mirror of
https://git.postgresql.org/git/postgresql.git
synced 2024-08-22 03:33:23 +02:00
407 lines
10 KiB
C
407 lines
10 KiB
C
#include "postgres.h"
|
|
#include "executor/spi.h"
|
|
#include "commands/trigger.h"
|
|
#include <ctype.h> /* tolower */
|
|
#include <stdio.h> /* debugging */
|
|
|
|
/*
|
|
* Trigger function takes 2 arguments:
|
|
1. relation in which to store the substrings
|
|
2. field to extract substrings from
|
|
|
|
The relation in which to insert *must* have the following layout:
|
|
|
|
string varchar(#)
|
|
id oid
|
|
|
|
Example:
|
|
|
|
create function fti() returns opaque as
|
|
'/home/boekhold/src/postgresql-6.2/contrib/fti/fti.so' language 'c';
|
|
|
|
create table title_fti (string varchar(25), id oid);
|
|
create index title_fti_idx on title_fti (string);
|
|
|
|
create trigger title_fti_trigger after update or insert or delete on product
|
|
for each row execute procedure fti(title_fti, title);
|
|
^^^^^^^^^
|
|
where to store index in
|
|
^^^^^
|
|
which column to index
|
|
|
|
ofcourse don't forget to create an index on title_idx, column string, else
|
|
you won't notice much speedup :)
|
|
|
|
After populating 'product', try something like:
|
|
|
|
select p.* from product p, title_fti f1, title_fti f2 where
|
|
f1.string='slippery' and f2.string='wet' and f1.id=f2.id and p.oid=f1.id;
|
|
*/
|
|
|
|
/*
|
|
march 4 1998 Changed breakup() to return less substrings. Only breakup
|
|
in word parts which are in turn shortened from the start
|
|
of the word (ie. word, ord, rd)
|
|
Did allocation of substring buffer outside of breakup()
|
|
oct. 5 1997, fixed a bug in string breakup (where there are more nonalpha
|
|
characters between words then 1).
|
|
|
|
oct 4-5 1997 implemented the thing, at least the basic functionallity
|
|
of it all....
|
|
*/
|
|
|
|
/* IMPROVEMENTS:
|
|
|
|
save a plan for deletes
|
|
create a function that will make the index *after* we have populated
|
|
the main table (probably first delete all contents to be sure there's
|
|
nothing in it, then re-populate the fti-table)
|
|
|
|
can we do something with operator overloading or a seperate function
|
|
that can build the final query automatigally?
|
|
*/
|
|
|
|
HeapTuple fti(void);
|
|
char *breakup(char *, char *);
|
|
bool is_stopword(char *);
|
|
|
|
bool new_tuple = false;
|
|
|
|
|
|
/* THIS LIST MUST BE IN SORTED ORDER, A BINARY SEARCH IS USED!!!! */
|
|
char *StopWords[] = { /* list of words to skip in indexing */
|
|
#ifdef SAMPLE_STOP_WORDS
|
|
"no"
|
|
"the",
|
|
"yes",
|
|
#endif
|
|
};
|
|
|
|
/* stuff for caching query-plans, stolen from contrib/spi/\*.c */
|
|
typedef struct
|
|
{
|
|
char *ident;
|
|
int nplans;
|
|
void **splan;
|
|
} EPlan;
|
|
|
|
static EPlan *InsertPlans = NULL;
|
|
static EPlan *DeletePlans = NULL;
|
|
static int nInsertPlans = 0;
