Re: extend VacAttrStats to allow stavalues of different types - Mailing list pgsql-patches

Tom Lane wrote:
> I think the correct solution is to initialize the fields to match the
> column type before calling the typanalyze function.  Then you don't
> break compatibility for existing typanalyze functions.  It's also less
> code, since the standard typanalyze functions can rely on those preset
> values.

Right. Updated patch attached.

--
Jan Urbanski
GPG key ID: E583D7D2

ouden estin
*** src/backend/commands/analyze.c
--- /tmp/.diff_sIxSwv    2008-06-02 17:55:58.000000000 +0200
***************
*** 683,688 ****
--- 683,689 ----
      Form_pg_attribute attr = onerel->rd_att->attrs[attnum - 1];
      HeapTuple    typtuple;
      VacAttrStats *stats;
+     int            i;
      bool        ok;

      /* Never analyze dropped columns */
***************
*** 711,716 ****
--- 712,730 ----
      stats->tupattnum = attnum;

      /*
+      * Initialize fields describing the stats->stavalues[n] element types, so
+      * the typanalyze function will have some defaults in case it neglects to
+      * set them itself.
+      */
+     for (i = 0; i < STATISTIC_NUM_SLOTS; i++)
+     {
+         stats->statypid[i] = stats->attr->atttypid;
+         stats->statyplen[i] = stats->attrtype->typlen;
+         stats->statypbyval[i] = stats->attrtype->typbyval;
+         stats->statypalign[i] = stats->attrtype->typalign;
+     }
+
+     /*
       * Call the type-specific typanalyze function.    If none is specified, use
       * std_typanalyze().
       */
***************
*** 1321,1330 ****

                  arry = construct_array(stats->stavalues[k],
                                         stats->numvalues[k],
!                                        stats->attr->atttypid,
!                                        stats->attrtype->typlen,
!                                        stats->attrtype->typbyval,
!                                        stats->attrtype->typalign);
                  values[i++] = PointerGetDatum(arry);    /* stavaluesN */
              }
              else
--- 1335,1344 ----

                  arry = construct_array(stats->stavalues[k],
                                         stats->numvalues[k],
!                                        stats->statypid[k],
!                                        stats->statyplen[k],
!                                        stats->statypbyval[k],
!                                        stats->statypalign[k]);
                  values[i++] = PointerGetDatum(arry);    /* stavaluesN */
              }
              else
***************
*** 1854,1859 ****
--- 1868,1877 ----
              stats->numnumbers[0] = num_mcv;
              stats->stavalues[0] = mcv_values;
              stats->numvalues[0] = num_mcv;
+             /*
+              * Accept the defaults for stats->statypid and others.
+              * They have been set before we were called (see vacuum.h)
+              */
          }
      }
      else if (null_cnt > 0)
***************
*** 2197,2202 ****
--- 2215,2224 ----
              stats->numnumbers[slot_idx] = num_mcv;
              stats->stavalues[slot_idx] = mcv_values;
              stats->numvalues[slot_idx] = num_mcv;
+             /*
+              * Accept the defaults for stats->statypid and others.
+              * They have been set before we were called (see vacuum.h)
+              */
              slot_idx++;
          }

***************
*** 2281,2286 ****
--- 2303,2312 ----
              stats->staop[slot_idx] = mystats->ltopr;
              stats->stavalues[slot_idx] = hist_values;
              stats->numvalues[slot_idx] = num_hist;
+             /*
+              * Accept the defaults for stats->statypid and others.
+              * They have been set before we were called (see vacuum.h)
+              */
              slot_idx++;
          }

*** src/include/commands/vacuum.h
--- /tmp/.diff_YRgK4O    2008-06-02 17:55:58.000000000 +0200
***************
*** 94,99 ****
--- 94,111 ----
      Datum       *stavalues[STATISTIC_NUM_SLOTS];

      /*
+      * These fields describe the stavalues[n] element types. They will
+      * be initialized to be the same as the column's that's underlying the slot,
+      * but a custom typanalyze function might want to store an array of
+      * something other that the analyzed column's elements. It should then
+      * overwrite these fields.
+      */
+     Oid            statypid[STATISTIC_NUM_SLOTS];
+     int2        statyplen[STATISTIC_NUM_SLOTS];
+     bool        statypbyval[STATISTIC_NUM_SLOTS];
+     char        statypalign[STATISTIC_NUM_SLOTS];
+
+     /*
       * These fields are private to the main ANALYZE code and should not be
       * looked at by type-specific functions.
       */