Re: [HACKERS] Displaying accumulated autovacuum cost
On Tue, Feb 21, 2012 at 11:55 PM, Greg Smith g...@2ndquadrant.com wrote: I just took this for spin. Everything I tried worked, docs built and read fine. The description of how dirty differs from written is a bit cryptic, but I don't see an easy way to do better without a whole new section on that topic. Once the extension upgrade questions are sorted out, I'd say this is ready to commit. Example I have at the bottom here shows a case where this is a big improvement over the existing tracking. I think this is a must-have improvement if we're going to advocate using pg_stat_statements for more things. Glad you like it; committed. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Displaying accumulated autovacuum cost
Fujii Masao masao.fu...@gmail.com writes: Though I'm not familiar with CREATE EXTENSION. Why did you exclude 1.0.sql from DATA? In hstore/Makefile, 1.0.sql is included. You think we should prevent old version (i.e., 1.0) of pg_stat_statements from being used in 9.2? I'm not sure. My feeling is that we probably don't want to ship all the old scripts forever. People should install the latest version, and use the upgrade scripts to get there if they have an older one. So my gut feeling here is to change hstore to exclude that file rather than adding it here. Any other opinions? The problem with the hstore scripts is that you had to copy the 1.0 script, change a couple of lines, and call that 1.1, and you also had to provide the 1.0--1.1 script file. The solution would be to be able to create hstore 1.1 from 1.0 automatically and I sent over a very simple patch to do that, albeit after the deadline for the current CF (that's why it's not listed). Maybe that's simple enough to be considered? (re-attaching here) b/contrib/hstore/Makefile |2 b/contrib/hstore/hstore.control|1 b/src/backend/commands/extension.c | 83 +++-- contrib/hstore/hstore--1.1.sql | 524 - 4 files changed, 57 insertions(+), 553 deletions(-) Agreed. But I wonder why VERSION option is usable in CREATE EXTENSION if people always should use the latest version. Maybe I'm missing something.. I think not that many people are using 9.1 in production already. Also bear in mind that the mechanism is not made only for contrib, it makes sense to ship in-house procedure code as an extension too. Regards, -- Dimitri Fontaine http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support diff --git a/contrib/hstore/Makefile b/contrib/hstore/Makefile index e9e5e53..2d624d3 100644 --- a/contrib/hstore/Makefile +++ b/contrib/hstore/Makefile @@ -5,7 +5,7 @@ OBJS = hstore_io.o hstore_op.o hstore_gist.o hstore_gin.o hstore_compat.o \ crc32.o EXTENSION = hstore -DATA = hstore--1.0.sql hstore--1.1.sql hstore--1.0--1.1.sql \ +DATA = hstore--1.0.sql hstore--1.1.sql.orig hstore--1.0--1.1.sql \ hstore--unpackaged--1.0.sql REGRESS = hstore diff --git a/contrib/hstore/hstore--1.1.sql b/contrib/hstore/hstore--1.1.sql deleted file mode 100644 index e95ad32..000 --- a/contrib/hstore/hstore--1.1.sql +++ /dev/null @@ -1,524 +0,0 @@ -/* contrib/hstore/hstore--1.1.sql */ - --- complain if script is sourced in psql, rather than via CREATE EXTENSION -\echo Use CREATE EXTENSION hstore to load this file. \quit - -CREATE TYPE hstore; - -CREATE FUNCTION hstore_in(cstring) -RETURNS hstore -AS 'MODULE_PATHNAME' -LANGUAGE C STRICT IMMUTABLE; - -CREATE FUNCTION hstore_out(hstore) -RETURNS cstring -AS 'MODULE_PATHNAME' -LANGUAGE C STRICT IMMUTABLE; - -CREATE FUNCTION hstore_recv(internal) -RETURNS hstore -AS 'MODULE_PATHNAME' -LANGUAGE C STRICT IMMUTABLE; - -CREATE FUNCTION hstore_send(hstore) -RETURNS bytea -AS 'MODULE_PATHNAME' -LANGUAGE C STRICT IMMUTABLE; - -CREATE TYPE hstore ( -INTERNALLENGTH = -1, -INPUT = hstore_in, -OUTPUT = hstore_out, -RECEIVE = hstore_recv, -SEND = hstore_send, -STORAGE = extended -); - -CREATE FUNCTION hstore_version_diag(hstore) -RETURNS integer -AS 'MODULE_PATHNAME','hstore_version_diag' -LANGUAGE C STRICT IMMUTABLE; - -CREATE FUNCTION fetchval(hstore,text) -RETURNS text -AS 'MODULE_PATHNAME','hstore_fetchval' -LANGUAGE C STRICT IMMUTABLE; - -CREATE OPERATOR - ( - LEFTARG = hstore, - RIGHTARG = text, - PROCEDURE = fetchval -); - -CREATE FUNCTION slice_array(hstore,text[]) -RETURNS text[] -AS 'MODULE_PATHNAME','hstore_slice_to_array' -LANGUAGE C STRICT IMMUTABLE; - -CREATE OPERATOR - ( - LEFTARG = hstore, - RIGHTARG = text[], - PROCEDURE = slice_array -); - -CREATE FUNCTION slice(hstore,text[]) -RETURNS hstore -AS 'MODULE_PATHNAME','hstore_slice_to_hstore' -LANGUAGE C STRICT IMMUTABLE; - -CREATE FUNCTION isexists(hstore,text) -RETURNS bool -AS 'MODULE_PATHNAME','hstore_exists' -LANGUAGE C STRICT IMMUTABLE; - -CREATE FUNCTION exist(hstore,text) -RETURNS bool -AS 'MODULE_PATHNAME','hstore_exists' -LANGUAGE C STRICT IMMUTABLE; - -CREATE OPERATOR ? ( - LEFTARG = hstore, - RIGHTARG = text, - PROCEDURE = exist, - RESTRICT = contsel, - JOIN = contjoinsel -); - -CREATE FUNCTION exists_any(hstore,text[]) -RETURNS bool -AS 'MODULE_PATHNAME','hstore_exists_any' -LANGUAGE C STRICT IMMUTABLE; - -CREATE OPERATOR ?| ( - LEFTARG = hstore, - RIGHTARG = text[], - PROCEDURE = exists_any, - RESTRICT = contsel, - JOIN = contjoinsel -); - -CREATE FUNCTION exists_all(hstore,text[]) -RETURNS bool -AS 'MODULE_PATHNAME','hstore_exists_all' -LANGUAGE C STRICT IMMUTABLE; - -CREATE OPERATOR ? ( - LEFTARG = hstore, - RIGHTARG = text[], - PROCEDURE = exists_all, - RESTRICT = contsel, - JOIN = contjoinsel -); - -CREATE FUNCTION isdefined(hstore,text) -RETURNS bool -AS 'MODULE_PATHNAME','hstore_defined' -LANGUAGE C STRICT
Re: [HACKERS] Displaying accumulated autovacuum cost
On 02/21/2012 04:44 PM, Dimitri Fontaine wrote: The solution would be to be able to create hstore 1.1 from 1.0 automatically and I sent over a very simple patch to do that, albeit after the deadline for the current CF (that's why it's not listed). Maybe that's simple enough to be considered? (re-attaching here) I can't find any message that matches this description--from you, touches extensions in this way, and was submitted after the CF deadline. Help? If that's something that ripples out to impacting how changes to upgraded extensions should look, that should get its own thread I think. This one is pretty deep and already far off its titled topic. -- Greg Smith 2ndQuadrant USg...@2ndquadrant.com Baltimore, MD PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Displaying accumulated autovacuum cost
I just took this for spin. Everything I tried worked, docs built and read fine. The description of how dirty differs from written is a bit cryptic, but I don't see an easy way to do better without a whole new section on that topic. Once the extension upgrade questions are sorted out, I'd say this is ready to commit. Example I have at the bottom here shows a case where this is a big improvement over the existing tracking. I think this is a must-have improvement if we're going to advocate using pg_stat_statements for more things. This works as expected in all of the EXPLAIN forms, I tried all of the supported formats. Sample of the text one: $ psql -d pgbench -c EXPLAIN (ANALYZE,BUFFERS,FORMAT text) UPDATE pgbench_accounts SET aid=aid+0 WHERE aid1000 QUERY PLAN -- Update on pgbench_accounts (cost=0.00..86.09 rows=860 width=103) (actual time=8.587..8.587 rows=0 loops=1) Buffers: shared hit=8315 read=70 dirtied=16 - Index Scan using pgbench_accounts_pkey on pgbench_accounts (cost=0.00..86.09 rows=860 width=103) (actual time=0.017..2.086 rows=999 loops=1) Index Cond: (aid 1000) Buffers: shared hit=1828 read=28 Total runtime: 8.654 ms Also ran just the UPDATE statement alone, then retrieved the counts from pg_stat_statements: $ psql -x -c select * from pg_stat_statements -[ RECORD 1 ]---+--- userid | 10 dbid| 16385 query | UPDATE pgbench_accounts SET aid=aid+0 WHERE aid1000 calls | 1 total_time | 0.007475 rows| 999 shared_blks_hit | 8370 shared_blks_read| 15 shared_blks_dirtied | 15 shared_blks_written | 0 ... Note that there are no blocks shown as written there. That is