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Commit23c75b5

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Improve documentation around TS_execute().
I got frustrated by the lack of commentary in this area, so here is somereverse-engineered documentation, along with minor stylistic cleanup.No code changes more significant than removal of unused variables.Back-patch to 9.6, not because that's useful in itself, but becausewe have some bugs to fix in phrase search and this would cause mergefailures if it's only in HEAD.
1 parent3761fe3 commit23c75b5

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4 files changed

+103
-64
lines changed

4 files changed

+103
-64
lines changed

‎src/backend/tsearch/wparser_def.c

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -2123,7 +2123,7 @@ hlCover(HeadlineParsedText *prs, TSQuery query, int *p, int *q)
21232123

21242124
ch.words=&(prs->words[*p]);
21252125
ch.len=*q-*p+1;
2126-
if (TS_execute(GETQUERY(query),&ch,false,checkcondition_HL))
2126+
if (TS_execute(GETQUERY(query),&ch,TS_EXEC_EMPTY,checkcondition_HL))
21272127
return true;
21282128
else
21292129
{

‎src/backend/utils/adt/tsginidx.c

Lines changed: 5 additions & 7 deletions
Original file line numberDiff line numberDiff line change
@@ -188,7 +188,7 @@ checkcondition_gin_internal(GinChkVal *gcv, QueryOperand *val, ExecPhraseData *d
188188
* information then set recheck flag
189189
*/
190190
if (val->weight!=0||data!=NULL)
191-
*gcv->need_recheck= true;
191+
*(gcv->need_recheck)= true;
192192

193193
/* convert item's number to corresponding entry's (operand's) number */
194194
j=gcv->map_item_operand[((QueryItem*)val)-gcv->first_item];
@@ -289,19 +289,18 @@ gin_tsquery_consistent(PG_FUNCTION_ARGS)
289289
bool*recheck= (bool*)PG_GETARG_POINTER(5);
290290
boolres= FALSE;
291291

292-
/*Thequeryrequires recheck only if it involves weights */
292+
/*Initially assumequerydoesn't require recheck */
293293
*recheck= false;
294294

295295
if (query->size>0)
296296
{
297-
QueryItem*item;
298297
GinChkValgcv;
299298

300299
/*
301300
* check-parameter array has one entry for each value (operand) in the
302301
* query.
303302
*/
304-
gcv.first_item=item=GETQUERY(query);
303+
gcv.first_item=GETQUERY(query);
305304
gcv.check=check;
306305
gcv.map_item_operand= (int*) (extra_data[0]);
307306
gcv.need_recheck=recheck;
@@ -328,19 +327,18 @@ gin_tsquery_triconsistent(PG_FUNCTION_ARGS)
328327
GinTernaryValueres=GIN_FALSE;
329328
boolrecheck;
330329

331-
/*Thequeryrequires recheck only if it involves weights */
330+
/*Initially assumequerydoesn't require recheck */
332331
recheck= false;
333332

334333
if (query->size>0)
335334
{
336-
QueryItem*item;
337335
GinChkValgcv;
338336

339337
/*
340338
* check-parameter array has one entry for each value (operand) in the
341339
* query.
342340
*/
343-
gcv.first_item=item=GETQUERY(query);
341+
gcv.first_item=GETQUERY(query);
344342
gcv.check=check;
345343
gcv.map_item_operand= (int*) (extra_data[0]);
346344
gcv.need_recheck=&recheck;

‎src/backend/utils/adt/tsvector_op.c

Lines changed: 50 additions & 42 deletions
Original file line numberDiff line numberDiff line change
@@ -1405,20 +1405,26 @@ checkcondition_str(void *checkval, QueryOperand *val, ExecPhraseData *data)
14051405
}
14061406