|
|
static int nDeletePlans = 0;
|
|
|
|
static EPlan *find_plan(char *ident, EPlan ** eplan, int *nplans);
|
|
|
|
/***********************************************************************/
|
|
HeapTuple
|
|
fti()
|
|
{
|
|
Trigger *trigger; /* to get trigger name */
|
|
int nargs; /* # of arguments */
|
|
char **args; /* arguments */
|
|
char *relname; /* triggered relation name */
|
|
Relation rel; /* triggered relation */
|
|
char *indexname; /* name of table for substrings */
|
|
HeapTuple rettuple = NULL;
|
|
TupleDesc tupdesc; /* tuple description */
|
|
bool isinsert = false;
|
|
bool isdelete = false;
|
|
int ret;
|
|
char query[8192];
|
|
Oid oid;
|
|
|
|
/*
|
|
* FILE *debug;
|
|
*/
|
|
|
|
/*
|
|
* debug = fopen("/dev/xconsole", "w"); fprintf(debug, "FTI: entered
|
|
* function\n"); fflush(debug);
|
|
*/
|
|
|
|
if (!CurrentTriggerData)
|
|
elog(ERROR, "Full Text Indexing: triggers are not initialized");
|
|
if (TRIGGER_FIRED_FOR_STATEMENT(CurrentTriggerData->tg_event))
|
|
elog(ERROR, "Full Text Indexing: can't process STATEMENT events");
|
|
if (TRIGGER_FIRED_BEFORE(CurrentTriggerData->tg_event))
|
|
elog(ERROR, "Full Text Indexing: must be fired AFTER event");
|
|
|
|
if (TRIGGER_FIRED_BY_INSERT(CurrentTriggerData->tg_event))
|
|
isinsert = true;
|
|
if (TRIGGER_FIRED_BY_UPDATE(CurrentTriggerData->tg_event))
|
|
{
|
|
isdelete = true;
|
|
isinsert = true;
|
|
}
|
|
if (TRIGGER_FIRED_BY_DELETE(CurrentTriggerData->tg_event))
|
|
isdelete = true;
|
|
|
|
trigger = CurrentTriggerData->tg_trigger;
|
|
rel = CurrentTriggerData->tg_relation;
|
|
relname = SPI_getrelname(rel);
|
|
rettuple = CurrentTriggerData->tg_trigtuple;
|
|
if (isdelete && isinsert) /* is an UPDATE */
|
|
rettuple = CurrentTriggerData->tg_newtuple;
|
|
|
|
CurrentTriggerData = NULL; /* invalidate 'normal' calls to this
|
|
* function */
|
|
|
|
if ((ret = SPI_connect()) < 0)
|
|
elog(ERROR, "Full Text Indexing: SPI_connect failed, returned %d\n", ret);
|
|
|
|
nargs = trigger->tgnargs;
|
|
if (nargs != 2)
|
|
elog(ERROR, "Full Text Indexing: trigger can only have 2 arguments");
|
|
|
|
args = trigger->tgargs;
|
|
indexname = args[0];
|
|
tupdesc = rel->rd_att; /* what the tuple looks like (?) */
|
|
|
|
/* get oid of current tuple, needed by all, so place here */
|
|
oid = rettuple->t_data->t_oid;
|
|
if (!OidIsValid(oid))
|
|
elog(ERROR, "Full Text Indexing: oid of current tuple is NULL");
|
|
|
|
if (isdelete)
|
|
{
|
|
void *pplan;
|
|
Oid *argtypes;
|
|
Datum values[1];
|
|
EPlan *plan;
|
|
|
|
sprintf(query, "D%s$%s", args[0], args[1]);
|
|
plan = find_plan(query, &DeletePlans, &nDeletePlans);
|
|
if (plan->nplans <= 0)
|
|
{
|
|
argtypes = (Oid *) palloc(sizeof(Oid));
|
|
|
|
argtypes[0] = OIDOID;
|
|
|
|
sprintf(query, "DELETE FROM %s WHERE id = $1", indexname);
|
|