also demonstrated by the results after some pgbench -M prepared stress testing against a small database. The pgbench tables are structured such that the number of branches tellers accounts. On a small scale database (I used 10 here), there might only be a single page of branch data. That shows up clearly in the different amount of dirtied blocks in each update: $ psql -x -c select query,shared_blks_hit,shared_blks_read,shared_blks_dirtied,shared_blks_written from pg_stat_statements order by calls desc limit 7 ... query | UPDATE pgbench_branches SET bbalance = bbalance + $1 WHERE bid = $2; shared_blks_hit | 32929 shared_blks_read| 0 shared_blks_dirtied | 1 shared_blks_written | 0 query | UPDATE pgbench_tellers SET tbalance = tbalance + $1 WHERE tid = $2; shared_blks_hit | 19074 shared_blks_read| 0 shared_blks_dirtied | 7 shared_blks_written | 0 query | UPDATE pgbench_accounts SET abalance = abalance + $1 WHERE aid = $2; shared_blks_hit | 35563 shared_blks_read| 9982 shared_blks_dirtied | 4945 shared_blks_written | 2812 Note how in the branches and tellers case, the existing written counter shows 0. Those hot pages stay in cache the whole time with a high usage count, backends never get to write them out; only the checkpointer does. Only this new dirtied one reflects a useful write count for frequently used pages like that, and it does show that more pages are being touched by pgbench_tellers than pgbench_branches. I'd never ran into this before because I normally test against larger databases. But once I tried to find an example of this form, it was easy to do so. Systems where much of the database fits into shared_buffers in particular are likely to see a deceptively small write count. -- Greg Smith 2ndQuadrant USg...@2ndquadrant.com Baltimore, MD PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Displaying accumulated autovacuum cost
On Mon, Feb 20, 2012 at 2:49 AM, Fujii Masao masao.fu...@gmail.com wrote: In pg_stat_statements--1.0--1.1.sql, we should complain if script is sourced in psql, as follows? \echo Use ALTER EXTENSION pg_stat_statements UPDATE TO '1.1' to load this file. \quit Yeah, maybe. I don't know if we want to put that in every file forever, but I guess it probably makes sense to do it here. +DATA = pg_stat_statements--1.1.sql pg_stat_statements--1.0--1.1.sql \ + pg_stat_statements--unpackaged--1.0.sql Though I'm not familiar with CREATE EXTENSION. Why did you exclude 1.0.sql from DATA? In hstore/Makefile, 1.0.sql is included. You think we should prevent old version (i.e., 1.0) of pg_stat_statements from being used in 9.2? I'm not sure. My feeling is that we probably don't want to ship all the old scripts forever. People should install the latest version, and use the upgrade scripts to get there if they have an older one. So my gut feeling here is to change hstore to exclude that file rather than adding it here. Any other opinions? -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Displaying accumulated autovacuum cost
On Mon, Feb 20, 2012 at 11:00 PM, Robert Haas robertmh...@gmail.com wrote: On Mon, Feb 20, 2012 at 2:49 AM, Fujii Masao masao.fu...@gmail.com wrote: +DATA = pg_stat_statements--1.1.sql pg_stat_statements--1.0--1.1.sql \ + pg_stat_statements--unpackaged--1.0.sql Though I'm not familiar with CREATE EXTENSION. Why did you exclude 1.0.sql from DATA? In hstore/Makefile, 1.0.sql is included. You think we should prevent old version (i.e., 1.0) of pg_stat_statements from being used in 9.2? I'm not sure. My feeling is that we probably don't want to ship all the old scripts forever. People should install the latest version, and use the upgrade scripts to get there if they have an older one. So my gut feeling here is to change hstore to exclude that file rather than adding it here. Any other opinions? Agreed. But I wonder why VERSION option is usable in CREATE EXTENSION if people always should use the latest version. Maybe I'm missing something.. Anyway, shipping v1.0 of pg_stat_statement seems less useful in 9.2, so I agree to exclude it. Regards, -- Fujii Masao NIPPON TELEGRAPH AND TELEPHONE CORPORATION NTT Open Source Software Center -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Displaying accumulated autovacuum cost
On Sat, Feb 18, 2012 at 2:16 AM, Robert Haas robertmh...@gmail.com wrote: On Fri, Feb 17, 2012 at 5:04 AM, Fujii Masao masao.fu...@gmail.com wrote: Here are review comments: The document about EXPLAIN needs to be updated. You forgot to add the long-integer-valued property of shared/local_blks_dirtied. So when I ran EXPLAIN and used json as a format, no information about blks_dirtied was reported. Thanks for the review. Updated patch attached. Thanks for updating the patch! The patch looks good to me. But I have three minor comments: In pg_stat_statements--1.1.sql +/* contrib/pg_stat_statements/pg_stat_statements--1.0.sql */ Typo: s/1.0/1.1 In pg_stat_statements--1.0--1.1.sql, we should complain if script is sourced in psql, as follows? \echo Use ALTER EXTENSION pg_stat_statements UPDATE TO '1.1' to load this file. \quit +DATA = pg_stat_statements--1.1.sql pg_stat_statements--1.0--1.1.sql \ + pg_stat_statements--unpackaged--1.0.sql Though I'm not familiar with CREATE EXTENSION. Why did you exclude 1.0.sql from DATA? In hstore/Makefile, 1.0.sql is included. You think we should prevent old version (i.e., 1.0) of pg_stat_statements from being used in 9.2? Regards, -- Fujii Masao NIPPON TELEGRAPH AND TELEPHONE CORPORATION NTT Open Source Software Center -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Displaying accumulated autovacuum cost
On Sat, Nov 26, 2011 at 10:10 AM, Robert Haas robertmh...@gmail.com wrote: On Fri, Nov 25, 2011 at 11:39 AM, Alvaro Herrera alvhe...@commandprompt.com wrote: I'm going to push this now anyway, thanks. This patch adds a count of the number of buffers dirtied to VACUUM, but it strikes me that it would be useful to add similar tracking to pgBufferUsage. Attached is a patch for that. You can see the new counters through pg_stat_statements or with EXPLAIN (ANALYZE, BUFFERS). This is useful because the number of buffers that a query *writes* doesn't necessarily have much to do with anything - it may end up writing buffers dirtied by other queries while being read-only itself, or conversely it may not write anything at all even though it dirties quite a bit. Thoughts? Comments? Objections? Here are review comments: The document about EXPLAIN needs to be updated. You forgot to add the long-integer-valued property of shared/local_blks_dirtied. So when I ran EXPLAIN and used json as a format, no information about blks_dirtied was reported. Regards, -- Fujii Masao NIPPON TELEGRAPH AND TELEPHONE CORPORATION NTT Open Source Software Center -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Displaying accumulated autovacuum cost
On Fri, Feb 17, 2012 at 5:04 AM, Fujii Masao masao.fu...@gmail.com wrote: Here are review comments: The document about EXPLAIN needs to be updated. You forgot to add the long-integer-valued property of shared/local_blks_dirtied. So when I ran EXPLAIN and used json as a format, no information about blks_dirtied was reported. Thanks for the review. Updated patch attached. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company dirty_buffers_v2.patch Description: Binary data -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Displaying accumulated autovacuum cost
