Re: [PERFORM] how to plan for vacuum?

Jim C. Nasby wrote: I'll generally start with a cost delay of 20ms and adjust based on IO utilization. I've been considering set a default autovacuum cost delay to 10ms; does this sound reasonable? -- Alvaro Herrerahttp://www.CommandPrompt.com/ PostgreSQL

Re: [PERFORM] max() versus order/limit (WAS: High update activity, PostgreSQL vs BigDBMS)

to reference exactly one table, since join * conditions can't be handled reasonably. (We could perhaps handle a * query containing cartesian-product joins, but it hardly seems worth the * trouble.) */ so you should keep using your hand-written order by/limit query. -- Alvaro Herrera

Re: [PERFORM] max() versus order/limit (WAS: High update

Luke Lonergan wrote: Adam, This optimization would require teaching the planner to use an index for MAX/MIN when available. It seems like an OK thing to do to me. This optimization already exists, albeit for queries that use a single table. -- Alvaro Herrera

Re: [HACKERS] [PERFORM] unusual performance for vac following 8.2 upgrade

should be sent to the collector unconditionally. (2) seems a perfectly reasonably answer, but ISTM (1) would be good to have anyway (at least in HEAD). -- Alvaro Herrerahttp://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc

Re: [HACKERS] [PERFORM] unusual performance for vac following 8.2upgrade

get rid of pg_class entries for temp tables. Maybe creating a temp pg_class which would be local to each session? Heck, it doesn't even have to be an actual table -- it just needs to be somewhere from where we can load entries into the relcache. -- Alvaro Herrera

Re: [PERFORM] High inserts, bulk deletes - autovacuum vs scheduled vacuum

were blue on the face, but it would achieve nothing because it would consider that the dead tuples were visible to a running transaction: that running the vacuum on the large table. This is an annoyance that was fixed in 8.2. -- Alvaro Herrerahttp

Re: [PERFORM] High update activity, PostgreSQL vs BigDBMS

been suggested that a combination of ext2 (for WAL) and ext3 (for data, with data journalling disabled) is a good performer. AFAIK you don't want the overhead of journalling for the WAL partition. -- Alvaro Herrerahttp://www.CommandPrompt.com/ The PostgreSQL Company

Re: [PERFORM] URGENT: Out of disk space pg_xlog

as the update goes. -- Alvaro Herrerahttp://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc. ---(end of broadcast)--- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs

Re: [PERFORM] New to PostgreSQL, performance considerations

Tom Lane wrote: Alexander Staubo [EMAIL PROTECTED] writes: No, fsync=on. The tps values are similarly unstable with fsync=off, though -- I'm seeing bursts of high tps values followed by low-tps valleys, a kind of staccato flow indicative of a write caching being filled up and

Re: [PERFORM] Database-wide vacuum can take a long time, duringwhich tables are not being analyzed

, by not requiring database-wide vacuums). -- Alvaro Herrerahttp://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc. ---(end of broadcast)--- TIP 4: Have you searched our list archives? http

Re: [PERFORM] Query plan for heavy SELECT with lite sub-SELECTs

world, you'd at least have an ORDER BY somewhere in the subqueries. Performance analysis of strange queries is useful, but the input queries have to be meaningful as well. Otherwise you end up optimizing bizarre and useless cases. -- Alvaro Herrerahttp

Re: [PERFORM] MVCC indexes?

little blocking involved. Two processes can be inserting into the same index concurrently (btree and GiST indexes at least; GiST only gained concurrency in a recent release, I don't remember if it was 8.0 or 8.1). -- Alvaro Herrerahttp://www.CommandPrompt.com

Re: [PERFORM] commit so slow program looks frozen

it several times and compare them. I wouldn't expect it to be stuck on locks, because if it's only on commit, then it probably has all the locks it needs. But try to see if you can find something not granted in pg_locks that it may be stuck on. -- Alvaro Herrera

Re: [PERFORM] Is ODBC that slow?

dated 2006.01.31. Everything appears to be at its default setting. Try Command Prompt's ODBC driver. Lately it has been measured to be consistently faster than psqlODBC. http://projects.commandprompt.com/public/odbcng -- Alvaro Herrerahttp://www.CommandPrompt.com

