public inbox for [email protected]help / color / mirror / Atom feed
[PATCH] remove deprecated v8.2 containment operators 2+ messages / 2 participants [nested] [flat]
* [PATCH] remove deprecated v8.2 containment operators @ 2020-04-12 03:57 Justin Pryzby <[email protected]> 0 siblings, 0 replies; 2+ messages in thread From: Justin Pryzby @ 2020-04-12 03:57 UTC (permalink / raw) See also: ba920e1c9182eac55d5f1327ab0d29b721154277 684ad6a92fcc33adebdab65c4e7d72a68ba05408 3165426e54df02a6199c0a216546e5095e875a0a 2f70fdb0644c32c4154236c2b5c241bec92eac5e 591d282e8d3e0448ec1339c6b066e10953f040a2 --- contrib/cube/Makefile | 2 +- contrib/cube/cube--1.4--1.5.sql | 8 ++++++++ contrib/cube/cube.control | 2 +- contrib/hstore/Makefile | 1 + contrib/hstore/hstore--1.8--1.9.sql | 7 +++++++ contrib/hstore/hstore.control | 2 +- contrib/intarray/Makefile | 2 +- contrib/intarray/intarray--1.4--1.5.sql | 10 ++++++++++ contrib/intarray/intarray.control | 2 +- contrib/seg/Makefile | 2 +- contrib/seg/seg--1.3--1.4.sql | 8 ++++++++ contrib/seg/seg.control | 2 +- doc/src/sgml/cube.sgml | 8 -------- doc/src/sgml/hstore.sgml | 10 ---------- doc/src/sgml/intarray.sgml | 8 -------- doc/src/sgml/seg.sgml | 8 -------- 16 files changed, 41 insertions(+), 41 deletions(-) create mode 100644 contrib/cube/cube--1.4--1.5.sql create mode 100644 contrib/hstore/hstore--1.8--1.9.sql create mode 100644 contrib/intarray/intarray--1.4--1.5.sql create mode 100644 contrib/seg/seg--1.3--1.4.sql diff --git a/contrib/cube/Makefile b/contrib/cube/Makefile index 54f609db17..cf195506c7 100644 --- a/contrib/cube/Makefile +++ b/contrib/cube/Makefile @@ -7,7 +7,7 @@ OBJS = \ cubeparse.o EXTENSION = cube -DATA = cube--1.2.sql cube--1.2--1.3.sql cube--1.3--1.4.sql \ +DATA = cube--1.2.sql cube--1.2--1.3.sql cube--1.3--1.4.sql cube--1.4--1.5.sql \ cube--1.1--1.2.sql cube--1.0--1.1.sql PGFILEDESC = "cube - multidimensional cube data type" diff --git a/contrib/cube/cube--1.4--1.5.sql b/contrib/cube/cube--1.4--1.5.sql new file mode 100644 index 0000000000..54492e5d18 --- /dev/null +++ b/contrib/cube/cube--1.4--1.5.sql @@ -0,0 +1,8 @@ +/* contrib/cube/cube--1.4--1.5.sql */ + +-- complain if script is sourced in psql, rather than via ALTER EXTENSION +\echo Use "ALTER EXTENSION cube UPDATE TO '1.5'" to load this file. \quit + +-- Remove @ and ~ +DROP OPERATOR @ (cube, cube); +DROP OPERATOR ~ (cube, cube); diff --git a/contrib/cube/cube.control b/contrib/cube/cube.control index 3e238fc937..50427ec117 100644 --- a/contrib/cube/cube.control +++ b/contrib/cube/cube.control @@ -1,6 +1,6 @@ # cube extension comment = 'data type for multidimensional cubes' -default_version = '1.4' +default_version = '1.5' module_pathname = '$libdir/cube' relocatable = true trusted = true diff --git a/contrib/hstore/Makefile b/contrib/hstore/Makefile index c4e339b57c..97b228b65f 100644 --- a/contrib/hstore/Makefile +++ b/contrib/hstore/Makefile @@ -12,6 +12,7 @@ OBJS = \ EXTENSION = hstore DATA = hstore--1.4.sql \ + hstore--1.8--1.9.sql \ hstore--1.7--1.8.sql \ hstore--1.6--1.7.sql \ hstore--1.5--1.6.sql \ diff --git a/contrib/hstore/hstore--1.8--1.9.sql b/contrib/hstore/hstore--1.8--1.9.sql new file mode 100644 index 0000000000..7cd3467c55 --- /dev/null +++ b/contrib/hstore/hstore--1.8--1.9.sql @@ -0,0 +1,7 @@ +/* contrib/hstore/hstore--1.8--1.9.sql */ + +-- complain if script is sourced in psql, rather than via