On 11/25/2011 08:39 AM, Alvaro Herrera wrote: I was about to commit this when I noticed that the avg values may not be all that representative of reality after all; consider that it's computed across the whole duration of the vacuuming operation, including the index scans ... it'd be possibly useful to keep separate timings for the heap scan (which is likely to use I/O more quickly) from index scans. That way you can tune for the max, not a possibly misleading average. That's a much larger change though, so I'm not going to get into it. Yes, that's one of the interesting additional things to track. At the point I was writing this originally, things like Single Pass VACUUM were still on the table; maybe it still is. Didn't seem worthwhile to try and get any more detailed than the average when the underlying work might still be whacked around. Just having some useful numbers on both costs and speeds for the first time was such an improvement I didn't want to get too far lost on chasing perfection here, at the risk of not getting anything done. One funny thing in the test I did was that the buffer count might add to a much larger amount than total disk pages: Good catch, I didn't think about the ramifications of multi-pass work here. I'll revisit that and see if I can do a bit better before the final 9.2 CommitFest; I'm not done with this area yet. I kind of needed this basic logging patch in place before it's easy to experiment with behavior changes and see what they do though. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Displaying accumulated autovacuum cost
On 11/25/2011 05:10 PM, Robert Haas wrote: This patch adds a count of the number of buffers dirtied to VACUUM, but it strikes me that it would be useful to add similar tracking to pgBufferUsage. Attached is a patch for that. You can see the new counters through pg_stat_statements or with EXPLAIN (ANALYZE, BUFFERS). This looks pretty useful to me. I just threw it into the current CommitFest, on the basis that there's already so many other thing trying to whack around pg_stat_statements right now we might as well keep them together. Let me clear my queue of patches submitted on time I need to do something with (re-review Scott Mead's pg_stat_activity change, respond to Jeff Janes on relation free space) and I'll take a quick spin on this one. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Displaying accumulated autovacuum cost
Excerpts from Greg Smith's message of mié nov 16 04:37:43 -0300 2011: On 10/05/2011 03:02 AM, Greg Smith wrote: Presumably you meant to ask if this makes sense to show when cost accounting isn't enabled, because the code doesn't do that right now. No cost accounting, no buffer usage/write rate data as this was submitted. This is done in the attached update. I just made the page accounting happen all the time, regardless of whether the costs were being accumulated. Added a read rate too, which is how fast reads happened from the OS cache to shared_buffers. Simple test case generates a 600MB pgbench_accounts database and wipes out enough to take a while to clean up; it needs log_autovacuum_min_duration = 0 and then: $ createdb pgbench $ pgbench -i -s 10 pgbench $ psql -d pgbench -c delete from pgbench_accounts where aid20 LOG: automatic vacuum of table pgbench.public.pgbench_accounts: index scans: 1 pages: 0 removed, 16394 remain tuples: 19 removed, 640011 remain buffer usage: 13742 hits, 2708 misses, 1058 dirtied avg read rate: 3.067 MiB/s, avg write rate: 1.198 MiB/s system usage: CPU 0.05s/0.61u sec elapsed 6.89 sec I was about to commit this when I noticed that the avg values may not be all that representative of reality after all; consider that it's computed across the whole duration of the vacuuming operation, including the index scans ... it'd be possibly useful to keep separate timings for the heap scan (which is likely to use I/O more quickly) from index scans. That way you can tune for the max, not a possibly misleading average. That's a much larger change though, so I'm not going to get into it. Does anybody else think this would be worthwhile? If so we can stick it into the TODO with an easy tag for someone to tackle -- seems like a useful first project. One funny thing in the test I did was that the buffer count might add to a much larger amount than total disk pages: LOG: automatic vacuum of table alvherre.public.foo: index scans: 4 pages: 0 removed, 8850 remain tuples: 68 removed, 132 remain buffer usage: 14675 hits, 33857 misses, 20274 dirtied avg read rate: 2.823 MiB/s, avg write rate: 1.690 MiB/s system usage: CPU 1.26s/8.08u sec elapsed 93.69 sec The table and index: alvherre=# select relname, relpages from pg_class where relname like 'foo%'; relname | relpages -+-- foo | 8850 foo_idx | 5487 (2 filas) My guess is that this is roughly counting three heap scans plus the four index scans mentioned in the log report (there were so many because I reduced maintenance_work_mem to its 1 MB minimum): alvherre=# select 5487 * 4 + 8850 * 3; ?column? -- 48498 (1 fila) alvherre=# select 14675 + 33857; ?column? -- 48532 (1 fila) My test case was create table foo (a int); insert into foo select * from generate_series (1, 200); create index foo_idx on foo (a); delete from foo where a % 6 in (1,2); I then checkpointed before autovac had the chance to process the table, just to see a higher number of pages dirtied. Note how the number of pages dirtied is also much higher the total number of existing pages! I'm going to push this now anyway, thanks. -- Álvaro Herrera alvhe...@commandprompt.com The PostgreSQL Company - Command Prompt, Inc. PostgreSQL Replication, Consulting, Custom Development, 24x7 support -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Displaying accumulated autovacuum cost
On Fri, Nov 25, 2011 at 11:39 AM, Alvaro Herrera alvhe...@commandprompt.com wrote: I'm going to push this now anyway, thanks. This patch adds a count of the number of buffers dirtied to VACUUM, but it strikes me that it would be useful to add similar tracking to pgBufferUsage. Attached is a patch for that. You can see the new counters through pg_stat_statements or with EXPLAIN (ANALYZE, BUFFERS). This is useful because the number of buffers that a query *writes* doesn't necessarily have much to do with anything - it may end up writing buffers dirtied by other queries while being read-only itself, or conversely it may not write anything at all even though it dirties quite a bit. Thoughts? Comments? Objections? -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company dirty_buffers.patch Description: Binary data -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Displaying accumulated autovacuum cost
On 10/05/2011 03:02 AM, Greg Smith wrote:
Presumably you meant to ask if this makes sense to show when cost
accounting isn't enabled, because the code doesn't do that right now.
No cost accounting, no buffer usage/write rate data as this was
submitted.
This is done in the attached update. I just made the page accounting
happen all the time, regardless of whether the costs were being
accumulated. Added a read rate too, which is how fast reads happened
from the OS cache to shared_buffers. Simple test case generates a 600MB
pgbench_accounts database and wipes out enough to take a while to clean
up; it needs log_autovacuum_min_duration = 0 and then:
$ createdb pgbench
$ pgbench -i -s 10 pgbench
$ psql -d pgbench -c delete from pgbench_accounts where aid20
LOG: automatic vacuum of table pgbench.public.pgbench_accounts: index
scans: 1
pages: 0 removed, 16394 remain
tuples: 19 removed, 640011 remain
buffer usage: 13742 hits, 2708 misses, 1058 dirtied
avg read rate: 3.067 MiB/s, avg write rate: 1.198 MiB/s
system usage: CPU 0.05s/0.61u sec elapsed 6.89 sec
Now that you mention it, people who do a manual, full-speed VACUUM
would certainly appreciate some feedback on the rate it ran at.
This is more of a pain because this whole code path is only active when
IsAutoVacuumWorkerProcess. I have some larger refactoring in mind to
perhaps make that more feasible. I didn't want to hold this update
aiming at the more valuable autovac case for that though, can always
layer it on later.
--
Greg Smith 2ndQuadrant USg...@2ndquadrant.com Baltimore, MD
PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.us
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index f42504c..6ef85dd 100644
*** a/src/backend/commands/vacuum.c
--- b/src/backend/commands/vacuum.c
*** vacuum(VacuumStmt *vacstmt, Oid relid, b
*** 214,219
--- 214,222
VacuumCostActive = (VacuumCostDelay 0);
VacuumCostBalance = 0;
+ VacuumPageHit = 0;
+ VacuumPageMiss = 0;
+ VacuumPageDirty = 0;
/*
* Loop to process each selected relation.