Re: [HACKERS] [PERFORM] Hints proposal

of joins), so not all problems will be solved with a per-table design. I think if it were per table, you could get away with storing stuff in pg_statistics or some such. But how do you express statistics for joins? How do you express cross-column correlation? -- Alvaro Herrera

Re: [HACKERS] [PERFORM] Hints proposal

. That gets ugly pretty fast when you have to extract selectivities for all the possible join paths in any given query. But please don't talk about regular expressions. -- Alvaro Herrerahttp://www.CommandPrompt.com/ PostgreSQL Replication, Consulting, Custom Development

Re: [PERFORM] Poor performance on seq scan

, namely if the affected column is part of the index key, then we could do the filtering before fetching the heap tuple. -- Alvaro Herrerahttp://www.CommandPrompt.com/ PostgreSQL Replication, Consulting, Custom Development, 24x7 support ---(end

Re: [Fwd: Re: [PERFORM] Performance problem with Sarge compared

). That way you're more likely to get useful responses. -- Alvaro Herrerahttp://www.CommandPrompt.com/ PostgreSQL Replication, Consulting, Custom Development, 24x7 support ---(end of broadcast)--- TIP 4: Have you searched

Re: [PERFORM] database bloat,non removovable rows, slow query etc... [RESOLVED]

we could track per-database xmin values as well, but the distributed overhead that'd be added to *every* GetSnapshotData call is a bit worrisome. Don't we do that now in CVS (ie, in 8.2)? No, we don't. -- Alvaro Herrerahttp://www.CommandPrompt.com

Re: [PERFORM] Postgre SQL 7.1 cygwin performance issue.

. Please note that the name is PostgreSQL and is usually shortened to Postgres. It's never postgre. -- Alvaro Herrerahttp://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc. ---(end of broadcast

Re: [PERFORM] Postgre SQL 7.1 cygwin performance issue.

at this point of time due to some reasons. That's too bad :-( -- Alvaro Herrerahttp://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc. ---(end of broadcast)--- TIP 1: if posting/reading through

Re: [PERFORM] Identifying bloated tables

workaround that gives approximate figures is a good idea anyway. -- Alvaro Herrerahttp://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc. ---(end of broadcast)--- TIP 5: don't forget to increase your

Re: [PERFORM] stats reset during pg_restore?

). -- Alvaro Herrerahttp://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc. ---(end of broadcast)--- TIP 6: explain analyze is your friend

Re: [PERFORM] stats reset during pg_restore?

-- while you could save the values it returns on queries to the stats views, there is no way to feed those saved values back to the system after a dump/restore. -- Alvaro Herrerahttp://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc

Re: [PERFORM] select max(column) from parent table very slow

Tom nightmares by sending patches to the optimizer? -- Alvaro Herrerahttp://www.CommandPrompt.com/ PostgreSQL Replication, Consulting, Custom Development, 24x7 support ---(end of broadcast)--- TIP 1: if posting

Re: [PERFORM] query planner: automatic rescribe of LIKE to BETWEEN ?

if you create it with opclass varchar_pattern_ops or text_pattern_ops, as appropiate. Thus you don't need any hack here. -- Alvaro Herrerahttp://www.CommandPrompt.com/ PostgreSQL Replication, Consulting, Custom Development, 24x7 support ---(end

Re: [PERFORM] query planner: automatic rescribe of LIKE to BETWEEN ?

Thomas Samson wrote: On 8/22/06, Alvaro Herrera [EMAIL PROTECTED] wrote: Ulrich Habel wrote: Hello all, had an idea of optimizing a query that may work generally. In case a 'column' is indexed, following two alterations could be done I think: A) select ... where column

Re: [PERFORM] VACUUM FULL needed sometimes to prevent transaction ID wraparound?

fine. What's the warning anyway? Does it say that wraparound point is nearing, or does it merely say that it is on Xid some number here and you don't know how far that number actually is? -- Alvaro Herrerahttp://www.CommandPrompt.com/ The PostgreSQL Company

Re: [PERFORM] XFS filessystem for Datawarehousing

Jim C. Nasby wrote: On Tue, Aug 01, 2006 at 08:42:23PM -0400, Alvaro Herrera wrote: Most likely ext3 was used on the default configuration, which logs data operations as well as metadata, which is what XFS logs. I don't think I've seen any credible comparison between XFS and ext3

