Re: Support for REINDEX CONCURRENTLY

On Wed, Jul 3, 2013 at 11:16 PM, Andres Freund <andres(at)2ndquadrant(dot)com> wrote:
> On 2013-07-03 10:03:26 +0900, Michael Paquier wrote:
>> index 9ee9ea2..23e0373 100644
>> --- a/src/bin/pg_dump/pg_dump.c
>> +++ b/src/bin/pg_dump/pg_dump.c
>> @@ -2778,10 +2778,9 @@ binary_upgrade_set_pg_class_oids(Archive *fout,
>> PQExpBuffer upgrade_query = createPQExpBuffer();
>> PGresult *upgrade_res;
>> Oid pg_class_reltoastrelid;
>> - Oid pg_class_reltoastidxid;
>>
>> appendPQExpBuffer(upgrade_query,
>> - "SELECT c.reltoastrelid, t.reltoastidxid "
>> + "SELECT c.reltoastrelid "
>> "FROM pg_catalog.pg_class c LEFT JOIN "
>> "pg_catalog.pg_class t ON (c.reltoastrelid = t.oid) "
>> "WHERE c.oid = '%u'::pg_catalog.oid;",
>> @@ -2790,7 +2789,6 @@ binary_upgrade_set_pg_class_oids(Archive *fout,
>> upgrade_res = ExecuteSqlQueryForSingleRow(fout, upgrade_query->data);
>>
>> pg_class_reltoastrelid = atooid(PQgetvalue(upgrade_res, 0, PQfnumber(upgrade_res, "reltoastrelid")));
>> - pg_class_reltoastidxid = atooid(PQgetvalue(upgrade_res, 0, PQfnumber(upgrade_res, "reltoastidxid")));
>>
>> appendPQExpBuffer(upgrade_buffer,
>> "\n-- For binary upgrade, must preserve pg_class oids\n");
>> @@ -2803,6 +2801,10 @@ binary_upgrade_set_pg_class_oids(Archive *fout,
>> /* only tables have toast tables, not indexes */
>> if (OidIsValid(pg_class_reltoastrelid))
>> {
>> + PQExpBuffer index_query = createPQExpBuffer();
>> + PGresult *index_res;
>> + Oid indexrelid;
>> +
>> /*
>> * One complexity is that the table definition might not require
>> * the creation of a TOAST table, and the TOAST table might have
>> @@ -2816,10 +2818,23 @@ binary_upgrade_set_pg_class_oids(Archive *fout,
>> "SELECT binary_upgrade.set_next_toast_pg_class_oid('%u'::pg_catalog.oid);\n",
>> pg_class_reltoastrelid);
>>
>> - /* every toast table has an index */
>> + /* Every toast table has one valid index, so fetch it first... */
>> + appendPQExpBuffer(index_query,
>> + "SELECT c.indexrelid "
>> + "FROM pg_catalog.pg_index c "
>> + "WHERE c.indrelid = %u AND c.indisvalid;",
>> + pg_class_reltoastrelid);
>> + index_res = ExecuteSqlQueryForSingleRow(fout, index_query->data);
>> + indexrelid = atooid(PQgetvalue(index_res, 0,
>> + PQfnumber(index_res, "indexrelid")));
>> +
>> + /* Then set it */
>> appendPQExpBuffer(upgrade_buffer,
>> "SELECT binary_upgrade.set_next_index_pg_class_oid('%u'::pg_catalog.oid);\n",
>> - pg_class_reltoastidxid);
>> + indexrelid);
>> +
>> + PQclear(index_res);
>> + destroyPQExpBuffer(index_query);
>
> Wouldn't it make more sense to fetch the toast index oid in the query
> ontop instead of making a query for every relation?
With something like a CASE condition in the upper query for
reltoastrelid? This code path is not only taken by indexes but also by
tables. So I thought that it was cleaner and more readable to fetch
the index OID only if necessary as a separate query.

Regards,
--
Michael