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Commit620dddf

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> The previous patch fixed an infinite recursion bug in
> contrib/tablefunc/tablefunc.c:connectby. But, other unmanageable error> seems to occur even if a table has commonplace tree data(see below).>> I would think the patch, ancestor check, should be>> if (strstr(branch_delim || branchstr->data || branch_delim,> branch_delim || current_key || branch_delim))>> This is my image, not a real code. However, if branchstr->data includes> branch_delim, my image will not be perfect.Good point. Thank you Masaru for the suggested fix.Attached is a patch to fix the bug found by Masaru. His example nowproduces:regression=# SELECT * FROM connectby('connectby_tree', 'keyid','parent_keyid', '11', 0, '-') AS t(keyid int, parent_keyid int, levelint,branch text); keyid | parent_keyid | level | branch-------+--------------+-------+---------- 11 | | 0 | 11 10 | 11 | 1 | 11-10 111 | 11 | 1 | 11-111 1 | 111 | 2 | 11-111-1(4 rows)While making the patch I also realized that the "no show branch" form ofthe function was not going to work very well for recursion detection.Therefore there is now a default branch delimiter ('~') that is usedinternally, for that case, to enable recursion detection to work. Ifyou need a different delimiter for your specific data, you will have touse the "show branch" form of the function.Joe Conway
1 parenta0bf250 commit620dddf

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2 files changed

+29
-7
lines changed

2 files changed

+29
-7
lines changed

‎contrib/tablefunc/README.tablefunc‎

Lines changed: 7 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -365,7 +365,9 @@ Inputs
365365

366366
branch_delim
367367

368-
if optional branch value is desired, this string is used as the delimiter
368+
If optional branch value is desired, this string is used as the delimiter.
369+
When not provided, a default value of '~' is used for internal
370+
recursion detection only, and no "branch" field is returned.
369371

370372
Outputs
371373

@@ -388,7 +390,10 @@ Notes
388390
the level value output
389391

390392
3. If the branch field is not desired, omit both the branch_delim input
391-
parameter *and* the branch field in the query column definition
393+
parameter *and* the branch field in the query column definition. Note
394+
that when branch_delim is not provided, a default value of '~' is used
395+
for branch_delim for internal recursion detection, even though the branch
396+
field is not returned.
392397

393398
4. If the branch field is desired, it must be the forth column in the query
394399
column definition, and it must be type TEXT

‎contrib/tablefunc/tablefunc.c‎

Lines changed: 22 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -652,6 +652,9 @@ connectby_text(PG_FUNCTION_ARGS)
652652
branch_delim=GET_STR(PG_GETARG_TEXT_P(5));
653653
show_branch= true;
654654
}
655+
else
656+
/* default is no show, tilde for the delimiter */
657+
branch_delim=pstrdup("~");
655658

656659
per_query_ctx=rsinfo->econtext->ecxt_per_query_memory;
657660
oldcontext=MemoryContextSwitchTo(per_query_ctx);
@@ -798,10 +801,16 @@ build_tuplestore_recursively(char *key_fld,
798801
char*current_branch;
799802
char**values;
800803
StringInfobranchstr=NULL;
804+
StringInfochk_branchstr=NULL;
805+
StringInfochk_current_key=NULL;
801806

802807
/* start a new branch */
803808
branchstr=makeStringInfo();
804809

810+
/* need these to check for recursion */
811+
chk_branchstr=makeStringInfo();
812+
chk_current_key=makeStringInfo();
813+
805814
if (show_branch)
806815
values= (char**)palloc(CONNECTBY_NCOLS*sizeof(char*));
807816
else
@@ -854,22 +863,24 @@ build_tuplestore_recursively(char *key_fld,
854863
{
855864
/* initialize branch for this pass */
856865
appendStringInfo(branchstr,"%s",branch);
866+
appendStringInfo(chk_branchstr,"%s%s%s",branch_delim,branch,branch_delim);
857867

858868
/* get the next sql result tuple */
859869
spi_tuple=tuptable->vals[i];
860870

861871
/* get the current key and parent */
862872
current_key=SPI_getvalue(spi_tuple,spi_tupdesc,1);
873+
appendStringInfo(chk_current_key,"%s%s%s",branch_delim,current_key,branch_delim);
863874
current_key_parent=pstrdup(SPI_getvalue(spi_tuple,spi_tupdesc,2));
864875

865-
/* check to see if this key is also an ancestor */
866-
if (strstr(branchstr->data,current_key))
867-
elog(ERROR,"infinite recursion detected");
868-
869876
/* get the current level */
870877
sprintf(current_level,"%d",level);
871878

872-
/* extend the branch */
879+
/* check to see if this key is also an ancestor */
880+
if (strstr(chk_branchstr->data,chk_current_key->data))
881+
elog(ERROR,"infinite recursion detected");
882+
883+
/* OK, extend the branch */
873884
appendStringInfo(branchstr,"%s%s",branch_delim,current_key);
874885
current_branch=branchstr->data;
875886

@@ -913,6 +924,12 @@ build_tuplestore_recursively(char *key_fld,
913924
/* reset branch for next pass */
914925
xpfree(branchstr->data);
915926
initStringInfo(branchstr);
927+
928+
xpfree(chk_branchstr->data);
929+
initStringInfo(chk_branchstr);
930+
931+
xpfree(chk_current_key->data);
932+
initStringInfo(chk_current_key);
916933
}
917934
}
918935

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