pplan = SPI_prepare(query, 1, argtypes);
|
|
if (!pplan)
|
|
elog(ERROR, "Full Text Indexing: SPI_prepare returned NULL "
|
|
"in delete");
|
|
pplan = SPI_saveplan(pplan);
|
|
if (pplan == NULL)
|
|
elog(ERROR, "Full Text Indexing: SPI_saveplan returned NULL "
|
|
"in delete");
|
|
|
|
plan->splan = (void **) malloc(sizeof(void *));
|
|
*(plan->splan) = pplan;
|
|
plan->nplans = 1;
|
|
}
|
|
|
|
values[0] = oid;
|
|
|
|
ret = SPI_execp(*(plan->splan), values, NULL, 0);
|
|
if (ret != SPI_OK_DELETE)
|
|
elog(ERROR, "Full Text Indexing: error executing plan in delete");
|
|
}
|
|
|
|
if (isinsert)
|
|
{
|
|
char *substring,
|
|
*column;
|
|
void *pplan;
|
|
Oid *argtypes;
|
|
Datum values[2];
|
|
int colnum;
|
|
struct varlena *data;
|
|
EPlan *plan;
|
|
|
|
sprintf(query, "I%s$%s", args[0], args[1]);
|
|
plan = find_plan(query, &InsertPlans, &nInsertPlans);
|
|
|
|
/* no plan yet, so allocate mem for argtypes */
|
|
if (plan->nplans <= 0)
|
|
{
|
|
argtypes = (Oid *) palloc(2 * sizeof(Oid));
|
|
|
|
argtypes[0] = VARCHAROID; /* create table t_name (string
|
|
* varchar, */
|
|
argtypes[1] = OIDOID; /* id oid); */
|
|
|
|
/* prepare plan to gain speed */
|
|
sprintf(query, "INSERT INTO %s (string, id) VALUES ($1, $2)",
|
|
indexname);
|
|
pplan = SPI_prepare(query, 2, argtypes);
|
|
if (!pplan)
|
|
elog(ERROR, "Full Text Indexing: SPI_prepare returned NULL "
|
|
"in insert");
|
|
|
|
pplan = SPI_saveplan(pplan);
|
|
if (pplan == NULL)
|
|
elog(ERROR, "Full Text Indexing: SPI_saveplan returned NULL"
|
|
" in insert");
|
|
|
|
plan->splan = (void **) malloc(sizeof(void *));
|
|
*(plan->splan) = pplan;
|
|
plan->nplans = 1;
|
|
}
|
|
|
|
|
|
/* prepare plan for query */
|
|
colnum = SPI_fnumber(tupdesc, args[1]);
|
|
if (colnum == SPI_ERROR_NOATTRIBUTE)
|
|
elog(ERROR, "Full Text Indexing: column '%s' of '%s' not found",
|
|
args[1], args[0]);
|
|
|
|
/* Get the char* representation of the column with name args[1] */
|
|
column = SPI_getvalue(rettuple, tupdesc, colnum);
|
|
|
|
if (column)
|
|
{ /* make sure we don't try to index NULL's */
|
|
char *buff;
|
|
char *string = column;
|
|
|
|
while (*string != '\0')
|
|
{ /* placed 'really' inline. */
|
|
*string = tolower(*string); /* some compilers will
|
|
* choke */
|
|
string++; /* on 'inline' keyword */
|
|
}
|
|
|
|
data = (struct varlena *) palloc(sizeof(int32) + strlen(column) +1);
|
|
buff = palloc(strlen(column) + 1);
|
|
/* saves lots of calls in while-loop and in breakup() */
|
|
|
|
new_tuple = true;
|
|
while ((substring = breakup(column, buff)))
|
|
{
|
|
int l;
|
|
|
|
l = strlen(substring);
|
|
|
|
data->vl_len = l + sizeof(int32);
|
|
memcpy(VARDATA(data), substring, l);
|
|
values[0] = PointerGetDatum(data);
|
|
values[1] = oid;
|
|
|
|
ret = SPI_execp(*(plan->splan), values, NULL, 0);
|
|
if (ret != SPI_OK_INSERT)