14071407
/*
1408-
* Check for phrase condition. Fallback to the AND operation
1409-
* if there is no positional information.
1408+
* Execute tsquery at or below an OP_PHRASE operator.
1409+
*
1410+
* This handles the recursion at levels where we need to care about
1411+
* match locations. In addition to the same arguments used for TS_execute,
1412+
* the caller may pass a preinitialized-to-zeroes ExecPhraseData struct to
1413+
* be filled with lexeme match positions on success. data == NULL if no
1414+
* match data need be returned. (In practice, outside callers pass NULL,
1415+
* and only the internal recursion cases pass a data pointer.)
14101416
*/
14111417
staticbool
1412-
TS_phrase_execute(QueryItem*curitem,
1413-
void*checkval,uint32flags,ExecPhraseData*data,
1414-
bool (*chkcond) (void*,QueryOperand*,ExecPhraseData*))
1418+
TS_phrase_execute(QueryItem*curitem,void*arg,uint32flags,
1419+
ExecPhraseData*data,
1420+
TSExecuteCallbackchkcond)
14151421
{
14161422
/* since this function recurses, it could be driven to stack overflow */
14171423
check_stack_depth();
14181424

14191425
if (curitem->type==QI_VAL)
14201426
{
1421-
returnchkcond(checkval, (QueryOperand*)curitem,data);
1427+
returnchkcond(arg, (QueryOperand*)curitem,data);
14221428
}
14231429
else
14241430
{
@@ -1432,33 +1438,31 @@ TS_phrase_execute(QueryItem *curitem,
14321438
Assert(curitem->qoperator.oper==OP_PHRASE);
14331439

14341440
if (!TS_phrase_execute(curitem+curitem->qoperator.left,
1435-
checkval,flags,&Ldata,chkcond))
1441+
arg,flags,&Ldata,chkcond))
14361442
return false;
14371443

1438-
if (!TS_phrase_execute(curitem+1,checkval,flags,&Rdata,chkcond))
1444+
if (!TS_phrase_execute(curitem+1,arg,flags,&Rdata,chkcond))
14391445
return false;
14401446

14411447
/*
1442-
*if at least one of the operandshas no position information, then
1443-
* return false. But if TS_EXEC_PHRASE_AS_AND flag is set then we
1444-
* return true as it is a AND operation
1448+
*If either operandhas no position information, then we normally
1449+
* return false.But if TS_EXEC_PHRASE_AS_AND flag is set then we
1450+
* return true, treating OP_PHRASE as if it were OP_AND.
14451451
*/
14461452
if (Ldata.npos==0||Rdata.npos==0)
14471453
return (flags&TS_EXEC_PHRASE_AS_AND) ? true : false;
14481454

14491455
/*
1450-
* Result of the operation is a list of the corresponding positions of
1451-
* RIGHT operand.
1456+
* Prepare output position array if needed.
14521457
*/
14531458
if (data)
14541459
{
1460+
/*
1461+
* We can recycle the righthand operand's result array if it was
1462+
* palloc'd, else must allocate our own. The number of matches
1463+
* couldn't be more than the smaller of the two operands' matches.
1464+
*/
14551465
if (!Rdata.allocated)
1456-
1457-
/*
1458-
* OP_PHRASE is based on the OP_AND, so the number of
1459-
* resulting positions could not be greater than the total
1460-
* amount of operands.
1461-
*/
14621466
data->pos=palloc(sizeof(WordEntryPos)*Min(Ldata.npos,Rdata.npos));
14631467
else
14641468
data->pos=Rdata.pos;
@@ -1469,10 +1473,12 @@ TS_phrase_execute(QueryItem *curitem,
14691473
}
14701474