Re: [PERFORM] XFS filessystem for Datawarehousing

on a PostgreSQL environment. Metadata is enough, given that we log data on WAL anyway. -- Alvaro Herrerahttp://www.CommandPrompt.com/ PostgreSQL Replication, Consulting, Custom Development, 24x7 support ---(end of broadcast

Re: [PERFORM] performance issue with a specific query

about this particular area of their packaging. Stupid how? -- Alvaro Herrerahttp://www.CommandPrompt.com/ PostgreSQL Replication, Consulting, Custom Development, 24x7 support ---(end of broadcast)--- TIP 4: Have

Re: [PERFORM] Savepoint performance

-only issue, so the server does not provide any special support for it (just like autocommit mode). -- Alvaro Herrerahttp://www.CommandPrompt.com/ PostgreSQL Replication, Consulting, Custom Development, 24x7 support ---(end of broadcast

Re: [PERFORM] FWD: Update touches unrelated indexes?

the update. Not at all -- the option is just continue to operate normally after the update, because all the indexes are always updated. If you see an index not being updated, it's a bug and by all means report it, preferably with a test case other people can reproduce. -- Alvaro Herrera

Re: [PERFORM] Index Being Ignored?

. -- Alvaro Herrerahttp://www.CommandPrompt.com/ PostgreSQL Replication, Consulting, Custom Development, 24x7 support ---(end of broadcast)--- TIP 5: don't forget to increase your free space map settings

Re: [PERFORM] Regarding pg_dump utility

to get dumps easily, in whatever format. -- Alvaro Herrerahttp://www.CommandPrompt.com/ PostgreSQL Replication, Consulting, Custom Development, 24x7 support ---(end of broadcast)--- TIP 2: Don't 'kill -9

Re: [PERFORM] Regarding pg_dump utility

Jim C. Nasby wrote: On Thu, Jun 08, 2006 at 06:33:28PM +0200, Andreas Pflug wrote: Alvaro Herrera wrote: Personally I think it would be neat. For example the admin-tool guys would be able to get a dump without invoking an external program. Second it would really be independent

Re: [PERFORM] INSERT OU UPDATE WITHOUT SELECT?

that's in the documentation? http://www.postgresql.org/docs/8.1/static/plpgsql-control-structures.html#PLPGSQL-ERROR-TRAPPING Example 36-1 MERGE would be really useful. It has been discussed before -- MERGE is something different. -- Alvaro Herrerahttp

Re: [PERFORM] Selects query stats?

pgstat_report_activity into a routine that sent a count (presumably always 1) instead of the query string, and then just add the count to a counter on receiving. -- Alvaro Herrerahttp://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc

Re: [PERFORM] Query runs 38 seconds for small database!

would know about that -- he invented them. I take no responsability :-) -- Alvaro Herrerahttp://www.CommandPrompt.com/ PostgreSQL Replication, Consulting, Custom Development, 24x7 support ---(end of broadcast)--- TIP

Re: [PERFORM] Memory and/or cache issues?

I'll grant that it doesn't mean anything. $ dc 2 o 18446744073709551613 p 1101 -- Alvaro Herrerahttp://www.CommandPrompt.com/ PostgreSQL Replication, Consulting, Custom Development, 24x7 support

Re: [PERFORM] postgresql transaction id monitoring with nagios

answer. That's right, because a database's age is only decremented in database-wide vacuums. (Wow, who wouldn't want a person-wide vacuum if it did the same thing ...) -- Alvaro Herrerahttp://www.CommandPrompt.com/ PostgreSQL Replication, Consulting, Custom Development

Re: [PERFORM] Inactive memory Grows unlimited

consumption. You should upgrade to 8.1.3 BTW. -- Alvaro Herrerahttp://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc. ---(end of broadcast)--- TIP 3: Have you checked our extensive FAQ

Re: [PERFORM] Stored Procedure Performance

/pgSQL function (really, a function in any language except SQL) is a black box. If you have a complex join of two or three functions, and they don't return 1000 rows, it's very likely that the optimizer is going to get it wrong. -- Alvaro Herrerahttp

Re: [PERFORM] Restore performance?

goes faster. -- Alvaro Herrerahttp://www.CommandPrompt.com/ PostgreSQL Replication, Consulting, Custom Development, 24x7 support ---(end of broadcast)--- TIP 3: Have you checked our extensive FAQ? http

