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/*
This file is part of TALER
Copyright (C) 2022 Taler Systems SA
TALER is free software; you can redistribute it and/or modify it under the
terms of the GNU General Public License as published by the Free Software
Foundation; either version 3, or (at your option) any later version.
TALER is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with
TALER; see the file COPYING. If not, see <http://www.gnu.org/licenses/>
*/
/**
* @file exchangedb/pg_begin_revolving_shard.c
* @brief Implementation of the begin_revolving_shard function for Postgres
* @author Christian Grothoff
*/
#include "platform.h"
#include "taler_error_codes.h"
#include "taler_dbevents.h"
#include "taler_pq_lib.h"
#include "pg_begin_revolving_shard.h"
#include "pg_commit.h"
#include "pg_helper.h"
#include "pg_start.h"
#include "pg_rollback.h"
enum GNUNET_DB_QueryStatus
TEH_PG_begin_revolving_shard (void *cls,
const char *job_name,
uint32_t shard_size,
uint32_t shard_limit,
uint32_t *start_row,
uint32_t *end_row)
{
struct PostgresClosure *pg = cls;
GNUNET_assert (shard_limit <= 1U + (uint32_t) INT_MAX);
GNUNET_assert (shard_limit > 0);
GNUNET_assert (shard_size > 0);
for (unsigned int retries = 0; retries<3; retries++)
{
if (GNUNET_OK !=
TEH_PG_start (pg,
"begin_revolving_shard"))
{
GNUNET_break (0);
return GNUNET_DB_STATUS_HARD_ERROR;
}
/* First, find last 'end_row' */
{
enum GNUNET_DB_QueryStatus qs;
uint32_t last_end;
struct GNUNET_PQ_QueryParam params[] = {
GNUNET_PQ_query_param_string (job_name),
GNUNET_PQ_query_param_end
};
struct GNUNET_PQ_ResultSpec rs[] = {
GNUNET_PQ_result_spec_uint32 ("end_row",
&last_end),
GNUNET_PQ_result_spec_end
};
/* Used in #postgres_begin_revolving_shard() */
PREPARE (pg,
"get_last_revolving_shard",
"SELECT"
" end_row"
" FROM revolving_work_shards"
" WHERE job_name=$1"
" ORDER BY end_row DESC"
" LIMIT 1;");
qs = GNUNET_PQ_eval_prepared_singleton_select (pg->conn,
"get_last_revolving_shard",
params,
rs);
switch (qs)
{
case GNUNET_DB_STATUS_HARD_ERROR:
GNUNET_break (0);
TEH_PG_rollback (pg);
return qs;
case GNUNET_DB_STATUS_SOFT_ERROR:
TEH_PG_rollback (pg);
continue;
case GNUNET_DB_STATUS_SUCCESS_ONE_RESULT:
*start_row = 1U + last_end;
break;
case GNUNET_DB_STATUS_SUCCESS_NO_RESULTS:
*start_row = 0; /* base-case: no shards yet */
break; /* continued below */
}
} /* get_last_shard */
if (*start_row < shard_limit)
{
/* Claim fresh shard */
enum GNUNET_DB_QueryStatus qs;
struct GNUNET_TIME_Absolute now;
struct GNUNET_PQ_QueryParam params[] = {
GNUNET_PQ_query_param_string (job_name),
GNUNET_PQ_query_param_absolute_time (&now),
GNUNET_PQ_query_param_uint32 (start_row),
GNUNET_PQ_query_param_uint32 (end_row),
GNUNET_PQ_query_param_end
};
*end_row = GNUNET_MIN (shard_limit,
*start_row + shard_size - 1);
now = GNUNET_TIME_absolute_get ();
GNUNET_log (GNUNET_ERROR_TYPE_INFO,
"Trying to claim shard %llu-%llu\n",
(unsigned long long) *start_row,
(unsigned long long) *end_row);
/* Used in #postgres_claim_revolving_shard() */
PREPARE (pg,
"create_revolving_shard",
"INSERT INTO revolving_work_shards"
"(job_name"
",last_attempt"
",start_row"
",end_row"
",active"
