void **)
     138           0 :             repalloc0(root->extension_state,
     139           0 :                       root->extension_state_allocated * sizeof(void *),
     140             :                       i * sizeof(void *));
     141           0 :         root->extension_state_allocated = i;
     142             :     }
     143             : 
     144          84 :     root->extension_state[extension_id] = opaque;
     145          84 : }
     146             : 
     147             : /*
     148             :  * Store extension-specific state into a RelOptInfo.
     149             :  */
     150             : void
     151           0 : SetRelOptInfoExtensionState(RelOptInfo *rel, int extension_id,
     152             :                             void *opaque)
     153             : {
     154             :     Assert(extension_id >= 0);
     155             : 
     156             :     /* If there is no array yet, create one. */
     157           0 :     if (rel->extension_state == NULL)
     158             :     {
     159             :         MemoryContext planner_cxt;
     160             :         Size        sz;
     161             : 
     162           0 :         planner_cxt = GetMemoryChunkContext(rel);
     163           0 :         rel->extension_state_allocated =
     164           0 :             Max(4, pg_nextpower2_32(extension_id + 1));
     165           0 :         sz = rel->extension_state_allocated * sizeof(void *);
     166           0 :         rel->extension_state = MemoryContextAllocZero(planner_cxt, sz);
     167             :     }
     168             : 
     169             :     /* If there's an array but it's currently full, expand it. */
     170           0 :     if (extension_id >= rel->extension_state_allocated)
     171             :     {
     172             :         int         i;
     173             : 
     174           0 :         i = pg_nextpower2_32(extension_id + 1);
     175           0 :         rel->extension_state = (void **)
     176           0 :             repalloc0(rel->extension_state,
     177           0 :                       rel->extension_state_allocated * sizeof(void *),
     178             :                       i * sizeof(void *));
     179           0 :         rel->extension_state_allocated = i;
     180             :     }
     181             : 
     182           0 :     rel->extension_state[extension_id] = opaque;
     183           0 : }