Re: [PERFORM] serious problems with vacuuming databases

suggest to dump/reload. I suggested CLUSTER. You need to apply it only to tables where you have lots of dead tuples, which IIRC are A, C and D. -- Alvaro Herrerahttp://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc

Re: [PERFORM] serious problems with vacuuming databases

the indexes on the table (if the table has for example two indexes?). Yes, it will rebuild all indexes. -- Alvaro Herrerahttp://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc. ---(end of broadcast

Re: [PERFORM] bad performance on Solaris 10

. This essentially means stopping all bgwriter activity, thereby deferring all I/O until checkpoint. Was this considered? With checkpoint_segments to 128, it wouldn't surprise me that there wasn't any checkpoint executed at all during the whole test ... -- Alvaro Herrera

Re: [PERFORM] Measuring the execution time of functions within functions...

Mario Splivalo wrote: Since the function is written in plpgsql I tried to calculate the durations by using now() function, but realized that within the transaction now() always retunrs the same value. Maybe you can use timeofday(). -- Alvaro Herrerahttp

Re: [PERFORM] optimizing db for small table with tons of updates

how I can call psql -c without it prompting me. Is it possible? Sure it is. Set up a .pgpass file. -- Alvaro Herrerahttp://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc. ---(end of broadcast

Re: [PERFORM] Query using SeqScan instead of IndexScan

chris smith wrote: I believe postgres (because it's a lot more standards compliant).. but sheesh - what a difference! This week's task - stop reading mysql documentation. You don't _have_ to believe Postgres -- this is stuff taught in any statistics course. -- Alvaro Herrera

Re: [PERFORM] count(*) performance

daemon is not unexpected however, so if it doesn't work after tuning, let us know. -- Alvaro Herrerahttp://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc. ---(end of broadcast)--- TIP 5: don't forget

Re: [PERFORM] WAL logging of SELECT ... INTO command

. -- Alvaro Herrerahttp://www.CommandPrompt.com/ PostgreSQL Replication, Consulting, Custom Development, 24x7 support ---(end of broadcast)--- TIP 6: explain analyze is your friend

Re: [PERFORM] WAL logging of SELECT ... INTO command

Jim C. Nasby wrote: On Fri, Mar 24, 2006 at 08:39:02AM -0400, Alvaro Herrera wrote: Jim C. Nasby wrote: Why would the content of the old_table be unreliable? If we've replayed logs up to the point of the CTAS then any data that would be visible to the CTAS should be fine

Re: [PERFORM] Indexes with descending date columns

commercial and non commercial databases, but I do not know if this is a SQL standard. This can be done. You need to create an operator class which specifies the reverse sort order (i.e. reverse the operators), and then use it in the new index. -- Alvaro Herrerahttp

Re: [PERFORM] Migration study, step 1: bulk write performance

! -- Alvaro Herrerahttp://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc. ---(end of broadcast)--- TIP 6: explain analyze is your friend

Re: [PERFORM] BETWEEN optimizer problems with single-value

Simon Riggs wrote: [BTW how do you add new indexes to system tables? I want to add one to pg_inherits but not sure where to look.] See src/include/catalog/indexing.h -- I don't remember if there's anything else that needs modification. -- Alvaro Herrerahttp

Re: [PERFORM] No vacuum for insert-only database?

Craig A. James wrote: If I only insert data into a table, never update or delete, then I should never have to vacuum it. Is that correct? You still need to vacuum eventually, to avoid transaction Id wraparound issues. But not as often. -- Alvaro Herrerahttp

Re: [PERFORM] No vacuum for insert-only database?

Craig A. James wrote: Alvaro Herrera wrote: If I only insert data into a table, never update or delete, then I should never have to vacuum it. Is that correct? You still need to vacuum eventually, to avoid transaction Id wraparound issues. But not as often. Thanks. Any suggestions

Re: [PERFORM] firebird X postgresql 8.1.2 windows, performance

that clustering all indexes does not really make sense. You can cluster only on one index. If you cluster on another, then the first clustering will be lost. Better make sure to cluster on the one index where it makes the most difference. -- Alvaro Herrerahttp

Re: [PERFORM] firebird X postgresql 8.1.2 windows, performance

Scott Marlowe wrote: On Tue, 2006-03-07 at 11:15, Alvaro Herrera wrote: Scott Marlowe wrote: Lastly, I noticed that after you clusters on all your indexes, the query planner switched from a merge join to a hash join, and it was slower. You might wanna try turning off hash joins

Re: [PERFORM] neverending vacuum

to fill maintenance_work_mem. Scan the indexes to clean them. Start again. And again. So one very effective way of speeding this process up is giving the vacuum process lots of memory, because it will have to do fewer passes at each index. How much do you have? -- Alvaro Herrera

Re: [PERFORM] The trigger can be specified to fire on time condition?