|
|
elog(ERROR, "Full Text Indexing: error executing plan "
|
|
"in insert");
|
|
}
|
|
pfree(buff);
|
|
pfree(data);
|
|
}
|
|
}
|
|
|
|
SPI_finish();
|
|
return (rettuple);
|
|
}
|
|
|
|
char *
|
|
breakup(char *string, char *substring)
|
|
{
|
|
static char *last_start;
|
|
static char *cur_pos;
|
|
|
|
if (new_tuple)
|
|
{
|
|
cur_pos = last_start = &string[strlen(string) - 1];
|
|
new_tuple = false; /* don't initialize this next time */
|
|
}
|
|
|
|
while (cur_pos > string) /* don't read before start of 'string' */
|
|
{
|
|
|
|
/*
|
|
* skip pieces at the end of a string that are not alfa-numeric
|
|
* (ie. 'string$%^&', last_start first points to '&', and after
|
|
* this to 'g'
|
|
*/
|
|
if (!isalnum((int) *last_start))
|
|
{
|
|
while (!isalnum((int) *last_start) &&
|
|
last_start > string)
|
|
last_start--;
|
|
cur_pos = last_start;
|
|
}
|
|
|
|
cur_pos--; /* substrings are at minimum 2 characters
|
|
* long */
|
|
|
|
if (isalnum((int) *cur_pos))
|
|
{
|
|
/* Houston, we have a substring! :) */
|
|
memcpy(substring, cur_pos, last_start - cur_pos + 1);
|
|
substring[last_start - cur_pos + 1] = '\0';
|
|
if (!is_stopword(substring))
|
|
return substring;
|
|
}
|
|
else
|
|
{
|
|
last_start = cur_pos - 1;
|
|
cur_pos = last_start;
|
|
}
|
|
}
|
|
|
|
return NULL; /* we've processed all of 'string' */
|
|
}
|
|
|
|
/* copied from src/backend/parser/keywords.c and adjusted for our situation*/
|
|
bool
|
|
is_stopword(char *text)
|
|
{
|
|
char **StopLow; /* for list of stop-words */
|
|
char **StopHigh;
|
|
char **StopMiddle;
|
|
unsigned int difference;
|
|
|
|
StopLow = &StopWords[0]; /* initialize stuff for binary search */
|
|
StopHigh = endof(StopWords);
|
|
|
|
if (lengthof(StopWords) == 0)
|
|
return false;
|
|
|
|
while (StopLow <= StopHigh)
|
|
{
|
|
StopMiddle = StopLow + (StopHigh - StopLow) / 2;
|
|
difference = strcmp(*StopMiddle, text);
|
|
if (difference == 0)
|
|
return (true);
|
|
else if (difference < 0)
|
|
StopLow = StopMiddle + 1;
|
|
else
|
|
StopHigh = StopMiddle - 1;
|
|
}
|
|
|
|
return (false);
|
|
}
|
|
|
|
/* for caching of query plans, stolen from contrib/spi/\*.c */
|
|
static EPlan *
|
|
find_plan(char *ident, EPlan ** eplan, int *nplans)
|
|
{
|
|
EPlan *newp;
|
|
int i;
|
|
|
|
if (*nplans > 0)
|
|
{
|
|
for (i = 0; i < *nplans; i++)
|
|
{
|
|
if (strcmp((*eplan)[i].ident, ident) == 0)
|
|
break;
|
|
}
|
|
if (i != *nplans)
|
|
return (*eplan + i);
|
|
*eplan = (EPlan *) realloc(*eplan, (i + 1) * sizeof(EPlan));
|
|
newp = *eplan + i;
|
|
}
|
|
else
|
|
{
|
|
newp = *eplan = (EPlan *) malloc(sizeof(EPlan));
|
|
(*nplans) = i = 0;
|
|
}
|
|
|
|
newp->ident = (char *) malloc(strlen(ident) + 1);
|
|
strcpy(newp->ident, ident);
|
|
newp->nplans = 0;
|
|
newp->splan = NULL;
|
|
(*nplans)++;
|
|
|
|
return (newp);
|
|
}
|