ALTER EXTENSION +\echo Use "ALTER EXTENSION hstore UPDATE TO '1.9'" to load this file. \quit + +-- Remove @ +DROP OPERATOR @ (hstore, hstore); diff --git a/contrib/hstore/hstore.control b/contrib/hstore/hstore.control index 89e3c746c4..b73c28aa4d 100644 --- a/contrib/hstore/hstore.control +++ b/contrib/hstore/hstore.control @@ -1,6 +1,6 @@ # hstore extension comment = 'data type for storing sets of (key, value) pairs' -default_version = '1.8' +default_version = '1.9' module_pathname = '$libdir/hstore' relocatable = true trusted = true diff --git a/contrib/intarray/Makefile b/contrib/intarray/Makefile index 01faa36b10..3817c1669a 100644 --- a/contrib/intarray/Makefile +++ b/contrib/intarray/Makefile @@ -12,7 +12,7 @@ OBJS = \ _intbig_gist.o EXTENSION = intarray -DATA = intarray--1.3--1.4.sql intarray--1.2--1.3.sql \ +DATA = intarray--1.4--1.5.sql intarray--1.3--1.4.sql intarray--1.2--1.3.sql \ intarray--1.2.sql intarray--1.1--1.2.sql \ intarray--1.0--1.1.sql PGFILEDESC = "intarray - functions and operators for arrays of integers" diff --git a/contrib/intarray/intarray--1.4--1.5.sql b/contrib/intarray/intarray--1.4--1.5.sql new file mode 100644 index 0000000000..d0ac11545c --- /dev/null +++ b/contrib/intarray/intarray--1.4--1.5.sql @@ -0,0 +1,10 @@ +/* contrib/intarray/intarray--1.4--1.5.sql */ + +-- complain if script is sourced in psql, rather than via ALTER EXTENSION +\echo Use "ALTER EXTENSION intarray UPDATE TO '1.5'" to load this file. \quit + +-- Remove @ +DROP OPERATOR @ (_int4, _int4); + +-- Remove ~ from GIN - it was removed from gist in 1.4 +DROP OPERATOR ~ (_int4, _int4); diff --git a/contrib/intarray/intarray.control b/contrib/intarray/intarray.control index bbc837c573..c3ff753e2c 100644 --- a/contrib/intarray/intarray.control +++ b/contrib/intarray/intarray.control @@ -1,6 +1,6 @@ # intarray extension comment = 'functions, operators, and index support for 1-D arrays of integers' -default_version = '1.4' +default_version = '1.5' module_pathname = '$libdir/_int' relocatable = true trusted = true diff --git a/contrib/seg/Makefile b/contrib/seg/Makefile index f3578a8634..bb63e83506 100644 --- a/contrib/seg/Makefile +++ b/contrib/seg/Makefile @@ -7,7 +7,7 @@ OBJS = \ segparse.o EXTENSION = seg -DATA = seg--1.1.sql seg--1.1--1.2.sql seg--1.2--1.3.sql \ +DATA = seg--1.1.sql seg--1.1--1.2.sql seg--1.2--1.3.sql seg--1.3--1.4.sql \ seg--1.0--1.1.sql PGFILEDESC = "seg - line segment data type" diff --git a/contrib/seg/seg--1.3--1.4.sql b/contrib/seg/seg--1.3--1.4.sql new file mode 100644 index 0000000000..13babddba4 --- /dev/null +++ b/contrib/seg/seg--1.3--1.4.sql @@ -0,0 +1,8 @@ +/* contrib/seg/seg--1.3--1.4.sql */ + +-- complain if script is sourced in psql, rather than via ALTER EXTENSION +\echo Use "ALTER EXTENSION seg UPDATE TO '1.4'" to load this file. \quit + +-- Remove @ and ~ +DROP OPERATOR @ (seg, seg); +DROP OPERATOR ~ (seg, seg); diff --git a/contrib/seg/seg.control b/contrib/seg/seg.control index 9ac3080848..e2c6a4750f 100644 --- a/contrib/seg/seg.control +++ b/contrib/seg/seg.control @@ -1,6 +1,6 @@ # seg extension comment = 'data type for representing line segments or floating-point intervals' -default_version = '1.3' +default_version = '1.4' module_pathname = '$libdir/seg' relocatable = true trusted = true diff --git a/doc/src/sgml/cube.sgml b/doc/src/sgml/cube.sgml index 3dd89bb14d..adf8dbaa91 100644 --- a/doc/src/sgml/cube.sgml +++ b/doc/src/sgml/cube.sgml @@ -222,14 +222,6 @@ </tgroup> </table> - <para> - (Before PostgreSQL 8.2, the containment operators <literal>@></literal> and <literal><@</literal> were - respectively called <literal>@</literal> and <literal>~</literal>. These names are still available, but are - deprecated and will eventually be retired. Notice that the old names - are reversed from the convention formerly followed by the core geometric - data types!) - </para> - <para> In addition to the above operators, the usual comparison operators shown in <xref linkend="functions-comparison-op-table"/> are diff --git a/doc/src/sgml/hstore.sgml b/doc/src/sgml/hstore.sgml index e867fcc5ae..db5779052a 100644 --- a/doc/src/sgml/hstore.sgml +++ b/doc/src/sgml/hstore.sgml @@ -318,16 +318,6 @@ key => NULL </tgroup> </table> - <note> - <para> - Prior to PostgreSQL 8.2, the containment operators <literal>@></literal> - and <literal><@</literal> were called <literal>@</literal> and <literal>~</literal>, - respectively. These names are still available, but are deprecated and will - eventually be removed. Notice that the old names are reversed from the - convention formerly followed by the core geometric data types! - </para> - </note> - <table id="hstore-func-table"> <title><type>hstore</type> Functions</title> <tgroup cols="1"> diff --git a/doc/src/sgml/intarray.sgml b/doc/src/sgml/intarray.sgml index af44c7b214..dfe98279c0 100644 --- a/doc/src/sgml/intarray.sgml +++ b/doc/src/sgml/intarray.sgml @@ -364,14 +364,6 @@ </tgroup> </table> - <para> - (Before PostgreSQL 8.2, the containment operators <literal>@></literal> and - <literal><@</literal> were respectively called <literal>@</literal> and <literal>~</literal>. - These names are still available, but are deprecated and will eventually be - retired. Notice that the old names are reversed from the convention - formerly followed by the core geometric data types!) - </para> - <para> The operators <literal>&&</literal>, <literal>@></literal> and <literal><@</literal> are equivalent to <productname>PostgreSQL</productname>'s built-in diff --git a/doc/src/sgml/seg.sgml b/doc/src/sgml/seg.sgml index e0dfbc76cf..9be69e3609 100644 --- a/doc/src/sgml/seg.sgml +++ b/doc/src/sgml/seg.sgml @@ -352,14 +352,6 @@ test=> select '6.25 .. 6.50'::seg as "pH"; </tgroup> </table> - <para> - (Before PostgreSQL 8.2, the containment operators <literal>@></literal> and <literal><@</literal> were - respectively called <literal>@</literal> and <literal>~</literal>. These names are still available, but are - deprecated and will eventually be retired. Notice that the old names - are reversed from the convention formerly followed by the core geometric - data types!) - </para> - <para> In addition to the above operators, the usual comparison operators shown in <xref linkend="functions-comparison-op-table"/> are -- 2.17.0 --0OWHXb1mYLuhj1Ox-- ^ permalink raw reply [nested|flat] 2+ messages in thread