! (On Windows, scheduled tasks or whatever). -- Alvaro Herrerahttp://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc. ---(end of broadcast)--- TIP 3: Have you checked our extensive FAQ

Re: [PERFORM] Schema vs Independant Databases, ACLS,Overhead,pg_hba.conf

are shared among all databases anyway. You'd save a bit by not having multiple copies of system caches (pg_class cache, etc), but I wouldn't know if that's going to be very noticeable next to the primary improvement. -- Alvaro Herrerahttp://www.CommandPrompt.com

Re: [PERFORM] LIKE query on indexes

/indexes-opclass.html -- Alvaro Herrerahttp://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc. ---(end of broadcast)--- TIP 9: In versions below 8.0, the planner will ignore your desire to choose

Re: [PERFORM] [GENERAL] Creation of tsearch2 index is very

a hard requirement though). After reading the various papers available on GiST and RD trees, I think I have a decent suggestion. I for one don't understand what does your suggestion have to do with the problem at hand ... not that I have a better one myself. -- Alvaro Herrera http

Re: [PERFORM] Autovacuum / full vacuum

the table's indexes and toast table). Are there some plans to remove vacuum altogether? No, but there are plans to make it as automatic and unintrusive as possible. (User configuration will probably always be needed.) -- Alvaro Herrera Developer, http://www.PostgreSQL.org

Re: [PERFORM] Autovacuum / full vacuum

. This is free software, remember. -- Alvaro Herrera Developer, http://www.PostgreSQL.org God is real, unless declared as int ---(end of broadcast)--- TIP 3: Have you checked our extensive FAQ? http

Re: [PERFORM] Autovacuum / full vacuum

are acquired and released one by one, as the operation proceeds. And as you know, autovacuum (both 8.1's and contrib) does issue database-wide vacuums, if it finds a database close to an xid wraparound. -- Alvaro Herrerahttp://www.advogato.org/person/alvherre Las mujeres

Re: [PERFORM] Suspending SELECTs

that crossed my mind. -- Alvaro Herrera Developer, http://www.PostgreSQL.org Oh, oh, las chicas galacianas, lo harán por las perlas, ¡Y las de Arrakis por el agua! Pero si buscas damas Que se consuman como llamas, ¡Prueba una hija de Caladan! (Gurney Halleck

Re: [PERFORM] 8.1 - pg_autovacuum question

one? Yes it is; and you can set autovacuum-specific values in postgresql.conf and table-specific values (used for autovacuum only) in pg_autovacuum. -- Alvaro Herrerahttp://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc

Re: [PERFORM] How much expensive are row level statistics?

a normal OLTP operation to be like this. (If it is you have a serious shortage of hardware ...) -- Alvaro Herrerahttp://www.CommandPrompt.com/ PostgreSQL Replication, Consulting, Custom Development, 24x7 support ---(end of broadcast

Re: [PERFORM] BLCKSZ

from the log, one after another? That may not be a representative test -- try sending multiple queries in parallel, to see how the server would perform in the real world. -- Alvaro Herrerahttp://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc

Re: [PERFORM] 15,000 tables - next step

have ten times that at the very least. -- Alvaro Herrerahttp://www.CommandPrompt.com/ PostgreSQL Replication, Consulting, Custom Development, 24x7 support ---(end of broadcast)--- TIP 3: Have you checked our extensive

Re: [PERFORM] 15,000 tables

and let us know so we can improve it. http://www.postgresql.org/docs/8.1/static/maintenance.html#AUTOVACUUM Maybe what you need is to lower the vacuum base threshold for tables that are small. -- Alvaro Herrerahttp://www.CommandPrompt.com/ PostgreSQL Replication