14711475
/*
1472-
* Find matches by distance, WEP_GETPOS() is needed because
1473-
* ExecPhraseData->data can point to the tsvector's WordEntryPosVector
1476+
* Find matches by distance. WEP_GETPOS() is needed because
1477+
* ExecPhraseData->data can point to a tsvector's WordEntryPosVector.
1478+
*
1479+
* Note that the output positions are those of the matching RIGHT
1480+
* operands.
14741481
*/
1475-
14761482
Rpos=Rdata.pos;
14771483
LposStart=Ldata.pos;
14781484
while (Rpos<Rdata.pos+Rdata.npos)
@@ -1505,8 +1511,9 @@ TS_phrase_execute(QueryItem *curitem,
15051511
else
15061512
{
15071513
/*
1508-
* We are in the root of the phrase tree and hence we
1509-
* don't have to store the resulting positions
1514+
* We are at the root of the phrase tree and hence we
1515+
* don't have to identify all the match positions.
1516+
* Just report success.
15101517
*/
15111518
return true;
15121519
}
@@ -1546,50 +1553,53 @@ TS_phrase_execute(QueryItem *curitem,
15461553
/*
15471554
* Evaluate tsquery boolean expression.
15481555
*
1549-
* chkcond is a callback function used to evaluate each VAL node in the query.
1550-
* checkval can be used to pass information to the callback. TS_execute doesn't
1551-
* do anything with it.
1552-
* It believes that ordinary operators are always closier to root than phrase
1553-
* operator, so, TS_execute() may not take care of lexeme's position at all.
1556+
* curitem: current tsquery item (initially, the first one)
1557+
* arg: opaque value to pass through to callback function
1558+
* flags: bitmask of flag bits shown in ts_utils.h
1559+
* chkcond: callback function to check whether a primitive value is present
1560+
*
1561+
* The logic here deals only with operators above any phrase operator, for
1562+
* which we do not need to worry about lexeme positions. As soon as we hit an
1563+
* OP_PHRASE operator, we pass it off to TS_phrase_execute which does worry.
15541564
*/
15551565
bool
1556-
TS_execute(QueryItem*curitem,void*checkval,uint32flags,
1557-
bool (*chkcond) (void*checkval,QueryOperand*val,ExecPhraseData*data))
1566+
TS_execute(QueryItem*curitem,void*arg,uint32flags,
1567+
TSExecuteCallbackchkcond)
15581568
{
15591569
/* since this function recurses, it could be driven to stack overflow */
15601570
check_stack_depth();
15611571

15621572
if (curitem->type==QI_VAL)
1563-
returnchkcond(checkval, (QueryOperand*)curitem,
1573+
returnchkcond(arg, (QueryOperand*)curitem,
15641574
NULL/* we don't need position info */ );
15651575

15661576
switch (curitem->qoperator.oper)
15671577
{
15681578
caseOP_NOT:
15691579
if (flags&TS_EXEC_CALC_NOT)
1570-
return !TS_execute(curitem+1,checkval,flags,chkcond);
1580+
return !TS_execute(curitem+1,arg,flags,chkcond);
15711581
else
15721582
return true;
15731583

15741584
caseOP_AND:
1575-
if (TS_execute(curitem+curitem->qoperator.left,checkval,flags,chkcond))
1576-
returnTS_execute(curitem+1,checkval,flags,chkcond);
1585+
if (TS_execute(curitem+curitem->qoperator.left,arg,flags,chkcond))
1586+
returnTS_execute(curitem+1,arg,flags,chkcond);
15771587
else
15781588
return false;
15791589

15801590
caseOP_OR:
1581-
if (TS_execute(curitem+curitem->qoperator.left,checkval,flags,chkcond))
1591+
if (TS_execute(curitem+curitem->qoperator.left,arg,flags,chkcond))
15821592
return true;
15831593
else
1584-
returnTS_execute(curitem+1,checkval,flags,chkcond);
1594+
returnTS_execute(curitem+1,arg,flags,chkcond);
15851595

15861596
caseOP_PHRASE:
15871597

15881598
/*
15891599
* do not check TS_EXEC_PHRASE_AS_AND here because chkcond() could
15901600
* do something more if it's called from TS_phrase_execute()
15911601
*/
1592-
returnTS_phrase_execute(curitem,checkval,flags,NULL,chkcond);
1602+
returnTS_phrase_execute(curitem,arg,flags,NULL,chkcond);
15931603

15941604
default:
15951605
elog(ERROR,"unrecognized operator: %d",curitem->qoperator.oper);
@@ -1684,12 +1694,10 @@ ts_match_vq(PG_FUNCTION_ARGS)
16841694
chkval.arre=chkval.arrb+val->size;
16851695
chkval.values=STRPTR(val);
16861696
chkval.operand=GETOPERAND(query);
1687-
result=TS_execute(
1688-
GETQUERY(query),
1697+
result=TS_execute(GETQUERY(query),
16891698
&chkval,
16901699
TS_EXEC_CALC_NOT,
1691-
checkcondition_str
1692-
);
1700+
checkcondition_str);
16931701

16941702
PG_FREE_IF_COPY(val,0);
16951703
PG_FREE_IF_COPY(query,1);

‎src/include/tsearch/ts_utils.h

Lines changed: 47 additions & 14 deletions
Original file line numberDiff line numberDiff line change
@@ -12,9 +12,9 @@
1212
#ifndef_PG_TS_UTILS_H_
1313
#define_PG_TS_UTILS_H_
1414