") VALUES "
"($1, $2, $3, $4, TRUE);");
qs = GNUNET_PQ_eval_prepared_non_select (pg->conn,
"create_revolving_shard",
params);
switch (qs)
{
case GNUNET_DB_STATUS_HARD_ERROR:
GNUNET_break (0);
TEH_PG_rollback (pg);
return qs;
case GNUNET_DB_STATUS_SOFT_ERROR:
TEH_PG_rollback (pg);
continue;
case GNUNET_DB_STATUS_SUCCESS_ONE_RESULT:
/* continued below (with commit) */
break;
case GNUNET_DB_STATUS_SUCCESS_NO_RESULTS:
/* someone else got this shard already,
try again */
TEH_PG_rollback (pg);
continue;
}
} /* end create fresh reovlving shard */
else
{
/* claim oldest existing shard */
enum GNUNET_DB_QueryStatus qs;
struct GNUNET_PQ_QueryParam params[] = {
GNUNET_PQ_query_param_string (job_name),
GNUNET_PQ_query_param_end
};
struct GNUNET_PQ_ResultSpec rs[] = {
GNUNET_PQ_result_spec_uint32 ("start_row",
start_row),
GNUNET_PQ_result_spec_uint32 ("end_row",
end_row),
GNUNET_PQ_result_spec_end
};
/* Used in #postgres_begin_revolving_shard() */
PREPARE (pg,
"get_open_revolving_shard",
"SELECT"
" start_row"
",end_row"
" FROM revolving_work_shards"
" WHERE job_name=$1"
" AND active=FALSE"
" ORDER BY last_attempt ASC"
" LIMIT 1;");
qs = GNUNET_PQ_eval_prepared_singleton_select (pg->conn,
"get_open_revolving_shard",
params,
rs);
switch (qs)
{
case GNUNET_DB_STATUS_HARD_ERROR:
GNUNET_break (0);
TEH_PG_rollback (pg);
return qs;
case GNUNET_DB_STATUS_SOFT_ERROR:
TEH_PG_rollback (pg);
continue;
case GNUNET_DB_STATUS_SUCCESS_NO_RESULTS:
/* no open shards available */
TEH_PG_rollback (pg);
return qs;
case GNUNET_DB_STATUS_SUCCESS_ONE_RESULT:
{
enum GNUNET_DB_QueryStatus qs;
struct GNUNET_TIME_Timestamp now;
struct GNUNET_PQ_QueryParam params[] = {
GNUNET_PQ_query_param_string (job_name),
GNUNET_PQ_query_param_timestamp (&now),
GNUNET_PQ_query_param_uint32 (start_row),
GNUNET_PQ_query_param_uint32 (end_row),
GNUNET_PQ_query_param_end
};
now = GNUNET_TIME_timestamp_get ();
/* Used in #postgres_begin_revolving_shard() */
PREPARE (pg,
"reclaim_revolving_shard",
"UPDATE revolving_work_shards"
" SET last_attempt=$2"
" ,active=TRUE"
" WHERE job_name=$1"
" AND start_row=$3"
" AND end_row=$4");
qs = GNUNET_PQ_eval_prepared_non_select (pg->conn,
"reclaim_revolving_shard",
params);
switch (qs)
{
case GNUNET_DB_STATUS_HARD_ERROR:
GNUNET_break (0);
TEH_PG_rollback (pg);
return qs;
case GNUNET_DB_STATUS_SOFT_ERROR:
TEH_PG_rollback (pg);
continue;
case GNUNET_DB_STATUS_SUCCESS_ONE_RESULT:
break; /* continue with commit */
case GNUNET_DB_STATUS_SUCCESS_NO_RESULTS:
GNUNET_break (0); /* logic error, should be impossible */
TEH_PG_rollback (pg);
return GNUNET_DB_STATUS_HARD_ERROR;
}
}
break; /* continue with commit */
}
} /* end claim oldest existing shard */
/* commit */
{
enum GNUNET_DB_QueryStatus qs;
qs = TEH_PG_commit (pg);
switch (qs)
{
case GNUNET_DB_STATUS_HARD_ERROR:
GNUNET_break (0);
TEH_PG_rollback (pg);
return qs;
case GNUNET_DB_STATUS_SOFT_ERROR:
TEH_PG_rollback (pg);
continue;
case GNUNET_DB_STATUS_SUCCESS_NO_RESULTS:
case GNUNET_DB_STATUS_SUCCESS_ONE_RESULT:
return GNUNET_DB_STATUS_SUCCESS_ONE_RESULT;
}
}
} /* retry 'for' loop */
return GNUNET_DB_STATUS_SOFT_ERROR;
}
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