* TruncateMultiXact() bugs @ 2024-06-14 11:37 Heikki Linnakangas <[email protected]> 0 siblings, 0 replies; 2+ messages in thread From: Heikki Linnakangas @ 2024-06-14 11:37 UTC (permalink / raw) To: pgsql-hackers I was performing tests around multixid wraparound, when I ran into this assertion: > TRAP: failed Assert("CritSectionCount == 0 || (context)->allowInCritSection"), File: "../src/backend/utils/mmgr/mcxt.c", Line: 1353, PID: 920981 > postgres: autovacuum worker template0(ExceptionalCondition+0x6e)[0x560a501e866e] > postgres: autovacuum worker template0(+0x5dce3d)[0x560a50217e3d] > postgres: autovacuum worker template0(ForwardSyncRequest+0x8e)[0x560a4ffec95e] > postgres: autovacuum worker template0(RegisterSyncRequest+0x2b)[0x560a50091eeb] > postgres: autovacuum worker template0(+0x187b0a)[0x560a4fdc2b0a] > postgres: autovacuum worker template0(SlruDeleteSegment+0x101)[0x560a4fdc2ab1] > postgres: autovacuum worker template0(TruncateMultiXact+0x2fb)[0x560a4fdbde1b] > postgres: autovacuum worker template0(vac_update_datfrozenxid+0x4b3)[0x560a4febd2f3] > postgres: autovacuum worker template0(+0x3adf66)[0x560a4ffe8f66] > postgres: autovacuum worker template0(AutoVacWorkerMain+0x3ed)[0x560a4ffe7c2d] > postgres: autovacuum worker template0(+0x3b1ead)[0x560a4ffecead] > postgres: autovacuum worker template0(+0x3b620e)[0x560a4fff120e] > postgres: autovacuum worker template0(+0x3b3fbb)[0x560a4ffeefbb] > postgres: autovacuum worker template0(+0x2f724e)[0x560a4ff3224e] > /lib/x86_64-linux-gnu/libc.so.6(+0x27c8a)[0x7f62cc642c8a] > /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0x85)[0x7f62cc642d45] > postgres: autovacuum worker template0(_start+0x21)[0x560a4fd16f31] > 2024-06-14 13:11:02.025 EEST [920971] LOG: server process (PID 920981) was terminated by signal 6: Aborted > 2024-06-14 13:11:02.025 EEST [920971] DETAIL: Failed process was running: autovacuum: VACUUM pg_toast.pg_toast_13407 (to prevent wraparound) The attached python script reproduces this pretty reliably. It's a reduced version of a larger test script I was working on, it probably could be simplified further for this particular issue. Looking at the code, it's pretty clear how it happens: 1. TruncateMultiXact does START_CRIT_SECTION(); 2. In the critical section, it calls PerformMembersTruncation() -> SlruDeleteSegment() -> SlruInternalDeleteSegment() -> RegisterSyncRequest() -> ForwardSyncRequest() 3. If the fsync request queue is full, it calls CompactCheckpointerRequestQueue(), which calls palloc0. Pallocs are not allowed in a critical section. A straightforward fix is to add a check to CompactCheckpointerRequestQueue() to bail out without compacting, if it's called in a critical section. That would cover any other cases like this, where RegisterSyncRequest() is called in a critical section. I haven't tried searching if any more cases like this exist. But wait there is more! After applying that fix in CompactCheckpointerRequestQueue(), the test script often gets stuck. There's a deadlock between the checkpointer, and the autovacuum backend trimming the SLRUs: 1. TruncateMultiXact does this: MyProc->delayChkptFlags |= DELAY_CHKPT_START; 2. It then makes that call to PerformMembersTruncation() and RegisterSyncRequest(). If it cannot queue the request, it sleeps a little and retries. But the checkpointer is stuck waiting for the autovacuum backend, because of delayChkptFlags, and will never clear the queue. To fix, I propose to add AbsorbSyncRequests() calls to the wait-loops in CreateCheckPoint(). Attached patch fixes both of those issues. I can't help thinking that TruncateMultiXact() should perhaps not have such a long critical section. TruncateCLOG() doesn't do that. But it was added for good reasons in commit 4f627f897367, and this fix seems appropriate for