diff --git a/src/backend/commands/vacuumlazy.c b/src/backend/commands/vacuumlazy.c
index 38deddc..c59fceb 100644
*** a/src/backend/commands/vacuumlazy.c
--- b/src/backend/commands/vacuumlazy.c
*** lazy_vacuum_rel(Relation onerel, VacuumS
*** 154,160
int nindexes;
BlockNumber possibly_freeable;
PGRUsage ru0;
! TimestampTz starttime = 0;
bool scan_all;
TransactionId freezeTableLimit;
BlockNumber new_rel_pages;
--- 154,163
int nindexes;
BlockNumber possibly_freeable;
PGRUsage ru0;
! TimestampTz starttime = 0, endtime;
! long secs;
! int usecs;
! double read_rate, write_rate;
bool scan_all;
TransactionId freezeTableLimit;
BlockNumber new_rel_pages;
*** lazy_vacuum_rel(Relation onerel, VacuumS
*** 166,173
if (IsAutoVacuumWorkerProcess() Log_autovacuum_min_duration = 0)
{
pg_rusage_init(ru0);
! if (Log_autovacuum_min_duration 0)
! starttime = GetCurrentTimestamp();
}
if (vacstmt-options VACOPT_VERBOSE)
--- 169,175
if (IsAutoVacuumWorkerProcess() Log_autovacuum_min_duration = 0)
{
pg_rusage_init(ru0);
! starttime = GetCurrentTimestamp();
}
if (vacstmt-options VACOPT_VERBOSE)
*** lazy_vacuum_rel(Relation onerel, VacuumS
*** 262,274
/* and log the action if appropriate */
if (IsAutoVacuumWorkerProcess() Log_autovacuum_min_duration = 0)
{
if (Log_autovacuum_min_duration == 0 ||
! TimestampDifferenceExceeds(starttime, GetCurrentTimestamp(),
Log_autovacuum_min_duration))
ereport(LOG,
(errmsg(automatic vacuum of table \%s.%s.%s\: index scans: %d\n
pages: %d removed, %d remain\n
tuples: %.0f removed, %.0f remain\n
system usage: %s,
get_database_name(MyDatabaseId),
get_namespace_name(RelationGetNamespace(onerel)),
--- 264,290
/* and log the action if appropriate */
if (IsAutoVacuumWorkerProcess() Log_autovacuum_min_duration = 0)
{
+ endtime = GetCurrentTimestamp();
if (Log_autovacuum_min_duration == 0 ||
! TimestampDifferenceExceeds(starttime, endtime,
Log_autovacuum_min_duration))
+ {
+ TimestampDifference(starttime, endtime, secs, usecs);
+ read_rate = 0;
+ write_rate = 0;
+ if ((secs 0) || (usecs 0))
+ {
+ read_rate = (double) BLCKSZ * VacuumPageMiss / (1024 * 1024) /
+ (secs + usecs / 100.0);
+ write_rate = (double) BLCKSZ * VacuumPageDirty / (1024 * 1024) /
+ (secs + usecs / 100.0);
+ }
ereport(LOG,
(errmsg(automatic vacuum of table \%s.%s.%s\: index scans: %d\n
pages: %d removed, %d remain\n
tuples: %.0f removed, %.0f remain\n
+ buffer usage: %d hits, %d misses, %d dirtied\n
+ avg read rate: %.3f MiB/s, avg write
Re: [HACKERS] Displaying accumulated autovacuum cost
On 09/26/2011 05:58 AM, Shigeru Hanada wrote: * Local variables added by the patch (secs, usecs, write_rate and endtime) can be moved into narrower scope. * Initializing starttime to zero seems unnecessary. Setting starttime to 0 is already in the code; the change made to that line was to add endtime, which is not initialized. You may be right that initializing it isn't necessary, but I'm sure not going to touch that part of the working code. You're right about the the local variables; they were placed to look like the surrounding code rather than to be as local as possible. I'm not sure if all the PostgreSQL code is completely consistent here; a quick survey shows examples of both put all the variables at the top and make variables as local to blocks as possible styles. I don't know that it really makes any difference with modern compilers, either. I'm sure someone else will have a stronger opinion on this subject now that I've trolled the list for one by writing this. In addition, documents about how to use the statistics would be necessary, maybe in 23.1.5. The Autovacuum Daemon. I'll set the status of this patch to waiting-on-author. Would you rebase the patch and post it again? I didn't do that because there's not really much documentation at this level of detail yet--how to interpret all the information in the logs. That's an open-ended bit of work; there's a lot more that could be written on this topic than the docs have right now. It's probably worth pointing out that this specific info is now in the logs, though, given that people might not notice it otherwise. I'll see what I can do about that. As a general FYI, rebasing is normally requested only when the existing patch doesn't apply anymore. If patch or git apply can consume it, complaints about code shifting around isn't by itself enough reason to ask for an updated patch. -- Greg Smith 2ndQuadrant USg...@2ndquadrant.com Baltimore, MD PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.us -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Displaying accumulated autovacuum cost
On 09/29/2011 10:40 AM, Alvaro Herrera wrote: I reviewed this patch. My question for you is: does it make sense to enable to reporting of write rate even when vacuum cost accounting is enabled? In my opinion it would be useful to do so. If you agree, please submit an updated patch. Presumably you meant to ask if this makes sense to show when cost accounting isn't enabled, because the code doesn't do that right now. No cost accounting, no buffer usage/write rate data as this was submitted. Looks like making this work even in cases where cost accounting isn't on will make the patch a bit larger obtrusive, but it's not unreasonable. Now that you mention it, people who do a manual, full-speed VACUUM would certainly appreciate some feedback on the rate it ran at. I'll include that in the next update. -- Greg Smith 2ndQuadrant USg...@2ndquadrant.com Baltimore, MD PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.us -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Displaying accumulated autovacuum cost
Excerpts from Greg Smith's message of mié oct 05 04:02:12 -0300 2011: On 09/29/2011 10:40 AM, Alvaro Herrera wrote: I reviewed this patch. My question for you is: does it make sense to enable to reporting of write rate even when vacuum cost accounting is enabled? In my opinion it would be useful to do so. If you agree, please submit an updated patch. Presumably you meant to ask if this makes sense to show when cost accounting isn't enabled, because the code doesn't do that right now. No cost accounting, no buffer usage/write rate data as this was submitted. Yes, sorry, that's what I meant. Looks like making this work even in cases where cost accounting isn't on will make the patch a bit larger obtrusive, but it's not unreasonable. Now that you mention it, people who do a manual, full-speed VACUUM would certainly appreciate some feedback on the rate it ran at. I'll include that in the next update. Thanks. -- Álvaro Herrera alvhe...@commandprompt.com The PostgreSQL Company - Command Prompt, Inc. PostgreSQL Replication, Consulting, Custom Development, 24x7 support -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Displaying accumulated autovacuum cost
I reviewed this patch. My question for you is: does it make sense to enable to reporting of write rate even when vacuum cost accounting is enabled? In my opinion it would be useful to do so. If you agree, please submit an updated patch. -- Álvaro Herrera alvhe...@commandprompt.com The PostgreSQL Company - Command Prompt, Inc. PostgreSQL Replication, Consulting, Custom Development, 24x7 support -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Displaying accumulated autovacuum cost
Hi Greg,
(2011/08/28 18:54), Greg Smith wrote:
Updated patch cleans up two diff mistakes made when backing out the
progress report feature. The tip-off I screwed up should have been the
absurdly high write rate shown. The usleep was accidentally deleted, so
it was running without cost limits even applying. Here's a good one
instead:
LOG: automatic vacuum of table pgbench.public.pgbench_accounts: index
scans: 1
pages: 0 removed, 163935 remain
tuples: 200 removed, 2928356 remain
buffer usage: 117393 hits, 123351 misses, 102684 dirtied, 2.168 MiB/s
write rate
system usage: CPU 2.54s/6.27u sec elapsed 369.99 sec
I took a look at your patch, and it seems fine about fundamental
functionality, though the patch needed to be rebased against current
HEAD. Please see attached patch which I used for review.
IIUC, this patch provides:
* Three counters, which are used to keep # of buffers which were (1)
Hits: found in shared buffers, (2) Missed: not found in shared buffers,
and (3) Dirtied: marked as dirty, in an autovacuum of a relation.
These counters are used only when cost-based autovacuum is enabled by
setting vacuum_cost_delay to non-zero.
* Capability to report # of buffers above, and buffer write rate
(MiB/sec) in the existing autovacuum logging message, only when actual
duration autovacuum_min_duration, and cost-based autovacuum is enabled.
I think one concern is the way showing statistics. If showing summary
of statistics (at the end of an autovacuum) in server log is enough,
current implementation is fine. Also showing progress report in server
log would be easy to achieve. In contrast, reporting progress via
another backend would require shared memory or statistics collector,
rather than per-process global variables. Anyway, this patch can be the
base of such enhancement.
There are some trivial comments:
* Local variables added by the patch (secs, usecs, write_rate and
endtime) can be moved into narrower scope.
* Initializing starttime to zero seems unnecessary.
In addition, documents about how to use the statistics would be
necessary, maybe in 23.1.5. The Autovacuum Daemon.
I'll set the status of this patch to waiting-on-author. Would you rebase
the patch and post it again?
Regards,
--
Shigeru Hanada
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index 7fe787e..768c658 100644
*** a/src/backend/commands/vacuum.c
--- b/src/backend/commands/vacuum.c
*** vacuum(VacuumStmt *vacstmt, Oid relid, b
*** 214,219
--- 214,222
VacuumCostActive = (VacuumCostDelay 0);
VacuumCostBalance = 0;
+ VacuumPageHit = 0;
+ VacuumPageMiss = 0;
+ VacuumPageDirty = 0;
/*
* Loop to process each selected relation.
