rdelaage
/
postgresql
mirror of https://git.postgresql.org/git/postgresql.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

postgres_fdw: Remove redundancy in postgresAcquireSampleRowsFunc(). 

Previously, in the loop in postgresAcquireSampleRowsFunc() to iterate
fetching rows from a given remote table, we redundantly 1) determined the
fetch size by parsing the table's server/table-level options and then 2)
constructed the fetch command; remove that redundancy.

Author: Etsuro Fujita
Reviewed-by: Julien Rouhaud
Discussion: https://postgr.es/m/CAPmGK17_urk9qkLV65_iYMFw64z5qhdfhY=tMVV6Jg4KNYx8+w@mail.gmail.com
This commit is contained in:
Etsuro Fujita 2019-07-03 17:51:00 +09:00
parent e72489e101
commit 2a1612104c
1 changed files with 34 additions and 29 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

63
contrib/postgres_fdw/postgres_fdw.c
View File

@ -4490,20 +4490,51 @@ postgresAcquireSampleRowsFunc(Relation relation, int elevel,
/* In what follows, do not risk leaking any PGresults. */
PG_TRY();
{
char fetch_sql[64];
int fetch_size;
ListCell *lc;
res = pgfdw_exec_query(conn, sql.data);
if (PQresultStatus(res) != PGRES_COMMAND_OK)
pgfdw_report_error(ERROR, res, conn, false, sql.data);
PQclear(res);
res = NULL;
/*
* Determine the fetch size. The default is arbitrary, but shouldn't
* be enormous.
*/
fetch_size = 100;
foreach(lc, server->options)
{
DefElem *def = (DefElem *) lfirst(lc);
if (strcmp(def->defname, "fetch_size") == 0)
{
fetch_size = strtol(defGetString(def), NULL, 10);
break;
}
}
foreach(lc, table->options)
{
DefElem *def = (DefElem *) lfirst(lc);
if (strcmp(def->defname, "fetch_size") == 0)
{
fetch_size = strtol(defGetString(def), NULL, 10);
break;
}
}
/* Construct command to fetch rows from remote. */
snprintf(fetch_sql, sizeof(fetch_sql), "FETCH %d FROM c%u",
fetch_size, cursor_number);
/* Retrieve and process rows a batch at a time. */
for (;;)
{
char fetch_sql[64];
int fetch_size;
int numrows;
int i;
ListCell *lc;
/* Allow users to cancel long query */
CHECK_FOR_INTERRUPTS();
@ -4514,33 +4545,7 @@ postgresAcquireSampleRowsFunc(Relation relation, int elevel,
* then just adjust rowstoskip and samplerows appropriately.
*/
/* The fetch size is arbitrary, but shouldn't be enormous. */
fetch_size = 100;
foreach(lc, server->options)
{
DefElem *def = (DefElem *) lfirst(lc);
if (strcmp(def->defname, "fetch_size") == 0)
{
fetch_size = strtol(defGetString(def), NULL, 10);
break;
}
}
foreach(lc, table->options)
{
DefElem *def = (DefElem *) lfirst(lc);
if (strcmp(def->defname, "fetch_size") == 0)
{
fetch_size = strtol(defGetString(def), NULL, 10);
break;
}
}
/* Fetch some rows */
snprintf(fetch_sql, sizeof(fetch_sql), "FETCH %d FROM c%u",
fetch_size, cursor_number);
res = pgfdw_exec_query(conn, fetch_sql);
/* On error, report the original query, not the FETCH. */
if (PQresultStatus(res) != PGRES_TUPLES_OK)