the stable branches anyway, even if we come up with something better for master. -- Heikki Linnakangas Neon (https://neon.tech) Attachments: [text/x-python] repro-multixid-trim-assertion.py (6.0K, ../../[email protected]/2-repro-multixid-trim-assertion.py) download | inline: import time import logging import psycopg2 from typing import Any, Callable, Dict, Iterator, List, Optional, Tuple, Type, Union, cast import subprocess PGDATA = "pgdata-multixid-repro" log = logging.getLogger(__name__) def connect(): return psycopg2.connect( database="postgres", user="postgres", host="/tmp/", ) # Constants and macros copied from PostgreSQL multixact.c and headers. These are needed to # calculate the SLRU segments that a particular multixid or multixid-offsets falls into. BLCKSZ = 8192 MULTIXACT_OFFSETS_PER_PAGE = int(BLCKSZ / 4) SLRU_PAGES_PER_SEGMENT = int(32) MXACT_MEMBER_BITS_PER_XACT = 8 MXACT_MEMBER_FLAGS_PER_BYTE = 1 MULTIXACT_FLAGBYTES_PER_GROUP = 4 MULTIXACT_MEMBERS_PER_MEMBERGROUP = MULTIXACT_FLAGBYTES_PER_GROUP * MXACT_MEMBER_FLAGS_PER_BYTE MULTIXACT_MEMBERGROUP_SIZE = 4 * MULTIXACT_MEMBERS_PER_MEMBERGROUP + MULTIXACT_FLAGBYTES_PER_GROUP MULTIXACT_MEMBERGROUPS_PER_PAGE = int(BLCKSZ / MULTIXACT_MEMBERGROUP_SIZE) MULTIXACT_MEMBERS_PER_PAGE = MULTIXACT_MEMBERGROUPS_PER_PAGE * MULTIXACT_MEMBERS_PER_MEMBERGROUP def MultiXactIdToOffsetSegment(xid: int): return int(xid / (SLRU_PAGES_PER_SEGMENT * MULTIXACT_OFFSETS_PER_PAGE)) def MXOffsetToMemberSegment(off: int): return int(off / (SLRU_PAGES_PER_SEGMENT * MULTIXACT_MEMBERS_PER_PAGE)) def advance_multixid_to(next_multi_xid: int, next_multi_offset: int ): """ Use pg_resetwal to advance the nextMulti and nextMultiOffset values in a stand-alone Postgres cluster. This is useful to get close to wraparound or some other interesting value, without having to burn a lot of time consuming the (multi-)XIDs one by one. The new values should be higher than the old ones, in a wraparound-aware sense. On entry, the server should be running. It will be shut down and restarted. """ # Read old values from the last checkpoint. We will pass the old oldestMultiXid value # back to pg_resetwal, there's no option to leave it alone. with connect() as conn: with conn.cursor() as cur: # Make sure the oldest-multi-xid value in the control file is up-to-date cur.execute("checkpoint") cur.execute("select oldest_multi_xid, next_multixact_id from pg_control_checkpoint()") (ckpt_oldest_multi_xid, ckpt_next_multi_xid) = cur.fetchone() log.info(f"oldestMultiXid was {ckpt_oldest_multi_xid}, nextMultiXid was {ckpt_next_multi_xid}") log.info(f"Resetting to {next_multi_xid}") # Use pg_resetwal to reset the next multiXid and multiOffset to given values. subprocess.check_call(["pg_ctl", "-D", PGDATA, "stop"]) cmd = [ "pg_resetwal", f"--multixact-ids={next_multi_xid},{ckpt_oldest_multi_xid}", f"--multixact-offset={next_multi_offset}", "-D", PGDATA, ] subprocess.check_call(cmd) # Because we skip over a lot of values, Postgres hasn't created the SLRU segments for # the new values yet. Create them manually, to allow Postgres to start up. # # This leaves "gaps" in the SLRU where segments between old value and new value are # missing. That's OK for our purposes. Autovacuum will print some warnings about the # missing segments, but will clean it up by truncating the SLRUs up to the new value, # closing the gap. segname = "%04X" % MultiXactIdToOffsetSegment(next_multi_xid) log.info(f"Creating dummy segment pg_multixact/offsets/{segname}") with open(f"{PGDATA}/pg_multixact/offsets/{segname}", "w") as of: of.write("\0" * SLRU_PAGES_PER_SEGMENT * BLCKSZ) of.flush() segname = "%04X" % MXOffsetToMemberSegment(next_multi_offset) log.info(f"Creating dummy segment pg_multixact/members/{segname}") with open(f"{PGDATA}/pg_multixact/members/{segname}", "w") as of: of.write("\0" * SLRU_PAGES_PER_SEGMENT * BLCKSZ) of.flush() # Start Postgres again and wait until autovacuum has processed all the databases # # This allows truncating the SLRUs, fixing the gaps with missing segments. subprocess.check_call(["pg_ctl", "-D", PGDATA, "start"]) with connect().cursor() as cur: for _ in range(1000): cur.execute("select min(datminmxid::text::int8) from pg_database") datminmxid = int(cur.fetchall()[0][0]) log.info(f"datminmxid {datminmxid}") if next_multi_xid - datminmxid < 1_000_000: # not wraparound-aware! break time.sleep(0.5) def main(): # In order to to test multixid wraparound, we need to first advance the counter to # within spitting distance of the wraparound, that is 2^32 multi-XIDs. We could simply # run a workload that consumes a lot of multi-XIDs until we approach that, but that # takes a very long time. So we cheat. # # Our strategy is to create a Postgres cluster, and use pg_resetwal to # set the multi-xid counter a higher value. However, we cannot directly set # it to just before 2^32 (~ 4 billion), because that would make the exisitng # 'relminmxid' values to look like they're in the future. It's not clear how the # system would behave in that situation. So instead, we bump it up ~ 1 billion # multi-XIDs at a time, and let autovacuum to process all the relations and update # 'relminmxid' between each run. subprocess.check_call(["initdb", "-D", PGDATA, "-U", "postgres"]) with open(f"{PGDATA}/postgresql.conf", "a") as file1: file1.writelines([ "log_autovacuum_min_duration = 0\n", # Perform anti-wraparound vacuuming aggressively "autovacuum_naptime='1 s'\n", "autovacuum_freeze_max_age = 1000000\n", "autovacuum_multixact_freeze_max_age = 1000000\n", "shared_buffers='1 MB'", ]) subprocess.check_call(["pg_ctl", "-D", PGDATA, "start"]) advance_multixid_to(0x40000000, 0x10000000) advance_multixid_to(0x80000000, 0x20000000) advance_multixid_to(0xC0000000, 0x30000000) advance_multixid_to(0xFFFFFF00, 0xFFFFFF00) if __name__ == "__main__": main() [text/x-patch] 0001-Fix-bugs-in-MultiXact-truncation.patch (7.1K, ../../[email protected]/3-0001-Fix-bugs-in-MultiXact-truncation.patch) download | inline diff: From abe096fb960106410baaa84dc4ba96ba5b37c6d0 Mon Sep 17 00:00:00 2001 From: Heikki Linnakangas <[email protected]> Date: Fri, 14 Jun 2024 14:20:58 +0300 Subject: [PATCH 1/1] Fix bugs in MultiXact truncation 1. TruncateMultiXact() performs the SLRU truncations in a critical section. Deleting the SLRU segments calls ForwardSyncRequest(), which will try to compact the request queue if it's full (CompactCheckpointerRequestQueue()). That in turn allocates memory, which is not allowed in a critical section. Backtrace: TRAP: failed Assert("CritSectionCount == 0 || (context)->allowInCritSection"), File: "../src/backend/utils/mmgr/mcxt.c", Line: 1353, PID: 920981 postgres: autovacuum worker template0(ExceptionalCondition+0x6e)[0x560a501e866e] postgres: autovacuum worker