diff --git a/src/backend/commands/vacuumlazy.c
b/src/backend/commands/vacuumlazy.c
index cf8337b..d9bb272 100644
*** a/src/backend/commands/vacuumlazy.c
--- b/src/backend/commands/vacuumlazy.c
*** lazy_vacuum_rel(Relation onerel, VacuumS
*** 153,170
int nindexes;
BlockNumber possibly_freeable;
PGRUsageru0;
! TimestampTz starttime = 0;
boolscan_all;
TransactionId freezeTableLimit;
BlockNumber new_rel_pages;
double new_rel_tuples;
TransactionId new_frozen_xid;
/* measure elapsed time iff autovacuum logging requires it */
if (IsAutoVacuumWorkerProcess() Log_autovacuum_min_duration = 0)
{
pg_rusage_init(ru0);
! if (Log_autovacuum_min_duration 0)
starttime = GetCurrentTimestamp();
}
--- 153,173
int nindexes;
BlockNumber possibly_freeable;
PGRUsageru0;
! TimestampTz starttime = 0, endtime;
boolscan_all;
TransactionId freezeTableLimit;
BlockNumber new_rel_pages;
double new_rel_tuples;
TransactionId new_frozen_xid;
+ longsecs;
+ int usecs;
+ double write_rate;
/* measure elapsed time iff autovacuum logging requires it */
if (IsAutoVacuumWorkerProcess() Log_autovacuum_min_duration = 0)
{
pg_rusage_init(ru0);
! if (Log_autovacuum_min_duration 0 || VacuumCostActive)
starttime = GetCurrentTimestamp();
}
*** lazy_vacuum_rel(Relation onerel, VacuumS
*** 250,272
/* and log the action if appropriate */
if (IsAutoVacuumWorkerProcess() Log_autovacuum_min_duration = 0)
{
if (Log_autovacuum_min_duration == 0 ||
! TimestampDifferenceExceeds(starttime,
GetCurrentTimestamp(),
Re: [HACKERS] Displaying accumulated autovacuum cost
On Sun, Aug 28, 2011 at 5:54 AM, Greg Smith g...@2ndquadrant.com wrote: Updated patch cleans up two diff mistakes made when backing out the progress report feature. The tip-off I screwed up should have been the absurdly high write rate shown. The usleep was accidentally deleted, so it was running without cost limits even applying. Here's a good one instead: LOG: automatic vacuum of table pgbench.public.pgbench_accounts: index scans: 1 pages: 0 removed, 163935 remain tuples: 200 removed, 2928356 remain buffer usage: 117393 hits, 123351 misses, 102684 dirtied, 2.168 MiB/s write rate system usage: CPU 2.54s/6.27u sec elapsed 369.99 sec I postulate that this change isn't needed until you get to the part where we do some kind of intermediate progress reporting: ! if (Log_autovacuum_min_duration 0 || VacuumCostActive) Instead of doing this only when vacuum costing is active, could we drive it off of the pgBufferUsage stuff (maybe with a few tweaks...) and do it unconditionally? To me it seems like it would better to say write rate xyz MB/s rather than xyz MB/s write rate, but maybe I'm in the minority on that one. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Displaying accumulated autovacuum cost
On 08/29/2011 11:03 AM, Robert Haas wrote: Instead of doing this only when vacuum costing is active, could we drive it off of the pgBufferUsage stuff (maybe with a few tweaks...) and do it unconditionally? Sure. I've wondered about an ever larger refactoring, to reorient vacuum costing around completely: drive it all from the pgBufferUsage side rather than running its own totals. I didn't even start wandering down that path yet because of time constraints, plus the desire to have something I could backport to installs having VACUUM issues on earlier versions. This code I'd backport without hesitation; something that wanders toward a more complicated rearrangement becomes harder to deal with. To me it seems like it would better to say write rate xyz MB/s rather than xyz MB/s write rate, but maybe I'm in the minority on that one. I was just trying to mimic the style of the logging already there as closely as I could. I don't like the way the existing log message looks either. I wasn't going to ignore its style over that though. -- Greg Smith 2ndQuadrant USg...@2ndquadrant.com Baltimore, MD PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.us -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Displaying accumulated autovacuum cost
Attached patch includes math is hard reworking, so it displays the
average write rate in the log output automatically:
LOG: automatic vacuum of table pgbench.public.pgbench_accounts: index
scans: 1
pages: 0 removed, 163935 remain
tuples: 200 removed, 4625165 remain
buffer usage: 111901 hits, 123348 misses, 102351 dirtied, 23.365
MiB/s write rate
system usage: CPU 1.84s/4.22u sec elapsed 34.22 sec
All of the updates to the process title are gone, in favor of some
progress report mechanism TBD. The summary is much more important than
the progress tracking part as far as I'm concerned, I don't mind
splitting things apart to try and get this part in earlier.
--
Greg Smith 2ndQuadrant USg...@2ndquadrant.com Baltimore, MD
PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.us
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index 889737e..fa15b2e 100644
*** a/src/backend/commands/vacuum.c
--- b/src/backend/commands/vacuum.c
***
*** 43,48
--- 43,49
#include utils/fmgroids.h
#include utils/guc.h
#include utils/memutils.h
+ #include utils/ps_status.h
#include utils/snapmgr.h
#include utils/syscache.h
#include utils/tqual.h
*** vacuum(VacuumStmt *vacstmt, Oid relid, b
*** 214,219
--- 215,223
VacuumCostActive = (VacuumCostDelay 0);
VacuumCostBalance = 0;
+ VacuumPageHit = 0;
+ VacuumPageMiss = 0;
+ VacuumPageDirty = 0;
/*
* Loop to process each selected relation.
*** vacuum_delay_point(void)
*** 1160,1167
if (msec VacuumCostDelay * 4)
msec = VacuumCostDelay * 4;
- pg_usleep(msec * 1000L);
-
VacuumCostBalance = 0;
/* update balance values for workers */
--- 1164,1169
diff --git a/src/backend/commands/vacuumlazy.c b/src/backend/commands/vacuumlazy.c
index b5547c5..a41f1cd 100644
*** a/src/backend/commands/vacuumlazy.c
--- b/src/backend/commands/vacuumlazy.c
*** lazy_vacuum_rel(Relation onerel, VacuumS
*** 151,165
int nindexes;
BlockNumber possibly_freeable;
PGRUsage ru0;
! TimestampTz starttime = 0;
bool scan_all;
TransactionId freezeTableLimit;
/* measure elapsed time iff autovacuum logging requires it */
if (IsAutoVacuumWorkerProcess() Log_autovacuum_min_duration = 0)
{
pg_rusage_init(ru0);
! if (Log_autovacuum_min_duration 0)
starttime = GetCurrentTimestamp();
}
--- 151,168
int nindexes;
BlockNumber possibly_freeable;
PGRUsage ru0;
! TimestampTz starttime = 0, endtime;
bool scan_all;
TransactionId freezeTableLimit;
+ long secs;
+ int usecs;
+ double write_rate;
/* measure elapsed time iff autovacuum logging requires it */
if (IsAutoVacuumWorkerProcess() Log_autovacuum_min_duration = 0)
{
pg_rusage_init(ru0);
! if (Log_autovacuum_min_duration 0 || VacuumCostActive)
starttime = GetCurrentTimestamp();
}
*** lazy_vacuum_rel(Relation onerel, VacuumS
*** 225,247
/* and log the action if appropriate */
if (IsAutoVacuumWorkerProcess() Log_autovacuum_min_duration = 0)
{
if (Log_autovacuum_min_duration == 0 ||
! TimestampDifferenceExceeds(starttime, GetCurrentTimestamp(),
Log_autovacuum_min_duration))
! ereport(LOG,
! (errmsg(automatic vacuum of table \%s.%s.%s\: index scans: %d\n
! pages: %d removed, %d remain\n
! tuples: %.0f removed, %.0f remain\n
! system usage: %s,
! get_database_name(MyDatabaseId),
! get_namespace_name(RelationGetNamespace(onerel)),
! RelationGetRelationName(onerel),
! vacrelstats-num_index_scans,
! vacrelstats-pages_removed,
! vacrelstats-rel_pages,
! vacrelstats-tuples_deleted,
! vacrelstats-new_rel_tuples,
! pg_rusage_show(ru0;
}
}
--- 228,282
/* and log the action if appropriate */
if (IsAutoVacuumWorkerProcess() Log_autovacuum_min_duration = 0)
{
+ endtime = GetCurrentTimestamp();
if (Log_autovacuum_min_duration == 0 ||
! TimestampDifferenceExceeds(starttime, endtime,
Log_autovacuum_min_duration))
! {
! if (VacuumCostActive)
! {
! TimestampDifference(starttime, endtime, secs, usecs);
! write_rate = 0;
! if ((secs 0) || (usecs 0))
! write_rate = (double) BLCKSZ * VacuumPageDirty / (1024 * 1024) /
! (secs + usecs / 100.0);
!
! ereport(LOG,
! (errmsg(automatic vacuum of table \%s.%s.%s\: index scans: %d\n
! pages: %d removed, %d remain\n
! tuples: %.0f removed, %.0f remain\n
! buffer usage: %d hits, %d misses, %d dirtied, %.3f MiB/s write rate\n
! system usage: %s,
! get_database_name(MyDatabaseId),
! get_namespace_name(RelationGetNamespace(onerel)),
! RelationGetRelationName(onerel),
! vacrelstats-num_index_scans,
! vacrelstats-pages_removed,
!