Re: [PERFORM] 8.1 count(*) distinct: IndexScan/SeqScan

at how to improve the optimizer. -- Alvaro Herrerahttp://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc. ---(end of broadcast)--- TIP 6: explain analyze is your friend

Re: [PERFORM] Hardware/OS recommendations for large databases (

. There's certainly true in that the memory requirements have increased a bit, but I don't think it really qualifies as high end even on 8.1. -- Alvaro Herrera Developer, http://www.PostgreSQL.org Jude: I wish humans laid eggs Ringlord: Why would you want humans to lay

Re: [PERFORM] Some help on buffers and other performance tricks

prove unnecessary. -- Alvaro Herrerahttp://www.CommandPrompt.com/ The PostgreSQL Company - Command Prompt, Inc. ---(end of broadcast)--- TIP 3: Have you checked our extensive FAQ? http

Re: [PERFORM] Some help on buffers and other performance tricks

the schema -- I was actually thinking in systems where some queries are not using indexes, some queries are plain wrong, etc. Buying a very expensive RAID and then noticing that you just needed to create an index, is going to make somebody feel at least somewhat stupid. -- Alvaro Herrera Valdivia

Re: [PERFORM] Temporary Table

in pg_class, pg_attribute, or other system catalogs. You may want to make sure these are vacuumed often. -- Alvaro Herrerahttp://www.CommandPrompt.com/ PostgreSQL Replication, Consulting, Custom Development, 24x7 support ---(end of broadcast

Re: [PERFORM] Sequential scan on FK join

and work_mem. Do you realize that the former is an obsolete name, and currently a synonym for the latter? Maybe the problem is that you are using too much memory for sorts, forcing swap usage, etc. -- Alvaro Herrera http://www.amazon.com/gp/registry/DXLWNGRJD34J La persona que no quería

Re: [PERFORM] Performance on SUSE w/ reiserfs

too, and so the OOM killer (is this Linux?) comes around and kills the appserver. Certainly the problem is not the caching. You should be monitoring when and why the appserver dies. -- Alvaro Herrera Architect, http://www.EnterpriseDB.com On the other flipper, one wrong

Re: [PERFORM] count(*) using index scan in query often, update rarely environment

. This is not acceptable. Plus, it would be very hard to implement, and a very wide door to bugs. -- Alvaro Herrerahttp://www.advogato.org/person/alvherre Et put se mouve (Galileo Galilei) ---(end of broadcast)--- TIP 6: explain

Re: [PERFORM] wal_buffers

of cycles just waiting for the disk to spin. Were you to use multiple connections, some transactions could be doing some useful work while others are waiting for their transaction to be committed. -- Alvaro Herrera http://www.amazon.com/gp/registry/5ZYLFMCVHXC I suspect most samba

Re: [HACKERS] [PERFORM] A Better External Sort?

represents a native kernel call or not ... The problem kernels would be Linux 2.0, which I very much doubt is going to be present in to-be-deployed database servers. Unless someone runs glibc on top of some other kernel, I guess. Is this a common scenario? I've never seen it. -- Alvaro Herrera

Re: [PERFORM] int2 vs int4 in Postgres

fields you would save some the space. Or int2/bool/bool (bool has 1-byte alignment), etc. This assumes you are in a tipical x86 environment ... in other environments the situation may be different. -- Alvaro Herrera Valdivia, Chile ICBM: S 39º 49' 17.7, W 73º 14' 26.8 Voy a acabar con

Re: [PERFORM] VACUUM FULL vs CLUSTER

that had the index bloat problem? The worst problems were solved in 7.4. There are problems in certain limited circumstances even with current releases. -- Alvaro Herrera http://www.amazon.com/gp/registry/DXLWNGRJD34 The ability to monopolize a planet is insignificant next

Re: [PERFORM] Battery Backed Cache for RAID

to disk. If the battery does not last through the outage, the data is lost. Just curious: how long are the batteries supposed to last? -- Alvaro Herrera -- Valdivia, Chile Architect, www.EnterpriseDB.com Hi! I'm a .signature virus! cp me into your .signature file to help me spread

Re: [PERFORM] Performance considerations for very heavy INSERT

missed something in this thread, but don't forget you still need vacuum to reclaim XIDs. Yes, but if you are going to drop the partition before 1 billion transactions, you can skip vacuuming it completely. -- Alvaro Herrera -- Valdivia, Chile Architect, www.EnterpriseDB.com Es filósofo