template0(+0x5dce3d)[0x560a50217e3d] postgres: autovacuum worker template0(ForwardSyncRequest+0x8e)[0x560a4ffec95e] postgres: autovacuum worker template0(RegisterSyncRequest+0x2b)[0x560a50091eeb] postgres: autovacuum worker template0(+0x187b0a)[0x560a4fdc2b0a] postgres: autovacuum worker template0(SlruDeleteSegment+0x101)[0x560a4fdc2ab1] postgres: autovacuum worker template0(TruncateMultiXact+0x2fb)[0x560a4fdbde1b] postgres: autovacuum worker template0(vac_update_datfrozenxid+0x4b3)[0x560a4febd2f3] postgres: autovacuum worker template0(+0x3adf66)[0x560a4ffe8f66] postgres: autovacuum worker template0(AutoVacWorkerMain+0x3ed)[0x560a4ffe7c2d] postgres: autovacuum worker template0(+0x3b1ead)[0x560a4ffecead] postgres: autovacuum worker template0(+0x3b620e)[0x560a4fff120e] postgres: autovacuum worker template0(+0x3b3fbb)[0x560a4ffeefbb] postgres: autovacuum worker template0(+0x2f724e)[0x560a4ff3224e] /lib/x86_64-linux-gnu/libc.so.6(+0x27c8a)[0x7f62cc642c8a] /lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0x85)[0x7f62cc642d45] postgres: autovacuum worker template0(_start+0x21)[0x560a4fd16f31] To fix, bail out in CompactCheckpointerRequestQueue() without doing anything, if it's called in a critical section. That covers the above call path, as well as any other similar cases where RegisterSyncRequest might be called in a critical section. 2. After fixing that, another problem became apparent: Autovacuum process doing that truncation can deadlock with the checkpointer process. TruncateMultiXact() sets "MyProc->delayChkptFlags |= DELAY_CHKPT_START". If the sync request queue is full and cannot be compacted, the process will repeatedly sleep and retry, until there is room in the queue. However, if the checkpointer is trying to start a checkpoint at the same time, and is waiting for the DELAY_CHKPT_START processes to finish, the queue will never shrink. More concretely, the autovacuum process is stuck here: #0 0x00007fc934926dc3 in epoll_wait () from /lib/x86_64-linux-gnu/libc.so.6 #1 0x000056220b24348b in WaitEventSetWaitBlock (set=0x56220c2e4b50, occurred_events=0x7ffe7856d040, nevents=1, cur_timeout=<optimized out>) at ../src/backend/storage/ipc/latch.c:1570 #2 WaitEventSetWait (set=0x56220c2e4b50, timeout=timeout@entry=10, occurred_events=<optimized out>, occurred_events@entry=0x7ffe7856d040, nevents=nevents@entry=1, wait_event_info=wait_event_info@entry=150994949) at ../src/backend/storage/ipc/latch.c:1516 #3 0x000056220b243224 in WaitLatch (latch=<optimized out>, latch@entry=0x0, wakeEvents=wakeEvents@entry=40, timeout=timeout@entry=10, wait_event_info=wait_event_info@entry=150994949) at ../src/backend/storage/ipc/latch.c:538 #4 0x000056220b26cf46 in RegisterSyncRequest (ftag=ftag@entry=0x7ffe7856d0a0, type=type@entry=SYNC_FORGET_REQUEST, retryOnError=true) at ../src/backend/storage/sync/sync.c:614 #5 0x000056220af9db0a in SlruInternalDeleteSegment (ctl=ctl@entry=0x56220b7beb60 <MultiXactMemberCtlData>, segno=segno@entry=11350) at ../src/backend/access/transam/slru.c:1495 #6 0x000056220af9dab1 in SlruDeleteSegment (ctl=ctl@entry=0x56220b7beb60 <MultiXactMemberCtlData>, segno=segno@entry=11350) at ../src/backend/access/transam/slru.c:1566 #7 0x000056220af98e1b in PerformMembersTruncation (oldestOffset=<optimized out>, newOldestOffset=<optimized out>) at ../src/backend/access/transam/multixact.c:3006 #8 TruncateMultiXact (newOldestMulti=newOldestMulti@entry=3221225472, newOldestMultiDB=newOldestMultiDB@entry=4) at ../src/backend/access/transam/multixact.c:3201 #9 0x000056220b098303 in vac_truncate_clog (frozenXID=749, minMulti=<optimized out>, lastSaneFrozenXid=749, lastSaneMinMulti=3221225472) at ../src/backend/commands/vacuum.c:1917 #10 vac_update_datfrozenxid () at ../src/backend/commands/vacuum.c:1760 #11 0x000056220b1c3f76 in do_autovacuum () at ../src/backend/postmaster/autovacuum.c:2550 #12 0x000056220b1c2c3d in AutoVacWorkerMain (startup_data=<optimized out>, startup_data_len=<optimized out>) at ../src/backend/postmaster/autovacuum.c:1569 and the checkpointer is stuck here: #0 0x00007fc9348ebf93 in clock_nanosleep () from /lib/x86_64-linux-gnu/libc.so.6 #1 0x00007fc9348fe353 in nanosleep () from /lib/x86_64-linux-gnu/libc.so.6 #2 0x000056220b40ecb4 in pg_usleep (microsec=microsec@entry=10000) at ../src/port/pgsleep.c:50 #3 0x000056220afb43c3 in CreateCheckPoint (flags=flags@entry=108) at ../src/backend/access/transam/xlog.c:7098 #4 0x000056220b1c6e86 in CheckpointerMain (startup_data=<optimized out>, startup_data_len=<optimized out>) at ../src/backend/postmaster/checkpointer.c:464 To fix, add AbsorbSyncRequests() to the loops where the checkpointer waits for DELAY_CHKPT_START or DELAY_CHKPT_COMPLETE operations to finish. --- src/backend/access/transam/xlog.c | 9 +++++++++ src/backend/postmaster/checkpointer.c | 4 ++++ 2 files changed, 13 insertions(+) diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c index 330e058c5f..8dcdf5a764 100644 --- a/src/backend/access/transam/xlog.c +++ b/src/backend/access/transam/xlog.c @@ -7094,6 +7094,13 @@ CreateCheckPoint(int flags) { do { + /* + * Keep absorbing fsync requests while we wait. There could even + * be a deadlock if we don't, if the process that prevents the + * checkpoint is trying to add a request to the queue. + */ + AbsorbSyncRequests(); + pgstat_report_wait_start(WAIT_EVENT_CHECKPOINT_DELAY_START); pg_usleep(10000L); /* wait for 10 msec */ pgstat_report_wait_end(); @@ -7109,6 +7116,8 @@ CreateCheckPoint(int flags) { do { + AbsorbSyncRequests(); + pgstat_report_wait_start(WAIT_EVENT_CHECKPOINT_DELAY_COMPLETE); pg_usleep(10000L); /* wait for 10 msec */ pgstat_report_wait_end(); diff --git a/src/backend/postmaster/checkpointer.c b/src/backend/postmaster/checkpointer.c index 3c68a9904d..199f008bcd 100644 --- a/src/backend/postmaster/checkpointer.c +++ b/src/backend/postmaster/checkpointer.c @@ -1169,6 +1169,10 @@ CompactCheckpointerRequestQueue(void) /* must hold CheckpointerCommLock in exclusive mode */ Assert(LWLockHeldByMe(CheckpointerCommLock)); + /* Avoid memory allocations in a critical section. */ + if (CritSectionCount > 0) + return false; + /* Initialize skip_slot array */ skip_slot = palloc0(sizeof(bool) * CheckpointerShmem->num_requests); -- 2.39.2 ^ permalink raw reply [nested|flat] 2+ messages in thread
end of thread, other threads:[~2024-06-14 11:37 UTC | newest] Thread overview: 2+ messages (download: mbox mbox.gz follow: Atom feed) -- links below jump to the message on this page -- 2020-04-12 03:57 [PATCH] remove deprecated v8.2 containment operators Justin Pryzby <[email protected]> 2024-06-14 11:37 TruncateMultiXact() bugs Heikki Linnakangas <[email protected]>
This inbox is served by agora; see mirroring instructions for how to clone and mirror all data and code used for this inbox