Re: [HACKERS] Displaying accumulated autovacuum cost
Updated patch cleans up two diff mistakes made when backing out the
progress report feature. The tip-off I screwed up should have been the
absurdly high write rate shown. The usleep was accidentally deleted, so
it was running without cost limits even applying. Here's a good one
instead:
LOG: automatic vacuum of table pgbench.public.pgbench_accounts: index
scans: 1
pages: 0 removed, 163935 remain
tuples: 200 removed, 2928356 remain
buffer usage: 117393 hits, 123351 misses, 102684 dirtied, 2.168
MiB/s write rate
system usage: CPU 2.54s/6.27u sec elapsed 369.99 sec
--
Greg Smith 2ndQuadrant USg...@2ndquadrant.com Baltimore, MD
PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.us
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index 889737e..c9890b4 100644
*** a/src/backend/commands/vacuum.c
--- b/src/backend/commands/vacuum.c
*** vacuum(VacuumStmt *vacstmt, Oid relid, b
*** 214,219
--- 214,222
VacuumCostActive = (VacuumCostDelay 0);
VacuumCostBalance = 0;
+ VacuumPageHit = 0;
+ VacuumPageMiss = 0;
+ VacuumPageDirty = 0;
/*
* Loop to process each selected relation.
diff --git a/src/backend/commands/vacuumlazy.c b/src/backend/commands/vacuumlazy.c
index b5547c5..a41f1cd 100644
*** a/src/backend/commands/vacuumlazy.c
--- b/src/backend/commands/vacuumlazy.c
*** lazy_vacuum_rel(Relation onerel, VacuumS
*** 151,165
int nindexes;
BlockNumber possibly_freeable;
PGRUsage ru0;
! TimestampTz starttime = 0;
bool scan_all;
TransactionId freezeTableLimit;
/* measure elapsed time iff autovacuum logging requires it */
if (IsAutoVacuumWorkerProcess() Log_autovacuum_min_duration = 0)
{
pg_rusage_init(ru0);
! if (Log_autovacuum_min_duration 0)
starttime = GetCurrentTimestamp();
}
--- 151,168
int nindexes;
BlockNumber possibly_freeable;
PGRUsage ru0;
! TimestampTz starttime = 0, endtime;
bool scan_all;
TransactionId freezeTableLimit;
+ long secs;
+ int usecs;
+ double write_rate;
/* measure elapsed time iff autovacuum logging requires it */
if (IsAutoVacuumWorkerProcess() Log_autovacuum_min_duration = 0)
{
pg_rusage_init(ru0);
! if (Log_autovacuum_min_duration 0 || VacuumCostActive)
starttime = GetCurrentTimestamp();
}
*** lazy_vacuum_rel(Relation onerel, VacuumS
*** 225,247
/* and log the action if appropriate */
if (IsAutoVacuumWorkerProcess() Log_autovacuum_min_duration = 0)
{
if (Log_autovacuum_min_duration == 0 ||
! TimestampDifferenceExceeds(starttime, GetCurrentTimestamp(),
Log_autovacuum_min_duration))
! ereport(LOG,
! (errmsg(automatic vacuum of table \%s.%s.%s\: index scans: %d\n
! pages: %d removed, %d remain\n
! tuples: %.0f removed, %.0f remain\n
! system usage: %s,
! get_database_name(MyDatabaseId),
! get_namespace_name(RelationGetNamespace(onerel)),
! RelationGetRelationName(onerel),
! vacrelstats-num_index_scans,
! vacrelstats-pages_removed,
! vacrelstats-rel_pages,
! vacrelstats-tuples_deleted,
! vacrelstats-new_rel_tuples,
! pg_rusage_show(ru0;
}
}
--- 228,282
/* and log the action if appropriate */
if (IsAutoVacuumWorkerProcess() Log_autovacuum_min_duration = 0)
{
+ endtime = GetCurrentTimestamp();
if (Log_autovacuum_min_duration == 0 ||
! TimestampDifferenceExceeds(starttime, endtime,
Log_autovacuum_min_duration))
! {
! if (VacuumCostActive)
! {
! TimestampDifference(starttime, endtime, secs, usecs);
! write_rate = 0;
! if ((secs 0) || (usecs 0))
! write_rate = (double) BLCKSZ * VacuumPageDirty / (1024 * 1024) /
! (secs + usecs / 100.0);
!
! ereport(LOG,
! (errmsg(automatic vacuum of table \%s.%s.%s\: index scans: %d\n
! pages: %d removed, %d remain\n
! tuples: %.0f removed, %.0f remain\n
! buffer usage: %d hits, %d misses, %d dirtied, %.3f MiB/s write rate\n
! system usage: %s,
! get_database_name(MyDatabaseId),
! get_namespace_name(RelationGetNamespace(onerel)),
! RelationGetRelationName(onerel),
! vacrelstats-num_index_scans,
! vacrelstats-pages_removed,
! vacrelstats-rel_pages,
! vacrelstats-tuples_deleted,
! vacrelstats-new_rel_tuples,
! VacuumPageHit,
! VacuumPageMiss,
! VacuumPageDirty,
! write_rate,
! pg_rusage_show(ru0;
! }
! else
! ereport(LOG,
! (errmsg(automatic vacuum of table \%s.%s.%s\: index scans: %d\n
! pages: %d removed, %d remain\n
! tuples: %.0f removed, %.0f remain\n
! system usage: %s,
! get_database_name(MyDatabaseId),
! get_namespace_name(RelationGetNamespace(onerel)),
!
Re: [HACKERS] Displaying accumulated autovacuum cost
On Aug 18, 2011, at 10:41 AM, Greg Smith wrote: that was all they got. I'm going to add directly computing the write MB/s figure from the dirty data written too, since that ends up being the thing that I keep deriving by hand anyway. I know folks have talked about progress, but I haven't seen anything specific... could you add info about what table/index vacuum is working on, and how far along it is? I realize that's not very close to an actual % completion, but it's far better than what we have right now. FWIW, the number I end up caring about isn't so much write traffic as read. Thanks to a good amount of battery-backed write cache (and possibly some iSCSI misconfiguration), our writes are generally much cheaper than our reads. -- Jim C. Nasby, Database Architect j...@nasby.net 512.569.9461 (cell) http://jim.nasby.net -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Displaying accumulated autovacuum cost
On 08/22/2011 05:54 PM, Jim Nasby wrote: I know folks have talked about progress, but I haven't seen anything specific... could you add info about what table/index vacuum is working on, and how far along it is? I realize that's not very close to an actual % completion, but it's far better than what we have right now. Due to complaints about the mechanism the first version used to inform the user of the progress, I'm yanking that from the next patch altogether. The goal for now is to get a good report into the logs, and then maybe that gets extended later with a progress report. (All of the proposed alternate mechanisms are way more complicated than anything I have time to do right now) FWIW, the number I end up caring about isn't so much write traffic as read. Thanks to a good amount of battery-backed write cache (and possibly some iSCSI misconfiguration), our writes are generally much cheaper than our reads. VACUUM can't really know its true read rate from what's inside the database. I can add a summary of the accumulated read amounts into the logs, in more useful figures than what is provided so far, which is better than nothing. But those will be kind of deceptive, which is one reason I wasn't so focused on them yet. If the relation is largely in the OS cache, but not the PostgreSQL one, the summary can show a read rate even when that isn't actually doing any reads at all. That was exactly the case in the sample data I posted. VACUUM thought it was reading anywhere from 2.5 to 6MB/s. But at the OS level, it was actually reading zero bytes, since the whole thing was in cache already. What you actually want is a count of the accumulated read counters at the OS level. I've recently figured out how to track those, too, but that code is something that lives outside the database. If this is something useful to you, I think you're about to sign up to be my next beta tester for that program. -- Greg Smith 2ndQuadrant USg...@2ndquadrant.com Baltimore, MD PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.us -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Displaying accumulated autovacuum cost
On Thu, Aug 18, 2011 at 03:23, Greg Smith g...@2ndquadrant.com wrote: On 08/17/2011 07:42 PM, Euler Taveira de Oliveira wrote: I don't like exposing this information only on title processes. It would be difficult for client apps (for example, PGAdmin) to track this kind of information and it is restricted to local access. I'm not objecting to display this information in process title; I'm just saying that that information should be exposed in functions (say pg_stat_get_vacuum_[hit|miss|dirty]) too. I tend to build the simplest possible thing that is useful enough to work. The data is getting stored and shown now, where it wasn't before. If it's possible to expose that in additional ways later too, great. The big step up for this information is to go from unobtainable to obtainable. I'd prefer not to add a quest for easily obtainable to the requirements until that big jump is made, for fear it will cause nothing to get delivered. By only putting it in the ps display, you exclude all the users who don't have an easy way to look at that information. The big group there is Windows, but it's not necessarily easy on all other platforms as well, afaik. And possibliy even more importantly, it makes it impossible to view it from tools like pgadmin. I think it's definitely worthwhile to add support to view it through the stats collector as well from the beginnig. The question there is if it's enough to just show it in the current_query (kind of like it's done in the ps output), or if we want a completely separate view with this info. Also, unrelated to that, wouldn't this information be interesting for non-autovacuum queries as well? -- Magnus Hagander Me: http://www.hagander.net/ Work: http://www.redpill-linpro.com/ -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Displaying accumulated autovacuum cost
Magnus Hagander mag...@hagander.net writes: Also, unrelated to that, wouldn't this information be interesting for non-autovacuum queries as well? I was about to say that I would like to see it for normal queries too, but I guess we already have it: = explain (analyze, buffers, costs off) select * from pg_attribute a join pg_class c on a.attrelid = c.oid; QUERY PLAN Hash Join (actual time=0.569..4.255 rows=2158 loops=1) Hash Cond: (a.attrelid = c.oid) Buffers: shared hit=48 - Seq Scan on pg_attribute a (actual time=0.008..0.462 rows=2158 loops=1) Buffers: shared hit=40 - Hash (actual time=0.541..0.541 rows=282 loops=1) Buckets: 1024 Batches: 1 Memory Usage: 54kB Buffers: shared hit=8 - Seq Scan on pg_class c (actual time=0.010..0.269 rows=282 loops=1) Buffers: shared hit=8 Total runtime: 4.551 ms (11 rows) Also, from where I sit the ps title update for normal queries is about useless, as I see loads of IDLE postgresql backends in top that are consuming 20% and more CPU time. The refresh rate is way to low to be useful, and having the title it updated more frequently would probably consume enough CPU that it would defeat its purpose (going from instrumenting to slowing down enough that you can see what's happening is not where I'd want to go). Regards, -- Dimitri Fontaine http://2ndQuadrant.fr PostgreSQL : Expertise, Formation et Support -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Displaying accumulated autovacuum cost