15-
#include"tsearch/ts_type.h"
16-
#include"tsearch/ts_public.h"
1715
#include"nodes/pg_list.h"
16+
#include"tsearch/ts_public.h"
17+
#include"tsearch/ts_type.h"
1818

1919
/*
2020
* Common parse definitions for tsvector and tsquery
@@ -102,34 +102,67 @@ extern void hlparsetext(Oid cfgId, HeadlineParsedText *prs, TSQuery query,
102102
externtext*generateHeadline(HeadlineParsedText*prs);
103103

104104
/*
105-
* Common check function for tsvector @@ tsquery
105+
* TSQuery execution support
106+
*
107+
* TS_execute() executes a tsquery against data that can be represented in
108+
* various forms. The TSExecuteCallback callback function is called to check
109+
* whether a given primitive tsquery value is matched in the data.
110+
*/
111+
112+
/*
113+
* struct ExecPhraseData is passed to a TSExecuteCallback function if we need
114+
* lexeme position data (because of a phrase-match operator in the tsquery).
115+
* The callback should fill in position data when it returns true (success).
116+
* If it cannot return position data, it may ignore its "data" argument, but
117+
* then the caller of TS_execute() must pass the TS_EXEC_PHRASE_AS_AND flag
118+
* and must arrange for a later recheck with position data available.
119+
*
120+
* The reported lexeme positions must be sorted and unique. Callers must only
121+
* consult the position bits of the pos array, ie, WEP_GETPOS(data->pos[i]).
122+
* This allows the returned "pos" to point directly to the WordEntryPos
123+
* portion of a tsvector value. If "allocated" is true then the pos array
124+
* is palloc'd workspace and caller may free it when done.
125+
*
126+
* All fields of the ExecPhraseData struct are initially zeroed by caller.
106127
*/
107128
typedefstructExecPhraseData
108129
{
109-
intnpos;
110-
boolallocated;
111-
WordEntryPos*pos;
130+
intnpos;/* number of positions reported */
131+
boolallocated;/* pos points to palloc'd data? */
132+
WordEntryPos*pos;/* ordered, non-duplicate lexeme positions */
112133
}ExecPhraseData;
113134

114135
/*
115-
* Evaluates tsquery, flags are followe below
136+
* Signature for TSQuery lexeme check functions
137+
*
138+
* arg: opaque value passed through from caller of TS_execute
139+
* val: lexeme to test for presence of
140+
* data: to be filled with lexeme positions; NULL if position data not needed
141+
*
142+
* Return TRUE if lexeme is present in data, else FALSE
116143
*/
117-
externboolTS_execute(QueryItem*curitem,void*checkval,uint32flags,
118-
bool (*chkcond) (void*,QueryOperand*,ExecPhraseData*));
144+
typedefbool(*TSExecuteCallback) (void*arg,QueryOperand*val,
145+
ExecPhraseData*data);
119146

147+
/*
148+
* Flag bits for TS_execute
149+
*/
120150
#defineTS_EXEC_EMPTY(0x00)
121151
/*
122-
*if TS_EXEC_CALC_NOT is not set then NOTexpression evaluated to be true,
123-
*usedin cases where NOT cannot be accurately computed (GiST) or
124-
* it isn't important (ranking)
152+
*If TS_EXEC_CALC_NOT is not set, then NOTexpressions are automatically
153+
*evaluated to be true. Usefulin cases where NOT cannot be accurately
154+
*computed (GiST) orit isn't important (ranking).
125155
*/
126156
#defineTS_EXEC_CALC_NOT(0x01)
127157
/*
128-
* Treat OP_PHRASE as OP_AND. Used when posiotional information is not
129-
* accessible, like in consistent methods of GIN/GiST indexes
158+
* Treat OP_PHRASE as OP_AND. Used when positional information is not
159+
* accessible, like in consistent methods of GIN/GiST indexes; rechecking
160+
* must occur later.
130161
*/
131162
#defineTS_EXEC_PHRASE_AS_AND(0x02)
132163

164+
externboolTS_execute(QueryItem*curitem,void*arg,uint32flags,
165+
TSExecuteCallbackchkcond);
133166
externbooltsquery_requires_match(QueryItem*curitem);
134167

135168
/*

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