diff options
Diffstat (limited to 'src/backend/parser/parse_clause.c')
| -rw-r--r-- | src/backend/parser/parse_clause.c | 199 |
1 files changed, 108 insertions, 91 deletions
diff --git a/src/backend/parser/parse_clause.c b/src/backend/parser/parse_clause.c index 5fa42d307ac..36a3efff876 100644 --- a/src/backend/parser/parse_clause.c +++ b/src/backend/parser/parse_clause.c @@ -52,9 +52,9 @@ #include "utils/syscache.h" -static void extractRemainingColumns(List *common_colnames, - List *src_colnames, List *src_colvars, - ParseNamespaceColumn *src_nscolumns, +static int extractRemainingColumns(ParseNamespaceColumn *src_nscolumns, + List *src_colnames, + List **src_colnos, List **res_colnames, List **res_colvars, ParseNamespaceColumn *res_nscolumns); static Node *transformJoinUsingClause(ParseState *pstate, @@ -76,6 +76,7 @@ static ParseNamespaceItem *getNSItemForSpecialRelationTypes(ParseState *pstate, static Node *transformFromClauseItem(ParseState *pstate, Node *n, ParseNamespaceItem **top_nsitem, List **namespace); +static Var *buildVarFromNSColumn(ParseNamespaceColumn *nscol); static Node *buildMergedJoinVar(ParseState *pstate, JoinType jointype, Var *l_colvar, Var *r_colvar); static void setNamespaceColumnVisibility(List *namespace, bool cols_visible); @@ -237,64 +238,61 @@ setTargetTable(ParseState *pstate, RangeVar *relation, /* * Extract all not-in-common columns from column lists of a source table * - * We hand back new lists in *res_colnames and *res_colvars. But - * res_nscolumns points to a caller-allocated array that we fill in - * the next few entries in. + * src_nscolumns and src_colnames describe the source table. + * + * *src_colnos initially contains the column numbers of the already-merged + * columns. We add to it the column number of each additional column. + * Also append to *res_colnames the name of each additional column, + * append to *res_colvars a Var for each additional column, and copy the + * columns' nscolumns data into res_nscolumns[] (which is caller-allocated + * space that had better be big enough). + * + * Returns the number of columns added. */ -static void -extractRemainingColumns(List *common_colnames, - List *src_colnames, List *src_colvars, - ParseNamespaceColumn *src_nscolumns, +static int +extractRemainingColumns(ParseNamespaceColumn *src_nscolumns, + List *src_colnames, + List **src_colnos, List **res_colnames, List **res_colvars, ParseNamespaceColumn *res_nscolumns) { - List *new_colnames = NIL; - List *new_colvars = NIL; - ListCell *lnames, - *lvars; - - Assert(list_length(src_colnames) == list_length(src_colvars)); + int colcount = 0; + Bitmapset *prevcols; + int attnum; + ListCell *lc; - forboth(lnames, src_colnames, lvars, src_colvars) + /* + * While we could just test "list_member_int(*src_colnos, attnum)" to + * detect already-merged columns in the loop below, that would be O(N^2) + * for a wide input table. Instead build a bitmapset of just the merged + * USING columns, which we won't add to within the main loop. + */ + prevcols = NULL; + foreach(lc, *src_colnos) { - char *colname = strVal(lfirst(lnames)); - bool match = false; - ListCell *cnames; - - /* - * Ignore any dropped columns in the src_nscolumns input. (The list - * inputs won't contain entries for dropped columns.) - */ - while (src_nscolumns->p_varno == 0) - src_nscolumns++; - - /* is current src column already accounted for in common_colnames? */ - foreach(cnames, common_colnames) - { - char *ccolname = strVal(lfirst(cnames)); + prevcols = bms_add_member(prevcols, lfirst_int(lc)); + } - if (strcmp(colname, ccolname) == 0) - { - match = true; - break; - } - } + attnum = 0; + foreach(lc, src_colnames) + { + char *colname = strVal(lfirst(lc)); - if (!match) + attnum++; + /* Non-dropped and not already merged? */ + if (colname[0] != '\0' && !bms_is_member(attnum, prevcols)) { - /* Nope, so emit it as next output column */ - new_colnames = lappend(new_colnames, lfirst(lnames)); - new_colvars = lappend(new_colvars, lfirst(lvars)); + /* Yes, so emit it as next output column */ + *src_colnos = lappend_int(*src_colnos, attnum); + *res_colnames = lappend(*res_colnames, lfirst(lc)); + *res_colvars = lappend(*res_colvars, + buildVarFromNSColumn(src_nscolumns + attnum - 1)); /* Copy the input relation's nscolumn data for this column */ - *res_nscolumns = *src_nscolumns; - res_nscolumns++; + res_nscolumns[colcount] = src_nscolumns[attnum - 1]; + colcount++; } - - src_nscolumns++; } - - *res_colnames = new_colnames; - *res_colvars = new_colvars; + return colcount; } /* transformJoinUsingClause() @@ -1154,10 +1152,12 @@ transformFromClauseItem(ParseState *pstate, Node *n, *l_colnames, *r_colnames, *res_colnames, - *l_colvars, - *r_colvars, + *l_colnos, + *r_colnos, *res_colvars; - ParseNamespaceColumn *res_nscolumns; + ParseNamespaceColumn *l_nscolumns, + *r_nscolumns, + *res_nscolumns; int res_colindex; bool lateral_ok; int sv_namespace_length; @@ -1211,12 +1211,15 @@ transformFromClauseItem(ParseState *pstate, Node *n, my_namespace = list_concat(l_namespace, r_namespace); /* - * Extract column name and var lists from both subtrees - * - * Note: expandNSItemVars returns new lists, safe for me to modify + * We'll work from the nscolumns data and eref alias column names for + * each of the input nsitems. Note that these include dropped + * columns, which is helpful because we can keep track of physical + * input column numbers more easily. */ - l_colvars = expandNSItemVars(l_nsitem, 0, -1, &l_colnames); - r_colvars = expandNSItemVars(r_nsitem, 0, -1, &r_colnames); + l_nscolumns = l_nsitem->p_nscolumns; + l_colnames = l_nsitem->p_rte->eref->colnames; + r_nscolumns = r_nsitem->p_nscolumns; + r_colnames = r_nsitem->p_rte->eref->colnames; /* * Natural join does not explicitly specify columns; must generate @@ -1240,6 +1243,9 @@ transformFromClauseItem(ParseState *pstate, Node *n, char *l_colname = strVal(lfirst(lx)); Value *m_name = NULL; + if (l_colname[0] == '\0') + continue; /* ignore dropped columns */ + foreach(rx, r_colnames) { char *r_colname = strVal(lfirst(rx)); @@ -1262,6 +1268,8 @@ transformFromClauseItem(ParseState *pstate, Node *n, /* * Now transform the join qualifications, if any. */ + l_colnos = NIL; + r_colnos = NIL; res_colnames = NIL; res_colvars = NIL; @@ -1297,6 +1305,8 @@ transformFromClauseItem(ParseState *pstate, Node *n, Node *u_colvar; ParseNamespaceColumn *res_nscolumn; + Assert(u_colname[0] != '\0'); + /* Check for USING(foo,foo) */ foreach(col, res_colnames) { @@ -1331,6 +1341,7 @@ transformFromClauseItem(ParseState *pstate, Node *n, (errcode(ERRCODE_UNDEFINED_COLUMN), errmsg("column \"%s\" specified in USING clause does not exist in left table", u_colname))); + l_colnos = lappend_int(l_colnos, l_index + 1); /* Find it in right input */ ndx = 0; @@ -1354,10 +1365,11 @@ transformFromClauseItem(ParseState *pstate, Node *n, (errcode(ERRCODE_UNDEFINED_COLUMN), errmsg("column \"%s\" specified in USING clause does not exist in right table", u_colname))); + r_colnos = lappend_int(r_colnos, r_index + 1); - l_colvar = list_nth(l_colvars, l_index); + l_colvar = buildVarFromNSColumn(l_nscolumns + l_index); l_usingvars = lappend(l_usingvars, l_colvar); - r_colvar = list_nth(r_colvars, r_index); + r_colvar = buildVarFromNSColumn(r_nscolumns + r_index); r_usingvars = lappend(r_usingvars, r_colvar); res_colnames = lappend(res_colnames, lfirst(ucol)); @@ -1371,26 +1383,12 @@ transformFromClauseItem(ParseState *pstate, Node *n, if (u_colvar == (Node *) l_colvar) { /* Merged column is equivalent to left input */ - res_nscolumn->p_varno = l_colvar->varno; - res_nscolumn->p_varattno = l_colvar->varattno; - res_nscolumn->p_vartype = l_colvar->vartype; - res_nscolumn->p_vartypmod = l_colvar->vartypmod; - res_nscolumn->p_varcollid = l_colvar->varcollid; - /* XXX these are not quite right, but doesn't matter yet */ - res_nscolumn->p_varnosyn = l_colvar->varno; - res_nscolumn->p_varattnosyn = l_colvar->varattno; + *res_nscolumn = l_nscolumns[l_index]; } else if (u_colvar == (Node *) r_colvar) { /* Merged column is equivalent to right input */ - res_nscolumn->p_varno = r_colvar->varno; - res_nscolumn->p_varattno = r_colvar->varattno; - res_nscolumn->p_vartype = r_colvar->vartype; - res_nscolumn->p_vartypmod = r_colvar->vartypmod; - res_nscolumn->p_varcollid = r_colvar->varcollid; - /* XXX these are not quite right, but doesn't matter yet */ - res_nscolumn->p_varnosyn = r_colvar->varno; - res_nscolumn->p_varattnosyn = r_colvar->varattno; + *res_nscolumn = r_nscolumns[r_index]; } else { @@ -1427,22 +1425,14 @@ transformFromClauseItem(ParseState *pstate, Node *n, } /* Add remaining columns from each side to the output columns */ - extractRemainingColumns(res_colnames, - l_colnames, l_colvars, - l_nsitem->p_nscolumns, - &l_colnames, &l_colvars, - res_nscolumns + res_colindex); - res_colindex += list_length(l_colvars); - extractRemainingColumns(res_colnames, - r_colnames, r_colvars, - r_nsitem->p_nscolumns, - &r_colnames, &r_colvars, - res_nscolumns + res_colindex); - res_colindex += list_length(r_colvars); - res_colnames = list_concat(res_colnames, l_colnames); - res_colvars = list_concat(res_colvars, l_colvars); - res_colnames = list_concat(res_colnames, r_colnames); - res_colvars = list_concat(res_colvars, r_colvars); + res_colindex += + extractRemainingColumns(l_nscolumns, l_colnames, &l_colnos, + &res_colnames, &res_colvars, + res_nscolumns + res_colindex); + res_colindex += + extractRemainingColumns(r_nscolumns, r_colnames, &r_colnos, + &res_colnames, &res_colvars, + res_nscolumns + res_colindex); /* * Check alias (AS clause), if any. @@ -1468,7 +1458,10 @@ transformFromClauseItem(ParseState *pstate, Node *n, res_colnames, res_nscolumns, j->jointype, + list_length(j->usingClause), res_colvars, + l_colnos, + r_colnos, j->alias, true); @@ -1538,6 +1531,30 @@ transformFromClauseItem(ParseState *pstate, Node *n, } /* + * buildVarFromNSColumn - + * build a Var node using ParseNamespaceColumn data + * + * We assume varlevelsup should be 0, and no location is specified + */ +static Var * +buildVarFromNSColumn(ParseNamespaceColumn *nscol) +{ + Var *var; + + Assert(nscol->p_varno > 0); /* i.e., not deleted column */ + var = makeVar(nscol->p_varno, + nscol->p_varattno, + nscol->p_vartype, + nscol->p_vartypmod, + nscol->p_varcollid, + 0); + /* makeVar doesn't offer parameters for these, so set by hand: */ + var->varnosyn = nscol->p_varnosyn; + var->varattnosyn = nscol->p_varattnosyn; + return var; +} + +/* * buildMergedJoinVar - * generate a suitable replacement expression for a merged join column */ |