Em 18-08-2011 03:39, Magnus Hagander escreveu: Also, unrelated to that, wouldn't this information be interesting for non-autovacuum queries as well? Yes, it would. AFAICS, the patch will display that message in process titles. However, analyze code also uses the vacuum_delay_point(). How do you handle it? It would be another patch... autovacuum has an option to display summarized information but vacuum don't. Isn't it time to be symmetrical here? -- Euler Taveira de Oliveira - Timbira http://www.timbira.com.br/ PostgreSQL: Consultoria, Desenvolvimento, Suporte 24x7 e Treinamento -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Displaying accumulated autovacuum cost
Magnus Hagander mag...@hagander.net writes: On Thu, Aug 18, 2011 at 03:23, Greg Smith g...@2ndquadrant.com wrote: On 08/17/2011 07:42 PM, Euler Taveira de Oliveira wrote: I don't like exposing this information only on title processes. I tend to build the simplest possible thing that is useful enough to work. By only putting it in the ps display, you exclude all the users who don't have an easy way to look at that information. The big group there is Windows, but it's not necessarily easy on all other platforms as well, afaik. Yeah. Also, process title updates are friggin expensive on some platforms --- so much so, that we have a GUC setting to disable them. So I don't think we should use that technique at all. Put the info into the stats collector instead (not also). regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Displaying accumulated autovacuum cost
On Wed, Aug 17, 2011 at 9:23 PM, Greg Smith g...@2ndquadrant.com wrote: On 08/17/2011 07:42 PM, Euler Taveira de Oliveira wrote: I don't like exposing this information only on title processes. It would be difficult for client apps (for example, PGAdmin) to track this kind of information and it is restricted to local access. I'm not objecting to display this information in process title; I'm just saying that that information should be exposed in functions (say pg_stat_get_vacuum_[hit|miss|dirty]) too. I tend to build the simplest possible thing that is useful enough to work. The data is getting stored and shown now, where it wasn't before. If it's possible to expose that in additional ways later too, great. The big step up for this information is to go from unobtainable to obtainable. I'd prefer not to add a quest for easily obtainable to the requirements until that big jump is made, for fear it will cause nothing to get delivered. Perhaps a reasonable way to break up the patch would be: - Part 1: Gather the information and display it in the log_autovacuum_min_duration output. - Part 2: Add the ability to see the information incrementally (via some mechanism yet to be agreed upon). -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Displaying accumulated autovacuum cost
On tor, 2011-08-18 at 08:39 +0200, Magnus Hagander wrote: Also, unrelated to that, wouldn't this information be interesting for non-autovacuum queries as well? Last year we were discussing some details on progress reporting, and some people suggested that instead of printing a single percentage, we should let each type of activity print out whatever metrics it has that would allow an experienced DBA to track the progress. Effectively, this is what this patch is trying to do. So how about adding a column to pg_stat_activity, progress_metrics or something like that, and add that information there. -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Displaying accumulated autovacuum cost
On Thu, Aug 18, 2011 at 10:54 AM, Peter Eisentraut pete...@gmx.net wrote: On tor, 2011-08-18 at 08:39 +0200, Magnus Hagander wrote: Also, unrelated to that, wouldn't this information be interesting for non-autovacuum queries as well? Last year we were discussing some details on progress reporting, and some people suggested that instead of printing a single percentage, we should let each type of activity print out whatever metrics it has that would allow an experienced DBA to track the progress. Effectively, this is what this patch is trying to do. So how about adding a column to pg_stat_activity, progress_metrics or something like that, and add that information there. That might be a good way to go. I don't think we want something like pg_stat_all_tables for this, because it seems that Greg's use case is to be able to see how a *particular* autovacuum process is doing *while it's running*, not to look at aggregate statistics over time. Putting it in pg_stat_activity would be good for that. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Displaying accumulated autovacuum cost
On Thu, Aug 18, 2011 at 17:13, Robert Haas robertmh...@gmail.com wrote: On Thu, Aug 18, 2011 at 10:54 AM, Peter Eisentraut pete...@gmx.net wrote: On tor, 2011-08-18 at 08:39 +0200, Magnus Hagander wrote: Also, unrelated to that, wouldn't this information be interesting for non-autovacuum queries as well? Last year we were discussing some details on progress reporting, and some people suggested that instead of printing a single percentage, we should let each type of activity print out whatever metrics it has that would allow an experienced DBA to track the progress. Effectively, this is what this patch is trying to do. So how about adding a column to pg_stat_activity, progress_metrics or something like that, and add that information there. That might be a good way to go. I don't think we want something like pg_stat_all_tables for this, because it seems that Greg's use case is to be able to see how a *particular* autovacuum process is doing *while it's running*, not to look at aggregate statistics over time. Putting it in pg_stat_activity would be good for that. It's also good to have it broken down into multiple columns, and not just a freetext column in the view - if tools should be able to parse it as well. -- Magnus Hagander Me: http://www.hagander.net/ Work: http://www.redpill-linpro.com/ -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Displaying accumulated autovacuum cost
On Thu, Aug 18, 2011 at 11:14 AM, Magnus Hagander mag...@hagander.net wrote: On Thu, Aug 18, 2011 at 17:13, Robert Haas robertmh...@gmail.com wrote: On Thu, Aug 18, 2011 at 10:54 AM, Peter Eisentraut pete...@gmx.net wrote: On tor, 2011-08-18 at 08:39 +0200, Magnus Hagander wrote: Also, unrelated to that, wouldn't this information be interesting for non-autovacuum queries as well? Last year we were discussing some details on progress reporting, and some people suggested that instead of printing a single percentage, we should let each type of activity print out whatever metrics it has that would allow an experienced DBA to track the progress. Effectively, this is what this patch is trying to do. So how about adding a column to pg_stat_activity, progress_metrics or something like that, and add that information there. That might be a good way to go. I don't think we want something like pg_stat_all_tables for this, because it seems that Greg's use case is to be able to see how a *particular* autovacuum process is doing *while it's running*, not to look at aggregate statistics over time. Putting it in pg_stat_activity would be good for that. It's also good to have it broken down into multiple columns, and not just a freetext column in the view - if tools should be able to parse it as well. True. We could have a separate system view that only shows the status of currently-running vacuum proceses. That wouldn't bother me either. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Displaying accumulated autovacuum cost
On Thu, Aug 18, 2011 at 17:23, Robert Haas robertmh...@gmail.com wrote: On Thu, Aug 18, 2011 at 11:14 AM, Magnus Hagander mag...@hagander.net wrote: On Thu, Aug 18, 2011 at 17:13, Robert Haas robertmh...@gmail.com wrote: On Thu, Aug 18, 2011 at 10:54 AM, Peter Eisentraut pete...@gmx.net wrote: On tor, 2011-08-18 at 08:39 +0200, Magnus Hagander wrote: Also, unrelated to that, wouldn't this information be interesting for non-autovacuum queries as well? Last year we were discussing some details on progress reporting, and some people suggested that instead of printing a single percentage, we should let each type of activity print out whatever metrics it has that would allow an experienced DBA to track the progress. Effectively, this is what this patch is trying to do. So how about adding a column to pg_stat_activity, progress_metrics or something like that, and add that information there. That might be a good way to go. I don't think we want something like pg_stat_all_tables for this, because it seems that Greg's use case is to be able to see how a *particular* autovacuum process is doing *while it's running*, not to look at aggregate statistics over time. Putting it in pg_stat_activity would be good for that. It's also good to have it broken down into multiple columns, and not just a freetext column in the view - if tools should be able to parse it as well. True. We could have a separate system view that only shows the status of currently-running vacuum proceses. That wouldn't bother me either. That's what I'd like to have. We could also have aggregate counters on the table/database level of course. -- Magnus Hagander Me: http://www.hagander.net/ Work: http://www.redpill-linpro.com/ -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Displaying accumulated autovacuum cost
