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postgres documentation suggests to avoid 'FOR UPDATE' with serializable transactions

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This commit is contained in:
Christian Grothoff 2020-08-08 20:01:56 +02:00
parent 1a37d9d805
commit c2a0196f16
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GPG Key ID: 939E6BE1E29FC3CC
1 changed files with 19 additions and 30 deletions
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49
src/exchangedb/plugin_exchangedb_postgres.c
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@ -254,6 +254,10 @@ postgres_get_session (void *cls)
GNUNET_PQ_make_try_execute ("SET auto_explain.log_min_duration=50;"),
GNUNET_PQ_make_try_execute ("SET auto_explain.log_timing=TRUE;"),
GNUNET_PQ_make_try_execute ("SET auto_explain.log_analyze=TRUE;"),
/* https://wiki.postgresql.org/wiki/Serializable suggests to really
force the default to 'serializable' if SSI is to be used. */
GNUNET_PQ_make_try_execute (
"SET SESSION CHARACTERISTICS AS TRANSACTION ISOLATION LEVEL SERIALIZABLE;"),
GNUNET_PQ_make_try_execute ("SET enable_sort=OFF;"),
GNUNET_PQ_make_try_execute ("SET enable_seqscan=OFF;"),
GNUNET_PQ_EXECUTE_STATEMENT_END
@ -356,8 +360,7 @@ postgres_get_session (void *cls)
",gc_date"
" FROM reserves"
" WHERE reserve_pub=$1"
" LIMIT 1"
" FOR UPDATE;",
" LIMIT 1;",
1),
/* Used in #postgres_reserves_in_insert() when the reserve is new */
GNUNET_PQ_make_prepare ("reserve_create",
@ -461,8 +464,7 @@ postgres_get_session (void *cls)
",execution_date"
",sender_account_details"
" FROM reserves_in"
" WHERE reserve_pub=$1"
" FOR UPDATE;",
" WHERE reserve_pub=$1;",
1),
/* Lock withdraw table; NOTE: we may want to eventually shard the
deposit table to avoid this lock being the main point of
@ -507,8 +509,7 @@ postgres_get_session (void *cls)
" FROM reserves_out"
" JOIN denominations denom"
" USING (denom_pub_hash)"
" WHERE h_blind_ev=$1"
" FOR UPDATE;",
" WHERE h_blind_ev=$1;",
1),
/* Used during #postgres_get_reserve_history() to
obtain all of the /reserve/withdraw operations that
@ -528,8 +529,7 @@ postgres_get_session (void *cls)
" FROM reserves_out"
" JOIN denominations denom"
" USING (denom_pub_hash)"
" WHERE reserve_pub=$1"
" FOR UPDATE",
" WHERE reserve_pub=$1;",
1),
/* Used in #postgres_select_withdrawals_above_serial_id() */
GNUNET_PQ_make_prepare ("audit_get_reserves_out_incr",
@ -564,8 +564,7 @@ postgres_get_session (void *cls)
" denom_pub_hash"
",denom_sig"
" FROM known_coins"
" WHERE coin_pub=$1"
" FOR UPDATE;",
" WHERE coin_pub=$1;",
1),
/* Used in #postgres_get_coin_denomination() to fetch
the denomination public key hash for
@ -701,8 +700,7 @@ postgres_get_session (void *cls)
" JOIN denominations denom "
" USING (denom_pub_hash)"
" WHERE rc=$1"
" ORDER BY freshcoin_index ASC"
" FOR UPDATE;",
" ORDER BY freshcoin_index ASC;",
1),
/* Used in #postgres_insert_refresh_reveal() to store the transfer
@ -830,8 +828,7 @@ postgres_get_session (void *cls)
" JOIN denominations USING (denom_pub_hash)"
" WHERE ((coin_pub=$1)"
" AND (merchant_pub=$3)"
" AND (h_contract_terms=$2))"
" FOR UPDATE;",
" AND (h_contract_terms=$2));",
3),
/* Fetch deposits with rowid '\geq' the given parameter */
GNUNET_PQ_make_prepare ("audit_get_deposits_incr",
@ -970,8 +967,7 @@ postgres_get_session (void *cls)
" USING (coin_pub)"
" JOIN denominations denom"
" USING (denom_pub_hash)"
" WHERE coin_pub=$1"
" FOR UPDATE;",
" WHERE coin_pub=$1;",
1),
/* Used in #postgres_get_link_data(). */
@ -1282,8 +1278,7 @@ postgres_get_session (void *cls)
" USING (coin_pub)"
" JOIN reserves_out ro"
" USING (h_blind_ev)"
" WHERE ro.reserve_pub=$1"
" FOR UPDATE;",
" WHERE ro.reserve_pub=$1;",
1),
/* Used in #postgres_get_coin_transactions() to obtain recoup transactions
affecting old coins of refreshed coins */
@ -1306,8 +1301,7 @@ postgres_get_session (void *cls)
" FROM refresh_commitments"
" JOIN refresh_revealed_coins rrc"
" USING (rc)"
" WHERE old_coin_pub=$1)"
" FOR UPDATE;",
" WHERE old_coin_pub=$1);",
1),
/* Used in #postgres_get_reserve_history() */
GNUNET_PQ_make_prepare ("close_by_reserve",
@ -1320,8 +1314,7 @@ postgres_get_session (void *cls)
",receiver_account"
",wtid"
" FROM reserves_close"
" WHERE reserve_pub=$1"
" FOR UPDATE",
" WHERE reserve_pub=$1;",
1),
/* Used in #postgres_get_expired_reserves() */
GNUNET_PQ_make_prepare ("get_expired_reserves",
@ -1355,8 +1348,7 @@ postgres_get_session (void *cls)
" USING (h_blind_ev)"
" JOIN known_coins coins"
" USING (coin_pub)"
" WHERE recoup.coin_pub=$1"
" FOR UPDATE;",
" WHERE recoup.coin_pub=$1;",
1),
/* Used in #postgres_get_coin_transactions() to obtain recoup transactions
for a refreshed coin */
@ -1378,8 +1370,7 @@ postgres_get_session (void *cls)
" ON (rrc.rc = rc.rc)"
" JOIN known_coins coins"
" USING (coin_pub)"
" WHERE coin_pub=$1"
" FOR UPDATE;",
" WHERE coin_pub=$1;",
1),
/* Used in #postgres_get_reserve_by_h_blind() */
GNUNET_PQ_make_prepare ("reserve_by_h_blind",
@ -1387,8 +1378,7 @@ postgres_get_session (void *cls)
" reserve_pub"
" FROM reserves_out"
" WHERE h_blind_ev=$1"
" LIMIT 1"
" FOR UPDATE;",
" LIMIT 1;",
1),
/* Used in #postgres_get_old_coin_by_h_blind() */
GNUNET_PQ_make_prepare ("old_coin_by_h_blind",
@ -1398,8 +1388,7 @@ postgres_get_session (void *cls)
" JOIN refresh_commitments rcom"
" USING (rc)"
" WHERE h_coin_ev=$1"
" LIMIT 1"
" FOR UPDATE;",
" LIMIT 1;",
1),
/* used in #postgres_commit */
GNUNET_PQ_make_prepare ("do_commit",