Re: [PERFORM] Massive performance issues

with char(x) you store the padding blanks, which are omitted with varchar(x), so less I/O (not necessarily a measurable amount, mind you, maybe even zero because of padding issues.) -- Alvaro Herrera -- Valdivia, Chile Architect, www.EnterpriseDB.com You liked Linux a lot when he was just

Re: [PERFORM] Some ideas for comment

(for you), I think the cost-based vacuum delay feature was only introduced in 8.0. -- Alvaro Herrera (alvherre[a]alvh.no-ip.org) Officer Krupke, what are we to do? Gee, officer Krupke, Krup you! (West Side Story, Gee, Officer Krupke) ---(end of broadcast

Re: [SPAM?] Re: [PERFORM] PG8 Tuning

happens if you give XLog a single drive (unmirrored single spindle), and that drive dies? So the question really is, should you be giving two disks to XLog? -- Alvaro Herrera (alvherre[a]alvh.no-ip.org) [PostgreSQL] is a great group; in my opinion it is THE best open source development communities

Re: [PERFORM] Performance pb vs SQLServer.

On Mon, Aug 15, 2005 at 10:25:47AM +0200, Magnus Hagander wrote: SQL 2005 has MVCC (they call it something different, of course, but that's basicallyi what it is) Interesting; do they use an overwriting storage manager like Oracle, or a non-overwriting one like Postgres? -- Alvaro Herrera

Re: [PERFORM] BG writer question?

page mappings are invalidated. There are no mmap/munmap calls in our code. The problematic code is probably somewhere in the libc. Maybe it'd be useful to figure out where it's called and why, with an eye on working around that. -- Alvaro Herrera (alvherre[a]alvh.no-ip.org) I love the Postgres

Re: [PERFORM] Odd Locking Problem

If I commit on session 1, session 2 is unlocked. This is a known problem, solved in 8.1. A workaround for previous releases is to defer FK checks until commit: create table b (a int references a initially deferred); -- Alvaro Herrera (alvherre[a]alvh.no-ip.org) Dios hizo a Adán, pero fue Eva

Re: [PERFORM] Performance problems testing with Spamassassin

were 5 minutes apart. With fsync off, there's no work _at all_ going on, not just the WAL -- heap/index file fsync at checkpoint is also skipped. This is no good. -- Alvaro Herrera (alvherre[a]alvh.no-ip.org) In a specialized industrial society, it would be a disaster to have kids running around

Re: [PERFORM] Really bad diskio

to the mirrors software raid where the root is found and onto the the SATA raid. Neither relieved the IO problems. What filesystem is this? -- Alvaro Herrera (alvherre[a]alvh.no-ip.org) Si no sabes adonde vas, es muy probable que acabes en otra parte. ---(end of broadcast

Re: [PERFORM] Quad Opteron stuck in the mud

in files after a crash and journal recovery. -- Alvaro Herrera (alvherre[a]alvh.no-ip.org) Officer Krupke, what are we to do? Gee, officer Krupke, Krup you! (West Side Story, Gee, Officer Krupke) ---(end of broadcast)--- TIP 3: Have

Re: [PERFORM] lots of updates on small table

of a few days we find that updates start getting painfully slow. We are running a full vacuum/analyze and reindex on the table every day, Full vacuum, eh? I wonder if what you really need is very frequent non-full vacuum. Say, once in 15 minutes (exact rate depending on dead tuple rate.) -- Alvaro

Re: [PERFORM] lots of updates on small table

know of at least one case where an app keeps a connection open for months, without a problem. (It's been running for four or five years, and monthly uptime for that particular daemon is not unheard of.) -- Alvaro Herrera (alvherre[a]alvh.no-ip.org) Everybody understands Mickey Mouse. Few

Re: [PERFORM] lots of updates on small table

On Thu, Jul 14, 2005 at 08:28:24PM -0400, Alvaro Herrera wrote: On Fri, Jul 15, 2005 at 09:42:12AM +1000, Alison Winters wrote: INFO: Pages 1221: Changed 3, reaped 256, Empty 0, New 0; Tup 108137: Vac 4176, Keep/VTL 108133/108133, UnUsed 19, MinLen 84, MaxLen 84; Re-using: Free/Avail

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