On 08/18/2011 10:12 AM, Robert Haas wrote: Perhaps a reasonable way to break up the patch would be: - Part 1: Gather the information and display it in the log_autovacuum_min_duration output. - Part 2: Add the ability to see the information incrementally (via some mechanism yet to be agreed upon). My reaction to all the suggestions for redesign is just that: pull out the part that does the incremental updates altogether, improve the part that dumps the info into the logs, and resubmit without any incremental progress for now. This is much more valuable to me if the first commit that hits is something I can backport trivially. I'm seeing enough production servers running into this problem right now on earlier versions to be worried about that, and the log dump at the end would be a huge help even if that was all they got. I'm going to add directly computing the write MB/s figure from the dirty data written too, since that ends up being the thing that I keep deriving by hand anyway. -- Greg Smith 2ndQuadrant USg...@2ndquadrant.com Baltimore, MD PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.us -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Displaying accumulated autovacuum cost
On 08/18/2011 10:54 AM, Peter Eisentraut wrote: So how about adding a column to pg_stat_activity, progress_metrics or something like that, and add that information there. Adding a field here (I'd go for the simpler progress) and updating it regularly would be a reasonable way to go here. This data doesn't really need to go into the traditional statistics infrastructure to be useful. I didn't start there because I was already getting pushback on overloading the stats collector with constantly updated metrics last time I did something in this area. I wasn't going to try and argue why it was worth it in this case, just like I'm not going to argue about the complaint over the command string overhead being too high--just going to not do that instead. If the bikeshed I built doesn't look fancy enough to hold the bike I put in there, I'm not going to build a better one right now--I'll just put a cheaper bike in there instead. I was hoping to eventually take the useful summary bits at the end, the totals, and save those into statistics somewhere each time a VACUUM of either sort finishes. It would fit with the information shown in pg_stat_tables, but that's obviously getting too wide. Breaking out a pg_stat_autovacuum view that contains all the relevant bits currently shown in that view, plus these 3 new fields, would be a reasonable start. -- Greg Smith 2ndQuadrant USg...@2ndquadrant.com Baltimore, MD PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.us -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Displaying accumulated autovacuum cost
On Thu, Aug 18, 2011 at 17:54, Greg Smith g...@2ndquadrant.com wrote: On 08/18/2011 10:54 AM, Peter Eisentraut wrote: So how about adding a column to pg_stat_activity, progress_metrics or something like that, and add that information there. Adding a field here (I'd go for the simpler progress) and updating it regularly would be a reasonable way to go here. This data doesn't really need to go into the traditional statistics infrastructure to be useful. I didn't start there because I was already getting pushback on overloading the stats collector with constantly updated metrics last time I did something in this area. I wasn't going to try and argue why it was worth it in this case, just like I'm not going to argue about the complaint over the command string overhead being too high--just going to not do that instead. If the bikeshed I built doesn't look fancy enough to hold the bike I put in there, I'm not going to build a better one right now--I'll just put a cheaper bike in there instead. The current values per-backend thing can go in shared memory. The reason the per table ones can't is obviously that they go away when the backend disconnects.. I was hoping to eventually take the useful summary bits at the end, the totals, and save those into statistics somewhere each time a VACUUM of either sort finishes. It would fit with the information shown in pg_stat_tables, but that's obviously getting too wide. Breaking out a pg_stat_autovacuum view that contains all the relevant bits currently shown in that view, plus these 3 new fields, would be a reasonable start. That depends on what you mea nby too wide. If it's intended to be consumed with SELECT * or not... -- Magnus Hagander Me: http://www.hagander.net/ Work: http://www.redpill-linpro.com/ -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Displaying accumulated autovacuum cost
On Thu, Aug 18, 2011 at 11:41 AM, Greg Smith g...@2ndquadrant.com wrote: On 08/18/2011 10:12 AM, Robert Haas wrote: Perhaps a reasonable way to break up the patch would be: - Part 1: Gather the information and display it in the log_autovacuum_min_duration output. - Part 2: Add the ability to see the information incrementally (via some mechanism yet to be agreed upon). My reaction to all the suggestions for redesign is just that: pull out the part that does the incremental updates altogether, improve the part that dumps the info into the logs, and resubmit without any incremental progress for now. This is much more valuable to me if the first commit that hits is something I can backport trivially. I'm seeing enough production servers running into this problem right now on earlier versions to be worried about that, and the log dump at the end would be a huge help even if that was all they got. I'm going to add directly computing the write MB/s figure from the dirty data written too, since that ends up being the thing that I keep deriving by hand anyway. By the way, since I forgot to say it earlier, I think it's great that you are working on some of this instrumentation stuff, so +1 for the basic concept here. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Displaying accumulated autovacuum cost
Em 18-08-2011 12:54, Greg Smith escreveu: I was hoping to eventually take the useful summary bits at the end, the totals, and save those into statistics somewhere each time a VACUUM of either sort finishes. It would fit with the information shown in pg_stat_tables, but that's obviously getting too wide. Breaking out a pg_stat_autovacuum view that contains all the relevant bits currently shown in that view, plus these 3 new fields, would be a reasonable start. IMHO the useful summary bits belongs to log. If you want to add it to stats collector go for it. But if you go to the latter road, it is recommended to move some fields (time-related fields) from pg_stat_*_tables to this new view (pg_stat_maintenance?). I don't know how generic you want to go but have in mind I would like to cover automatic and manual maintenance commands. Besides that another view will cover the maintenance activity. This new view could contain at least datname, schemaname, relname, command_start, command_schedule, operation, progress (?), procpid, and current_command. The name has to be generic to cover all maintenance commands (perhaps pg_maintenance_activity). -- Euler Taveira de Oliveira - Timbira http://www.timbira.com.br/ PostgreSQL: Consultoria, Desenvolvimento, Suporte 24x7 e Treinamento -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Displaying accumulated autovacuum cost
Em 17-08-2011 18:04, Greg Smith escreveu: Attached is a patch that tracks and displays the accumulated cost when autovacuum is running. Code by Noah Misch and myself. I hope this idea will bring a formal process to vacuum tuning, which is currently too hard to do. I was about to add without... to that, but I then realized it needs no disclaimer; it's just too hard, period. Vacuum issues are enemy #1 at all the terabyte scale customer sites I've been fighting with lately. Interesting patch. I drafted a similar idea but didn't have a chance to publish it. It is a complement to the idea about autovacuum tuning [1]. Hope I will have time to post something for the next CF. And, of course, I will review this patch. The patch updates the command string just before the workers sleep to show how much work they've done so far. And at the end, it adds a few new lines to the information written to the logs, when the autovacuum is notable enough to be logged at all. The overhead it adds is at most a few integer operations per buffer processed and a slower title string update once per sleep. It's trivial compared to both the vacuum itself, and to the instrumentation's value to sites with vacuum issues. I don't like exposing this information only on title processes. It would be difficult for client apps (for example, PGAdmin) to track this kind of information and it is restricted to local access. I'm not objecting to display this information in process title; I'm just saying that that information should be exposed in functions (say pg_stat_get_vacuum_[hit|miss|dirty]) too. I'm not sure about adding this information to incremental counters but that would be useful to trace a vacuum work pattern. [1] http://archives.postgresql.org/pgsql-hackers/2011-06/msg00678.php -- Euler Taveira de Oliveira - Timbira http://www.timbira.com.br/ PostgreSQL: Consultoria, Desenvolvimento, Suporte 24x7 e Treinamento -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Displaying accumulated autovacuum cost
On 08/17/2011 07:42 PM, Euler Taveira de Oliveira wrote: I don't like exposing this information only on title processes. It would be difficult for client apps (for example, PGAdmin) to track this kind of information and it is restricted to local access. I'm not objecting to display this information in process title; I'm just saying that that information should be exposed in functions (say pg_stat_get_vacuum_[hit|miss|dirty]) too. I tend to build the simplest possible thing that is useful enough to work. The data is getting stored and shown now, where it wasn't before. If it's possible to expose that in additional ways later too, great. The big step up for this information is to go from unobtainable to obtainable. I'd prefer not to add a quest for easily obtainable to the requirements until that big jump is made, for fear it will cause nothing to get delivered. -- Greg Smith 2ndQuadrant USg...@2ndquadrant.com Baltimore, MD PostgreSQL Training, Services, and 24x7 Support www.2ndQuadrant.us -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
